Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Abstract OT1-03-06: Phase IB/II clinical trial to evaluate safety and efficacy of tucatinib in combination with palbociclib and letrozole in patients with hormone receptor positive and HER2-positive metastatic breast cancer

Breast cancers overexpressing HER2-oncogene and hormone receptors (HR) represent therapeutic challenge because of a bi-directional cross-talk between HR and HER2 pathways leading to tumor progression and drug resistance. There is a strong rationale for evaluation of novel targeted drug combinations in this breast cancer subtype.

We designed a phase IB /II clinical trial to test the combination of novel oral HER2 small molecule inhibitor tucatinib with CDK4/6 inhibitor palbociclib and aromatase inhibitor letrozole in patients with HR+/HER2+ metastatic breast cancer (NCT03054363). In addition to the rationale for the synergy of targeting HR, HER2 and CDK4/6 pathways simultaneously in this disease setting and its potential for anti-tumor efficacy, we propose this novel combination of three oral agents, if well tolerated, will be highly patient-centered as an effective non-chemotherapy based regimen for treatment of HR+/HER2+ breast cancer.

This multicenter clinical trial is conducted through the Academic Breast Cancer Consortium (ABRCC), with the University of Colorado Cancer Center as the lead site.

Target enrollment: 40 patients (20 patients in phase IB and 20 patients in phase II part).

Main inclusion criteria:

1. HR+/HER2+ locally advanced unresectable / metastatic breast cancer

2. Measurable or evaluable disease. Bone only disease is allowed.

3. Subjects without brain metastases are eligible; subjects with untreated asymptomatic CNS metastases not needing immediate local therapy, and subjects with stable brain metastases previously treated with radiation therapy or surgery are eligible

4. ECOG 0-1

5. Postmenopausal women, or premenopausal women on ovarian suppression

6. Prior treatments:

- At least two approved HER2-targeted agents (trastuzumab, pertuzumab, or TDM-1) at any time in the course of the disease

- At least 1 line of HER2-targeted therapy in the metastatic setting (with the exception of asymptomatic subjects with oligometastatic or bone / soft tissue only disease who, on investigator opinion, are appropriate for a front line single agent anti-endocrine therapy per NCCN guidelines)

- Up to 2 lines of prior endocrine therapy in the metastatic setting are allowed

7. Adequate organ and marrow function

Main exclusion criteria:

1. Previously treated progressing brain metastases

2. Brain metastases and contraindications to undergo contrast brain MRI

3. Toxicities of prior cancer therapies that have not resolved to grade 1 or less, except peripheral neuropathy, which must have resolved to grade 2 or less, and alopecia

4. Previous treatment with EGFR or HER2 tyrosine kinase inhibitors or CDK4/6 inhibitors

5. Systemic anti-cancer therapy or radiation within 2 weeks of the first dose of study drugs

6. Active bacterial, fungal or viral infections, hepatitis B, C, or HIV

7. Clinically significant cardio-vascular disease

Primary objectives:

- Phase IB: safety and tolerability of combination therapy

- Phase II: efficacy by PFS

Exploratory assessment of biomarkers of resistance and response will be performed in the blood and biopsy samples

Study contact: Elena Shagisultanova, MD, PhD, elena.shagisultanova@ucdenver.edu

Citation Format: Shagisultanova E, Diamond J, Stopeck A, Pusztai L, O'Regan R, Gradishar W, Brown-Glaberman U, Chalasani P, McSpadden T, Borakove M, Shedin T, Kabos P, Borges V. Phase IB/II clinical trial to evaluate safety and efficacy of tucatinib in combination with palbociclib and letrozole in patients with hormone receptor positive and HER2-positive metastatic breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT1-03-06.

Report on the accident at Windscale No. 1 Pile on 10 October 1957

A serious fire developed in the core of a nuclear reactor at Windscale Works, Sellafield, northwest England, which led to the release of significant quantities of radioactive material into the environment during 10-11th October, 1957. In 1957, Windscale Works was operated by the United Kingdom Atomic Energy Authority (UKAEA), and on 15th October it was announced by the Chairman of the UKAEA that a Committee of Inquiry had been established under the chairmanship of Sir William Penney to conduct an investigation into the accident. The Committee sat at Windscale Works during 17-25th October, interviewed 37 people (some more than once), and examined 73 technical exhibits. The Committee reported to the Chairman of the UKAEA on 26th October. The Report of the Committee formed the technical basis of a UK Government White Paper (Cmnd. 302) published on 8th November, 1957, but the Penney Report itself was not published, and was only made public (at what is now The National Archives, TNA, Kew) in January, 1988. The original Report of the Committee of Inquiry is reproduced here from a copy of the Report supplied by TNA from TNA File AB 86/25.

