Distribution of glucose-6-phosphatase activity in normal, hyperplastic, and preneoplastic rat liver

Neoadjuvant chemoradiation for non-metastatic pancreatic cancer increases margin-negative and node-negative rates at resection

OBJECTIVE

To compare neoadjuvant to adjuvant chemoradiation in non-metastatic pancreatic cancer patients.

METHODS

Single-institution data were obtained for patients with non-metastatic pancreatic cancer treated with concurrent chemoradiation from 2011 to 2014. Univariate analyses were performed to evaluate clinical and pathological outcomes.

RESULTS

Fifty-two well-matched patients were enrolled (21 underwent neoadjuvant chemoradiation, 11 with adjuvant chemoradiation and 20 in the definitive group). Median tumor size was 2.6 cm pretreatment and 2.5 cm after neoadjuvant chemoradiation but 3.2 cm on pathology, with a treatment effect in 95.2% of specimens. Clinical node positivity at diagnosis for neoadjuvant and adjuvant chemoradiation groups was similar (28.6% vs 27.3%, P = 0.12). Of the 36 neoadjuvant patients, 21 (58.3%) underwent complete resection. In the neoadjuvant vs adjuvant chemoradiation groups, positive margins were decreased (4.8% vs 63.6%, P < 0.001), as was pathological nodal positivity (23.8% vs 90.9%, P < 0.001). After a median follow-up of 13.3 months, locoregional control for neoadjuvant and adjuvant chemoradiation was 7.7 and 7.2 months, respectively (P = 0.12) and the definitive group was 1.2 months (P = 0.014 compared with the surgical cohort). One-year overall survival was better with neoadjuvant than with adjuvant chemoradiation but this was not significant (94% vs 82%, P = 0.20); 1-year survival for the definitive group was 59% (P = 0.03 compared with the surgical cohort).

CONCLUSIONS

Neoadjuvant chemoradiation remains a promising approach for non-metastatic pancreatic cancer for improving resectability and pathological and clinical findings. Computed tomography may not fully demonstrate the effectiveness of neoadjuvant treatment.

Integrative toxicopathological evaluation of aflatoxin B₁ exposure in F344 rats

In this study, male F344 rats were orally exposed to a single dose of aflatoxin B₁ (AFB₁) at 0, 50, 250, or 1,000 µg/kg body weight (BW) or repeated dose of 0, 5, 10, 25, or 75 µg/kg BW for up to 5 weeks. Biochemical and histological changes were assessed together with the formation of AFB1-lysine adduct (AFB-Lys) and liver foci positive for placental form glutathione S transferase (GST-P⁺). In single-dose protocol, serum aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP) showed dose-related elevation, with maximal changes observed (>100-fold) at day 3 after treatment. Animals that received 250 µg/kg AFB₁ showed concurrent bile duct proliferation, necrosis, and GST-P⁺ hepatocytes at 3 day, followed by liver GST-P⁺ foci appearance at 1 week. In repeated-dose protocol, bile duct proliferation and liver GST-P⁺ foci co-occurred after 3-week exposure to 75 µg/kg AFB₁, followed by proliferation foci formation after 4 week and dramatic ALT, AST, and CK elevations after 5 weeks. Liver GST-P⁺ foci were induced temporally and in a dose-related manner. Serum AFB-Lys increased temporally at low doses (5-25 µg/kg), and reached the maximum after 2-week exposure at 75 µg/kg. This integrative study demonstrated that liver GST-P⁺ cells and foci are sensitive biomarkers for AFB₁ toxic effect and correlated with bile duct proliferation and biochemical alterations in F344 rats.

Glucose-6-phosphatase and age: biochemical and histochemical studies

Glucose-6-phosphatase catalyzes the final reactions in both gluconeogenesis and glycolysis. It occurs mainly in glycogenic tissues, such as the liver, where it plays an important role in the synthesis of glucose, a carbohydrate essential for tissue functioning. The effect of age on liver glucose-6-phosphatase activity was evaluated in male Wistar rats treated with mixed function oxidase system (MFO) inducers. The rats were divided into the following age groups: 0.5, 1, 2, 4, 8, 12, 20 and 28 months of age. Glucose-6-phosphatase activity was evaluated biochemically and histochemically. Biochemical glucose-6-phosphatase activity increased up to the 20th month of rat life and then decreased rapidly. A similar tendency was observed in inducer-treated groups, though only dexamethasone stimulated this enzyme activity in all age groups studied. Histochemical glucose-6-phosphatase activity was strongest in the periportal zones. Glucose-6-phosphatase activity decreased significantly at month 8 and then it increased significantly until month 20. In the oldest age group, glucose-6-phosphatase activity decreased again. On histochemical analysis, the inducers used variably affected glucose-6-phosphatase activity.

Recent advances in the isolation of liver cells

The development of new and refined separation techniques--including FACS, FFE, CFE and isopyknic gradients--has had a profound impact on the ability of investigators to isolate specific cell types from the liver. Although some of these techniques, such as FFE, may be of limited preparative value, they are nonetheless important analytical tools that detect subtle differences among cell subpopulations. The isolation of highly purified preparations of liver cells in large yields requires the use of more conventional purification methods such as CFE and isopyknic centrifugation. Immunological approaches represent a key development for the isolation of specific liver cell types, especially when they are used in combination with other techniques. Excellent, reliable and relatively simple techniques now exist to isolate highly purified preparations of hepatocytes, cholangiocytes, KCs, SCs, FSC, myofibroblasts and pit cells. Additional work is necessary to refine techniques for the isolation of dendritic cells and lymphocytes.