General anaesthesia in rats undergoing experiments on central nervous system

The rat is one of the species most commonly used in laboratory practice. Numerous publications concerning various aspects of morphology and physiology are based on the results obtained in this species. It make these results comparable and under some precautions enables to transpose into the relationships observed in humans. Each experimental project must obtain the permission of the Local Ethical Committee, as well as comply with the regulations of the European Communities Council, outlined in the “European Convention for the protection of vertebrate animals used for experimental and other scientific purposes”. Adequate pre-operative care can eliminate or reduce the incidence of many complications, which may occur during anaesthesia. General anaesthesia in experimental practice can be achieved using a variety of drugs and ways of administration, among others inhalational or intravenous. The side effects of anaesthetic agents can be reduced in this way. Knowledge of the effect of anaesthetics on the cerebral circulation, metabolism and intracranial pressure in both normal and pathological conditions is crucial for neurobiological purposes. Many anaesthetic agents depress respiration, which can result in hypoxia, hypercapnia and acidosis. To maintain blood carbon dioxide and oxygen concentration in the physiological range, it is necessary to apply tracheal intubation and artificial ventilation. However, even when using sophisticated equipment, the role of basic clinical observation, such as the colour of the blood shed in the operation field, breathing depth and frequency, cannot be overestimated. The importance of monitoring mean arterial blood pressure and intracranial pressure in experiments on the central nervous system is fundamental. Special attention should be paid to controlling the temperature and monitoring the fluid balance. Appropriate postoperative care can have a decisive influence on the final results of the research

The different patterns of maturation of the claustrocortical connections in a rabbit

The quantitative analysis of the claustrocortical connections labeled with the fluorescent retrograde tracer Fluoro-Gold (FG) was conducted on 90 rabbits subdivided into the following age groups (P2, P7, P14, P21, P30, P60, P90, P120, P180). The equal volumes of retrograde fluorescent tracer FluoroGold (FG) were injected into the selected regions of the motor or somatosensory cortices. The volume of the dorsal part of the claustrum, total number of projecting neurons, numerical density and percentage distribution of projecting neurons were estimated by means of the unbiased stereological methods. The claustrocortical connections both with the motor and somatosensory areas in a rabbit are established in the postnatal life. The parts of the claustrum occupied by the motor and somatosensory projection zones as well as the morphology of the cortically projecting neurons do not reveal characteristic changes during the studied period. The significant decrease of the total number and numerical density of cortically projecting neurons as well as the increase of the claustral volume may reflect the process of adjustment of the claustrum to its modulatory function upon corresponding cortical areas. The intensity of the claustral connections with the motor and somatosensory cortices reveals significant difference during the studied period, being higher for the motor projection. It may be assumed that the claustrocortical connections established before birth undergosignificant quantitative changes during postnatal development

Morphological and functional circumstances of the cerebral blood flow regulation

Choroby naczyniowe ośrodkowego układu nerwowego (OUN) stanowią jedną z najczęstszych przyczyn niepełnosprawności oraz śmierci wśród rozwiniętych społeczeństw krajów europejskich. Pomimo intensywnych badań nad patogenezą tej grupy chorób wyniki ich leczenia nie są zadowalające. Uzasadnia to konieczność dalszego dokładniejszego poznawania mechanizmów regulacji mózgowego przepływu krwi. W pracy dokonano syntetycznego przeglądu współczesnych poglądów na temat podstaw morfologicznych i czynnościowych regulacji tego procesu w warunkach zdrowia i choroby . Omówiono aktualne poglądy na temat roli mechanizmów metabolicznych, miogennych, neurogennych oraz fizycznych. Podkreślono istotne znaczenie czynnościowej integracji struktur naczyniowych, komórek nerwowych oraz neurogleju, wchodzących w skład tak zwanej jednostki nerwowo-naczyniowej w skoordynowanej kontroli mózgowego przepływu krwi. Ponadto, przedyskutowano konsekwencje zmian wynikających z uszkodzenia wymienionych mechanizmów w warunkach patologicznych. W podsumowaniu autorzy podkreślają, iż dla pełniejszego zrozumienia mechanizmów regulacyjnych mózgowego krążenia krwi konieczne jest uwzględnienie ścisłego współdziałania wielu, często nawet słabiej poznanych lub uważanych za mniej istotne elementów morfologicznych (jak np. komórek glejowych czy części kapilarnej i żylnej układu naczyniowego) z czynnikami metabolicznymi, miogennymi i neurogennymi.Vascular diseases of the central ner vous system (CNS) and especially cerebral stroke consist one of the most frequent cause of disability and death among developed European communities. Despite of the intensive studies on their pathogenesis, the therapeutic results still remain unsatisfactory. This justifies fur ther intensive studies on regulator y mechanisms of the cerebral blood flow. The synthetic review of the current concepts concerning morphological and functional basis of this process is presented. The role of metabolic, myogenic, neurogenic and physical mechanisms of blood flow regu lation are discussed. Functional integration of the neuronal, vascular and neuroglial elements in the process of neurovascular coupling is stressed by the authors. Finally , the pathophysiology and consequences of the cerebral blood flow disturbances are underscored. In summary, the close functional cooperation between morphological structures previously regarded as less relevant for cerebral blood flow regulation (like neuroglia or capillary and venous parts of cerebral vasculature) with metabolic, myogenic and neurogenic factors must be taken into account for better understanding of brain circulation

