The impact of freezing and multiple freeze-thaw cycles on Brix refractometry estimates of immunoglobulin concentration in beef cattle colostrum

Evaluation of immunoglobulin G (IgG) concentration in colostrum is important to guide on-farm management. Studies have shown that digital Brix refractometry accurately estimates colostrum IgG concentration in both dairy and beef cattle colostrum. Colostrum is often frozen in both clinical and research settings. The implications of this freezing on the accuracy of Brix refractometry measurements are largely unknown. The first objective of this study was to evaluate the agreement between digital Brix percentage measurements of IgG in beef cattle colostrum taken before and after different durations of freezing. The second objective was to evaluate the effects of multiple freeze-thaw (FT) cycles on Brix percentage measurements of IgG in beef cattle colostrum. There was good agreement between Brix percentages in fresh colostrum and after short (2 to 8 d), medium (4 to 7 mo), and long (3 y) periods of freezing (concordance correlation coefficient: 0.95, 0.96, and 0.96, respectively). Although there was no significant change in mean Brix percentages over 2 FT cycles (P > 0.05), mean Brix percentages decreased with 3 FT cycles (P = 0.017). Samples from the fourth and fifth FT cycles were observably coagulated, and these measurements were therefore deemed inaccurate. Data from this study indicate that freezing had minimal impact on digital Brix refractometer estimates of IgG concentration in beef cattle colostrum, but that samples stored for future testing should not undergo more than 2 FT cycles.

Evaluation of 3 refractometers to determine transfer of passive immunity in neonatal beef calves

Background

Refractometry is used to assess transfer of passive immunity (TPI), but studies evaluating different refractometers and appropriate thresholds for recommended target immunoglobulin G (IgG) concentrations for beef calves are limited.

Objectives

To evaluate test performance of digital (DSTP) and optical (OSTP) serum total protein (STP) refractometers and a digital Brix (DBRIX) refractometer for assessment of passive immunity in beef calves.

Animals

A total of 398 beef calves from 6 herds, 1 to 7 days of age.

Methods

Serum IgG concentration was estimated by DSTP, OSTP, and DBRIX, and measured by radial immunodiffusion (RID). Correlation coefficients (r) among results were calculated. Optimal STP and Brix thresholds for identification of IgG <10, <16, and <24 g/L were determined using interval likelihood ratios. Refractometer performance and agreement were assessed using areas under the curve (AUC), diagnostic test characteristics, Cohen's kappa (κ), and Bland‐Altman analysis.

Results

Refractometer results were highly correlated with RID (r = 0.82‐0.91) and with each other (r = 0.91‐0.95), and overall test performance was excellent (AUC = 0.93‐0.99). The STP concentrations of ≤5.1, ≤5.1, and ≤5.7 g/dL and Brix percentages of ≤7.9%, ≤8.3%, and ≤8.7% indicated IgG concentrations <10, <16, and <24 g/L, respectively. Agreement of refractometers with RID was variable (κ = 0.46‐0.80) and among refractometers was substantial (κ = 0.62‐0.89).

Conclusions and Clinical Importance

All refractometers showed good utility as monitoring tools for assessment of TPI in beef calves.

Quantifying the Forces Applied During Manually and Mechanically Assisted Calvings in Beef Cattle

Dystocia is a leading cause of calf mortality, yet there is little available information quantifying the duration and forces applied to assisted deliveries. Objectives of this study were to: (1) develop a method to measure the magnitude and duration of various forces applied to a calf during calving assistance, and (2) quantify the forces applied to beef calves during manual or mechanical calving assistance. Twenty-five primiparous dams requiring calving assistance were enrolled. Calvings were assisted by manual (1 or 2 people pulling) or mechanical (calf extractor) delivery. A set of modified obstetric chains with integrated force measuring devices (Calving Assistance Force Logger; CAF-Log) were applied to the calf for delivery. The CAF-Log system was calibrated using known masses ranging from 25 to 200 kg in increasing increments of 25 kg. Duration of the assisted delivery and force parameters (peak force applied to one leg, peak force applied to both legs, cumulative force, and maximum jerk force) were described and assessed for their associations with method of delivery and ranch. Median duration was 112.6 s (IQR: 88.4–149.7) for manual and 312.6 s (IQR: 221.6–462.3) for mechanical deliveries. Mean peak force applied to one leg was 56.9 kg (SD: 22.9) for manual and 126.8 kg (SD: 48.2) for mechanical deliveries. Mean peak force applied to both legs was 95.4 kg (SD: 34.1) for manual and 188.6 kg (SD: 83.9) for mechanical deliveries. Median cumulative force was 178.3 kg min (IQR: 21.1–38.8) for manual and 380.6 kg min (IQR: 252.1–581.3) for mechanical deliveries. The maximum jerk force for manual deliveries was 36.6 kg/s (IQR: 21.1–38.8) and 77.2 kg/s (IQR: 60.9–97.1) for mechanical deliveries. An interaction occurred between ranch and method of delivery for peak force applied to one leg, peak force applied to both legs, and cumulative force. The CAF-Log system demonstrated that significantly greater forces were applied to mechanically delivered calves compared to manually delivered calves and could be used in future studies to investigate forces applied to a calf during calving assistance and their impacts on cow and calf well-being.

Assessment of Brix refractometry to estimate immunoglobulin G concentration in beef cow colostrum

Background

Brix refractometry can be used to assess colostral immunoglobulin G (IgG) concentration, but studies identifying Brix percentages to detect high‐ and low‐IgG colostrum are lacking for beef cows and interlaboratory agreement is unknown.

Objectives

Evaluate Brix refractometer performance and interlaboratory agreement for assessing beef cow colostrum IgG concentration, including determination of thresholds to identify colostrum containing IgG concentrations <100 g/L and ≥150 g/L.

Animals

Beef cows (n = 416) from 11 cow‐calf operations in Alberta, Canada.

Methods

Colostral IgG concentrations were measured using radial immunodiffusion (RID) and estimated by Brix refractometry for this retrospective study. Spearman correlation coefficients were assessed between RID and Brix refractometry. Likelihood ratios and misclassification cost‐term analysis were used to determine optimal Brix percentages for detecting colostrum containing IgG concentrations <100 g/L and ≥150 g/L. Concordance correlation coefficient (CCC) and Bland‐Altman analyses were performed for Brix percentages obtained at 3 different laboratories.

Results

Brix percentages obtained at 3 laboratories were positively correlated with IgG results (r = 0.72, 0.68, and 0.76, respectively). Colostrum Brix percentages of <24% and ≥30% were optimal for indicating IgG concentrations of <100 g/L and ≥150 g/L, respectively. Interlaboratory agreement was substantial, with CCC ranging from 0.89 to 0.96 and Bland‐Altman analysis showing small mean differences (−1.2% to 0.09% Brix) and narrow limits of agreements (−4.8% to 2.4% Brix) among laboratories.

Conclusions and Clinical Importance

Brix refractometry shows good potential for reliably estimating IgG concentrations in beef cow colostrum across multiple laboratories and can be recommended to aid colostrum management decisions on farms.

