Fatal Hypermagnesemia in Patients Taking Magnesium Hydroxide.

Hypermagnesemia is a rare but potentially fatal electrolyte disorder often overlooked because of its unfamiliarity. Magnesium is regulated through a balance of bone, intestinal absorption, and renal excretion. Hypermagnesemia typically arises from excessive magnesium intake or reduced renal excretion; however, it also occurs in patients with normal kidney function. Herein, we report two cases of hypermagnesemia in patients taking magnesium hydroxide for constipation. The first case involved an 82-year-old woman with end-stage renal disease who developed metabolic encephalopathy due to hypermagnesemia, after taking 3,000 mg of magnesium hydroxide daily for constipation. Her magnesium level was 9.9 mg/dL. Her treatment involved discontinuing magnesium hydroxide and continuing hemodialysis, which led to her recovery. In the second case, a 50-year-old woman with a history of cerebral hemorrhage and mental retardation developed hypermagnesemia despite having normal renal function. She was also taking magnesium hydroxide for constipation, and her magnesium level was 11.0 mg/dL. She experienced cardiac arrest while preparing for continuous renal replacement therapy (CRRT). After achieving return of spontaneous circulation, CRRT was initiated, and her magnesium level showed a decreasing trend. However, vital signs and lactate levels did not recover, leading to death. These cases highlight the importance of prompt diagnosis and intervention for hypermagnesemia and the need to regularly monitor magnesium levels in individuals receiving magnesium-containing preparations, especially those with impaired kidney function.

Startup of Demo-Scale Anaerobic Digestion Plant Treating Food Waste Leachate: Process Instability and Recovery.

A demo-scale (600 m3 working volume) anaerobic digester treating food waste leachate was monitored during its startup period. The operation strategy was adjusted twice (i.e., three distinct phases) during the operation to recover the process from instability. During the first phase, the organic loading rate (OLR) > 2.7 kg chemical oxygen demand (COD)/m3∙day corresponded to volatile fatty acid (VFA) accumulation along with a decreasing pH, resulting in the drop in biogas yield to 0.43 ± 0.9 m3/kg CODin. During phase 2, fast recovery of this process was aimed at using a sequencing batch operation. One batch cycle (5 to 2 days) consisted of the combined drawing and feeding step (5 h), the reacting step (91 to 17 h), and the settling step (24 h). The duration of the reacting step was determined for each cycle such that (1) the biogas production ceased before the cycle end and (2) the residual VFA concentration was < 1 g/L. In total, 11 cycles were operated with a gradual increase in biogas yield to 0.55 m3/kg CODin with the absence of any sign of system disturbance. After phase 2, the digester was fed at the designed OLR of 4.1 ± 0.3 kg COD/m3∙day. The biogas yield was elevated to 0.58 ± 0.2 m3/kg CODin during phase 3 with the residual VFA concentration maintained at 2.2 ± 0.6 g/L. Methanogen populations, as determined by real-time PCR, did not change significantly throughout the period. These results imply that the adaptation of this process to the OLR of ca. 4 kg COD/m3∙day was not due to the increase in methanogen population but due to the elevation of its activity. Overall, this study suggests that the sequencing batch operation with adjustable cycle duration can be one successful recovery strategy for biogas plants under system instability.

Environmental Risk and Credit Ratings, and the Moderating Effect of Market Competition.

This study examines the relationship between environmental risk and corporate bond credit ratings, and the moderating effect of market competition. We focus on Korean firms that are facing increasing risk of environmental crisis after the COVID-19 pandemic. Recently, the Korean government has been controlling businesses while promoting policies to transform the economy into a low-energy, low-carbon economy. We find that a firm's greenhouse gas emission and energy consumption, which are direct indicators of environmental risk, are negatively associated with bond credit ratings. We also report that the negative effect of environmental risk on credit ratings is stronger in firms with low market competition. This study contributes to prior research by improving the understanding of the effect of environmental risk on credit ratings. In particular, it is significant to examine the effect of environmental risk, measured as direct environmental performance not affected by green washing, on credit rating. Therefore, we shed light on environment-oriented management beyond the determinants of credit ratings, which have been discussed in previous studies. We also suggest that policymakers need to manage market competition in terms of environmental justice, given that market competition has a significant moderating effect on the relationship between environmental risk and credit ratings.

Real-world evidence of levofloxacin prophylaxis in elderly patients with newly diagnosed multiple myeloma who received bortezomib, melphalan, and prednisone regimen.

BACKGROUND: Although survival outcomes of multiple myeloma (MM) have improved with the development of new and effective agents, infection remains the major cause of morbidity and mortality. Here, we evaluated the efficacy of levofloxacin prophylaxis (in a real-world setting) during bortezomib, melphalan, and prednisone (VMP) therapy in elderly patients with newly diagnosed MM. METHODS: This study retrospectively analyzed the records of patients with newly diagnosed MM treated with the VMP regimen between February 2011 and September 2020 at three institutes of the Republic of Korea. RESULTS: Of a total of 258 patients, 204 (79.1%) received levofloxacin prophylaxis during VMP therapy. The median number of levofloxacin prophylaxis cycles was 4 (range, 1‒9), but 10 patients did not complete the planned prophylaxis because of side effects. Sixty-six patients (25.5%) experienced severe infections during VMP therapy, most of which (74.7%) occurred within the first four cycles of VMP therapy regardless of levofloxacin prophylaxis status. Early severe infection was significantly associated with poor survival. In multivariate analysis, levofloxacin prophylaxis was significantly associated with a lower risk in early severe infection. CONCLUSION: Our findings suggest that levofloxacin prophylaxis should be considered at least during the first four cycles of VMP therapy in elderly patients with newly diagnosed MM.

Shift in methanogenic community in protein degradation using different inocula.

Anaerobic digestion (AD) of protein-rich wastes is problematic due to production of ammonia and hydrogen sulfide. In this work, eight inocula were used in batch AD of solutions of gelatin and gluten at 3 g COD substrate/1g VSS inoculum. AD plants from which inocula originated were treating food waste or food wastewater, wastewater sludge, or a combination of them. Inocula were evaluated by fitting methane production data using the modified Gompertz model. Sequencing of 16 s rRNA of microorganisms showed that Methanoculleus was dominant in inocula from plants that were treating food waste, and Methanosaeta was dominant in the others. The maximum methane production rate varied by a factor of three for each substrate: 2.734-7.438 mLCH4 gCOD-1 d-1 for gelatin, and 1.950 to 5.532 mLCH4 gCOD-1 d-1 for gluten. This study demonstrates that inoculum must be chosen appropriately when treating proteinaceous waste by AD.

Shift in bacterial diversity in acidogenesis of gelatin and gluten seeded with various anaerobic digester inocula.

The aim of this study was to investigate divergence of bacteria degrading model proteins of food-processing wastewater. Gelatin and gluten were used as substrate to represent animal and plant proteins from food wastes, respectively. The inocula were obtained from eight full-scale anaerobic digestion reactors. Food-to-microorganism ratio was 3 g chemical oxygen demand equivalent of substrate per 1 g volatile suspended solids of inoculum. A first-order reaction model revealed reaction constants ranged 1.34 ≤ k ≤ 2.30 d-1 for gelatin and 0.63 ≤ k ≤ 1.69 d-1 for gluten. Metagenomic analysis of 16s rRNA sequences showed that dominant bacteria after gelatin degradation batch were different for each inocula. Klebsiella aerogenes, Hathewaya, Peptoclostridium, or Clostridium collagenovorans were most abundant. Klebsiella aerogenes was the most abundant species after gluten degradation for all inocula.