Artificial intelligence-based analysis of whole-body bone scintigraphy: The quest for the optimal deep learning algorithm and comparison with human observer performance

PURPOSE

Whole-body bone scintigraphy (WBS) is one of the most widely used modalities in diagnosing malignant bone diseases during the early stages. However, the procedure is time-consuming and requires vigour and experience. Moreover, interpretation of WBS scans in the early stages of the disorders might be challenging because the patterns often reflect normal appearance that is prone to subjective interpretation. To simplify the gruelling, subjective, and prone-to-error task of interpreting WBS scans, we developed deep learning (DL) models to automate two major analyses, namely (i) classification of scans into normal and abnormal and (ii) discrimination between malignant and non-neoplastic bone diseases, and compared their performance with human observers.

MATERIALS AND METHODS

After applying our exclusion criteria on 7188 patients from three different centers, 3772 and 2248 patients were enrolled for the first and second analyses, respectively. Data were split into two parts, including training and testing, while a fraction of training data were considered for validation. Ten different CNN models were applied to single- and dual-view input (posterior and anterior views) modes to find the optimal model for each analysis. In addition, three different methods, including squeeze-and-excitation (SE), spatial pyramid pooling (SPP), and attention-augmented (AA), were used to aggregate the features for dual-view input models. Model performance was reported through area under the receiver operating characteristic (ROC) curve (AUC), accuracy, sensitivity, and specificity and was compared with the DeLong test applied to ROC curves. The test dataset was evaluated by three nuclear medicine physicians (NMPs) with different levels of experience to compare the performance of AI and human observers.

RESULTS

DenseNet121_AA (DensNet121, with dual-view input aggregated by AA) and InceptionResNetV2_SPP achieved the highest performance (AUC = 0.72) for the first and second analyses, respectively. Moreover, on average, in the first analysis, Inception V3 and InceptionResNetV2 CNN models and dual-view input with AA aggregating method had superior performance. In addition, in the second analysis, DenseNet121 and InceptionResNetV2 as CNN methods and dual-view input with AA aggregating method achieved the best results. Conversely, the performance of AI models was significantly higher than human observers for the first analysis, whereas their performance was comparable in the second analysis, although the AI model assessed the scans in a drastically lower time.

CONCLUSION

Using the models designed in this study, a positive step can be taken toward improving and optimizing WBS interpretation. By training DL models with larger and more diverse cohorts, AI could potentially be used to assist physicians in the assessment of WBS images.

Clinical and polysomnographic characteristics in adults referred to the sleep laboratory: a single-center study

Background: Polysomnography is the gold standard diagnostic method for obstructive sleep apnea syndrome, and on-time treatment can help prevent further complications of obstructive sleep apnea. However, polysomnography is associated with some difficulties for the patients and physicians, which hinder its application. This study aimed to evaluate the clinical features and polysomnography findings of patients with obstructive sleep apnea.

Methods: Data were retrospectively collected from polysomnography studies at the Sleep Laboratory of Namazi Hospital, Shiraz, Iran, from February 2013 to December 2017. Polysomnography was performed for any patients suspected of obstructive sleep apnea. The researcher reviewed the data extracted and selected the essential clinical features for the statistical analysis. The association of variables with the polysomnography findings was analyzed.

Results: Significant associations were observed between the following factors and severity of obstructive sleep apnea: older age (p = 0.01), snoring (p = 0.122), history of sleep disorders (p = 0.11), no sedatives before sleep (p = 0.039), nocturia (p = 0.001), apnea (p = 0.035), no smoking (p = 0.039), no substance abuse (p = 0.011), hypertension (p = 0.001), cardiac diseases (p = 0.025), and overweight and obesity (p < 0.001).

Conclusion: Considering the concomitant occurrence of obstructive sleep apnea with obesity, hypertension, cardiac disease, snoring, and observed apnea, polysomnography is recommended in these patients before further assessments.

