Excitatory effect of 2,4-diaminobutyric acid on Retzius neurons and its underlying mechanisms

Neurodegenerativne bolesti su progresivna, hronična i neizlečiva neurološka oboljenja. Pretpostavlja se da je u osnovi etiopatogeneze ovih oboljenja udruženo delovanje genetskih i sredinskih faktora. Potonji imaju sve veći značaj jer produžetak životnog veka ljudi vodi do prolongiranog izlaganja činiocima životne okoline. Jedan od mogućih sredinskih činilaca je 2,4-diaminobuterna kiselina (2,4-DABA), produkt ubikvitarnih cijanobakterija, čiji neurotoksični potencijal nije sasvim istražen.Metodima klasične elektrofiziologije i merenjem ulaznog otpora membrane ispitivani su učinci, jačina i mehanizmi delovanja 2,4-DABA na Retzius-ove neurone pijavice Haemopis sanguisuga. Naša istraživanja pokazuju da 2,4-DABA ima ekscitatoran učinak na neuronima, izazivajući izraženu depolarizaciju membranskog potencijala koja se razvija kroz dve faze, što je prvi put opisan fenomen na našem modelu. Istovetan učinak imaju i DL- i L- izoforma 2,4-DABA. Ekscitatorno dejstvo 2,4-DABA višestruko je jače od učinaka glutamata i aspartata, kao i od sredinskih ekscitatornih aminokiselina BOAA i BMAA. Depolarizacioni učinak 2,4-DABA je zavisan od prisustva Na+ i praćen povećanjem provodljivosti membrane Retzius-ovih neurona. Blokada non-NMDA glutamatnih receptora izaziva smanjenje amplitude prve faze depolarizacije, dok inhibicija transportnog sistema za neutralne aminokiseline upadljivo slabi drugu fazu depolarizacije. Zaključujemo da je 2,4-DABA snažna ekscitatorna aminokiselina koja ostvaruje svoj učinak preko jonotropnih glutamatnih receptora tokom prve faze i aktivacijom natrijum-zavisnog transportera za neutralne aminokiseline tokom druge faze depolarizacije. Ovi mehanizmi pokreću procese ključne za razvoj neurodegeneracije - ekscitotoksičnost, osmotsko opterećenje i smanjenje energetskih rezervi neurona, što uz dokazano globalno prisustvo 2,4-DABA ukazuje na značaj navedenih rezultata.Neurodegenerative diseases are chronic, progressive and incurable neurological illnesses. It is proposed that etiopathogenesis of these diseases is based on cooperation of genetic and environmental factors. The latter are of growing importance as life expectancy and exposure of people increase. A putative causative agent is 2,4 diaminobutyric acid (2,4-DABA), a product of ubiquitous cyanobacteria, whose neurotoxic potential is insufficiently examined. Using classical electrophysiology methods and measurements of input membrane resistance, we have investigated the effect, potency and mechanisms of 2,4-DABA effect on Retzius neurons of the leech Haemopis sanguisuga. Our results show that 2,4-DABA has an excitatory effect on neurons, eliciting extensive membrane depolarization that evolves through two distinct stages, which is a novel excitatory phenomenon reported on our model. Both L- and DL- isomers of 2,4-DABA cause equivalent depolarizing effects. Excitatory response of neurons to 2,4-DABA is several times larger than that induced by glutamate and aspartate or environmental excitatory amino acids BOAA and BMAA. Depolarizing action of 2,4-DABA is dependent on sodium ions and coupled with an increase of Retzius neuron membrane permeability. Blocking non-NMDA glutamate receptor reduces the amplitude of the first stage, while inhibition of the transport system for neutral amino acids markedly decreases the second phase of depolarization. We conclude that 2,4-DABA is a potent excitatory amino acid that activates ionotropic glutamate receptors during the first stage and sodium-dependent transporter for neutral amino acids during the second stage of depolarization. These mechanisms initiate processes crucial for neurodegeneration - excitotoxicity, osmotic stress and energy depletion of neurons, which the global presence of 2,4-DABA indicate the significance of our results

