[Prehospital stabilization of a critically ill patient with telemetric medical guidance]. / Der Telenotarzt als "Einsatzleiter" zur Stabilisierung eines kritisch kranken Patienten.

We report about the prehospital treatment of an 82-year-old man with septic shock as a complication of acute pancreatitis. Initially only an advanced life support ambulance was on scene. After the primary assessment, the team decided to call for an emergency-physician-staffed helicopter. Because of the long estimated time of arrival on scene, the paramedics had to stabilize the patient without the physician. Therefore, they requested telemetric support. Despite massive centralization and difficult circumstances, the team succeeded to stabilize the patient in ongoing consultation of the tele-emergency physician. This cooperation made immediate und uneventful transportation after arrival of the helicopter possible.

Resuscitation (un-)wanted: Does anyone care? A retrospective real data analysis.

BACKGROUND AND OBJECTIVES: In case of out-of-hospital cardiac arrest (OHCA) personnel of the emergency medical services (EMS) are regularly confronted with advanced directives (AD) and do-not-attempt-resuscitation (DNACPR) orders. The authors conducted a retrospective analysis of EMS operation protocols to examine the prevalence of DNACPR in case of OHCA and the influence of a presented DNACPR on CPR-duration, performed Advanced-Life-Support (ALS) measures and decision making. MATERIALS AND METHODS: Retrospective analysis of prehospital medical documentation of all resuscitation incidents in a German county with 250,000 inhabitants from 1 January 2016 to 31 December 2022. Combined with data from the structured CPR team-feedback database patients characteristics, measures and course of the CPR were analysed. Statistic testing with significance level p < 0.05. RESULTS: In total n = 1,474 CPR events were analysed. Patients with DNACPR vs. no DNACPR: n = 263 (17.8%) vs. n = 1,211 (82.2%). Age: 80.0 ± 10.3 years vs. 68.0 ± 13.9 years; p < 0.001. Patients with ASA-status III/IV: n = 214 (81.3%) vs. n = 616 (50.9%); p < 0.001. Initial layperson-CPR: n = 148 (56.3%) vs. n = 647 (55.7%); p = 0.40. Airway management: n = 185 (70.3%) vs. n = 1,069 (88.3%); p < 0.001. With DNACPR CPR-duration initiated layperson-CPR vs. no layperson-CPR: 19:14 min (10:43-25:55 min) vs. 12:40 min (06:35-20:03 min); p < 0.001. CONCLUSION: In case of CPR EMS-personnel are often confronted with DNACPR-orders. Patients are older and have more previous diseases than patients without DNACPR. Initiated layperson-CPR might lead to misinterpretation of patients will with impact on CPR-duration and unwanted measures. Awareness of this issue should be created through measures such as training programs in particular to train staff in the interpretation and legal admissibility of ADs.

Hypomagnesemia with secondary hypocalcemia is caused by mutations in TRPM6, a new member of the TRPM gene family.

Magnesium is an essential ion involved in many biochemical and physiological processes. Homeostasis of magnesium levels is tightly regulated and depends on the balance between intestinal absorption and renal excretion. However, little is known about specific proteins mediating transepithelial magnesium transport. Using a positional candidate gene approach, we identified mutations in TRPM6 (also known as CHAK2), encoding TRPM6, in autosomal-recessive hypomagnesemia with secondary hypocalcemia (HSH, OMIM 602014), previously mapped to chromosome 9q22 (ref. 3). The TRPM6 protein is a new member of the long transient receptor potential channel (TRPM) family and is highly similar to TRPM7 (also known as TRP-PLIK), a bifunctional protein that combines calcium- and magnesium-permeable cation channel properties with protein kinase activity. TRPM6 is expressed in intestinal epithelia and kidney tubules. These findings indicate that TRPM6 is crucial for magnesium homeostasis and implicate a TRPM family member in human disease.

Pulmonary inflammatory response and immunomodulation to multiple trauma and hemorrhagic shock in pigs.