Renoprotective effects of prazosin on ischemia-reperfusion injury in rats

BACKGROUND

Renal ischemia-reperfusion (IR) injury is one of the main leading causes of acute kidney injury associated with inflammation, oxidative stress and cell apoptosis. We studied the effects of prazosin, as a specific blocker of α1-AR, on renal IR injury.

METHODS

Rats were divided into normal control; untreated IR and prazosin-treated IR (1 mg/kg body weight). Prazosin was administered by intraperitoneal injection 30 min prior to IR induction. The level of urea/creatinine and oxidative factors were detected by colorimetric methods. Apoptosis-associated factors, inflammatory, and signaling proteins were analyzed in renal tissue. The abnormalities of renal histopathology were detected by immunohistochemistry.

RESULTS

Administration of prazosin to IR rats ameliorated serum urea and creatinine and IR-induced histopathological damages. Lipid peroxidation was significantly improved after treatment by prazosin in IR injury rats, however, antioxidant status was not affected. Rats subjected to IR injury activated Bax protein and NF-κB mediated inflammatory response. Moreover, treatment with prazosin inhibited renal NF-κB activation, resulting in a significant decline in pro-inflammatory cytokine of IL-6.

CONCLUSION

These findings suggest that prazosin could be a good candidate to attenuate renal IR injury due to its ability to modulate renal function, apoptosis and inflammation.

Strategies for improving the emission performance of hybrid electric vehicles

Low emission vehicle technologies need widespread adoption in the transport sector to overcome its significant decarbonisation challenges. Hybrid Electric Vehicles (HEVs) represent an intermediate technology between pure electric vehicles and internal combustion engines that have proven capability in reducing petroleum consumption. HEV customers often cite improved fuel economy as a major benefit from adopting this technology; however, outstanding questions remain regarding their respective emission levels. Through an extensive literature study, we show that several issues remain with HEV emissions performance which stem from frequent high-power cold starts, engine calibration issues and inefficient operating conditions for catalytic converters. HEVs have more NO_x, HC, CO and particle number emissions compared to conventional vehicles by up to 21.0, 5.8, 9.0 and 23.3 times, respectively. Improved engine control algorithms, after-treatment design and thermal design of three-way catalysts emerge as research priorities for improving the emissions performance of HEVs.

The irradiated fuel-burnup experiment of Tehran Research Reactor using nondestructive gamma-ray spectroscopy

In this work, a nondestructive gamma scanning technique has been applied to determine the irradiated fuel burnup of Tehran Research Reactor (TRR). Thereby, a system was designed and installed at the rim of the TRR pool, which includes a High-Purity Germanium (HPGe) detector and associated electronics-devices, a proper shield, a collimator, and an elevator to radioactive fuel handling for any longitudinal and transverse fuel movement. In the system, it also was possible to measure fuel burnup for fuels with short cooling times at the minimum distance between the fuel and the detector. Five Standard Fuel Elements (SFEs) have been studied with U3O8Al fuel in burnup range of 14%-60% FIMA and cooling time range of 60 days-550 days. Then, by analyzing the gamma-ray emitted from 137Cs isotope as a fuel burnup indicator, an axial profile of fuel burnup was measured in the active fuel length of 61.5 cm and an active width of 6 cm. Finally, verification of results from reactor physics calculations was conducted based on fuel burnup measurements using a nondestructive gamma scanning technique that represents a well enough agreement between calculations and measurements.

P7142-AG impacts on endothelial cell activation and endothelial cell viability in vitro and impairs endothelial repair in vivo

Background

The endocannabinoid (eCB) 2-arachidonoylglycerol (2-AG) is a known modulator of inflammation and few studies have addressed its influence on myeloid cells in the context of atherogenesis. However, the impact of 2-AG on endothelial cell function has not been studied before.