PRECIPITATING FACTORS AND CLINICAL FEATURES OF DIABETIC KETOACIDOSIS

vod: Dijabetička ketoacidoza (DKA) jedna je od najozbiljnijih akutnih komplikacija šećerne bolesti (ŠB). Pojedina istraživanja su pokazala da su infekcije precipitirajući čimbenik u polovice ispitanika. Nekoliko novijih istraživanja naglašava da je loše pridržavanje liječenja također česti uzrok DKA. Cilj: Identifi cirati najčešće precipitirajuće čimbenike za DKA u Republici Hrvatskoj. Ispitanici i postupci: Ovo retrospektivno multicentrično istraživanje uključivalo je bolesnike sa ŠB-om tipa 1 ili tipa 2 s dijagnozom DKA između 1. siječnja 2014. i 31. prosinca 2018. i liječenih u 5 različitih središta za liječenje ŠB-a: Dubrovnik, Našice, Split, Zagreb i Osijek. U analizu je uključena samo prve epizoda DKA. Pacijenti koji boluju od steroidnog ŠB-a i ŠB-a zbog endokrinih poremećaja kao što su akromegalija i Cushingov sindrom bili su isključeni. Rezultati: Istraživanjem je obuhvaćeno 160 bolesnika (55 % muškaraca), od kojih je 68% imalo ŠB tip 1. Srednja dob ispitanika bila je 42 godine (od 18 do 89). Najčešći uzrok DKA bila je infekcija (57 %), zatim slabo kontrolirani ŠB (37 %) i prva prezentacija ŠB-a (9 %), dok je u 7% bolesnika DKA bila uzrokovana ostalim uzrocima kao što su kvar inzulinske pumpe, moždani ili srčani udar. U skupini bolesnika s infekcijama najčešće su bile infekcije mokraćnog sustava (30 %), probavne infekcije (30 %) i infekcije respiratornog trakta (19 %), dok je 21 % bolesnika imalo druge izvore infekcije. U 36 ovih bolesnika uz infekciju je bio prisutan i prethodno loše kontroliran ŠB, a u 12 % DKA uzrokovana infekcijom bila je prvo očitovanje bolesti. U bolesnika sa ŠB-om tipa 2 infekcije su češće bile uzrok DKA nego u bolesnika sa ŠB-om tipa 1 (P < 0,05). U bolesnika sa ŠB-om tipa 1, slabo regulirana glikemija je češće uzrok DKA (31%) nego u bolesnika sa ŠB-om tipa 2 (18 %). Zaključak: Najčešći precipitirajući čimbenici za razvoj DKA su infekcije i loša regulacija ŠB-a. Potrebna je bolja edukacija bolesnika o važnosti redovite primjene inzulina i korekcije terapije tijekom akutne bolesti.Introduction: Diabetic ketoacidosis (DKA) is one of the most serious acute complications of diabetes mellitus (DM). In some studies, infections have been found to be a precipitating factor in more than half of the subjects. On the other hand, several recent studies emphasize that poor treatment adherence is also a common cause of DKA. Objective: To identify the most common precipitating factors for DKA in Croatia. Patients and Methods: This retrospective, multicenter study included DM type 1 or DM type 2 patients diagnosed with DKA between January 1, 2014 and December 31, 2018, and treated in 5 different DM treatment centers, i.e., Dubrovnik, Našice, Split, Zagreb and Osijek. Only the fi rst episode of DKA was included in the analysis. Patients receiving steroids and DM due to endocrine disorders such as acromegaly and Cushing\u27s syndrome were excluded. Results: The study included 160 patients (55% of men), of whom 68% had DM type 1. The mean age of the respondents was 42 (18-89) years. The most common cause of DKA was infection (57%), followed by poorly controlled DM (37%) and fi rst presentation of DM (9%), while in 7% of patients DKA was due to other causes such as insulin pump failure, stroke or myocardial infarction. In the group of patients with infections, urinary tract infections (30%), gastrointestinal infections (30%) and respiratory tract infections (19%) were most common, whereas 21% of patients had other sources of infection. In 36% of these patients, the infection was associated with previously poorly controlled diabetes, and in 12% of them, DKA caused by the infection was the fi rst manifestation of the disease. In patients with type 2DM, infections were more often the cause of DKA than in patients with type 1DM (p<0.05).Poorly controlled glycemia appeared to be a more frequent cause of DKA in patients with type 1 DM (31%) than in patients with type 2 DM (18%). Conclusion: The most common precipitating factors for the development of DKA were infections and poor diabetes management. Better education of patients about the importance of regular insulin administration and correction of therapy in acute illness could reduce the risk of DKA

