Hyponatremia and antidiuresis syndrome

Antidiuretic hormone (ADH), or arginine vasopressin (AVP), is primarily regulated through plasma osmolarity, as well as non-osmotic stimuli including blood volume and stress. Links between water-electrolyte and carbohydrate metabolism have also been recently demonstrated. AVP acts via the intermediary of three types of receptors: V1a, or V1, which exerts vasoconstrictive effects; pituitary gland V1b, or V3, which participates in the secretion of ACTH; and renal V2, which reduces the excretion of pure water by combining with water channels (aquaporin 2). Antidiuresis syndrome is a form of euvolaemic, hypoosmolar hyponatraemia, which is characterised by a negative free water clearance with inappropriate urine osmolality and intracellular hyper-hydration in the absence of renal, adrenal and thyroid insufficiency. Ninety percent of cases of antidiuresis syndrome occur in association with hypersecretion of vasopressin, while vasopressin is undetectable in 10% of cases. Thus the term “antidiuresis syndrome” is more appropriate than the classic name “syndrome of inappropriate ADH secretion” (SIADH). The clinical symptoms, morbidity and mortality of hyponatraemia are related to its severity, as well as to the rapidity of its onset and duration. Even in cases of moderate hyponatraemia that are considered asymptomatic, there is a very high risk of falls due to gait and attention disorders, as well as rhabdomyolysis, which increases the fracture risk. The aetiological diagnosis of hyponatraemia is based on the analysis of calculated or measured plasma osmolality (POsm), as well as blood volume (skin tenting of dehydration, oedema). Hyperglycaemia and hypertriglyceridaemia lead to hyper- and normoosmolar hyponatraemia, respectively. Salt loss of gastrointestinal, renal, cutaneous and sometimes cerebral origin is hypovolaemic, hypoosmolar hyponatraemia (skin tenting), whereas oedema is present with hypervolaemic, hypoosmolar hyponatraemia of heart failure, nephrotic syndrome and cirrhosis. Some endocrinopathies (glucocorticoid deficiency and hypothyroidism) are associated with euvolaemic, hypoosmolar hyponatraemia, which must be distinguished from SIADH. Independent of adrenal insufficiency, isolated hypoaldosteronism can also be accompanied by hypersecretion of vasopressin secondary to hypovolaemia, which responds to mineralocorticoid administration. The causes of SIADH are classic: neoplastic (notably small-cell lung cancer), iatrogenic (particularly psychoactive drugs, chemotherapy), lung and cerebral. Some causes have been recently described: familial hyponatraemia via X-linked recessive disease caused by an activating mutation of the vasopressin 2 receptor; and corticotropin insufficiency related to drug interference between some inhaled glucocorticoids and cytochrome p450 inhibitors, such as the antiretroviral drugs and itraconazole, etc. SIADH in marathon runners exposes them to a risk of hypotonic encephalopathy with fatal cerebral oedema. SIADH treatment is based on water restriction and demeclocycline. V2 receptor antagonists are still not marketed in France. These aquaretics seem effective clinically and biologically, without demonstrated improvement to date of mortality in eu- and hypervolaemic hyponatraemia. Obviously treatment of a corticotropic deficit, even subtle, should not be overlooked, as well as the introduction of fludrocortisone in isolated hypoaldosteronism and discontinuation of iatrogenic drugs.     

Inhibitory effects of 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside on experimental inflammation and cyclooxygenase 2 activity

The inhibitory effects of 2,3,5,4'-tetrahydroxystilbene-2-O-beta-d-glucoside (THSG), extracted from the roots of Polygonum multiflorum Thunb, on inflammatory activity in animal models and cyclooxygenase-2 (COX-2) activity in lipopolysaccharide (LPS)-induced mouse RAW264.7 macrophage cells were investigated. The carrageenin (CGN)-induced rat paw oedema model and dimethylbenzene-induced mouse ear oedema model were prepared; MTT assay, semi-quantitative RT-PCR, Western blot and ELISA were adopted. THSG 2.3, 4.6 and 9.2 mg kg(- 1) by oral administration inhibited mouse ear oedema and the percentage of inhibition of THSG 9.2 mg kg(- 1) is 87%. THSG 3.2, 6.4 and 12.8 mg kg(- 1) by oral administration dose-dependently inhibited rat paw oedema and the percentage of inhibition of THSG 12.8 mg kg(- 1) is 56% at 6 h. Indomethacin 13 and 9 mg kg(- 1) showed 90% and 57% inhibition in the same animal models, respectively. LPS 1 microg ml(- 1) significantly up-regulated prostaglandin E(2) (PGE(2)) production (inducing COX-2 activity) by 35% (exogenous arachidonic acid, AA), which was dose-dependently decreased by THSG 1, 10, and 100 micromol L(- 1) and the percentage of inhibition of THSG 10 micromol L(- 1) was 40%. NS-398 10 micromol L(- 1) decreased PGE(2) production by 42%. THSG 1, 10, 100 micromol L(- 1) was shown to markedly inhibit the LPS-induced COX-2 protein and mRNA expression in RAW264.7 cells (P < 0.05) but had no effect on COX-1 protein and mRNA (P>0.05). In summary, the data showed that THSG possessed an anti-inflammatory effect, which was perhaps related to the inhibition of COX-2 enzyme activity and expression in RAW264.7 macrophage cells.     