Methods

Endothelial repair was studied in two treatment groups of wildtype mice following electrical denudation of the common carotid artery at a length of 3000 μm. One group received the monoacylglycerol lipase (MAGL)-inhibitor JZL184 [5 mg/kg i.p.], which impairs 2-AG degradation and thus causes elevated 2-AG levels, the other group received vehicle. The residual endothelial gap at five days in either group was visualized by Evan's blue staining. In vitro, the effect of 2-AG on human coronary artery endothelial cell (HCAEC) viability was assessed by an XTT-based assay. Endothelial activation was studied by an adhesion assay of THP-1 monocytes to 2-AG-preconditioned HCAEC. HCAEC migration, ROS-production, expression of NADPH oxidases, and secretion of inflammatory cytokines were assessed by Boyden chamber, qPCR, and colorimetric assays.

Results

Treatment with JZL184 produced a significant increase in 2-AG levels and impaired reendothelialisation in wildtype mice following electrical injury of the common carotid artery. The residual denudation at 5 days yielded 2291±286 μm in JZL184-treated animals vs. 1505±223 μm in vehicle treated controls (n=18–19; p<0.05). In vitro, JZL184 significantly reduced viability of HCAEC at 24 hours (0.31±0.10 vs. 1.00±0.08; n=3; p<0.01). Finally, 2-AG promoted HCAEC activation resulting in a significant increase in THP-1 monocyte adhesion to HCAEC following pre-treatment of HCAEC with 2-AG (0.17±0.03 THP-1 cells per HCAEC vs. 0.07±0.01 THP-1 cells per HCAEC; n=3; p<0.05). Besides, HCAEC migration, ROS-production, expression of NADPH oxidases and secretion of inflammatory cytokines were unaffected by 2-AG.

Conclusion

Elevated 2-AG levels appear to hamper endothelial repair and to promote HCAEC activation and cell death. Our data suggest that besides its influence on myeloid cells, 2-AG is also adverse to endothelial integrity which might promote early atherosclerotic lesion formation. Thus, decreasing vascular 2-AG levels might represent a promising therapeutic strategy for the prevention of atherosclerosis and coronary heart disease.

P4140Myeloid but not endothelial expression of the CB2 receptor promotes atherogenesis in the context of elevated levels of the endocannabinoid 2-arachidonoylglycerol

Background

The endocannabinoid 2-arachidonoylglycerol (2-AG) is an inflammatory mediator and ligand to the cannabinoid receptors CB1 and CB2, which are expressed on myeloid and endothelial cells. 2-AG has recently been described to promote atherogenesis in ApoE-deficient mice. While the CB2 receptor has previously been considered to solely exert anti-inflammatory and atheroprotective effects, newer data have raised the notion, that CB2 might exert atherogenic effects in the context of elevated 2-AG plasma levels. In the present study, we investigated the atherogenic mechanisms of 2-AG and the role of the CB2 receptor on myeloid and endothelial cells in atherogenesis using cell-specific knockout mouse models.

Methods

Two mouse models with atherogenic background and distinct cell-specific knockouts of the CB2 receptor on myeloid (ApoE−/−LysMcreCB2fl/fl) or endothelial cells (ApoE−/−Tie2creCB2fl/fl) were created. Mice were treated with JZL184, which inhibits 2-AG-degrading enzyme monoacylglycerol lipase, and thereby elevates 2-AG plasma levels, or with vehicle (DMSO), while being fed a high-fat diet for four weeks. Plaque volume and plaque composition were analyzed. In vitro, macrophages were treated with 2-AG and mRNA levels of adhesion molecules, scavenger receptors and chemokines, the production of reactive oxygen species (ROS) and the release of myeloperoxidase (MPO) were determined using qPCR, fluorometric assays and ELISA respectively.