BACKGROUND: Patients suffering from severe trauma experience substantial immunological stress. Lung injury is a known risk factor for the development of posttraumatic complications, but information on the long-term course of the pulmonary inflammatory response and treatment with mild hypothermia are scarce. AIM: To investigate the pulmonary inflammatory response to multiple trauma and hemorrhagic shock in a porcine model of combined trauma and to assess the immunomodulatory properties of mild hypothermia. METHODS: Following induction of trauma (blunt chest trauma, liver laceration, tibia fracture), two degrees of hemorrhagic shock (45 and 50%) over 90 (n = 30) and 120 min. (n = 20) were induced. Animals were randomized to hypothermia (33°C) or normothermia (38°C). We evaluated bronchoalveolar lavage (BAL) fluid and tissue levels of cytokines and investigated changes in microRNA- and gene-expression as well as tissue apoptosis. RESULTS: We observed a significant induction of Interleukin (IL) 1ß, IL-6, IL-8, and Cyclooxygenase-2 mRNA in lung tissue. Likewise, an increased IL-6 protein concentration could be detected in BAL-fluid, with a slight decrease of IL-6 protein in animals treated with hypothermia. Lower IL-10 protein levels in normothermia and higher IL-10 protein concentrations in hypothermia accompanied this trend. Tissue apoptosis increased after trauma. However, intervention with hypothermia did not result in a meaningful reduction of pro-inflammatory biomarkers or tissue apoptosis. CONCLUSION: We observed signs of a time-dependent pulmonary inflammation and apoptosis at the site of severe trauma, and to a lower extent in the trauma-distant lung. Intervention with mild hypothermia had no considerable effect during 48 hours following trauma.

Interaction of the Ca2+-sensing receptor with the inwardly rectifying potassium channels Kir4.1 and Kir4.2 results in inhibition of channel function.

The Ca(2+)-sensing receptor (CaR), a G protein-coupled receptor, is expressed in many epithelial tissues including the parathyroid glands, kidney, and GI tract. Although its role in regulating PTH levels and Ca(2+) metabolism are best characterized, it may also regulate salt and water transport in the kidney as demonstrated by recent reports showing association of potent gain-of-function mutations in the CaR with a Bartter-like, salt-wasting phenotype. To determine whether this receptor interacts with novel proteins that control ion transport, we screened a human adult kidney cDNA library with the COOH-terminal 219 amino acid cytoplasmic tail of the CaR as bait using the yeast two-hybrid system. We identified two independent clones coding for approximately 125 aa from the COOH terminus of the inwardly rectifying K(+) channel, Kir4.2. The CaR and Kir4.2 as well as Kir4.1 (another member of Kir4 subfamily) were reciprocally coimmunoprecipitated from HEK-293 cells in which they were expressed, but the receptor did not coimmunoprecipitate with Kir5.1 or Kir1.1. Both Kir4.1 and Kir4.2 were immunoprecipitated from rat kidney extracts with the CaR. In Xenopus laevis oocytes, expression of the CaR with either Kir4.1 or Kir4.2 channels resulted in inactivation of whole cell current as measured by two-electrode voltage clamp, but the nonfunctional CaR mutant CaR(R796W), and that does not coimmunoprecipitate with the channels, had no effect. Kir4.1 and the CaR were colocalized in the basolateral membrane of the distal nephron. The CaR interacts directly with Kir4.1 and Kir4.2 and can decrease their currents, which in turn could reduce recycling of K(+) for the basolateral Na(+)-K(+)-ATPase and thereby contribute to inhibition of Na(+) reabsorption.

Increased apical targeting of renal ENaC subunits and decreased expression of 11betaHSD2 in HgCl2-induced nephrotic syndrome in rats.