Sphingosine kinase-2 is overexpressed in large granular lymphocyte leukaemia and promotes survival through Mcl-1

Sphingolipid metabolism is increasingly recognised as a therapeutic target in cancer due to its regulation of cell proliferation and apoptosis. The sphingolipid rheostat is proposed to control cell fate through maintaining balance between pro-apoptotic and pro-survival sphingolipids. This balance is regulated by metabolising enzymes involved in sphingolipid production. One such enzyme, sphingosine kinase-2 (SPHK2), produces pro-survival sphingosine 1-phosphate (S1P) by phosphorylation of pro-apoptotic sphingosine. Elevated SPHK2 has been found in multiple cancer types and contributes to cell survival, chemotherapeutic resistance and apoptosis resistance. We have previously shown elevation of S1P in large granular lymphocyte (LGL) leukaemia serum and cells isolated from patients. Here, we examined SPHK2 expression in LGL leukaemia and found SPHK2 mRNA and protein upregulation in a majority of LGL leukaemia patient samples. Knockdown of SPHK2 with siRNA in LGL leukaemia cell lines decreased proliferation. Additionally, the use of ABC294640 or K145, both SPHK2-specific inhibitors, decreased viability of LGL leukaemia cell lines. ABC294640 selectively induced apoptosis in LGL cell lines and freshly isolated LGL leukaemia patient cells compared to normal controls. Mechanistically, SPHK2 inhibition downregulated pro-survival myeloid cell leukaemia-1 (Mcl-1) protein through proteasomal degradation. Targeting of SPHK2 therefore provides a novel therapeutic approach for the treatment of LGL leukaemia.

Ceramide Analogue SACLAC Modulates Sphingolipid Levels and MCL-1 Splicing to Induce Apoptosis in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a disease characterized by uncontrolled proliferation of immature myeloid cells in the blood and bone marrow. The 5-year survival rate is approximately 25%, and recent therapeutic developments have yielded little survival benefit. Therefore, there is an urgent need to identify novel therapeutic targets. We previously demonstrated that acid ceramidase (ASAH1, referred to as AC) is upregulated in AML and high AC activity correlates with poor patient survival. Here, we characterized a novel AC inhibitor, SACLAC, that significantly reduced the viability of AML cells with an EC₅₀ of approximately 3 μmol/L across 30 human AML cell lines. Treatment of AML cell lines with SACLAC effectively blocked AC activity and induced a decrease in sphingosine 1-phosphate and a 2.5-fold increase in total ceramide levels. Mechanistically, we showed that SACLAC treatment led to reduced levels of splicing factor SF3B1 and alternative MCL-1 mRNA splicing in multiple human AML cell lines. This increased proapoptotic MCL-1S levels and contributed to SACLAC-induced apoptosis in AML cells. The apoptotic effects of SACLAC were attenuated by SF3B1 or MCL-1 overexpression and by selective knockdown of MCL-1S. Furthermore, AC knockdown and exogenous C16-ceramide supplementation induced similar changes in SF3B1 level and MCL-1S/L ratio. Finally, we demonstrated that SACLAC treatment leads to a 37% to 75% reduction in leukemic burden in two human AML xenograft mouse models. IMPLICATIONS: These data further emphasize AC as a therapeutic target in AML and define SACLAC as a potent inhibitor to be further optimized for future clinical development.

A randomised controlled trial investigating the effects of administering a non-steroidal anti-inflammatory drug to beef calves assisted at birth and risk factors associated with passive immunity, health, and growth

BACKGROUND

The objectives of this study were to investigate the impact of pain mitigation at birth to assisted beef calves and determine the risk factors associated with transfer of passive immunity (TPI), health, and growth.

METHODS

Two hundred and thirty cow-calf pairs requiring calving assistance were enrolled. Calves were randomised to receive meloxicam (0.5 mg/kg) or an equivalent volume of placebo subcutaneously at birth. Calf blood samples were collected between one and seven days of age to determine serum immunoglobulin (IgG) concentration. Colostrum intake, treatment for disease, mortality, and weaning weights were recorded. Multilevel linear or logistic regression models were used to determine the effects of meloxicam and to identify risk factors.

RESULTS

There was no effect of meloxicam on serum IgG concentrations, average daily gain (ADG), or risk of inadequate TPI (serum IgG concentration <24 g/l), treatment for disease, or mortality (P>0.05). Bottle or tube feeding calves were associated with decreased serum IgG concentrations (P=0.01) compared with nursing. Calves with an incomplete tongue withdrawal reflex had higher odds of being treated for disease compared with those with complete withdrawal (P=0.009). Being born meconium-stained and having decreased serum IgG concentrations were associated with an increased risk of mortality (P=0.03). Being born of a mature cow, having a higher birth weight, and increased serum IgG concentrations were associated with greater ADG to weaning (P<0.05).

CONCLUSION

Vigour assessment at birth along with good colostrum management may be important to improve TPI and health in high-risk calves such as those assisted at birth.

Clinical impacts of administering a nonsteroidal anti-inflammatory drug to beef calves after assisted calving on pain and inflammation, passive immunity, health, and growth

Assisted calves are often born weak, injured, or oxygen deprived and have a higher risk of morbidity and mortality. The objective was to investigate the impact of using pain mitigation at birth in assisted beef calves on physiological indicators of pain and inflammation, passive immunity, health, and growth. Thirty-three primiparous cows and their calves requiring assistance at birth on two ranches located in southern Alberta were enrolled. Data collected at birth include date and time of calving, calf sex, meconium staining, presentation of calf, and calving difficulty (easy assist: one person manually delivered the calf; difficult assist: delivery by two or more people, or mechanical assistance). Within 10 min of birth, calves were stratified by calving difficulty, randomized to a medication group, and received a subcutaneous dose of meloxicam (0.5 mg/kg BW) or an equivalent volume of placebo. Cow–calf pairs were then placed in individual box stalls for observation and sampling. At birth, 1, 4, and 24 h after birth, heart rate, respiratory rate, and rectal temperature were assessed and blood samples collected to measure indicators of pain and inflammation (cortisol, corticosterone, substance P, and haptoglobin). Serum IgG concentration and failed transfer of passive immunity (serum IgG concentration <24 g/L) were assessed in the 24-h blood samples. Preweaning treatment for disease and mortality information was collected and calves were weighed at 7 to 10 d of age and at weaning. Of the 33 calves enrolled, 17 calves received meloxicam and 16 calves received a placebo. Meloxicam-medicated calves had significantly greater ADG to 7 to 10 d of age (P = 0.05) (mean = 0.9 kg/d; SE = 0.10) compared with placebo-medicated calves (mean = 0.6 kg/d; SE = 0.12). There was no significant effect of meloxicam on physiological indicators of pain and inflammation, standing or nursing by 1 h, passive immunity, health outcomes, or ADG to weaning (P > 0.1). Although this was a small sample population, meloxicam given to assisted calves at birth improved ADG in the first week of life, which may indicate an important production management tool for improving well-being in assisted calves.

Benchmarking calving management practices on western Canada cow-calf operations

Benchmarking current calving management practices and herd demographics in the western Canadian cow–calf production system helps to fill the gap in knowledge and understanding of how this production system works. Further investigation into the relationships between management decisions and calf health may guide the development of management practices and protocols to improve calf health, especially in compromised calves after a difficult birth. Therefore, the objectives of this cross-sectional study were to describe current calving management practices on western Canadian cow–calf ranches and to investigate the association of herd demographics with herd-level incidence of calving assistance, morbidity, mortality, and use of calving and colostrum management practices. Cow–calf producers were surveyed in January 2017 regarding herd inventory and management practices during the 2016 calving season. Ninety-seven of 110 producers enrolled in the western Canadian Cow-Calf Surveillance Network responded. Average herd-level incidence of assisted calvings was 4.9% (13.5% heifers, 3.2% cows), stillbirths was 2.1% (3.3% heifers, 1.9% cows), preweaning mortality was 4.5%, and preweaning treatment for disease was 9.4% (3.0% neonatal calf diarrhea, 3.8% bovine respiratory disease, 2.6% other diseases). Greater than 90% of producers assisted calvings and would intervene with colostrum consumption if the calf did not appear to have nursed from its dam. Late calving herds (i.e., started calving in March or later) had significantly lower average herd-level incidence of assistance, treatment for disease, and mortality (P < 0.05). In earlier calving herds (i.e., started calving in January or February) producers had shorter intervals between checking on dams for signs of calving or intervening to assist with a calving (P < 0.05). In early calving herds, producers were more likely to perform hands-on colostrum management techniques such as placing the cow and calf together or feeding stored, frozen colostrum (P < 0.05). There were no associations between herd size and herd-level incidences or management techniques (P > 0.05). This study suggests that in western Canada earlier calving herds are more intensively managed, whereas later calving herds are more extensively managed. Herd demographics may be important to consider when investigating factors associated with management strategies, health, and productivity in cow–calf herds.