Results

Elevated levels of 2-AG promote atherogenesis in ApoE-deficient mice (JZL184 vs. DMSO: 39.6±2.1% vs. 32.6±2.4%; n=14; p<0.05). The atherogenic effect of 2-AG is abrogated in mice lacking myeloid CB2 receptor expression (35.0±2.0% vs. 34.0±2.5%; n=14–16; p>0.05) but not in mice lacking endothelial CB2 receptor expression (37.1±3.1% vs. 20.9±2.6%; n=10–12; p<0.01). In vitro, 2-AG significantly increases transcription of adhesion molecule ICAM-1 (2.09±0.42 –fold; n=5–6; p<0.05), chemokine receptor CCR-1 (2.04±0.46 -fold; n=10–11; p<0.05) and scavenger receptor CD36 (8.02±1.89-fold; n=3; p<0.05) in 2-AG-treated macrophages. These effects are mitigated by pharmacological inhibition of CB2. Furthermore, 2-AG significantly increases myeloperoxidase (MPO) release in monocytes in a CB receptor-dependent fashion (451±23 pg/ml vs. 151±8.3 pg/ml; n=3–4; p<0.01) and promotes ROS production (2698±24 pdu vs. 1981±27 pdu; n=8; p<0.01).

Conclusion

Elevated 2-AG levels show an atherogenic effect in vivo which is dependent on the presence of the CB2 receptor on myeloid cells. Our in vitro data reveal 2-AG to promote pro-inflammatory signaling in macrophages and elucidate a previously unrecognized link between the endocannabinoid system and MPO in monocytes. In summary, cell-specific effects of the endocannabinoid system will have to be taken into account to facilitate its exploitation as an anti-atherosclerotic drug target.

Acknowledgement/Funding

This work was supported by the Bonfor program of the University of Bonn [grant number O-109.0057 to JJ].

Adenosine deaminase inhibition

Adenosine deaminase is a critical enzyme in purine metabolism that regulates intra and extracellular adenosine concentrations by converting it to inosine. Adenosine is an important purine that regulates numerous physiological functions by interacting with its receptors. Adenosine and consequently adenosine deaminase can have pro or anti-inflammatory effects on tissues depending on how much time has passed from the start of the injury. In addition, an increase in adenosine deaminase activity has been reported for various diseases and the significant effect of deaminase inhibition on the clinical course of different diseases has been reported. However, the use of inhibitors is limited to only a few medical indications. Data on the increase of adenosine deaminase activity in different diseases and the impact of its inhibition in various cases have been collected and are discussed in this review. Overall, the evidence shows that many studies have been done to introduce inhibitors, however, in vivo studies have been much less than in vitro, and often have not been expanded for clinical use.

An efficient method for detecting damaged FAs; burnup and PPF estimations by gamma spectroscopy

The purpose of this study is to provide a quick and efficient experimental method to identify and find damaged fuel assemblies (FAs) among all assemblies of the core. This method is based on gamma spectroscopy by measuring the activity ratio of the desired fission fragments that leaked into the coolant. Using the ¹³⁴Cs/¹³⁷Cs activity ratio, and considering the history factor for each FA, we determine the fuel burnup. Furthermore, from the ¹³³I × ¹³⁵I /¹³³Xe activity ratio, the power peaking factor can be determined. This spectroscopy is carried out for the Tehran Research Reactor to find its failed FA positions. Then, the spectrum at different cooling times has been studied. Specifically, from the ¹³⁴Cs/¹³⁷Cs (0.1212 ± 0.003) activity ratio and the fuel history factor (2.1023), the fuel burnup of damaged fuel is anticipated to be 33.9%, and the result of the computational codes is found to be 33.1%; these two results are consistent with each other. The results of both experiment and code analysis show the relatively reasonable estimation of this method in finding the location of damaged FAs.

A computational continuum model of poroelastic beds

Despite the ubiquity of fluid flows interacting with porous and elastic materials, we lack a validated non-empirical macroscale method for characterizing the flow over and through a poroelastic medium. We propose a computational tool to describe such configurations by deriving and validating a continuum model for the poroelastic bed and its interface with the above free fluid. We show that, using stress continuity condition and slip velocity condition at the interface, the effective model captures the effects of small changes in the microstructure anisotropy correctly and predicts the overall behaviour in a physically consistent and controllable manner. Moreover, we show that the performance of the effective model is accurate by validating with fully microscopic resolved simulations. The proposed computational tool can be used in investigations in a wide range of fields, including mechanical engineering, bio-engineering and geophysics.

