Down-regulation of magnesium transporting molecule, claudin-16, as a possible cause of hypermagnesiuria with the development of tubulo-interstitial nephropathy.

Tubulo-interstitial nephropathy (TIN) is a critical pathological setting for the renal prognosis, and an increase in the urine magnesium excretion is a well-known characteristic feature as one of clinical parametets for the assessment of TIN. We examined the correlation between the development of TIN and the changes in the mRNA expression of renal magnesium-transporting molecules in rats with unilateral ureter obstruction (UUO). Ureter-ligated kidney was sampled at day-0 (control), day-1 (early phase) and day-7 (late phase). The development of TIN was assessed by immunohistochemistry and the real-time PCR of fibrosis-related genes (MCP-1: 105.1 ± 14.8% on day-0, 132.9 ± 25.7% on day-1, 302.7 ± 32.7% on day-7, TGF-ß: 101.1 ± 7.6% on day-0, 93.6 ± 4.1% on day-1, 338.9 ± 20.7% on day-7) . The respective expressions of claudin-10, 14, 16, 19, and transient receptor potential (TRP) M6 as magnesium-transporting molecules were also studied. The expression of calcium sensing receptor (CaSR) as an inhibitory regulator of claudin-14 was additionally studied. The gene expression of claudin-16 was decreased in the late phase of UUO (100.2 ± 2.9% at day-0, 90.3 ± 6.3% at day-1, 36.4 ± 1.6% at day-7) which was consistent with the increased urine magnesium excretion. Immunohistochemistry showed an apparent reduction of the immunoreactivity of claudin-16 in the late phase. The expression of TRPM6 was reduced even in the early phase. The immunohistochemistry and gene expression of MCP-1 and TGF-ß showed that TIN was not apparent in the early phase but was significant in the late phase of UUO. The density of peritubular capillaries was diminished in the late phase but not in the early phase. Expression of claudin-14 and CaSR was up- and down-regulated, respectively. Our findings may indicate that the characteristic hypermagnesiuria in TIN is principally caused by the dysfunction of magnesium reabsorption in the thick ascending limb of Henle resulting from a significant decrease in the claudin-16 expression. The down-regulation might be closely related to the development of TIN.

Our Approaches to Selective Plasma Exchange.

Plasma exchange (PE) therapy is the most commonly used treatment in Japan today. The issue with PE is that it removes coagulation factors and other essential molecules during the treatment process. Fresh frozen plasma (FFP) is used to replace the essential molecules which are lost. However, FFP can be a source of various complications. We have been researching an alternative method, selective PE, consisting of a membrane with smaller pores, which prevents large and essential molecules from being removed while removing waste from the patient's blood.

Evaluation of the functions of the temporary catheter with various tip types.

INTRODUCTION: A temporary catheter (TC) is used short-term and for emergencies. There are some cases when we cannot withdraw blood immediately after inserting the catheter in our patients. The reason is said to be the tips of the TC sticking to the vascular walls. OBJECTIVE: We evaluated examined 3 catheters with different tip shapes in a simulation circuit to assess the effect on the blood flow. METHODS: Water was circulated in the simulation circuit at 1 L/minute. Next, we inserted each TC into the model, and the TCs were connected to the dialysis circuit at 200 mL/minute. We put gold powder into the simulation circuit. We visually observed the movement of the gold power at the head of the catheter and measured the recirculation rate. RESULT: The uplift type TC was able to perform blood removal and reinfusion with the least difficulties. All recirculation rates were less than 1%. The hindrance caused by hitting a vascular wall is believed to have been reduced. CONCLUSION: With the manipulation of the catheter tip shapes, blood was able to circulate smoothly. We expect less blood clots and a decrease in sticking to the vascular wall. We plan to study these 3 catheters at clinical tests in the future.

Severe hyponatremia in a patient with schizophrenia associated with prolonged consciousness disturbance.

Hyponatremia presents with various central nervous system symptoms during its course and treatment. We treated a patient who presented with a prolonged consciousness disorder and was suspected of having complications of neuroleptic malignant syndrome and osmotic demyelination syndrome (ODS) during the treatment for his hyponatremia, which was caused by syndrome of inappropriate secretion of antidiuretic hormone (SIADH). The patient was a 30-year-old Japanese man who had been under treatment for schizophrenia. He presented with profound hyponatremia (96 mEq/L) and a consciousness disorder. Because he was taking a number of antipsychotic drugs and since psychogenic polydipsia was present along with laboratory findings, the patient was diagnosed with SIADH. However, the consciousness disorder reappeared after his serum sodium concentrations were normalized, and it persisted over a long period. Although ODS was suspected from the clinical course and imaging findings, there were several inconsistencies, such as the lack of quadriplegia. The patient also showed muscular rigidity and fever, and we, therefore, diagnosed complications of malignant hyperthermia syndrome caused by the discontinuation of all antipsychotic drugs at the time of onset. There have been no reports of complications of these two conditions, and we report this case for its clinically valuable information.

How to monitor vascular access in our hospital.

BACKGROUND: The number of dialysis patients in Japan has amounted to approximately 310,000. Most of the patients undergo hemodialysis. The reason why they can undergo hemodialysis is because maintaining and managing vascular access (VA) has improved. Recently, thanks to the progress of medical equipment, a variety of monitoring systems have been developed. It is important to make good use of these monitoring systems. RESULTS: In our hospital, we have been monitoring with an ultrasonic device and HD02. We measure blood flow of brachial artery with an ultrasonic device during nondialysis treatment. We examine real blood flow and blood recirculation with HD02 and evaluate the function of VA during dialysis. CONCLUSIONS: In order to provide good dialysis care, good use of monitoring devices of VA is significant.