Severe hyponatremia and diabetes insipidus caused by low-dose cyclophosphamide in breast cancer patients: A case report and literature review.

RATIONALE: Cyclophosphamide (CTX) is widely used in the treatment of malignancies and autoimmune diseases. Although severe hyponatremia caused by low-dose CTX chemotherapy is uncommon, it can lead to serious complications and even death. PATIENT CONCERNS: A 44-year-old woman with left-sided breast cancer suddenly experienced headaches, disorientation and weakness after receiving low-dose neoadjuvant chemotherapy combined with CTX and doxorubicin. DIAGNOSES: The patient pathology showed invasive breast carcinoma. She developed severe hyponatremia and a generalized seizure after completing the first cycle of neoadjuvant chemotherapy with CTX and doxorubicin. Laboratory tests showed a serum sodium of 118 mmol/L (normal range 135-145 mmol/L) and potassium sodium 3.16 mmol/L (normal range 3.5-5.5 mmol/L). Subsequently, the patient developed secondary diabetes insipidus 4 hours after sodium supplementation, her 24-hour urine volume was 4730 mL (normal range 1000-2000 mL/24 hours), and the urine specific gravity decreased to 1.005. INTERVENTIONS: The patient was given intravenous sodium chloride (500 mL of 3%NaCl, 100 mL/hour) and potassium chloride (500 mL of 0.3%KCl, 250 mL/hour). Meanwhile, she was advised to reduce her water intake, and pituitrin was administered to prevent dehydration caused by diabetes insipidus. OUTCOMES: The patient completely recovered after correcting of the serum sodium concentration (137 mmol/L) without any neurological deficits. After discontinuing pituitrin, her 24-hour urine volume was 2060 mL and the urine specific gravity was 1.015. LESSONS: This is a typical case of severe hyponatremia induced by low-dose CTX. Clinicians and healthcare providers should be aware of this potential toxicity, and appropriate monitoring should be implemented.

Adsorption isotherm, kinetics simulation and breakthrough analysis of 5-hydroxymethylfurfural adsorption/desorption behavior of a novel polar-modified post-cross-linked poly (divinylbenzene-co-ethyleneglycoldimethacrylate) resin.

A polar modified post-cross-linked poly (divinylbenzene-co-ethyleneglycol-dimethacrylate) (PCL-PDE) resin was synthesized by suspension polymerization of ethylene glycol dimethacrylate (EGDMA) and divinylbenzene (DVB), and a post-cross-linked reaction. After characterization, the adsorption behaviors of 5-hydroxymethylfurfural (5-HMF) on PCL-PDE resin were determined in comparison with the starting copolymers PDE resin. The equilibrium adsorption capacity of 5-HMF on PCL-PDE resin was much larger than PDE resin and the increase rate was greater than 52.6%. The equilibrium data of 5-HMF onto PCL-PDE resin were found to be better fitted by the Langmuir isotherm model. The kinetic data shows that the adsorption reached equilibrium in a short time (less than 20 min) can be fitted by the pore diffusion model (PDM) at various operating conditions. The effective pore diffusion coefficient was dependent upon adsorption temperature, and were 6.706 × 10-10, 8.958 × 10-10, 1.136 × 10-9 and 1.429 × 10-9 m2 s-1 at 288, 298, 308 and 318 K, respectively. Furthermore, the effects of feed flow rate (Qf = 0.6, 1.5, 3.0 and 6.0 mL min-1) and initial 5-HMF concentration (cf = 0.52, 1.02, 2.00 and 4.96 g L-1) on the adsorption were investigated systematically. Besides, a general rate model (GRM) was used to predict adsorption breakthrough curves of 5-HMF. The simulation results are highly consistent with the experimental data, indicating that the GRM can successfully simulate this process. In the desorption process, the desorption capacity reaches 99.6% of adsorbed capacity, suggesting that the PCL-PDE resin exhibited good reusability. Therefore, it could be suggested that the PCL-PDE resin has a potential application in the separation and purification of 5-HMF.

H2S inhibition of chemical hypoxia-induced proliferation of HPASMCs is mediated by the upregulation of COX-2/PGI2.

The hypoxia-induced proliferation of pulmonary artery smooth muscle cells (PASMCs) is the main cause of pulmonary arterial hypertension (PAH), in which oxidative stress, cyclooxygenase (COX)-2 and hydrogen sulfide (H(2)S) all play an important role. In the present study, we aimed to examine the effects of H(2)S on the hypoxia-induced proliferation of human PASMCs (HPASMCs) and to elucidate the underlying mechanisms. The HPASMCs were treated with cobalt chloride (CoCl(2)), a hypoxia-mimicking agent, to establish a cellular model of hypoxic PAH. Prior to treatment with CoCl(2), the cells were pre-conditioned with sodium hydrosulfide (NaHS), a donor of H(2)S. Cell proliferation, reactive oxygen species (ROS) production, COX-2 expression, prostacyclin (also known as prostaglandin I2 or PGI(2)) secretion and H(2)S levels were detected in the cells. The exposure of the HPASMCs to CoCl(2) markedly increased cell proliferation, accompanied by a decrease in COX-2 expression, PGI(2) secretion and H(2)S levels; however, the levels of ROS were not altered. Although the exogenous ROS donor, H(2)O(2), triggered similar degrees of proliferation to CoCl(2), the ROS scavenger, N-acetyl-L-cysteine (NAC), markedly abolished the H(2)O(2)­induced cell proliferation, as opposed to the CoCl(2)-induced proliferation. The CoCl(2)-induced proliferation of HPASMCs was suppressed by exogenously applied PGI(2). The addition of H(2)S (NaHS) attenuated the CoCl(2)-induced cell proliferation through the increase in the intercellular content of H(2)S. Importantly, the exposure of the cells to H(2)S suppressed the CoCl(2)-induced downregulation in COX-2 expression and PGI(2) secretion from the HPASMCs. In conclusion, the results from the current study suggest that H(2)S enhances hypoxia-induced cell proliferation through the upregulation of COX-2/PGI(2), as opposed to ROS.