Psychiatric assessment of suicide attempters in Japan: a pilot study at a critical emergency unit in an urban area

<p>Abstract</p> <p>Background</p> <p>The incidence of suicide has increased markedly in Japan since 1998. As psychological autopsy is not generally accepted in Japan, surveys of suicide attempts, an established risk factor of suicide, are highly regarded. We have carried out this study to gain insight into the psychiatric aspects of those attempting suicide in Japan.</p> <p>Methods</p> <p>Three hundred and twenty consecutive cases of attempted suicide who were admitted to an urban emergency department were interviewed, with the focus on psychosocial background and DSM-IV diagnosis. Moreover, they were divided into two groups according to the method of attempted suicide in terms of lethality, and the two groups were compared.</p> <p>Results</p> <p>Ninety-five percent of patients received a psychiatric diagnosis: 81% of subjects met the criteria for an axis I disorder. The most frequent diagnosis was mood disorder. The mean age was higher and living alone more common in the high-lethality group. Middle-aged men tended to have a higher prevalence of mood disorders.</p> <p>Conclusion</p> <p>This is the first large-scale study of cases of attempted suicide since the dramatic increase in suicides began in Japan. The identification and introduction of treatments for psychiatric disorders at emergency departments has been indicated to be important in suicide prevention.</p

Magnesium homeostasis in cardiac myocytes of Mg-deficient rats.

To study possible modulation of Mg(2+) transport in low Mg(2+) conditions, we fed either a Mg-deficient diet or a Mg-containing diet (control) to Wistar rats for 1-6 weeks. Total Mg concentrations in serum and cardiac ventricular tissues were measured by atomic absorption spectroscopy. Intracellular free Mg(2+) concentration ([Mg(2+)]i) of ventricular myocytes was measured with the fluorescent indicator furaptra. Mg(2+) transport rates, rates of Mg(2+) influx and Mg(2+) efflux, were estimated from the rates of change in [Mg(2+)]i during Mg loading/depletion and recovery procedures. In Mg-deficient rats, the serum total Mg concentration (0.29±0.026 mM) was significantly lower than in control rats (0.86±0.072 mM) after 4-6 weeks of Mg deficiency. However, neither total Mg concentration in ventricular tissues nor [Mg(2+)]i of ventricular myocytes was significantly different between Mg-deficient rats and control rats. The rates of Mg(2+) influx and efflux were not significantly different in both groups. In addition, quantitative RT-PCR revealed that Mg deficiency did not substantially change mRNA expression levels of known Mg(2+) channels/transporters (TRPM6, TRPM7, MagT1, SLC41A1 and ACDP2) in heart and kidney tissues. These results suggest that [Mg(2+)]i as well as the total Mg content of cardiac myocytes, was well maintained even under chronic hypomagnesemia without persistent modulation in function and expression of major Mg(2+) channels/transporters in the heart

Body weight and serum Mg concentration during Mg-deficiency.

<p>Rats (8 weeks old) were divided into two groups and fed either a control diet or a Mg-deficient diet for 1 to 6 weeks. Body weight (A) and total concentrations of serum Mg (B) were plotted as a function of time after either the control diet (filled circles) or the Mg-deficient diet (open circles) was started at time 0. For serum Mg, the small number of data obtained from 4-week-old rats (at the beginning of feeding) was also included, because the serum Mg concentration was similar between the 8-week-old and 4-week-old rats in the pilot experiments. Each symbol represents mean±SEM of the number of rats indicated nearby. For both A and B, the average values of Mg-deficient rats were significantly different from those of control rats (p<0.01, 2-way ANOVA).</p

The increase in [Mg²⁺]_i by Mg²⁺-loading.

<p>Measurements of [Mg²⁺]_i from the cells isolated from control (A) or Mg-deficient (B) rats. The incubation solution of the cells was initially Ca²⁺-free Tyrode’s solution, and was switched to the Mg²⁺-loading solution at time 0 on the abscissa. Each symbol represents mean±SEM from 22 cells for (A) and 21 cells for (B).</p

Measurements of extracellular Na⁺-dependent Mg²⁺ efflux.