PRECIPITATING FACTORS AND CLINICAL FEATURES OF DIABETIC KETOACIDOSIS

vod: Dijabetička ketoacidoza (DKA) jedna je od najozbiljnijih akutnih komplikacija šećerne bolesti (ŠB). Pojedina istraživanja su pokazala da su infekcije precipitirajući čimbenik u polovice ispitanika. Nekoliko novijih istraživanja naglašava da je loše pridržavanje liječenja također česti uzrok DKA. Cilj: Identifi cirati najčešće precipitirajuće čimbenike za DKA u Republici Hrvatskoj. Ispitanici i postupci: Ovo retrospektivno multicentrično istraživanje uključivalo je bolesnike sa ŠB-om tipa 1 ili tipa 2 s dijagnozom DKA između 1. siječnja 2014. i 31. prosinca 2018. i liječenih u 5 različitih središta za liječenje ŠB-a: Dubrovnik, Našice, Split, Zagreb i Osijek. U analizu je uključena samo prve epizoda DKA. Pacijenti koji boluju od steroidnog ŠB-a i ŠB-a zbog endokrinih poremećaja kao što su akromegalija i Cushingov sindrom bili su isključeni. Rezultati: Istraživanjem je obuhvaćeno 160 bolesnika (55 % muškaraca), od kojih je 68% imalo ŠB tip 1. Srednja dob ispitanika bila je 42 godine (od 18 do 89). Najčešći uzrok DKA bila je infekcija (57 %), zatim slabo kontrolirani ŠB (37 %) i prva prezentacija ŠB-a (9 %), dok je u 7% bolesnika DKA bila uzrokovana ostalim uzrocima kao što su kvar inzulinske pumpe, moždani ili srčani udar. U skupini bolesnika s infekcijama najčešće su bile infekcije mokraćnog sustava (30 %), probavne infekcije (30 %) i infekcije respiratornog trakta (19 %), dok je 21 % bolesnika imalo druge izvore infekcije. U 36 ovih bolesnika uz infekciju je bio prisutan i prethodno loše kontroliran ŠB, a u 12 % DKA uzrokovana infekcijom bila je prvo očitovanje bolesti. U bolesnika sa ŠB-om tipa 2 infekcije su češće bile uzrok DKA nego u bolesnika sa ŠB-om tipa 1 (P < 0,05). U bolesnika sa ŠB-om tipa 1, slabo regulirana glikemija je češće uzrok DKA (31%) nego u bolesnika sa ŠB-om tipa 2 (18 %). Zaključak: Najčešći precipitirajući čimbenici za razvoj DKA su infekcije i loša regulacija ŠB-a. Potrebna je bolja edukacija bolesnika o važnosti redovite primjene inzulina i korekcije terapije tijekom akutne bolesti.Introduction: Diabetic ketoacidosis (DKA) is one of the most serious acute complications of diabetes mellitus (DM). In some studies, infections have been found to be a precipitating factor in more than half of the subjects. On the other hand, several recent studies emphasize that poor treatment adherence is also a common cause of DKA. Objective: To identify the most common precipitating factors for DKA in Croatia. Patients and Methods: This retrospective, multicenter study included DM type 1 or DM type 2 patients diagnosed with DKA between January 1, 2014 and December 31, 2018, and treated in 5 different DM treatment centers, i.e., Dubrovnik, Našice, Split, Zagreb and Osijek. Only the fi rst episode of DKA was included in the analysis. Patients receiving steroids and DM due to endocrine disorders such as acromegaly and Cushing\u27s syndrome were excluded. Results: The study included 160 patients (55% of men), of whom 68% had DM type 1. The mean age of the respondents was 42 (18-89) years. The most common cause of DKA was infection (57%), followed by poorly controlled DM (37%) and fi rst presentation of DM (9%), while in 7% of patients DKA was due to other causes such as insulin pump failure, stroke or myocardial infarction. In the group of patients with infections, urinary tract infections (30%), gastrointestinal infections (30%) and respiratory tract infections (19%) were most common, whereas 21% of patients had other sources of infection. In 36% of these patients, the infection was associated with previously poorly controlled diabetes, and in 12% of them, DKA caused by the infection was the fi rst manifestation of the disease. In patients with type 2DM, infections were more often the cause of DKA than in patients with type 1DM (p<0.05).Poorly controlled glycemia appeared to be a more frequent cause of DKA in patients with type 1 DM (31%) than in patients with type 2 DM (18%). Conclusion: The most common precipitating factors for the development of DKA were infections and poor diabetes management. Better education of patients about the importance of regular insulin administration and correction of therapy in acute illness could reduce the risk of DKA

Excitatory effect of 2,4-diaminobutyric acid on Retzius neurons and its underlying mechanisms