Rationalization and Effectiveness in Use of Electric Energy

The article while taking in to account the present deficit of electric energy in the Polish economy and new possibilities which can be afforded by the introduced economic reform, indicates some ways of cushioning the effects of the electric energy shortage . There may be distinguished here two directions of activities aiming at improvement of the situation in the field of using electric energy. The first one of them envisages its rational use. In this par t of this article, the author analyzes administrative methods of alleviating the energy crisis, which a is at rational use of electric energy. There is also presented here a model of optimal capacity use , which combined with the listed organizational and administrative measure way largely contribute to "straightening up” the power, consumption curve, and consequently to its optimal consumption. The other direction of activity is aimed at promoting effective consumption of electric energy . The author proposes here a two-stage model aiming at maximization of effectiveness in consumption of electric energy . Finally , there are proposed two models in the area of Identification of activity pursued by an economic unit in the field of electric power consumption.Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 dofinansowane zostało ze środków MNiSW w ramach działalności upowszechniającej naukę

Molekularne mechanizmy bakteryjnego zakażenia ośrodkowego układu nerwowego

Central nervous system (CNS) infections may involve the meninges, brain and/or spinal cord. The most common etiologic agents are Streptococcus pneumoniae, group B Streptococci, Neisseria meningitidis, Haemophilus influenzae, and Listeria monocytogenes. CNS is characterized by specific structure and function. Despite a unique system of brain barriers and autonomous immune system, CNS is very susceptible to microorganisms which may invade directly, via the blood, or less frequently by reverse axonal transport. The complex process of bacteria and activated polymorphonuclear leukocyte transfer to the subarachnoid space, which is devoid of natural immune defence mechanisms, initiates an inflammatory response that subsequently spreads to the brain tissue. Consequences of these changes include damage to the blood-brain barrier, development of vasogenic cerebral oedema, and intracranial pressurevolume disturbances leading to impaired CNS perfusion.Central nervous system (CNS) infections may involve the meninges, brain and/or spinal cord. The most common etiologic agents are Streptococcus pneumoniae, group B Streptococci, Neisseria meningitidis, Haemophilus influenzae, and Listeria monocytogenes. CNS is characterized by specific structure and function. Despite a unique system of brain barriers and autonomous immune system, CNS is very susceptible to microorganisms which may invade directly, via the blood, or less frequently by reverse axonal transport. The complex process of bacteria and activated polymorphonuclear leukocyte transfer to the subarachnoid space, which is devoid of natural immune defence mechanisms, initiates an inflammatory response that subsequently spreads to the brain tissue. Consequences of these changes include damage to the blood-brain barrier, development of vasogenic cerebral oedema, and intracranial pressurevolume disturbances leading to impaired CNS perfusion