<p>Cells isolated from control (A) or Mg-deficient (B) rats were initially incubated in Mg-loading solution that contained 1.6 mM Na⁺ and 24 mM Mg²⁺ (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073171#pone-0073171-t001" target="_blank">Table 1</a>) for 3 h to load the cells with Mg²⁺. Then Ca²⁺-free Tyrode’s solution that contained 140 mM Na⁺ and 1 mM Mg²⁺ was introduced, as shown at the top. For each data set, a solid line was drawn by the linear least-squares fit to data points between 30 s and 150 s after solution exchange, and the initial rate of change in [Mg²⁺]_i estimated from the slope is indicated near the trace.</p

Summary of results obtained from single ventricular myocytes.

<p>Rats (8 weeks old) were fed the control diet or the Mg-deficient diet for 4–6 weeks, and [Mg²⁺]_i was measured with the fluorescent indicator furaptra in the myocytes isolated from control rats (Control) and Mg-deficient rats (Mg-deficient). Each data represents mean ± SEM from the number of cells indicated in parentheses. The basal level of [Mg²⁺]_i was measured either at 1 mM [Mg²⁺]_o (i.e., Ca²⁺-free Tyrode’s solution) or at 0.2 mM [Mg²⁺]_o (Mg²⁺ concentration of Ca²⁺-free Tyrode’s solution was reduced to 0.2 mM). Mg²⁺ influx rates were estimated by two different methods: the rates of Mg²⁺ loading (as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073171#pone-0073171-g003" target="_blank">Fig. 3</a>) and the rates of Mg²⁺ recovery after depletion (as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073171#pone-0073171-g001" target="_blank">Fig. 1</a>). The Mg²⁺ efflux rate was estimated from the initial rate of decrease in [Mg²⁺]_i in the Mg²⁺-loaded cells as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073171#pone-0073171-g004" target="_blank">Fig. 4</a>. There was no significant difference between values obtained from control rats and those obtained from Mg-deficient rats.</p

Major constituents of the bathing solutions.

<p>Ms, methanesulfonate; NMDG, n-methyl-D-glutamine. All solutions contained 0.1 mM K₂EGTA, 0.33 mM NaH₂PO₄ and 10 mM HEPES, and were essentially free of Ca²⁺, and had osmolality of ∼290 mOsm/kg H₂O. The pH of the solutions was adjusted to 7.40 with NaOH (for Ca²⁺-free Tyrode’s solution), with NaOH plus HCl (for Mg-loading solution), with KOH (for Mg-depleting solution) or HCl (for Mg-free NMDG solution). Final concentrations of Mg²⁺, Na⁺ and K⁺ are shown in the rightmost three columns.</p

Total mineral concentrations in serum and ventricular tissues.

<p>Rats (8 weeks old) were fed the control diet (Control) or the Mg-deficient diet (Mg-deficient) for 4–6 weeks, and total mineral concentrations were measured by AAS. Each data represents mean±SEM from the number of rats indicated in parentheses.</p>**<p>p<0.01 (vs. control).</p

Observation of Mg²⁺ influx in the cells depleted of Mg²⁺.

<p>(A) Experimental protocol for depletion and recovery of Mg²⁺. A cell was depleted of Mg²⁺ by incubation in the Mg²⁺-depletion solution at 35°C for 20 min. During this period, [Mg²⁺]_i decreased from the basal level (∼0.9 mM) to the lower levels of 0.2–0.5 mM (open circles and dotted lines). Subsequent application of Ca²⁺-free Tyrode’s solution that contained 1 mM Mg²⁺ (25°C) caused a recovery of [Mg²⁺]_i towards the basal level (filled circles). The course of the recovery was well fitted by a single exponential function, as indicated by the continuous line. (B) Examples of two experimental runs showing Mg²⁺ influx in the Mg²⁺-depleted cells isolated from a control rat (filled circles) or a Mg-deficient rat (open circles). For filled circles and open circles, sets of values between 0 and 180 min were least-squares fitted by the exponential function (continuous lines: black for filled circles, red for open circles)</p