Neurodegenerativne bolesti su progresivna, hronična i neizlečiva neurološka oboljenja. Pretpostavlja se da je u osnovi etiopatogeneze ovih oboljenja udruženo delovanje genetskih i sredinskih faktora. Potonji imaju sve veći značaj jer produžetak životnog veka ljudi vodi do prolongiranog izlaganja činiocima životne okoline. Jedan od mogućih sredinskih činilaca je 2,4-diaminobuterna kiselina (2,4-DABA), produkt ubikvitarnih cijanobakterija, čiji neurotoksični potencijal nije sasvim istražen.Metodima klasične elektrofiziologije i merenjem ulaznog otpora membrane ispitivani su učinci, jačina i mehanizmi delovanja 2,4-DABA na Retzius-ove neurone pijavice Haemopis sanguisuga. Naša istraživanja pokazuju da 2,4-DABA ima ekscitatoran učinak na neuronima, izazivajući izraženu depolarizaciju membranskog potencijala koja se razvija kroz dve faze, što je prvi put opisan fenomen na našem modelu. Istovetan učinak imaju i DL- i L- izoforma 2,4-DABA. Ekscitatorno dejstvo 2,4-DABA višestruko je jače od učinaka glutamata i aspartata, kao i od sredinskih ekscitatornih aminokiselina BOAA i BMAA. Depolarizacioni učinak 2,4-DABA je zavisan od prisustva Na+ i praćen povećanjem provodljivosti membrane Retzius-ovih neurona. Blokada non-NMDA glutamatnih receptora izaziva smanjenje amplitude prve faze depolarizacije, dok inhibicija transportnog sistema za neutralne aminokiseline upadljivo slabi drugu fazu depolarizacije. Zaključujemo da je 2,4-DABA snažna ekscitatorna aminokiselina koja ostvaruje svoj učinak preko jonotropnih glutamatnih receptora tokom prve faze i aktivacijom natrijum-zavisnog transportera za neutralne aminokiseline tokom druge faze depolarizacije. Ovi mehanizmi pokreću procese ključne za razvoj neurodegeneracije - ekscitotoksičnost, osmotsko opterećenje i smanjenje energetskih rezervi neurona, što uz dokazano globalno prisustvo 2,4-DABA ukazuje na značaj navedenih rezultata.Neurodegenerative diseases are chronic, progressive and incurable neurological illnesses. It is proposed that etiopathogenesis of these diseases is based on cooperation of genetic and environmental factors. The latter are of growing importance as life expectancy and exposure of people increase. A putative causative agent is 2,4 diaminobutyric acid (2,4-DABA), a product of ubiquitous cyanobacteria, whose neurotoxic potential is insufficiently examined. Using classical electrophysiology methods and measurements of input membrane resistance, we have investigated the effect, potency and mechanisms of 2,4-DABA effect on Retzius neurons of the leech Haemopis sanguisuga. Our results show that 2,4-DABA has an excitatory effect on neurons, eliciting extensive membrane depolarization that evolves through two distinct stages, which is a novel excitatory phenomenon reported on our model. Both L- and DL- isomers of 2,4-DABA cause equivalent depolarizing effects. Excitatory response of neurons to 2,4-DABA is several times larger than that induced by glutamate and aspartate or environmental excitatory amino acids BOAA and BMAA. Depolarizing action of 2,4-DABA is dependent on sodium ions and coupled with an increase of Retzius neuron membrane permeability. Blocking non-NMDA glutamate receptor reduces the amplitude of the first stage, while inhibition of the transport system for neutral amino acids markedly decreases the second phase of depolarization. We conclude that 2,4-DABA is a potent excitatory amino acid that activates ionotropic glutamate receptors during the first stage and sodium-dependent transporter for neutral amino acids during the second stage of depolarization. These mechanisms initiate processes crucial for neurodegeneration - excitotoxicity, osmotic stress and energy depletion of neurons, which the global presence of 2,4-DABA indicate the significance of our results

Upotreba Erector spinae plane bloka i perineuralnog katetera pri operativnom liječenju razvojnog poremećaja kuka kod djece