Autosomal dominant IFIH1 gain-of-function mutations cause Aicardi-Goutières syndrome

Aicardi-Goutières Syndrome is caused by IFIH1 mutations Oda et al.(2014) The American Journal of Human Genetics 95(1): 121-125. Gain-of-function mutations in IFIH1 cause a spectrum of human disease phenotypes associated with upregulated type I interferon signaling Rice et al.(2014) Nature Genetics 46(5): 503-510.

The DeepTree Exhibit: Visualizing the Tree of Life to Facilitate Informal Learning

In this paper, we present the DeepTree exhibit, a multi-user, multi-touch interactive visualization of the Tree of Life. We developed DeepTree to facilitate collaborative learning of evolutionary concepts. We will describe an iterative process in which a team of computer scientists, learning scientists, biologists, and museum curators worked together throughout design, development, and evaluation. We present the importance of designing the interactions and the visualization hand-in-hand in order to facilitate active learning. The outcome of this process is a fractal-based tree layout that reduces visual complexity while being able to capture all life on earth; a custom rendering and navigation engine that prioritizes visual appeal and smooth fly-through; and a multi-user interface that encourages collaborative exploration while offering guided discovery. We present an evaluation showing that the large dataset encouraged free exploration, triggers emotional responses, and facilitates visitor engagement and informal learning.

Phase I results of the randomized, placebo controlled, phase I/II study of the novel oral c-Met inhibitor, ARQ 197, irinotecan (CPT-11), and cetuximab (C) in patients (pts) with wild-type (WT) KRAS metastatic colorectal cancer (mCRC) who have received front-line systemic therapy

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Background: ARQ 197 selectively inhibits the c-Met receptor tyrosine kinase (RTK), which has been implicated in tumor cell migration, invasion, proliferation, and angiogenesis. CPT-11 plus C is a standard of care for CPT-11-refractory mCRC pts with WT KRAS tumors. Resistance to C has been associated with activation of alternative RTK pathways including c-Met. We hypothesize that adding ARQ 197 to CPT-11 plus C may decrease resistance to C therapy and improve pt outcomes.

Methods: The primary objectives of phase I were to evaluate safety and tolerability of ARQ 197 administered in combination with CPT-11 plus C, and to define a recommended phase II dose (RPTD). Pts with surgically unresectable locally advanced or mCRC who received at least 1 prior line of chemotherapy, KRAS WT and ECOG performance status < 2 were eligible. Cohorts of 3 pts each were treated with CPT-11 (180 mg/m2) and C (500 mg/m2) every 2 weeks along with escalating doses of ARQ 197 (120, 240, 360 mg) PO BID. Blood and tissue were collected for PK, biomarker, and other analyses. If no DLTs were observed during the first 28-day cycle in 3 pts treated in cohort 3, 360 mg BID would be defined as the RPTD. Responses were assessed every 8 weeks per RECIST v1.1.

Results: Nine pts were treated in 3 cohorts. Median age: 53 yrs (range 30-77); ECOG PS 0/1: 4/5; median prior therapies: 2 (range 1-4). No DLTs were observed. The RPTD for ARQ 197 was 360 mg BID. To date, two pts have discontinued (1 disease progression and 1 withdrew consent after achieving complete response) and 7 pts remain on study. The reported grade 3/4 adverse events were: neutropenia (3/4: 1/1), and one case each of grade 3 fatigue, leucopenia, acneiform rash, vomiting, anemia and syncope. Preliminary efficacy data in 9 evaluable pts include 1 CR (after 4 cycles), 2 PR (after 2 cycles), 5 SD, and 1 PD as best response.

Conclusions: The combination of ARQ 197 and CPT-11 plus C was well tolerated with encouraging preliminary antitumor activity. The RPTD for ARQ 197 was 360 mg BID. The randomized phase II portion of the study continues accrual.