Nephrotic syndrome is often accompanied by sodium retention and generalized edema. We hypothesize that dysregulation of the epithelial sodium channel (ENaC) and/or of sodium (co)transporters may be responsible for the increased sodium retention associated with HgCl(2)-induced nephropathy. In addition, we examined the hypothesis that the expression of type 2 11beta-hydroxysteroid dehydrogenase (11betaHSD2) is reduced, contributing to the enhanced mineralocorticoid activity. Membranous nephropathy was induced in Brown Norway rats by repeated injections of HgCl(2) (1 mg/kg sc), whereas the control group received only vehicle. After 13 days of treatment, the abundance of ENaC subunits, sodium (co)transporters, and 11betaHSD2 in the kidney was examined by immunoblotting and immunohistochemistry. HgCl(2) treatment induced marked proteinuria, hypoalbuminemia, decreased urinary sodium excretion, and ascites. The protein abundance of alpha-ENaC was increased in the cortex/outer stripe of outer medulla (OSOM) and inner stripe of the outer medulla (ISOM). The protein abundances of beta-ENaC and gamma-ENaC were decreased in the cortex/OSOM while increased in the ISOM. Immunoperoxidase microscopy demonstrated increased targeting of ENaC subunits to the apical plasma membrane in the distal convoluted tubule, connecting tubule, and cortical and medullary collecting duct segments. Moreover, 11betaHSD2 abundance was decreased in cortex/OSOM and ISOM. The protein abundances of type 3 Na/H exchanger (NHE3), Na-K-2Cl cotransporter (NKCC2), and thiazide-sensitive Na-Cl cotransporter (NCC) were decreased. Moreover, the abundance of the alpha-1 subunit of the Na-K-ATPase was decreased in the cortex/OSOM and ISOM but remained unchanged in the inner medulla. These results suggest that increased apical targeting of ENaC subunits combined with diminished abundance of 11betaHSD2 may contribute to sodium retention associated with HgCl(2)-induced nephrotic syndrome. The decreased abundance of NHE3, NKCC2, NCC, and Na-K-ATPase may play a compensatory role in promoting sodium excretion.

Novel TRPM6 mutations in 21 families with primary hypomagnesemia and secondary hypocalcemia.

Primary hypomagnesemia with secondary hypocalcemia is a rare autosomal recessive disorder characterized by profound hypomagnesemia associated with hypocalcemia. Pathophysiology is related to impaired intestinal absorption of magnesium accompanied by renal magnesium wasting as a result of a reabsorption defect in the distal convoluted tubule. Recently, mutations in the TRPM6 gene coding for TRPM6, a member of the transient receptor potential (TRP) family of cation channels, were identified as the underlying genetic defect. Here, the results of a TRPM6 mutational analysis of 21 families with 28 affected individuals are presented. In this large patient cohort, a retrospective clinical evaluation based on a standardized questionnaire was also performed. Genotype analysis revealed TRPM6 mutations in 37 of 42 expected mutant alleles. Sixteen new TRPM6 mutations were identified, including stop mutations, frame-shift mutations, splice-site mutations, and deletions of exons. Electrophysiologic analysis of mutated ion channels after heterologous expression in Xenopus oocytes proved complete loss of function of TRPM6. Clinical evaluation revealed a homogeneous clinical picture at manifestation with onset in early infancy with generalized cerebral convulsions. Initial laboratory evaluation yielded extremely low serum magnesium levels, low serum calcium levels, and inadequately low parathyroid hormone levels. Treatment usually consisted of acute intravenous magnesium supplementation leading to relief of clinical symptoms and normocalcemia, followed by lifelong oral magnesium supplementation. Serum magnesium levels remained in the subnormal range despite adequate therapy. This is best explained by a disturbed magnesium conservation in the distal convoluted tubule, which emerged in all patients upon magnesium supplementation. Delay of diagnosis resulted in permanent neurologic damage in three patients.

Disruption of TRPM6/TRPM7 complex formation by a mutation in the TRPM6 gene causes hypomagnesemia with secondary hypocalcemia.

Impaired magnesium reabsorption in patients with TRPM6 gene mutations stresses an important role of TRPM6 (melastatin-related TRP cation channel) in epithelial magnesium transport. While attempting to isolate full-length TRPM6, we found that the human TRPM6 gene encodes multiple mRNA isoforms. Full-length TRPM6 variants failed to form functional channel complexes because they were retained intracellularly on heterologous expression in HEK 293 cells and Xenopus oocytes. However, TRPM6 specifically interacted with its closest homolog, the Mg(2+)-permeable cation channel TRPM7, resulting in the assembly of functional TRPM6/TRPM7 complexes at the cell surface. The naturally occurring S141L TRPM6 missense mutation abrogated the oligomeric assembly of TRPM6, thus providing a cell biological explanation for the human disease. Together, our data suggest an important contribution of TRPM6/TRPM7 heterooligomerization for the biological role of TRPM6 in epithelial magnesium absorption.