The ultrasound-guided erector spinae plane (ESP) block is a novel interfascial plane block technique providing analgesic effects in different localizations of the body, in accordance with the level of administration. Although ESP block is usually performed in the thoracic region in pediatric patients, it is possible to achieve ESP block in the lumbar region as well. Postoperative pain management is essential in patients undergoing operative hip treatment, one of the most common procedures in pediatric orthopedic surgery. We report on a case of effective intraoperative analgesia achieved by ultrasound-guided lumbar ESP block and another case of effective intra- and postoperative analgesia accomplished with perineural catheter placement in addition to lumbar ESP block, both performed in children surgically treated for developmental hip disorders.Erector spinae plane (ESP) blok vođen ultrazvukom je nova interfascijalna tehnika blokade koja pruža analgetske učinke u različitim lokalizacijama tijela, u skladu s razinom primjene. Iako se ESP blok obično izvodi u torakalnoj regiji kod pedijatrijskih bolesnika, moguće je postići ESP blok i u lumbalnoj regiji. Poslijeoperacijsko liječenje boli od presudne je važnosti kod bolesnika koji se podvrgavaju operativnom liječenju kuka, što je jedan od najčešćih postupaka u dječjoj ortopedskoj kirurgiji. U dva slučaja postignuta je učinkovita intraoperacijska analgezija ultrazvučno vođenim lumbalnim ESP blokom te učinkovita intra- i poslijeoperacijska analgezija ostvarena postavljanjem perineuralnog katetera uz dodatak lumbalnom ESP bloku kod djece operirane zbog razvojnog poremećaja kuka

Effect of low potassium concentration on cadmium induced epileptiform activity of leech retzius neurons

Epilepsies have a large significance and require detailed investigation of cellular mechanisms that lead to this disorder. Environmental, especially industrial, toxins are having increasingly more prominent role in these investigations. The aim of our research was to investigate the significance of Cd2+ in generation of epileptiform electrical activity of neurons, and the role of Na+/K+ pump in mechanisms that lead to cessation of this activity. Experiments were performed on Retzius nerve cells of the leech Haemopis sanguisuga. Intracellularly placed microelectrodes were used to measure membrane potential changes upon administration of Cd2+ (100 µmol/l), and the same concentration of Cd2+ in low K+ (1 mmol/l) solution. In our experiments Cd2+ led to generation of rhythmic repetitive oscillatory activity. This activity closely resembles paroxysmal depolarizing shifts (PDS) which represent the cellular basis of epilepsy. Cd2+ induced epileptiform activity had the following characteristics: frequency of 3.9±0.8 PDS/minute, PDS duration of 4.0±0.3 s, and PDS amplitude of 8.1±0.7 mV. Cd2+ induces effects similar to those of Ni2+ and Co2+, but in 30 times smaller concentration. Application of Cd2+ in low K+ solution led to a significant reduction of PDS frequency (by 2.34±0.55 PDS/minute, p<0.05, Student's t-test), highly significant increase in PDS duration (by 2.84±0.23 s, p<0.01, Student's t-test) and highly significant reduction in PDS amplitude (by 1.91±0.33 mV, p=0.01, Student's t-test). Our results show that Cd2+ is a potent initiator of epileptiform activity, and that Na+/K+ pump significantly affects this activity and has a potentially important role in mechanisms that lead to its cessation

The simultaneous action of acute paradoxical sleep deprivation and hypothyroidism modulates synaptosomal ATPases and acetylcholinesterase activities in rat brain

Background: Thyroid dysfunctions as well as sleep abnormalities are usually followed by neurological, psychiatric and/or behavioral disorders. On the other hand, changes in the brain adenosine triphosphatases (ATPases) and acetylcholinesterase (AChE) activities show significant importance in pathogenetic pathways in the evolution of numerous neuropsychiatric diseases. Methods: This study aimed to evaluate the in vivo simultaneous effects of hypothyroidism and paradoxical sleep deprivation for 72 h on synaptosomalATPases and AChE activities of whole rat brains. In order to induce hypothyroidism, 6-n-propyl-2-thiouracil was administrated in drinking water during 21 days. The modified multiple platform method was used to induce paradoxical sleep deprivation. The AChE and ATPases activities were measured using spectrophotometric methods. Results: Hypothyroidism significantly increased the activity of Na+/K+-ATPase compared to other groups, while at the same time significantly decreased AChE activity compared to the CT and SD groups. Paradoxical sleep deprivation significantly increased AChE activity compared to other groups. The simultaneous effect of hypothyroidism and sleep deprivation reduced the activity of all three enzymes (for Na+/K+-ATPase between HT/SD and HT group p < 0.0001, SD group p < 0.001,CT group p = 0.013; for ecto-ATPases between HT/SD and HT group p = 0.0034, SD group p = 0.0001, CT group p = 0.0007; for AChE between HT/SD and HT group p < 0.05, SD group p < 0.0001, CT group p < 0.0001). Conclusions: The effect of simultaneous existence of hypothyroidism and paradoxical sleep deprivation reduces the activity of the Na+/K+-ATPase, ecto-ATPases, and AChE, what is different from individual effect of hypothyroidism and paradoxical sleep deprivation itself. This knowledge could help in the choice of appropriate therapy in such condition. © 2023 Elsevier B.V