Optymalizacja w logistyce, tom 2. Modelowanie przepływów w kanałach dystrybucji

W pracy Optymalizacja w logistyce. Modelowanie logistycznych procesów decyzyjnych (Iwona Konarzewska, Maciej Jewczak, Adam Kucharski, red. nauk. Iwona Konarzewska, Łódź 2020) przedstawiono podstawowe sposoby modelowania zagadnień logistycznych za pomocą wzorów programowania liniowego, przydziału oraz innych metod z zakresu badań operacyjnych. Omówiono także zagadnienia związane z planowaniem sieciowym, zarządzaniem projektami, modelowaniem zagadnień masowej obsługi i prognozowaniem popytu. Książka Optymalizacja w logistyce. Modelowanie przepływów w kanałach dystrybucji kontynuuje postawione zadanie poszukiwania optymalnych rozwiązań w problemach logistycznych. Adresowana jest zarówno do logistyków, rozwiązujących w praktyce problemy zasygnalizowane w pracy w licznych przykładach, jak i do studentów logistyki, zarządzania oraz informatyki, pragnących poznać tajniki metod optymalizacyjnych stosowanych w zagadnieniach logistycznych. Autorzy wzięli pod uwagę: zadania lokalizacji centrów dystrybucyjnych, szeroko rozumiane problemy transportowe i algorytmy ich rozwiązywania, problemy układania tras oraz optymalizacji w sieciach transportowych (w tym wyznaczania maksymalnego, a także najtańszego przepływu w sieci). Omówione zostały również sposoby klasyfikacji i analizy zapotrzebowania na produkty, a także modele wspomagające tworzenie strategii uzupełniania zapasów (wielkość dostawy, ustalanie momentu wykonania zamówienia). W publikacji przedstawiono algorytmy harmonogramowania zadań produkcyjnych i modelowania przepływów produkcyjnych oraz, w sposób syntetyczny, podstawowe metody modelowania symulacyjnego – metodę dynamiki systemów, symulacji zdarzeń dyskretnych, modelowania wieloagentowego

The use of sugammadex for the reversal of vecuronium-induced neuromuscular block following intracranial surgery

  BACKGROUND: Total intravenous anaesthesia with propofol and remifentanil is widely used in neuroanaesthesiology and enables the quick recovery and early neurological assessment of patients. The administration of muscle relaxants carries a risk of residual relaxation following surgery. The administration of a suitable dose of sugammadex reverses the neuromuscular block irrespective of its depth and has none of the side effects associated with acetylcholinesterase inhibitors. The aim of the present study was to evaluate the usefulness of sugammadex for the reversal of vecuronium-induced effects following intracranial surgery. METHODS: The study involved 38 women who underwent supratentorial tumour removal. These women were randomly divided into two groups. Total intravenous anaesthesia with propofol and remifentanil using target-controlled infusion was administered according to the Schnider and Minto models, respectively. Endotracheal intubation was performed after the target concentrations of propofol and remifentanil reached 4 μg mL-1 and 4 ng mL-1, respectively. Vecuronium (100 μg kg-1) was administered, and no response to TOF stimulation was observed. Relaxation was continued via the continuous infusion of vecuronium (0.8–1.2 μg kg-1 min-1) to provide a TOF of 2 throughout the surgery. In group I, neuromuscular conduction was restored with intravenous sugammadex (2 mg kg-1), whereas in group II, no reversal agents were administered. RESULTS: The times of the return of spontaneous breathing, extubation, eye opening (both spontaneous and in response to a verbal command) were found to be longer in group II than group I. CONCLUSION: The use of sugammadex following craniotomy accelerates the achievement of optimal extubation conditions.    BACKGROUND: Total intravenous anaesthesia with propofol and remifentanil is widely used in neuroanaesthesiology and enables the quick recovery and early neurological assessment of patients. The administration of muscle relaxants carries a risk of residual relaxation following surgery. The administration of a suitable dose of sugammadex reverses the neuromuscular block irrespective of its depth and has none of the side effects associated with acetylcholinesterase inhibitors. The aim of the present study was to evaluate the usefulness of sugammadex for the reversal of vecuronium-induced effects following intracranial surgery. METHODS: The study involved 38 women who underwent supratentorial tumour removal. These women were randomly divided into two groups. Total intravenous anaesthesia with propofol and remifentanil using target-controlled infusion was administered according to the Schnider and Minto models, respectively. Endotracheal intubation was performed after the target concentrations of propofol and remifentanil reached 4 μg mL-1 and 4 ng mL-1, respectively. Vecuronium (100 μg kg-1) was administered, and no response to TOF stimulation was observed. Relaxation was continued via the continuous infusion of vecuronium (0.8–1.2 μg kg-1 min-1) to provide a TOF of 2 throughout the surgery. In group I, neuromuscular conduction was restored with intravenous sugammadex (2 mg kg-1), whereas in group II, no reversal agents were administered. RESULTS: The times of the return of spontaneous breathing, extubation, eye opening (both spontaneous and in response to a verbal command) were found to be longer in group II than group I. CONCLUSION: The use of sugammadex following craniotomy accelerates the achievement of optimal extubation conditions.