Combined total hip and knee arthroplasty during the same hospital admission: is it safe?

AIMS

The purpose of this study was to compare outcomes of combined total joint arthroplasty (TJA) (total hip arthroplasty (THA) and total knee arthroplasty (TKA) performed during the same admission) versus bilateral THA, bilateral TKA, single THA, and single TKA. Combined TJAs performed on the same day were compared with those staged within the same admission episode.

PATIENTS AND METHODS

Data from the National (Nationwide) Inpatient Sample recorded between 2005 and 2014 were used for this retrospective cohort study. Postoperative in-hospital complications, total costs, and discharge destination were reviewed. Logistic and linear regression were used to perform the statistical analyses. p-values less than 0.05 were considered statistically significant.

RESULTS

Combined TJA was associated with increased risk of deep vein thrombosis, prosthetic joint infection, irrigation and debridement procedures, revision arthroplasty, length of stay (LOS), and in-hospital costs compared with bilateral THA, bilateral TKA, single THA, and single TKA. Combined TJA performed on separate days of the same admission showed no statistically significant differences when compared with same-day combined TJA, but trended towards decreased total costs and total complications despite increased LOS.

CONCLUSION

Combined TJA is associated with increased in-hospital complications, LOS, and costs. We do not recommend performing combined TJA during the same hospital stay. Cite this article: Bone Joint J 2019;101-B:573-581.

Quantifying subclinical trauma associated with calving difficulty, vigour, and passive immunity in newborn beef calves

This cross-sectional study quantifies subclinical trauma associated with calving difficulty, calf vigour, and passive immunity (PI) in newborn beef calves. The degree of calving difficulty was categorised as: unassisted, easy assist (one or two people manually pulling to deliver the calf) and difficult assist (more than two people pulling, a fetal extractor (ie, calf jack), or caesarean section). Vigour assessment occurred at 10 minutes and blood sampling at 24 hours after birth in 77 beef calves. The measured blood parameters associated with trauma were creatine kinase (CK), aspartate aminotransferase (AST), and haptoglobin. Serum IgG concentration was measured, and an IgG concentration at least 24 g/l was considered as adequate PI. Calving difficulty was associated with elevated levels of CK (P=0.002) and AST (P=0.01), weak suckle reflex (P=0.001), abnormal mucous membrane colour (P<0.0001), and decreased odds of adequate PI (P=0.004). Elevated levels of CK and AST were associated with abnormal mucous membrane colour, incomplete tongue withdrawal and weak suckle reflex at birth (P<0.001). An incomplete tongue withdrawal (P=0.005) and weak suckle reflex (P=0.02) were associated with decreased IgG concentrations. Abnormal mucous membrane colour, incomplete tongue withdrawal, and a weak suckle reflex were associated with decreased odds of having adequate PI (P<0.05). Haptoglobin was not associated with any of the parameters measured. Subclinical trauma was associated with calving difficulty, decreased vigour and decreased odds of having adequate PI. Understanding the impacts of a traumatic birth may aid the development of management strategies for compromised newborn beef calves.

Assessing the Efficacy of Ventilation of Anesthetized Neonatal Calves Using a Laryngeal Mask Airway or Mask Resuscitator

Calves that have undergone a dystocia are often hypoxic and acidemic, which can result in reduced vigor and subsequent mortality. Methods of field resuscitation of apneic newborn calves are often ineffective and therefore underutilized. This proof-of-concept study aimed to determine the efficacy of the laryngeal mask airway (LMA) as well as the current industry standard method of ventilation, the McCulloch Calf Aspirator/ Resuscitator (MMR) for positive pressure ventilation of neonatal calves. Five LMA models of various sizes were first tested in cadaver heads to assess anatomical fit. Three LMA models in two sizes each were then tested in two anesthetized calves to determine the model best suited to ventilate calves. Next, the selected LMA and the MMR were both assessed for efficacy of ventilation. Six anesthetized calves had hypoventilation induced by administering alfaxalone intravenously. Calves were ventilated for 3 min with the LMA, allowed a brief washout period, then given a second administration of alfaxalone prior to ventilation with the MMR. Serial arterial blood gas analyses were performed prior to ventilation (baseline), at 1, 2, and 3 min during ventilation, and 1 min after ventilation had ceased. Success of ventilation was assessed by monitoring partial pressure of oxygen (PaO₂), partial pressure of carbon dioxide (PaCO₂), bicarbonate (HCO3-), pH, L-lactate, and hemoglobin saturation (SaO₂) in arterial blood. A one-way ANOVA for repeated measures with Bonferroni correction was used to assess the efficacy of ventilation of each device compared to baseline. For the LMA, PaO₂, SaO₂, and pH were significantly higher than baseline throughout ventilation and PaCO₂ was significantly lower than baseline at 1 min of ventilation. For the MMR, PaO₂ and SaO₂ were significantly higher and PaCO₂ and HCO3- were significantly lower than baseline for 1 to 2 min of ventilation. This proof-of-concept study showed the LMA is an effective means of ventilating neonatal calves, as was the MMR.

Application of transmission infrared spectroscopy and partial least squares regression to predict immunoglobulin G concentration in dairy and beef cow colostrum

The objective of this study was to explore the potential of transmission infrared (TIR) spectroscopy in combination with partial least squares regression (PLSR) for quantification of dairy and beef cow colostral immunoglobulin G (IgG) concentration and assessment of colostrum quality. A total of 430 colostrum samples were collected from dairy (n = 235) and beef (n = 195) cows and tested by a radial immunodiffusion (RID) assay and TIR spectroscopy. Colostral IgG concentrations obtained by the RID assay were linked to the preprocessed spectra and divided into combined and prediction data sets. Three PLSR calibration models were built: one for the dairy cow colostrum only, the second for beef cow colostrum only, and the third for the merged dairy and beef cow colostrum. The predictive performance of each model was evaluated separately using the independent prediction data set. The Pearson correlation coefficients between IgG concentrations as determined by the TIR-based assay and the RID assay were 0.84 for dairy cow colostrum, 0.88 for beef cow colostrum, and 0.92 for the merged set of dairy and beef cow colostrum. The average of the differences between colostral IgG concentrations obtained by the RID- and TIR-based assays were -3.5, 2.7, and 1.4 g/L for dairy, beef, and merged colostrum samples, respectively. Further, the average relative error of the colostral IgG predicted by the TIR spectroscopy from the RID assay was 5% for dairy cow, 1.2% for beef cow, and 0.8% for the merged data set. The average intra-assay CV% of the IgG concentration predicted by the TIR-based method were 3.2%, 2.5%, and 6.9% for dairy cow, beef cow, and merged data set, respectively.The utility of TIR method for assessment of colostrum quality was evaluated using the entire data set and showed that TIR spectroscopy accurately identified the quality status of 91% of dairy cow colostrum, 95% of beef cow colostrum, and 89% and 93% of the merged dairy and beef cow colostrum samples, respectively. The results showed that TIR spectroscopy demonstrates potential as a simple, rapid, and cost-efficient method for use as an estimate of IgG concentration in dairy and beef cow colostrum samples and assessment of colostrum quality. The results also showed that merging the dairy and beef cow colostrum sample data sets improved the predictive ability of the TIR spectroscopy.