Transition delay using control theory

This review gives an account of recent research efforts to use feedback control for the delay of laminar-turbulent transition in wall-bounded shear flows. The emphasis is on reducing the growth of small-amplitude disturbances in the boundary layer using numerical simulations and a linear control approach. Starting with the application of classical control theory to two-dimensional perturbations developing in spatially invariant flows, flow control based on control theory has progressed towards more realistic three-dimensional, spatially inhomogeneous flow configurations with localized sensing/actuation. The development of low-dimensional models of the Navier-Stokes equations has played a key role in this progress. Moreover, shortcomings and future challenges, as well as recent experimental advances in this multi-disciplinary field, are discussed.

Neuroendocrinological effects of acupuncture treatment in patients with irritable bowel syndrome

OBJECTIVES

Quality of life (QoL) improvement in patients with irritable bowel syndrome (IBS) during acupuncture (AC) treatment seems to be due to a placebo effect. The aim was to explore if acupuncture has some specific influence on the neuroendocrinic and autonomic nervous system (ANS).

DESIGN/SETTING

Patients with IBS were randomly assigned to receive either acupuncture (AC) or sham acupuncture (SAC) using the so-called "Streitberger needle". QoL was measured with the functional quality of life diseases quality of life questionnaire (FDDQL) and SF-36. The effect on ANS was evaluated by measuring salivary cortisol and by cardiovascular responses on a tilt table before and after 10 AC treatments. Complete data sets of tilt table and salivary morning cortisol were available for 9 patients in the AC and 12 in SAC group.

RESULTS

QoL increased in both groups (p=0.001) with no group differences. Salivary cortisol decreased in all groups (F=10.55; p=0.006). However, the decrease was more pronounced in the AC group (F=4.07; p=0.033) (ANOVA repeated measures model). Heart rate response decreased during orthostatic stress in the AC group while it increased in the SAC group (F=9.234; p=0.005), indicating an increased parasympathetic tone in the AC group. Improvement of pain was positively associated with increased parasympathetic tone in the AC group (F=10.1; p=0.006), but not in the SAC group.

CONCLUSIONS

The acupuncture specific physiological effects are in contrast to the unspecific improvement of QoL in both AC and SAC groups. Thus, different mechanisms seem to be involved in placebo and real-acupuncture driven improvements. The specific mechanism of action of acupuncture on the ANS remains unclear and deserves further evaluation.

Acupuncture treatment in irritable bowel syndrome

BACKGROUND AND AIMS

Despite occasional positive reports on the efficacy of acupuncture (AC) on functions of the gastrointestinal tract, there is no conclusive evidence that AC is effective in the treatment of irritable bowel syndrome (IBS).

PATIENTS AND METHODS

Forty three patients with IBS according to the Rome II criteria were randomly assigned to receive either AC (n = 22) or sham acupuncture (SAC) (n = 21) using the so-called "Streitberger needle". Treatment duration was 10 sessions with an average of two AC sessions per week. The primary end point was improvement in quality of life (QOL) using the functional digestive diseases quality of life questionnaire (FDDQL) and a general quality of life questionnaire (SF-36), compared with baseline assessments. QOL measurements were repeated three months after treatment.

RESULTS

Both the AC and SAC groups improved significantly in global QOL, as assessed by the FDDQL, at the end of treatment (p = 0.022), with no differences between the groups. SF-36 was insensitive to these changes (except for pain). This effect was partially reversed three months later. Post hoc comparison of responders and non-responders in both groups combined revealed a significant prediction of the placebo response by two subscales of the FDDQL (sleep, coping) (F = 6.746, p = 0.003) in a stepwise regression model.

CONCLUSIONS

Acupuncture in IBS is primarily a placebo response. Based on the small differences found between the AC and SAC groups, a study including 566 patients would be necessary to prove the efficacy of AC over SAC. The placebo response may be predicted by high coping capacity and low sleep quality in individual patients.