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Animal art: Variation in bower decorating style among male bowerbirds Amblyornis inornatus

Courtship bowers of the bowerbird Amblyornis inornatus, the most elaborately decorated structures erected by an animal other than humans, vary geographically and individually. Bowers in the south Kumawa Mountains are tall towers of sticks glued together, resting on a circular mat of dead moss painted black, and decorated with dull objects such as snail shells, acorns, and stones. Bowers in the Wandamen Mountains are low woven towers covered by a stick hut with an entrance, resting on a green moss mat and decorated with colorful objects such as fruits, flowers, and butterfly wings. Young males build simpler bowers, and adult males differ among themselves. Experiments with poker chips of seven colors offered as decorations showed that individual birds prefer some colors over others, individuals and populations differ in these preferences, certain objects are placed in specific parts of the bower, and birds steal chips from neighbors. Bower style may be partly learned. Hence, geographically varying bower styles may be a culturally transmitted trait, like human art styles.

Effect of species pool size on species occurrence frequencies: Musical chairs on islands

If species interactions affect species distributions, then species occurrence frequencies (nu(i)), defined as the fraction of an archipelago's islands that species i inhabits, should vary with species pool size. A "natural experiment" approximating this test is provided by the Bismarck, Solomon, and New Hebrides archipelagoes, whose bird species pools decrease in that order, the species of each archipelago being mostly a subset of those of the next richer archipelago. The average nu for an archipelago's species decreases with archipelago pool size. In the archipelago with the largest pool, most species are on few islands and few species are on most islands, whereas the reverse is true in the archipelago with the smallest pool. For species shared between two or more archipelagoes, nu(i) decreases with pool size or number of species in the same guild. These interarchipelagal differences in nu(i) or average nu reflect differences in level of interspecific competition, which reduces nus in species-rich archipelagoes in two ways: usually, by reducing a species' incidence on small islands and restricting the species to larger islands; less often (for so-called supertramps), by restricting a species to small islands.

Loss of intramuscular and submuscular interstitial cells of Cajal and associated enteric nerves is related to decreased gastric emptying in streptozotocin-induced diabetes

Interstitial cells of Cajal (ICC) are associated with afferent innervation and peristalsis of the stomach suggestive of a key role in the pathophysiology of gastroparesis. We studied changes in the density and ultrastructure of ICC and enteric nerves in the streptozotocin-induced diabetes mellitus (STZ-DM) in Wistar rats using immunohistochemistry and electron microscopy. Gastric emptying was studied in vivo by single-photon emission computed tomography. In the STZ-DM antrum, a marked reduction was observed in the density of the intramuscular ICC (ICC-IM) and ICC located at the submucosal border of the circular muscle layer of the antrum (ICC-SM). The surviving ICC showed lamellar bodies and partial vacuolation of the cytoplasm content, loss of connections between ICC-IM and nerves; it appeared that injured ICC-IM developed into fibroblast-like ICC. ICC associated with Auerbach's plexus (ICC-AP) in the antrum and ICC in the fundus were not affected significantly except for a loss of connections with nerve structures. Marked reduction in nerve tissue (Protein Gene Product-9.5 positivity) was also restricted to the muscle layers including nitrergic nerves (neuronal nitric oxide synthase positivity). In vivo assessed gastric emptying was markedly reduced in STZ-DM rats. Our data demonstrate in the STZ-DM rat stomach a decreased density of ICC limited to the antrum and to ICC-IM and ICC-SM, and structural degeneration in ICC-IM and associated nerves with a special emphasis on loss of synaptic connections, accompanied by a decrease in gastric emptying. Hence, in this model of gastroparetic diabetes, regional injury to subsets of ICC and nerves are associated with gastric motor dysfunction.