Abstract 48: Acid ceramidase inhibition: A targeted therapy for acute myeloid leukemia

Acute myeloid leukemia (AML) is a disease characterized by uncontrolled proliferation of immature myeloid cells in the blood and bone marrow. Patient 5-year survival rate is only 26%, and there have been no significant treatment advances for decades. Therefore, there is an urgent need to identify novel therapeutic targets. We have previously shown that acid ceramidase (AC) is upregulated in AML and high AC activity correlates with poor patient survival. We continue to validate AC as a potential therapeutic target in AML through inhibitor screening and characterization. We utilize viability assays, enzyme activity assays, Western blotting, qPCR, lipidomics, and flow cytometry to examine the effects of inhibitors on AML cell lines, patient samples, and normal controls. We have found that a newly developed selective AC inhibitor, SACLAC, significantly reduces viability of AML cells with an EC50 of approximately 3 μM, with limited effect on normal cells at an EC50 of approximately 13 μM. Treatment of AML cell lines with SACLAC effectively blocks AC activity, induces a drastic decrease of sphingosine 1-phosphate, and a 2.5-fold increase in total ceramide levels. Ongoing studies continue to explore the mechanistic basis for the loss of viability. These data support the investigation of AC as a therapeutic target in AML and define SACLAC as a potent and selective inhibitor that presents promise for preclinical studies and future clinical development.

Citation Format: Jennifer M. Pearson, Su-Fern Tan, Arati Sharma, Todd E. Fox, Jose Luis Abad, Gemma Fabrias, David F. Claxton, David J. Feith, Mark Kester, Thomas P. Loughran, Jr.. Acid ceramidase inhibition: A targeted therapy for acute myeloid leukemia [abstract]. In: Proceedings of the Second AACR Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; May 6-9, 2017; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(24_Suppl):Abstract nr 48.

The phosphatidic acid-binding, polybasic domain is responsible for the differences in the phosphoregulation of lipins 1 and 3

Lipins 1, 2, and 3 are Mg²⁺-dependent phosphatidic acid phosphatases and catalyze the penultimate step of triacylglycerol synthesis. We have previously investigated the biochemistry of lipins 1 and 2 and shown that di-anionic phosphatidic acid (PA) augments their activity and lipid binding and that lipin 1 activity is negatively regulated by phosphorylation. In the present study, we show that phosphorylation does not affect the catalytic activity of lipin 3 or its ability to associate with PA in vitro The lipin proteins each contain a conserved polybasic domain (PBD) composed of nine lysine and arginine residues located between the conserved N- and C-terminal domains. In lipin 1, the PBD is the site of PA binding and sensing of the PA electrostatic charge. The specific arrangement and number of the lysines and arginines of the PBD vary among the lipins. We show that the different PBDs of lipins 1 and 3 are responsible for the presence of phosphoregulation on the former but not the latter enzyme. To do so, we generated lipin 1 that contained the PBD of lipin 3 and vice versa. The lipin 1 enzyme with the lipin 3 PBD lost its ability to be regulated by phosphorylation but remained downstream of phosphorylation by mammalian target of rapamycin. Conversely, the presence of the lipin 1 PBD in lipin 3 subjected the enzyme to negative intramolecular control by phosphorylation. These results indicate a mechanism for the observed differences in lipin phosphoregulation in vitro.

A Primer on Foraging and the Explore/Exploit Trade-Off for Psychiatry Research

Foraging is a fundamental behavior, and many types of animals appear to have solved foraging problems using a shared set of mechanisms. Perhaps the most common foraging problem is the choice between exploiting a familiar option for a known reward and exploring unfamiliar options for unknown rewards-the so-called explore/exploit trade-off. This trade-off has been studied extensively in behavioral ecology and computational neuroscience, but is relatively new to the field of psychiatry. Explore/exploit paradigms can offer psychiatry research a new approach to studying motivation, outcome valuation, and effort-related processes, which are disrupted in many mental and emotional disorders. In addition, the explore/exploit trade-off encompasses elements of risk-taking and impulsivity-common behaviors in psychiatric disorders-and provides a novel framework for understanding these behaviors within an ecological context. Here we explain relevant concepts and some common paradigms used to measure explore/exploit decisions in the laboratory, review clinically relevant research on the neurobiology and neuroanatomy of explore/exploit decision making, and discuss how computational psychiatry can benefit from foraging theory.

The emergence of acid ceramidase as a therapeutic target for acute myeloid leukemia

INTRODUCTION

Acute myeloid leukemia (AML) is the most common adult leukemia. Only a fraction of AML patients will survive with existing chemotherapy regimens. Hence, there is an urgent and unmet need to identify novel targets and develop better therapeutics in AML. In the past decade, the field of sphingolipid metabolism has emerged into the forefront of cancer biology due to its importance in cancer cell proliferation and survival. In particular, acid ceramidase (AC) has emerged as a promising therapeutic target due to its role in neutralizing the pro-death effects of ceramide. Areas covered: This review highlights key information about AML biology as well as current knowledge on dysregulated sphingolipid metabolism in cancer and AML. We describe AC function and dysregulation in cancer, followed by a review of studies that report elevated AC in AML and compounds known to inhibit the enzyme. Expert opinion: AML has a great need for new drug targets and better therapeutic agents. The finding of elevated AC in AML supports the concept that this enzyme represents a novel and realistic therapeutic target for this common leukemia. More effort is needed towards developing better AC inhibitors for clinical use and combination treatment with existing AML therapies.

Benign papilloma diagnosed on image-guided 14 G core biopsy of the breast: effect of lesion type on likelihood of malignancy at excision

AIM

To ascertain the negative predictive value (NPV) for atypia and malignancy of 14 G core biopsy of papillomas and to determine whether lesion type influences the likelihood of malignancy at lesion excision.

MATERIALS AND METHODS

Ninety-six lesions with a 14 G core biopsy diagnosis of benign papilloma without atypia in 95 women were included. The imaging features (mass or microcalcification), biopsy mode, and number of core samples taken were documented. All patients subsequently underwent lesion excision with either extensive vacuum-assisted biopsy (VAB; 72 lesions) or surgery (24 lesions). Mammographic follow-up of at least 2 years was available for 32 lesions that were benign at VAB.

RESULTS

Atypia or malignancy was found more commonly in association with microcalcification (six of 29 lesions: 21%; median number of nine 14 G cores) than a mass (five of 67 lesions: 7%; median number of three 14 G cores), although the difference does not reach statistical significance (p = 0.088). The NPV of a 14 G core biopsy diagnosis of papilloma for atypia or malignancy is 89% (85/96). Disease underestimation may be more common in microcalcification lesions despite the greater number of cores obtained.

CONCLUSION

Excision (using VAB or surgically) of all papillomas diagnosed as benign on 14 G needle core biopsy is recommended. Surgery may be more appropriate than VAB for some microcalcification lesions unless they are small and can be confidently removed in their entirety using VAB.

