Resistance against the development of diethylnitrosamine-induced hepatocellular carcinoma in female C3H mice: an experimental model.

Histopathological features of hepatocellular carcinoma (HCC) induced by diethylnitrosamine (DEN) in mice display strong similarities with those seen in humans, including the higher tumor prevalence in males than in females. Previous studies have demonstrated that continual production of the pro-inflammatory IL-6 by Kupffer cells is involved in the initiation and progression of DEN-induced HCC and that estrogen-mediated reduction of IL-6 secretion would decrease its incidence in females. Given the predominant utilization of male mice in hepatic carcinogenesis research, the objective of this study was to examine histopathological and immunological parameters in the DEN-induced liver carcinogenesis model in female C3H mice. We observed a significant prevalence of hepatocellular hyperplasias and adenomas alongside a minimal infiltration of inflammatory cells and a scarcity of senescent areas in females. Further, a low expression of immunosuppression markers is observed in females - such as neutrophil/lymphocyte ratio, PD-1 expression in CD8 T cells, and PD-L1 in myeloid cells - compared to males. Comparative studies between susceptible and resistant hosts to chemical carcinogenesis may help to unveil novel therapeutic strategies against cancer.

Addison disease and normocalcemic primary hyperparathyroidism in a dog with multiple endocrine neoplasia.

A 12-year old dog with a 9-year history of primary adrenal insufficiency was referred to the service for hyporexia, muscle weakness, polyuria and polydipsia. Ultrasound examination showed an unresectable mass in the left adrenal gland, with local vascular invasion, which prompted the euthanasia of the animal. Additionally, necropsy revealed a nodular lesion in the right adrenal gland and enlargement of one of the four parathyroid glands. Parathyroid hormone levels were elevated, but ionized and total calcium levels were normal. Histopathology supported the diagnosis of parathyroid chief cell adenoma and bilateral pheochromocytoma. Immunohistochemical staining was positive for synaptophysin, and negative for Melan-A and calretinin, which confirmed the diagnosis of pheochromocytoma. This case highlights an unusual presentation of multiple endocrine neoplasias within the context of primary adrenal insufficiency and normocalcemic primary hyperparathyroidism.

Differences in the contractile properties of the knee extensor and flexor muscles in professional road cyclists during the season.

The purpose of this study was to establish reference values of tensiomyography (TMG) in professional road cyclists and to examine how the planned periods of the Season produce differences in the muscles: vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF), and biceps femoris (BF), and to determine how these differences may depend on each cyclist, the assessed muscle, and the side of the body. Ten professional road cyclists (27.5 ± 5.5 years; 178.2 ± 7.8 cm; 65.6 ± 5.46 kg; 72.1 ± 3.7 ml·kg·min V[Combining Dot Above]O2; 6 ± 0.4 W·kg) were assessed by TMG, in microcycle recovery, at 2 moments of periods during the season: preparation period (PP) and competition period (CP). Student's t contrast for paired groups, Cohen's d effect sizes, and a repeated measures analysis of variance (ANOVA) was applied. We did not find significant differences (p < 0.01) between the lower limbs. The results showed a significantly large increment between the time contraction (TC) values of the PP and CP in the muscles VM (28.7 ± 5.5 vs. 40.6 ± 14.4 milliseconds; 41.4%, p < 0.05, d = 1.1), VL (28.3 ± 4.9 vs. 40.6 ± 10.2 milliseconds; 43.4%, p < 0.05, d = 1.53), and RF (35.9 ± 6.9 vs. 45.9 ± 16.2 milliseconds; 27.8%, p < 0.05, d = 0.8). Nevertheless, TC of the BF presents a significantly large decrease in the CP (35.9 ± 9.9 vs. 28.2 ± 5.2 milliseconds; -21.4%, p < 0.05, d = 0.97). Radial muscle displacement (DM) values are slightly lower during the CP, but the difference is not significant. ANOVA confirmed that these differences depend on the evaluated muscles (TC p = 0.02; DM p = 0.001) and on the cyclists (TC p = 0.001; DM p = 0.001) and does not depend on the side of the body. In conclusion, the TC values during the Season show marked differences between the knee extensors (large increased) and the knee flexor (large decreased). The DM has not changed significantly, keeping the muscular and tendon stiffness.