An open-label, dose escalation, safety, and pharmacokinetic study of ENMD-2076 administered orally to patients with advanced cancer

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Background: ENMD-2076, a novel, orally-active antimitotic and antiangiogenic molecule inhibits Aurora A as well as tyrosine kinases that drive tumor vascularization, including VEGFR2 (KDR), PDGFR and the FGF receptors. This Phase 1 study was designed to evaluate the safety, pharmacokinetics (PK) and preliminary efficacy of ENMD-2076 administered once daily to patients (pts) with advanced cancer. Methods: The dose escalation scheme utilizes 3 (or 4) + 3 (or 2) design. Pts receive ENMD-2076 once daily in 28-day cycles (followed by 7–14 days of rest between cycles 1 and cycle 2 only). Results: 14 pts have been enrolled in 3 dose cohorts (range 60 to 120 mg/m2/d). Median age/performance status is 62/1. The total number of treatment cycles to date is 45, with a median of 3 cycles (range <1 to 9 cycles). Most frequent, related toxicities (all grades, n=14) were hypertension (29%), fatigue (21%), proteinuria and diarrhea (both 14%). One pt experienced dose limiting toxicity of Grade 4 hypertension and Grade 3 cholecystitis in the first dose cohort of 60 mg/m2/d. Following drug interruption, the pt restarted at 30 mg/m2/d and continued for 4 additional cycles before being removed for progressive disease. Noncompartmental PK analysis of the first two dose levels shows that the plasma concentration of ENMD-981693 (the active free base of ENMD-2076) is dose- linear, as reflected in AUC and Cmax. The estimated terminal half-life (t1/2) is unaltered regardless of dose; however, t1/2 is approximately 50% greater at steady state than following single dose administration. Four ovarian cancer and 2 colon cancer pts have achieved decreases ranging from 11–61% in either CA125 or CEA, respectively (4 are associated with stable disease at Cycle 2 by modified RECIST criteria). Serum KDR concentrations assayed by ELISA decreased from baseline in all patients on treatment from a mean of 9153 pg/mL (SEM 464.2) at D1 to 6987 pg/mL (SEM 460.0) at D28 (p <0.05). Conclusions: ENMD-2076 is a small molecule kinase inhibitor with acceptable toxicity and preliminary evidence of antitumor activity in pts with ovarian and colorectal cancers.

[Table: see text]

Dual-action peptides: a new strategy in the treatment of diabetes-associated neuropathy

Peripheral neuropathy is one of the most common and debilitating complications of type 1 and type 2 diabetes mellitus. Recent studies have shown that several small, non-neural peptides possess neurotrophic activity and exert beneficial effects on nervous system function in experimental and clinical diabetes. Two of these, C-peptide and islet neogenesis-associated protein peptide, are derived from pancreatic proteins and use related signal transduction mechanisms. Derivatives of erythropoietin possess similar properties in the nervous system. As a group, these peptides are of increasing interest as leads to potential new approaches in the treatment of diabetes-associated neuropathies and other neurodegenerative conditions. This review addresses the recent advances made with these peptides in the context of diabetic neuropathy, and highlights similarities and differences in their mechanisms of action from the perspective of combination therapy.

Pertussis toxin-sensitive G protein but not NO/cGMP pathway mediates the negative inotropic effect of carbachol in adult rat cardiomyocytes

Previous studies have shown that muscarinic inhibition of cardiac contractility is mediated by either activation of nitric oxide (NO)/guanosine 3',5'-cyclic monophosphate (cGMP) pathway or stimulation of inhibitory G protein (G(i)). However, it still remains controversial as to whether NO/cGMP pathway or G(i) protein or both mediate(s) the negative inotropic effect of muscarinic agonists in adult ventricular myocytes. In the present study that involves the use of adult rat ventricular myocytes, the muscarinic agonist, carbachol, inhibited beta-adrenergic (isoproterenol) stimulation of contractility (cell shortening) by 82% and increased cGMP levels by 49% within 6 min. Pretreatment of myocytes with soluble guanylyl cyclase inhibitor (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, ODQ) or NO synthase inhibitor (N(G)-monomethyl-L-arginine, L-NMMA) for 30 min blocked carbachol-induced increases in cGMP levels. However, neither ODQ nor L-NMMA pretreatment had any effect on carbachol inhibition of isoproterenol-induced contractility. In addition, carbachol did not attenuate increases in myocyte contractility induced by forskolin (a direct activator of adenylyl cyclase) or 8-(4-chlorophenylthio)-adenosine 3',5'-cyclic monophosphate (a cell-permeable cAMP analog which activates cAMP-dependent protein kinase). Pretreatment of myocytes with G(i) protein inhibitor, pertussis toxin (PTX, 1 microg/ml), for 18-20 h abolished carbachol inhibition of isoproterenol-induced contractility. Furthermore, in ventricular myocytes isolated 3 days after in vivo treatment of rats with PTX (3 microg/100 g, i.p.), there was a complete loss of the negative inotropic effect of carbachol. These data indicate that pertussis toxin-sensitive G protein but not NO/cGMP pathway is required for muscarinic inhibition of beta-adrenoceptor-mediated increases in contractility in adult rat ventricular myocytes.