Complications after using the Airtraq laryngoscope for a predicted difficult intubation

Although standard management of an expected difficult intubation is based on fibre-optic techniques, the application of optical laryngoscopes such as Airtraq is gaining widespread acceptance. We here describe a case where an intubation attempt with the Airtraq laryngoscope was not only unsuccessful, but negatively influenced subsequent use of a flexible fibroscopic approach.Although standard management of an expected difficult intubation is based on fibre-optic techniques, the application of optical laryngoscopes such as Airtraq is gaining widespread acceptance. We here describe a case where an intubation attempt with the Airtraq laryngoscope was not only unsuccessful, but negatively influenced subsequent use of a flexible fibroscopic approach.

The effect of bispectral index monitoring on anaesthetic requirements in target-controlled infusion for lumbar microdiscectomy

Background: Target-controlled infusion (TCI) is used to maintain the desired concentration of a hypnotic drug in the plasma and brain. However, pharmacodynamic variability can cause problems with maintaining the adequate level of anaesthesia. The bispectral index (BIS) is one of only a few parameters that allow an assessment of the depth of anaesthesia. In the present study, we attempted to determine the optimal dosages of drugs used for total intravenous anaesthesia with TCI based on BIS-guided monitoring of depth of anaesthesia.Methods: The study was conducted in 60 ASA I patients undergoing elective surgery due to lumbar discopathy. The participants were divided into two groups of 30 individuals. The patients were premedicated with 15 mg oral midazolam. Group I was the control group; group II received BIS monitoring. Anaesthesia was induced with TCI propofol (4 mg mL-1), fentanyl (2 mg kg-1) and vecuronium (0.12 mg kg-1) and maintained with TCI propofol, continuous infusion of vecuronium (0.03 mg kg-1 h-1) and fractionated doses of fentanyl. ECG, HR, MAP, SaO2, ETCO2, and the degree of neuromuscular blockade were monitored, specifically at the following time points: T1 — before induction, T2 — after induction, T3 — after intubation, T4 — after positioning of the patient, T5-T13 — every 5 min during surgery, T14 — on completion of surgery, T15 — before extubation, T16 — after extubation.Results: The study groups were comparable in terms of age, body weight, duration of anaesthesia and recovery time. The haemodynamic parameters, such as HR and MAP, did not differ significantly between the groups. In both groups, changes in the mean MAP values were observed between T1 and T2, T2 and T3, T3 and T4 as well as T14and T15. The total dose of fentanyl and the doses of propofol were lower in the group that received BIS monitoring.Conclusion: BIS monitoring reduces the doses of opioids and hypnotics used during total intravenous anaesthesia by TCI.Background: Target-controlled infusion (TCI) is used to maintain the desired concentration of a hypnotic drug in the plasma and brain. However, pharmacodynamic variability can cause problems with maintaining the adequate level of anaesthesia. The bispectral index (BIS) is one of only a few parameters that allow an assessment of the depth of anaesthesia. In the present study, we attempted to determine the optimal dosages of drugs used for total intravenous anaesthesia with TCI based on BIS-guided monitoring of depth of anaesthesia.Methods: The study was conducted in 60 ASA I patients undergoing elective surgery due to lumbar discopathy. The participants were divided into two groups of 30 individuals. The patients were premedicated with 15 mg oral midazolam. Group I was the control group; group II received BIS monitoring. Anaesthesia was induced with TCI propofol (4 mg mL-1), fentanyl (2 mg kg-1) and vecuronium (0.12 mg kg-1) and maintained with TCI propofol, continuous infusion of vecuronium (0.03 mg kg-1 h-1) and fractionated doses of fentanyl. ECG, HR, MAP, SaO2, ETCO2, and the degree of neuromuscular blockade were monitored, specifically at the following time points: T1 — before induction, T2 — after induction, T3 — after intubation, T4 — after positioning of the patient, T5-T13 — every 5 min during surgery, T14 — on completion of surgery, T15 — before extubation, T16 — after extubation.Results: The study groups were comparable in terms of age, body weight, duration of anaesthesia and recovery time. The haemodynamic parameters, such as HR and MAP, did not differ significantly between the groups. In both groups, changes in the mean MAP values were observed between T1 and T2, T2 and T3, T3 and T4 as well as T14and T15. The total dose of fentanyl and the doses of propofol were lower in the group that received BIS monitoring.Conclusion: BIS monitoring reduces the doses of opioids and hypnotics used during total intravenous anaesthesia by TCI