Children with repaired bilateral cleft lip/palate: effect of age at premaxillary osteotomy on facial growth

This study compared facial growth in three groups of patients with bilateral complete cleft lip/palate: those who had (1) no premaxillary osteotomy, (2) premaxillary osteotomy before age 8 years, and (3) premaxillary osteotomy after age 8 years. Of 24 children with bilateral complete cleft lip/palate, 7 had early premaxillary osteotomy (mean age, 6.1; range, 3.7 to 7.6 years), 10 had late osteotomy (mean age, 11.2; range, 8.3 to 20.7 years), and 7 did not require premaxillary repositioning and served as controls (mean age, 12.4; range, 6.4 to 17.8 years). Presurgical and postsurgical lateral cephalograms were digitized using the Dentofacial Planner software; most current lateral cephalograms comprised the control group. Forty-one bony and 25 soft-tissue landmarks were digitized, and 8 angles were measured: SNA, (sella-nasion-A point), SNPg (sella-nasion-pogonion), ANB (A point-nasion-B point), NAPg (nasion-A point-pogonion), ST convexity (glabella-subnasale-soft-tissue pogonion), Sn-G vertical (line perpendicular to the horizontal plane dropped from glabella and distance measured from subnasale to this vertical), Cm-Sn-Ls (columella-subnasale-abial superioris), and Sn-Gn-C (subnasale-soft-tissue gnathion-chin point). Statistical difference in mean preoperative and postoperative values were measured with analysis of variance. Tests of significance were adjusted for multiple comparisons using the Bonferroni correction. Mean age at follow-up for early, late, and control groups was 11.8, 14.0, and 12.4 years, respectively. Mean follow-up for early and late groups was 5.7 and 2.8 years. There was a significant preoperative difference among the three groups for mean SNA (p < 0.01), ANB (p < 0.01), and NAPg (p < 0.01). Bonferroni analyses revealed that the early group had significantly greater SNA, ANB, and NAPg angles than the late (p < 0.01) and control groups (p < 0.05). There was a significant postoperative difference among groups for ANB (p < 0.05); Bonferroni analyses also showed that the control group had a significantly greater ANB than the late group (p < 0.05). The t test for equity of means established postoperative change for SNA (p < 0.01), ANB (p< 0.01), NAPg (p < 0.01), and ST convexity (p < 0.01) for the early group was significantly greater than for the late group. Children who required early premaxillary positioning had more significant preoperative deformity; however, this group's postoperative profile was not, on average, significantly different from either the late or control groups. Our findings that the early group had more significant change with premaxillary osteotomy than the late group suggest that premaxillary positioning can be done before completion of facial growth without compromise.

Effects of pancreastatin (24-49) on growth of normal pancreas and pancreatic cancer

In the present study, the effects of pancreastatin on growth are evaluated in two human pancreatic cancer cell lines, in vivo and in vitro, and on athymic nude mouse pancreas. SW-1990 and MIA PaCa-2 pancreatic cancer cell lines were grown in serum-supplemented and serum-free medium in the presence of pancreastatin (10(-11)-10(-6) M), or cholecystokinin (CCK) (10(-11)-10(-8) M) or combinations thereof. Growth was evaluated by [3H]thymidine incorporation and cell counts. Pancreastatin significantly inhibited DNA synthesis in both cell lines, and cell counts in SW-1990 on days 3 and 5 but not 7. CCK-stimulated cell growth was inhibited in both cell lines and mouse pancreas by pancreastatin. Pancreastatin had no effect in the presence of fetal bovine serum. In the in vivo experiments, pancreastatin (15 micrograms/kg) did not affect growth of SW-1990 xenografts to nude mice, but inhibited CCK-stimulated growth transiently. Pancreastatin (100 micrograms/kg) transiently decreased volumes of MIA PaCa-2 xenografts to nude mice and significantly decreased weight, protein, and DNA of mouse pancreas. Fasting glucose levels of mice treated with pancreastatin 100 micrograms/kg for 35 days were significantly lower than controls. Our results demonstrate that pancreastatin not only inhibits CCK-stimulated pancreatic growth but also has inhibitory effects by itself.