Skyrme-Hartree-Fock-Bogoliubov nuclear mass formulas: crossing the 0.6 MeV accuracy threshold with microscopically deduced pairing

We present a new Skyrme-Hartree-Fock-Bogoliubov nuclear-mass model in which the contact-pairing force is constructed from microscopic pairing gaps of symmetric nuclear matter and neutron matter calculated from realistic two- and three-body forces, with medium-polarization effects included. With the pairing being treated more realistically than in any of our earlier models, the rms deviation with respect to essentially all the available mass data falls to 0.581 MeV, the best value ever found within the mean-field framework. Since our Skyrme force is also constrained by the properties of pure neutron matter, this new model is particularly well suited for application to astrophysical problems involving a neutron-rich environment, such as the elucidation of the r process of nucleosynthesis, and the description of supernova cores and neutron-star crusts.

The behaviour of linear alkyl benzene sulphonate under direct discharge conditions in Vientiane, Lao PDR

Direct discharge of untreated sewage to surface waters is a common practice in many parts of the world. However, relatively little is known about the behaviour of synthetic organic pollutants under these conditions. This paper describes a sampling campaign designed to track changes in water quality in a surface water system in Vientiane (Lao PDR) receiving significant quantities of untreated waste water. The study was based on following in-channel transport using a fluorescent tracer injected as a pulse, with a focus on the anionic surfactant linear alkylbenzene sulphonate (LAS) and ammonia. Water samples were collected at a number of stations with sampling times estimated to coincide with solute time-of-travel. The reduction in LAS concentration with flow-time could be approximated by first-order kinetics with a half life of about 7 h. Free ammonia concentrations decreased more slowly than LAS and remained above the level believed to be toxic for sensitive aquatic species along the entire channel. Changes in the ratios of LAS alkyl chain homologues to total LAS concentrations suggest a preferential removal of longer chain lengths. The role of biodegradation in the removal of LAS was confirmed by the presence of LAS metabolites (sulphophenylcarboxylates, SPCs) which increased systematically (as a fraction of LAS remaining) with flow-time.

Small-molecule activation of procaspase-3 to caspase-3 as a personalized anticancer strategy

Mutation and aberrant expression of apoptotic proteins are hallmarks of cancer. These changes prevent proapoptotic signals from being transmitted to executioner caspases, thereby averting apoptotic death and allowing cellular proliferation. Caspase-3 is the key executioner caspase, and it exists as an inactive zymogen that is activated by upstream signals. Notably, concentrations of procaspase-3 in certain cancerous cells are significantly higher than those in noncancerous controls. Here we report the identification of a small molecule (PAC-1) that directly activates procaspase-3 to caspase-3 in vitro and induces apoptosis in cancerous cells isolated from primary colon tumors in a manner directly proportional to the concentration of procaspase-3 inside these cells. We found that PAC-1 retarded the growth of tumors in three different mouse models of cancer, including two models in which PAC-1 was administered orally. PAC-1 is the first small molecule known to directly activate procaspase-3 to caspase-3, a transformation that allows induction of apoptosis even in cells that have defective apoptotic machinery. The direct activation of executioner caspases is an anticancer strategy that may prove beneficial in treating the many cancers in which procaspase-3 concentrations are elevated.

A Dukes/Jass combination--is it more discriminating?

BACKGROUND

In 1987 Jass described a modified staging system for colorectal cancer using two anatomical criteria in common with the Dukes system; extent of spread through the bowel wall and the presence or absence of lymph node involvement. Additionally it used two 'biological' criteria; the nature of the expanding margin of the tumour (pushing or infiltrating), and the presence or absence of lymphocytic infiltration within the tumour. This study aims to determine whether a combination of the Dukes and Jass staging systems provides a better predictor of five year survival in patients with colorectal cancer than Dukes stage alone.

METHOD

The Dukes and Jass stages along with vital status at five years were recorded for all 612 patients undergoing resection for colorectal cancer at the Royal Bolton Hospital and the Beaumont (BMI) Hospital, Bolton between 1991 and 1998. Kaplan-Meier survival curves with log rank test were used to show how survival correlated with Jass group stratified by Dukes stage.

RESULTS

Both the Dukes B and the Dukes C tumours could be divided into groups with significantly different five year survival rates when stratified by Jass group. Five year survival for Dukes stage B, Jass group II tumours was 73.74% compared to Dukes B Jass III tumours whose survival was 51.38% (P = 0.0018). Five year survival for Dukes C Jass III tumours was 43.18% and for Dukes C Jass IV survival was 24.39% (P = 0.0029).

CONCLUSION

By combining the biological criteria of the Jass staging system with the anatomically based Dukes system, both Dukes B and C tumours can be divided into groups with significantly different five year survival figures.

Protein kinase C alpha expression in normal breast, ductal carcinoma in situ and invasive ductal carcinoma

The purpose of this study was to determine if Protein Kinase C alpha (PKC alpha) is altered in expression or localisation in normal breast, ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC). We obtained 14 mixed cases of invasive ductal carcinoma (IDC) and DCIS, 36 pure DCIS cases and 25 cases of normal breast. The sections were stained immunohistochemically for PKC alpha expression. Staining was cytoplasmic. The results showed a progressive reduction in staining intensity from normal breast to invasive ductal carcinoma. The staining pattern was heterogeneous in the cytoplasm of DCIS and IDC, but homogeneous in the cytoplasm of normal breast ductal epithelium. Interestingly, mitotic cells and cells with aberrant nuclear morphology showed increased cytoplasmic staining in DCIS and IDC. PKC alpha activity is altered in dividing or abnormal cells, but overall expression is reduced in IDC. This raises the possibility of an alteration in the subcellular localisation of PKC alpha which may relate to changes in desmosomal adhesive state.

Crude open biopsy rates for benign screen detected lesions no longer reflect breast screening quality--time to change the standard

OBJECTIVES

To investigate the changing nature of the benign screen detected breast abnormalities removed at open biopsy over a seven year period and to compare this with the improving cancer detection rate and non-operative diagnosis rate.

SETTING

The Bolton, Bury, and Rochdale Breast Screening Programme.

METHODS

The histopathology reports of the benign lesions removed from patients undergoing open biopsy for screen detected abnormalities between 1 April 1994 and 31 March 2001 were reviewed and the lesions classified on the B1 to B5 scale. Cancer detection rates and non-operative cancer diagnosis rates were ascertained from the breast screening computer system.

RESULTS

148 benign surgical biopsies were performed in the seven year period. There was a moderate increase in the overall benign biopsy rate over the period (from 1.26 open biopsies per 1000 women screened for the three years 1994-97 to 1.63 open biopsies per 1000 women screened for the three years 1998-2001). The biopsy rate for B2 (benign) lesions decreased slightly over the study period but the biopsy rate for B3 lesions (that is, of uncertain malignant potential) more than doubled. The majority (84%) of the B3 lesions were radial scars. There was a steady improvement in the cancer detection rate and the non-operative cancer diagnosis rate over the period, similar to that seen nationally.

CONCLUSIONS

Improvements in screening technique and detection ability result in an increase in the number of subtle radiologically indeterminate or suspicious lesions detected. Many of these are radial scars, which require excision. Crude benign open biopsy rates for screening programmes are no longer meaningful, and should now be refined with separate rates for B2 lesions and B3 lesions. High quality programmes can expect to have low B2 open biopsy rates and high B3 open biopsy rates. It is inappropriate to have an upper limit for the B3 open biopsy rate.