Neotrofin, a novel purine that induces NGF-dependent nociceptive nerve sprouting but not hyperalgesia in adult rat skin

We report peripheral actions in rats of Neotrofin, a purine derivative of therapeutic interest. Systemic injections mimicked NGF in eliciting sprouting of nociceptive nerves without affecting their regeneration. The sprouting was prevented by anti-NGF treatment, implicating endogenous NGF. We detected no Neotrofin-induced increases in cutaneous NGF levels or in retrograde NGF transport. In contrast, both NGF and phosphorylation of trkA increased significantly in DRGs, with a marginal appearance of phosphorylated trkA in axons. We conclude that the DRG effects of Neotrofin are responsible for its induction of sprouting. Neotrofin also induced a striking phosphorylation of axonal erk 1 and 2, which was, however, unaffected by anti-NGF treatment. We suggest that this NGF-independent MAP kinase activation is involved in nonsprouting functions of Neotrofin such as neuroprotection. Unlike injected NGF, Neotrofin did not induce hyperalgesia, supporting its candidacy as a treatment for peripheral neuropathies like those induced by diabetes and anticancer chemotherapy.

Computerized diagnostic decision support system for the classification of preinvasive cervical squamous lesions

Previous studies have revealed considerable interobserver and intraobserver variation in the histological classification of preinvasive cervical squamous lesions. The aim of the present study was to develop a decision support system (DSS) for the histological interpretation of these lesions. Knowledge and uncertainty were represented in the form of a Bayesian belief network that permitted the storage of diagnostic knowledge and, for a given case, the collection of evidence in a cumulative manner that provided a final probability for the possible diagnostic outcomes. The network comprised 8 diagnostic histological features (evidence nodes) that were each independently linked to the diagnosis (decision node) by a conditional probability matrix. Diagnostic outcomes comprised normal; koilocytosis; and cervical intraepithelial neoplasia (CIN) I, CIN II, and CIN III. For each evidence feature, a set of images was recorded that represented the full spectrum of change for that feature. The system was designed to be interactive in that the histopathologist was prompted to enter evidence into the network via a specifically designed graphical user interface (i-Path Diagnostics, Belfast, Northern Ireland). Membership functions were used to derive the relative likelihoods for the alternative feature outcomes, the likelihood vector was entered into the network, and the updated diagnostic belief was computed for the diagnostic outcomes and displayed. A cumulative probability graph was generated throughout the diagnostic process and presented on screen. The network was tested on 50 cervical colposcopic biopsy specimens, comprising 10 cases each of normal, koilocytosis, CIN I, CIN II, and CIN III. These had been preselected by a consultant gynecological pathologist. Using conventional morphological assessment, the cases were classified on 2 separate occasions by 2 consultant and 2 junior pathologists. The cases were also then classified using the DSS on 2 occasions by the 4 pathologists and by 2 medical students with no experience in cervical histology. Interobserver and intraobserver agreement using morphology and using the DSS was calculated with kappa statistics. Intraobserver reproducibility using conventional unaided diagnosis was reasonably good (kappa range, 0.688 to 0.861), but interobserver agreement was poor (kappa range, 0.347 to 0.747). Using the DSS improved overall reproducibility between individuals. Using the DSS, however, did not enhance the diagnostic performance of junior pathologists when comparing their DSS-based diagnosis against an experienced consultant. However, the generation of a cumulative probability graph also allowed a comparison of individual performance, how individual features were assessed in the same case, and how this contributed to diagnostic disagreement between individuals. Diagnostic features such as nuclear pleomorphism were shown to be particularly problematic and poorly reproducible. DSSs such as this therefore not only have a role to play in enhancing decision making but also in the study of diagnostic protocol, education, self-assessment, and quality control.