Cholecystokinin stimulates growth of human pancreatic adenocarcinoma SW-1990

The effect of a synthetic analogue of CCK (Thr4,Nle7CCK-9) on growth of SW-1990 human pancreatic cancer was examined in two experimental models. Nude mice bearing SW-1990 pancreatic cancer xenografts were injected with CCK (5, 15, or 25 micrograms/kg) or vehicle twice daily for 20 days. Animals were then sacrificed and tumor volume, weight, protein, and deoxyribonucleic acid (DNA) content were evaluated. SW-1990 cells were grown in vitro and the effects of CCK, secretin, vasoactive intestinal peptide (VIP), and proglumide (a CCK-receptor antagonist) on cell number and DNA synthesis were determined. The highest dose of CCK, 25 micrograms/kg, significantly increased tumor weight, protein content, and DNA content (P less than 0.005). In vitro, CCK caused significant increases in cell counts of up to 47% at six days and 66% at 12 days compared to control. Graded concentrations of CCK had a biphasic effect on DNA synthesis with significant increases of up to 65% (P less than 0.005). CCK-induced cell proliferation was inhibited by proglumide. Secretin slightly increased cancer cell growth, although not as potently as CCK, VIP or secretin in combination with CCK did not show potentiation. These results indicate that growth of some human pancreatic cancers may be influenced by gastrointestinal peptides, of which CCK is the most potent.

Effects of a high-fat diet and L364,718 on growth of human pancreas cancer

The effects of a high-fat diet and the CCK-receptor antagonist, L364,718, were examined on growth of human pancreas cell line SW-1990 xenografted to nude mice. Sixty animals were fed either low-fat (4.3%) or high-fat (20.25%) diet. Fifteen mice in each diet group were treated with L364,718 (2 mg/kg) subcutaneously twice daily for 23 days. On day 24 the animals were sacrificed. Tumor and animal pancreases were dissected and evaluated for weight, protein, and DNA content. When comparing within each diet group, L364,718 significantly decreased tumor volume, weight, protein, and DNA content compared to untreated mice (P less than 0.005). Tumor volume and protein content were significantly larger in untreated animals on the high-fat diet (P less than 0.05) compared to the low-fat diet. Mouse pancreatic weight, protein, and DNA content per kilogram of animal weight were all significantly lower (P less than 0.005) in mice on the low-fat diet treated with L364,718. Pancreatic DNA content was also decreased in both groups of animals on the high-fat diet compared to untreated mice on the low-fat diet. These findings suggest that diets high in unsaturated fat promote the growth of human pancreatic cancer. Since both tumor and pancreas growth are inhibited by the specific CCK-antagonist, L364,718, it is possible that endogenous CCK promotes the growth.

Effect of wheat bran and pectin on the absorption and retention of phosphorus, calcium, magnesium and zinc by the growing pig

Two separate balance experiments of P, Ca, Mg and Zn were carried out on 5 lots of 4 growing pigs each (35-40 kg) adapted for 3 weeks to one of the diets studied. In the first experiment, the control diet was compared with a diet containing 20% of coarse wheat bran, thus richer in minerals, the quantities ingested not being equalized. In the second experiment, three diets were compared: a control diet, a diet with 2.5% of high-methoxylated (HM) apple pectin, and a diet with 2.5% low-methoxylated (LM) apple pectin. The supplement of P and Mg provided by the wheat bran was well absorbed (apparent absorption) and retained by the pigs. On the contrary, in spite of higher intake of Ca and Zn with bran diet, the absorption of these minerals was not improved. The action of wheat bran phytase and the possible absorption of P and Mg (but not of Ca and Zn) in the large intestine could explain these results. Compared to HM pectin that had relatively little effect on mineral utilization, LM pectin drastically diminished the absorption and retention of the minerals studied and resulted in negative Ca, Mg and Zn balances. The degree of pectin esterification would thus be the main factor determining the effect of pectin on mineral availability. In conclusion, wheat bran is a source of available P and Mg for the pig but it might have an unfavorable effect on the utilization of Ca and Zn. LM pectin produces a deleterious influence on mineral balances.