Wpływ stopniowo narastających stężeń desfluranu na mózgowe ciśnienie perfuzyjne u królika

Background: In nearly all cases of general anaesthesia with a volatile agent, the anaesthetic concentration has to be increased. Since the anaesthetic affects both the factors determining intracranial homeostasis and the systemic circulation, it is crucial that cerebral perfusion pressure (CPP) is protected. The aim of the present study was to assess the influence of gradually increased concentrations of desflurane on the cerebral and systemic circulations based on CPP, mean arterial pressure (MAP), intracranial pressure (ICP) and their correlations. Methods: The study was carried out on 25 rabbits of the same gender (male) randomly assigned to two groups: control (n = 10) and group I (n = 15). Over three 15-minute periods, the animals were exposed to increase concentrations of desflurane so as to achieve 1/3, 2/3 and 1 MAC Minimal Alveolar Concentration (3, 6, 9 vol%) of the effective end-tidal concentration of desflurane (Et) at the end of each period, respectively. Results: Intragroup analysis of CPP changes demonstrated decreases in its successive values from minute 18, compared with baseline values. The mean values of ICP did not differ throughout the experiment. From minute 19 on, all successive values of MAP decreased compared with baseline values. A weak correlation (r = –0.2179) was found between ICP and CPP and a strong correlation between MAP and CPP (r = 0.98829). Moreover, there was a strong correlation between Etdesflurane vs. CPP (r = –0.8769) and MAP (r = –0.8224) and a weak correlation versus ICP (r = 0.15755). Conclusions: A decrease in CPP induced by desflurane was associated with a decrease in MAP but not an increase in ICP. The depressive effect of desflurane on the cerebral and systemic circulations is a consequence of its effector site concentration.Background: In nearly all cases of general anaesthesia with a volatile agent, the anaesthetic concentration has tobe increased. Since the anaesthetic affects both the factors determining intracranial homeostasis and the systemiccirculation, it is crucial that cerebral perfusion pressure (CPP) is protected. The aim of the present study was to assessthe influence of gradually increased concentrations of desflurane on the cerebral and systemic circulations based onCPP, mean arterial pressure (MAP), intracranial pressure (ICP) and their correlations. Methods: The study was carried out on 25 rabbits of the same gender (male) randomly assigned to two groups: control(n = 10) and group I (n = 15). Over three 15-minute periods, the animals were exposed to increase concentrations ofdesflurane so as to achieve 1/3, 2/3 and 1 MAC Minimal Alveolar Concentration (3, 6, 9 vol%) of the effective end-tidalconcentration of desflurane (Et) at the end of each period, respectively. Results: Intragroup analysis of CPP changes demonstrated decreases in its successive values from minute 18, comparedwith baseline values. The mean values of ICP did not differ throughout the experiment. From minute 19 on,all successive values of MAP decreased compared with baseline values. A weak correlation (r = –0.2179) was foundbetween ICP and CPP and a strong correlation between MAP and CPP (r = 0.98829). Moreover, there was a strong correlationbetween Etdesflurane vs. CPP (r = –0.8769) and MAP (r = –0.8224) and a weak correlation versus ICP (r = 0.15755). Conclusions: A decrease in CPP induced by desflurane was associated with a decrease in MAP but not an increasein ICP. The depressive effect of desflurane on the cerebral and systemic circulations is a consequence of its effectorsite concentration