Life style characteristics associated with nutritional risk in elderly subjects aged 80-85 years

A logistic regression model was applied to 627 elderly men and women, who participated in all three data collections of the SENECA study in 1989, 1993, and 1999, to test the hypothesis that nutritional status in 80-85 year old persons was related to functional and cognitive status, but not significantly affected by living arrangement. Additionally, the authors hypothesized that relationships between cognitive status and self-care ability, between self-care ability and living situation, and between cognitive status and living situation would be stronger with increasing age. Nutritional status was categorized as being well nourished (> or = 24) or at nutritional risk (<24) using the 18-item mini-nutritional assessment questionnaire (MNA). Diminished self-care ability was defined as inability to perform all 7 self-care items on the ADL instrument. Respondents were deemed to have possible cognitive impairment if they scored <24 on the MMSE test. Residence situation was categorized as either living alone, with spouse/partner, or with others. Nutritional risk was found to be associated with diminished cognitive status and diminished self-care ability, but not associated with living alone. Elderly people with diminished cognitive function and diminished self-care ability had a more than two times higher risk of being at nutritional risk. In addition, the strength of relationships between cognitive status and self-care ability, self-care ability and living situation, and cognitive ability and living situation all increased over time. In the oldest old lifestyle characteristics and functional ability appeared to be stronger predictors of risk for malnutrition than in younger adults.

A study of breast cancers detected in the incident round of the UK NHS Breast Screening Programme: the importance of early detection and treatment of ductal carcinoma in situ

One hundred and seventy eight cancers detected on incident round screening in the UK National Health Service Breast Screening Programme were reviewed. Critical review of the immediately preceding screening films (from 3 years previously) found abnormalities at the site of the subsequently detected cancer in 93 cases (52%). Forty-eight of these (27% of the total) had microcalcification as the sole abnormality. All of these 48 women had invasive ductal carcinoma and/or ductal carcinoma in situ (DCIS) (including four cases in which DCIS was associated with another type of primary invasive breast cancer). The finding of microcalcification on the previous mammograms at the site of a subsequently detected cancer was a strong predictor for the presence of DCIS (with or without associated invasive disease) (P<0.0001). Of the women with invasive ductal carcinoma, those with microcalcification on previous films were significantly more likely to have intermediate or high grade (grade 2 or 3) tumours than those women without microcalcification on previous films (P=0.0015). Previous films were also read blind by two independent experienced breast radiologists. Cancers were correctly identified by one or both readers in 39 cases. However, 35 of the remaining 139 cases showed microcalcification which was not detected or considered significant by the readers. If only these 139 'true negative' screens are analysed, similar associations are seen between microcalcification on previous films and subsequent finding of DCIS (P=0.03) and between microcalcification on previous films and high grade invasive ductal carcinomas (P=0.015). These findings provide support for the hypothesis that microcalcification seen on previous screening films at the site of a subsequently detected invasive ductal carcinoma represents ductal carcinoma in situ. In this series, 19 of 82 women (23%) with invasive ductal carcinoma in the 'true negative' screen group had microcalcification suggestive of DCIS on mammograms taken, on average, 3 years previously. Significant microcalcification is often overlooked using current detection criteria. Early detection and treatment of DCIS is essential in order to prevent the development of aggressive invasive disease. Revision of the NHSBSP targets for DCIS detection is recommended.

Evidence of nerve sheath differentiation and high grade morphology in sclerosing epithelioid fibrosarcoma

Sclerosing epithelioid fibrosarcoma is a recently described sarcoma in which ultrastructural evidence of fibroblastic differentiation forms part of the diagnostic criteria. This report describes a further case of this tumour, which showed evidence of both fibroblastic and perineurial differentiation by immunohistochemistry and electron microscopy, and which had areas of high grade morphology. The tumour metastasised and the patient died of disease 12 months after presentation. The relevance of these findings to diagnosis and differentiation in these tumours is discussed.

Induction of humoral and cellular responses in cynomolgus monkeys immunised with mannan-human MUC1 conjugates

Mice immunised with oxidised mannan conjugated to the human mucin 1 (MUC1), produce MHC Class 1 restricted CD8+ cytotoxic T-cells which eradicate MUC1 + tumours, indicating potential for the immunotherapy of MUC1 + cancers in humans. We now describe preclinical studies performed in cynomolgus monkeys immunised with human or murine MUC1 conjugated to oxidised mannan, where immune responses and toxicity were examined. High titred antibodies specific for MUC1 were produced, MUC1 specific CD4+ and CD8+ T-cell proliferative responses and specific cytotoxic precursor cells (CTLp) were found, but not MUC1 specific cytotoxic T-cells (CTL). There was no toxicity and monkeys can be immunised against human MUC1 with mannan-MUC1 conjugates, but a humoral response (Th2 type) predominates. The results contrast with those obtained in mice when a CTL response (Th1 type) predominates.

The plasminogen activator inhibitor-2 gene is not required for normal murine development or survival

Plasminogen activator inhibitor-2 (PAI-2), a member of the serpin gene family, is thought to serve as a primary regulator of plasminogen activation in the extravascular compartment. High levels of PAI-2 are found in keratinocytes, monocytes, and the human trophoblast, the latter suggesting a role in placental maintenance or embryo development. The primarily intracellular distribution of PAI-2 also may indicate a unique regulatory role in a protease-dependent cellular process such as apoptosis. To examine the potential functions of PAI-2 in vivo, we generated PAI-2-deficient mice by gene targeting in embryonic stem cells. Homozygous PAI-2-deficient mice exhibited normal development, survival, and fertility and were also indistinguishable from normal controls in response to a bacterial infectious challenge or endotoxin infusion. No differences in monocyte recruitment into the peritoneum were observed after thioglycollate injection. Epidermal wound healing was equivalent among PAI-2 -/- null and control mice. Finally, crossing PAI-2 -/- with PAI-1 -/- mice to generate animals deficient in both plasminogen activator inhibitors failed to uncover an overlap in function between these two related proteins.

Differentiating cells of murine stratified squamous epithelia constitutively express plasminogen activator inhibitor type 2 (PAI-2)

In stratified squamous epithelia a critical balance among cell proliferation, differentiation, and death must be maintained in order for these tissues to fulfill their barrier function. Previous studies have demonstrated that plasminogen activator inhibitor 2 (PAI-2) is a product of differentiating epidermal keratinocytes, suggesting a role for this inhibitor during squamous differentiation. Furthermore, in certain tumor cell lines, overexpression of PAI-2 confers resistance to the induction of programmed cell death, suggesting cytoprotective function(s). In the present study we demonstrate that PAI-2 mRNA and protein are constitutively and uniquely expressed in differentiating cells of murine stratified squamous epithelia, including epidermis, esophagus, vagina, oral mucosa, and tongue. PAI-2 immunohistochemical localization patterns suggest a predominantly cytosolic distribution, consistent with biochemical identification of the major PAI-2 species as a 43-kDa, presumably non-glycosylated protein. Functional analysis shows that the majority of epithelial PAI-2 is active. In contrast to the high levels of PAI-2 expression in stratified squamous epithelia, little or no PAI-2 is detectable in simple epithelia. These findings suggest that epithelial PAI-2 may mediate inhibition of intracellular proteinases associated with events during terminal differentiation and death that are unique to stratified squamous epithelia.