New tetraterpenoid from the soft coral Sarcophyton tortuosum

A novel tetraterpenoid named methyl tortuoate C (1) has been isolated from the soft coral Sarcophyton tortuosum Tix.-Dur. The structure of 1 was determined on the basis of spectroscopic methods.     

Disease progression in Chinese chronic hepatitis C patients with persistently normal alanine aminotransaminase levels

BACKGROUND: Although chronic hepatitis C virus-infected patients with persistently normal alanine aminotransaminase levels usually have mild liver disease, disease progression can still occur. However, it is uncertain which group of patients is at risk of disease progression. AIM: To examine the severity of liver disease on liver biopsy in Chinese patients with persistently normal alanine aminotransaminase levels, and their disease progression over time. METHODS: Eighty-two patients with persistently normal alanine aminotransaminase levels were followed up longitudinally. The median time of follow-up was 8.1 years. Forty-seven of the 82 patients (57.3%) had a second liver biopsy. RESULTS: At the time of analysis, six of the 82 patients (7.3%) developed decompensated liver cirrhosis. Patients with an initial fibrosis stage F2 or F3 [6/23 (26.1%) vs. 0/59 (0%), P < 0.0001] or inflammatory grade A2 or A3 [5/40 (12.5%) vs. 1/42 (2.4%), P = 0.04] were more likely to develop decompensated liver cirrhosis. On multivariate analysis, initial fibrosis stage F2 or F3 was independently associated with progression to decompensated liver cirrhosis (relative risk 2.3, 95% confidence interval 0.03-2.5, P = 0.02). CONCLUSION: Chinese chronic hepatitis C virus patients with persistently normal alanine aminotransaminase levels with moderate to severe fibrosis at initial evaluation are more likely to develop decompensated liver cirrhosis.     

Expression level of lipoprotein lipase in Chinese patients with chronic lymphocytic leukemia and its correlation with other prognostic factors

Chronic lymphocytic leukemia (CLL) is the most common adult form of leukemia in the Western world, however, infrequent in the Eastern. It shows a remarkable heterogeneity, with some patients having an almost normal lifespan, others surviving only several years after diagnosis despite intensive therapy. To investigate lipoprotein lipase (LPL) expression level in Chinese patients with CLL and its correlation with other prognostic factors, including immunoglobulin heavy-chain variable region (IgVH) mutation status, Binet stages, ZAP-70 protein and CD38 expression level, semiquantitative RT-PCR was used to detect LPL expression in peripheral blood samples of 58 Chinese patients with CLL. LPL expression level was significantly correlated with IgVH mutational status (r = 0.348, P = 0.010), Binet stages (r = 0.276, P = 0.036), ZAP-70 protein (r = 0.431, P = 0.001) and CD38 (r = 0.546, P < 0.001). Patients with unmutated IgVH genes had higher expression of LPL than patients with IgVH mutations. The higher expression level of LPL was also associated with higher level of ZAP-70 and CD38, and more aggressive Binet stage. We also analyzed LPL expression in different cytogenetic subgroups. Higher LPL level was found in patients with unfavorable cytogenetic aberrations (deletion in 17p13 or 11q22) in contrast to lower level in good risk cytogenetics (deletion in 13q as the sole abnormality) (r = 0.404, P = 0.002). It was showed that LPL expression correlates with IgVH mutational status and other clinical or laboratory prognostic factors, and might be applied for the assessment of prognosis in patients with CLL.