An intact intermediate filament network is required for collateral sprouting of small diameter nerve fibers

Expression of the intermediate filament (IF) protein peripherin is initiated during development at the time of axonal extension and increases during regeneration of nerve fibers. To test whether the IF network is essential for neuron process outgrowth in the mature organism in vivo, we disrupted endogenous peripherin IF in small-sized dorsal root ganglion (DRG) neurons in transgenic mice via expression of a mutant peripherin transgene under control of peripherin gene regulatory sequences. Anatomical and functional analyses showed that these neurons send peripheral and central axonal projections to correct targets, express correct neuropeptides, and mediate acute pain responses normally. However, disruption of IF significantly impaired the ability of uninjured small-sized DRG neurons to sprout collateral axons into adjacent denervated skin, indicating a critical role for intact IF in plasticity, specifically in compensatory nociceptive nerve sprouting.

Expert system support using a Bayesian belief network for the classification of endometrial hyperplasia

Accurate morphological classification of endometrial hyperplasia is crucial as treatments vary widely between the different categories of hyperplasia and are dependent, in part, on the histological diagnosis. However, previous studies have shown considerable inter-observer variation in the classification of endometrial hyperplasias. The aim of this study was to develop a decision support system (DSS) for the classification of endometrial hyperplasias. The system used a Bayesian belief network to distinguish proliferative endometrium, simple hyperplasia, complex hyperplasia, atypical hyperplasia and grade 1 endometrioid adenocarcinoma. These diagnostic outcomes were held in the decision node. Four morphological features were selected as diagnostic clues used routinely in the discrimination of endometrial hyperplasias. These represented the evidence nodes and were linked to the decision node by conditional probability matrices. The system was designed with a computer user interface (CytoInform) where reference images for a given clue were displayed to assist the pathologist in entering evidence into the network. Reproducibility of diagnostic classification was tested on 50 cases chosen by a gynaecological pathologist. These comprised ten cases each of proliferative endometrium, simple hyperplasia, complex hyperplasia, atypical hyperplasia and grade 1 endometrioid adenocarcinoma. The DSS was tested by two consultant pathologists, two junior pathologists and two medical students. Intra- and inter-observer agreement was calculated following conventional histological examination of the slides on two occasions by the consultants and junior pathologists without the use of the DSS. All six participants then assessed the slides using the expert system on two occasions, enabling inter- and intra-observer agreement to be calculated. Using unaided conventional diagnosis, weighted kappa values for intra-observer agreement ranged from 0.645 to 0.901. Using the DSS, the results for the four pathologists ranged from 0.650 to 0.845. Both consultant pathologists had slightly worse weighted kappa values using the DSS, while both junior pathologists achieved slightly better values using the system. The grading of morphological features and the cumulative probability curve provided a quantitative record of the decision route for each case. This allowed a more precise comparison of individuals and identified why discordant diagnoses were made. Taking the original diagnoses of the consultant gynaecological pathologist as the 'gold standard', there was excellent or moderate to good inter-observer agreement between the 'gold standard' and the results obtained by the four pathologists using the expert system, with weighted kappa values of 0.586-0.872. The two medical students using the expert system achieved weighted kappa values of 0.771 (excellent) and 0.560 (moderate to good) compared to the 'gold standard'. This study illustrates the potential of expert systems in the classification of endometrial hyperplasias.

Dinosaurs, dragons, and dwarfs: the evolution of maximal body size

Among local faunas, the maximum body size and taxonomic affiliation of the top terrestrial vertebrate vary greatly. Does this variation reflect how food requirements differ between trophic levels (herbivores vs. carnivores) and with taxonomic affiliation (mammals and birds vs. reptiles)? We gathered data on the body size and food requirements of the top terrestrial herbivores and carnivores, over the past 65,000 years, from oceanic islands and continents. The body mass of the top species was found to increase with increasing land area, with a slope similar to that of the relation between body mass and home range area, suggesting that maximum body size is determined by the number of home ranges that can fit into a given land area. For a given land area, the body size of the top species decreased in the sequence: ectothermic herbivore > endothermic herbivore > ectothermic carnivore > endothermic carnivore. When we converted body mass to food requirements, the food consumption of a top herbivore was about 8 times that of a top carnivore, in accord with the factor expected from the trophic pyramid. Although top ectotherms were heavier than top endotherms at a given trophic level, lower metabolic rates per gram of body mass in ectotherms resulted in endotherms and ectotherms having the same food consumption. These patterns explain the size of the largest-ever extinct mammal, but the size of the largest dinosaurs exceeds that predicted from land areas and remains unexplained.