Living alone does not adversely affect nutrient intake and nutritional status of 70- to 75-year-old men and women in small towns across Europe

This study determined the relationships between living alone and a variety of sociodemographic variables and dietary intake and nutritional status of 70- to 75-year-old men and women across Europe. Data from nine centers, collected as part of the SENECA study, were selected for analysis. Respondents were categorized as either living alone, living with a spouse/partner only, or living with a spouse/partner and/or other person(s). Analyses included chi-square statistics, t-tests, and analysis of variance, measures of relationships and differences between residential-status groups. The sample included 512 subjects who lived alone, 1017 who lived with a spouse/partner only, and 380 who lived with a spouse/partner and/or other person(s). Variables which differed significantly by living arrangement included higher vitamin A, calcium, riboflavin and water intake by both males and females living alone as compared to either those living with a spouse, those living with others, or both groups. Females who lived alone had lower energy intake than those who lived with other than a spouse/partner, and women who lived alone or as couples versus those who lived with others had lower protein and carbohydrate intakes. Males who lived alone had significantly lower intakes of vitamin C than those who lived with person(s) other than a spouse, but still they were considerably above recommended levels. Respondents who lived with a spouse/partner only were less likely to have an unfavorable BMI status than people in the other two groups. Thus, nutrient intakes of 70- to 75-year-olds across Europe are generally not adversely impacted by living alone, and relative to some nutrients, namely vitamin A, calcium, and riboflavin, their diets are better than those living in one or both of the other residential categories.

Neither platelet activating factor nor leukotrienes are critical mediators of liver injury after lipopolysaccharide administration

The intravenous administration of lipopolysaccharide (LPS) to rats results in liver lesions characterized by the infiltration of both platelets and neutrophils into the liver and by midzonal hepatocellular necrosis. The liver injury is dependent on neutrophils, platelets and the coagulation system, as removal or inhibition of any of these components inhibits the development of hepatocellular necrosis. Platelet activating factor (PAF) and the cysteinyl leukotrienes (LTs) are potent inflammatory lipids that are critical for the development of some LPS-mediated alterations. To test the hypothesis that PAF, alone or in combination with LTs, contributes to the development of liver injury during LPS exposure, we conducted studies with the PAF receptor antagonist, WEB 2086, and the 5-lipoxygenase inhibitor, Zileuton. Female, Sprague-Dawley rats were pretreated with WEB 2086 (10 mg/kg, i.p.) alone or with Zileuton (40 mg/kg, p.o.) 1 h before the administration of LPS (4 mg/kg, i.v.) or its saline vehicle. Treatment with WEB 2086, alone or in combination with Zileuton, did not inhibit LPS-mediated hepatic neutrophil infiltration or liver injury, as assessed by histologic evaluation and increases in plasma alanine aminotransferase activity. Pretreatment with these agents also had no effect on the activation of the coagulation system or on the thrombocytopenia induced by LPS. These results suggest that PAF, alone or in combination with 5-lipoxygenase products, is not a critical mediator of LPS-induced hepatocellular injury in this model.

Nodular erythema elevatum diutinum mimicking cutaneous neoplasms

AIMS

We describe the cutaneous pseudoneoplastic lesions in two patients with nodular erythema elevatum diutinum, a rare chronic disorder in which polymorph nuclear fragmentation (leukocytoclasis) is present within dermal nodules showing spindle cells and fibrosis. In both cases diagnostic difficulty was encountered clinically and pathologically and various benign and malignant neoplasms were considered in the differential diagnosis.

METHODS AND RESULTS

Immunohistochemically the spindle cells were negative for CAM5.2, AE1/3, S100 protein and desmin (D33). They were positive for vimentin and focally positive for CD34 and alpha-smooth muscle actin. Some of the spindle cells were positive for Mac 387 and KP1(CD68). By electron microscopy, the lesions were shown to consist of fibroblasts/myofibroblasts and fusiform macrophages.

CONCLUSIONS

Increased awareness of the features described will help to avoid misdiagnosis as a neoplastic process.

Thrombin is a distal mediator of lipopolysaccharide-induced liver injury in the rat

Previous results demonstrated that rats given Escherichia coli lipopolysaccharide (LPS; 4 mg/kg, i.v.) experience hepatocellular necrosis that begins within 4 hr and that prior treatment with anticoagulants (e.g., heparin) which target thrombin prevents the liver injury. In this study, hepatocellular injury, as marked by increased plasma alanine aminotransferase (ALT) activity and histologic changes, was prevented when heparin or hirudin was administered to rats shortly before the onset of injury. These results suggest that thrombin is a critical mediator that acts distally in the series of inflammatory events that culminates in hepatocellular damage. To explore further this hypothesis, livers isolated from rats 2 hr after LPS administration were perfused with various media. Perfusion of livers with medium comprising diluted blood from heparin-treated donors resulted in no release of ALT activity. By contrast, perfusion with similar medium anticoagulated with ancrod, which prevents clotting by depleting fibrinogen but does not inhibit thrombin, resulted in hepatocellular injury evidenced as a time-dependent appearance of ALT activity in the medium. Moreover, when livers from rats treated 2 hr previously with LPS were perfused with buffer to which thrombin had been added, injury resulted. No injury resulted when thrombin was omitted from the buffer or when livers from saline-treated rats were used. These results indicate that thrombin is a critical and distal mediator of LPS-induced liver damage and contributes to hepatocellular injury through a mechanism that is independent of clot formation. Furthermore, inflammatory events triggered by LPS exposure are a prerequisite for thrombin-induced injury.

The thrombin inhibitor, hirudin, attenuates lipopolysaccharide-induced liver injury in the rat

The administration of gram-negative bacterial lipopolysaccharide (LPS) to rats results in hepatic parenchymal cell injury within 6 hr. The coagulation system is critical to the pathogenesis, but previously reported results suggested that its critical role is independent of insoluble clot formation and that thrombin may be a key mediator of liver injury. To test the hypothesis that thrombin is involved in LPS-induced liver injury, animals were treated with the selective thrombin inhibitor, hirudin. The hirudin treatment regimen effectively inhibited thrombin, as evidenced by prolonged activated partial thromboplastin time and by maintenance of plasma fibrinogen concentrations in LPS-treated rats. Treatment with hirudin prevented LPS-induced liver injury, assessed by plasma alanine aminotransferase activity and histological evidence of hepatocellular necrosis. Previous studies have shown that LPS exposure results in the accumulation of neutrophils and platelets within the liver and that both of these cell types are critical for the development of LPS-induced liver injury. Hirudin attenuated in part the decrease in blood platelet concentration that accompanied LPS administration, but did not alter hepatic platelet or neutrophil accumulation. These results support the hypothesis that thrombin is required for hepatic injury from LPS exposure, but that it does not act by promoting the accumulation of platelets or neutrophils within the liver.

Gadolinium chloride treatment attenuates hepatic platelet accumulation after lipopolysaccharide administration

Intravenous administration of LPS to rats results in the accumulation of both neutrophils and platelets in the liver and the development of midzonal hepatocellular necrosis. The development of liver injury entails contributions from both cellular and soluble mediators, including neutrophils, platelets, Kupffer cells, tumor necrosis factor-alpha (TNF-alpha), and components of the coagulation system. Much remains unknown about the interactions among these mediators in the pathogenesis of liver injury in vivo. Accordingly, we conducted studies with gadolinium chloride (GdCl3), an agent that inhibits Kupffer cell phagocytosis, to evaluate the role of Kupffer cells in lipopolysaccharide (LPS)-mediated liver injury, elevation in plasma TNF-alpha activity, thrombocytopenia, hepatic platelet accumulation, and activation of the coagulation system. Female Sprague-Dawley rats were pretreated with GdCl3-6H2O (10 mg/kg, i.v.) or saline vehicle 24 h before the administration of LPS (4 mg/kg, i.v.) or saline vehicle. In a preliminary study, this GdCl3 treatment regimen decreased the clearance of colloidal carbon from blood, indicating inhibition of Kupffer cell phagocytosis. Pretreatment with GdCl3 attenuated LPS-induced liver injury, monitored as increased plasma alanine aminotransferase and isocitrate dehydrogenase activities and histologic analysis. Electron micrographs of livers from rats treated with LPS revealed platelets within the sinusoids as well as Kupffer cells with phagolysosomes containing material resembling platelets. Pretreatment with GdCl3 attenuated LPS-induced thrombocytopenia and hepatic platelet accumulation, as measured by radiolabeled platelets. Treatment with GdCl3 did not, however, alter the elevation in plasma TNF-alpha activity or the activation of the coagulation system, as evidenced by a decreased in plasma fibrinogen concentration. These results suggest that Kupffer cells contribute to LPS-induced hepatic platelet accumulation and raise the possibility that protection against LPS-induced hepatic injury by Kupffer cell inactivation may be due at least partly to decreased deposition of platelets within the liver.

Platelet activating factor receptor blockade alone or in combination with leukotriene synthesis inhibition does not ameliorate alpha-naphthylisothiocyanate-induced hepatotoxicity

Alpha-naphthylisothiocyanate (ANIT) is a cholangiolitic hepatotoxicant that causes periportal edema, hepatic parenchymal and biliary epithelial cell necrosis, and cholestasis in the rat. A hallmark of ANIT hepatotoxicity is periportal inflammation that includes neutrophil infiltration. Neutrophils are requisite for the expression of ANIT-induced liver injury; however, the mechanism(s) of neutrophil accumulation in the liver and the role of these cells in ANIT hepatotoxicity is incompletely understood. Platelet activating factor (PAF) is a proinflammatory agent that is both a chemoattractant for and an activator of neutrophils. Therefore, we evaluated the role of PAF in ANIT-induced liver injury. Rats were treated with the PAF receptor antagonist, WEB 2086 (WEB), to determine if it afforded protection from ANIT hepatotoxicity. In a separate study, a combination of WEB and the leukotriene synthesis inhibitor, Zileuton (ZIL), was used to address the possible interaction of PAF and leukotrienes in ANIT-induced liver injury. Treatment of rats with WEB, alone or in combination with Zileuton, did not attenuate ANIT-induced liver injury as assessed by increases in plasma alanine aminotransferase or gamma-glutamyl transferase activities. In addition, neither treatment ameliorated ANIT-induced cholestasis assessed as increased plasma bilirubin concentration. These results suggest that PAF, alone or in combination with products of 5-lipoxygenase, does not contribute to ANIT-induced liver injury.

Platelet participation in liver injury from gram-negative bacterial lipopolysaccharide in the rat

Intravenous administration of lipopolysaccharide (LPS) to rats results in multifocal, primarily midzonal hepatic necrosis. The hepatic injury is associated with inflammation and is dependent on neutrophils and the coagulation system. After LPS injection into rats, plasma fibrinogen concentration and numbers of blood platelets and leukocytes decrease. Results of our studies, using immunocytochemistry for the detection of neutrophils and 111indium-labeling to identify platelets, indicate that both neutrophils and platelets accumulate within the liver early after administration of LPS to rats. The accumulation of platelets in the liver before the onset of injury suggested that platelets contribute to the manifestation of LPS-induced hepatotoxicity. To test this hypothesis, the number of circulating blood platelets was decreased by the administration of an anti-rat platelet serum (APS) before LPS administration. The consequent thrombocytopenia by APS administration was associated with an attenuation of both LPS-induced liver injury and the activation of the coagulation system. However, the APS treatment did not prevent the hepatic neutrophil accumulation. These results suggest that platelets contribute to the pathogenesis of liver injury after LPS administration, perhaps through their integral role in coagulation and/or interaction with neutrophils, but they do not appear to contribute to hepatic neutrophil accumulation.

Platelets and alpha-naphthylisothiocyanate-induced liver injury

Administration of alpha-naphthylisothiocyanate (ANIT) to rats results in periportal cholangiolitic hepatopathy. Inflammation is a hallmark of the liver injury, and expression of toxicity is dependent on blood neutrophils. The role of other cellular mediators of inflammation in ANIT-induced hepatic insult is unknown. We hypothesized that platelets participate in the expression of ANIT hepatotoxicity. To test this, circulating platelets were decreased by administration of anti-rat platelet serum (PAb) prior to treatment of rats with ANIT. The PAb treatment regimen effectively reduced circulating thrombocytes over the course of the experiment. Twenty-four hours after oral ANIT administration, rats were euthanized and liver injury was estimated by increases in serum alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT) activities. Cholestasis was assessed by measurement of serum total bilirubin concentration and bile flow. Reduction in platelet numbers was associated with attenuation of the increases in plasma ALT activity and bilirubin concentration seen after ANIT administration. However, PAb treatment did not attenuate the increase in plasma GGT, a marker of biliary epithelial cell injury. ANIT-induced changes in platelet function were assessed by evaluating platelet aggregation responses in platelet-rich plasma from rats treated with ANIT in vivo. ANIT treatment modestly decreased ex vivo platelet aggregation in response to ADP and collagen stimuli. To address further the role of platelet-derived cyclooxygenase products in ANIT hepatotoxicity, rats were treated with aspirin or ibuprofen. Neither pretreatment ameliorated ANIT-induced hepatic insult. These results suggest that platelets contribute to the expression of ANIT-induced liver injury, but they do not appear to act through the production of cyclooxygenase metabolites.

An evaluation of five different methods for estimating proliferation in human colorectal adenocarcinomas

Five different methods of determining cell proliferation have been compared in samples taken from a group of 125 human colorectal tumours labelled in vivo with iododeoxy-uridine (IUdR). The labelling index (LI) was obtained immunocytochemically using monoclonal antibodies against proliferating cell nuclear antigen (PCNA), the Ki67 antigen and IUdR (IUdRimm). Incorporation of IUdR was also determined flow cytometrically (IUdRfcm) and PCNA expression was measured in both formalin- and methanol-fixed tissue (PCNAf and PCNAm respectively). There was significant variation in the results obtained both within and between the different assays. Paired analysis of the data showed that the correlation between the different methods of determining the LI was poor. However, the IUdRfcm LI was significantly correlated with both IUdRimm (r = 0.39; n = 78; P < 0.001 by Spearman's test) and Ki67 LIs (r = 0.32; n = 87; P < 0.001). The IUdRimm LI was also significantly related to the Ki67 LI (r = 0.44; n = 60; P < 0.001). The median IUdRfcm and IUdRimm LIs were significantly higher in the aneuploid vs. the diploid tumours (17.4% vs. 6.2% for IUdRfcm; 23.2% vs. 18.9 for the IUdRimm; P < 0.001 and P = 0.014 respectively by Mann-Whitney U-test) but none of the other proliferative indices showed this relationship. Finally, none of the LIs showed a significant association with the clinical characteristics of the tumours such as stage, grade, age, sex or fixity. The findings of this investigation highlight the need for carefully controlled studies when assessing the value of proliferation markers in solid human tumours.

Value of electron microscopy in diagnosis of renal disease

AIMS

To assess the role and value of electron microscopy in the diagnosis of renal disease.

METHODS

Retrospective evaluation of 88 renal biopsy specimens received for primary diagnosis by assessment of the contribution of electron microscopy to the final diagnosis in the knowledge of the light microscopy and immunofluorescence findings.

RESULTS

Electron microscopy had an important diagnostic role in 75% of cases and was essential or necessary for diagnosis in 25%. In 25% of cases electron microscopy was considered unhelpful in diagnosis.

CONCLUSION

Electron microscopy has an integral role in the diagnosis of renal disease, and tissue should be taken for electron microscopy in all cases if possible. In some selected cases once the light microscopy and immunofluorescence findings are known it may be possible to forego electron microscopic examination. Electron microscopy is particularly useful in the differential diagnosis of minimal change disease and the nephrotic syndrome.