The value of ventricular gradient for predicting pulmonary hypertension and mortality in hemodialysis patients.

Pulmonary hypertension (PHT) is associated with increased mortality in hemodialysis (HD) patients. The ventricular gradient optimized for right ventricular pressure overload (VG-RVPO) is sensitive to early changes in right ventricular overload. The study aimed to assess the ability of the VG-RVPO to detect PHT and predict all-cause and cardiac mortality in HD patients. 265 selected HD patients were enrolled. Clinical, biochemical, electrocardiographic, and echocardiographic parameters were evaluated. Patients were divided into normal and abnormal VG-RVPO groups, and were followed-up for 3 years. Abnormal VG-RVPO patients were more likely to be at high or intermediate risk for PHT, were older, had longer HD vintage, higher prevalence of myocardial infarction, higher parathormone levels, shorter pulmonary flow acceleration time, lower left ventricular ejection fraction, higher values of left atrial volume index, left ventricular mass index, and peak tricuspid regurgitant velocity. Both all-cause and CV mortality were higher in abnormal VG-RVPO group. In multivariate Cox analysis, VG-RVPO remained an independent and strong predictor of all-cause and CV mortality. In HD patients, abnormal VG-RVPO not only predicts PHT, but also all-cause and CV mortality.

Subdural infusion of dexamethasone inhibits leukomyelitis after acute spinal cord injury in a rat model.

Trauma in spinal cord injury often results in massive damage to the white matter and in damage to myelin that results in a severe phagocyte-rich infiltration apparently directed at removing immunologically toxic myelin debris. In the epidural balloon crush injury to the rat cranial thoracic spinal cord, the dorsal column was crushed, which at one week post-op resulted in its obliteration by a severe infiltration by a virtually pure population of macrophages that internalized all damaged myelin. A week-long subdural infusion of dexamethasone, a stable synthetic corticosteroid, resulted in remarkable inhibition of the macrophage infiltration of the crush cavity and in the lack of removal of myelin debris by phagocytosis. In this study we demonstrated that spinal cord injury results in a severe inflammatory response directed at massively damaged myelin, and we inhibited this response with a subdural infusion of a powerful anti-inflammatory drug, dexamethasone.

Association between intra-abdominal pressure and jugular bulb saturation in critically ill patients.

BACKGROUND: Disorders in cerebral circulation following elevated intra-abdominal pressure (IAP) may lead to silent brain ischemia, which can be serious problem in sedated critically ill patients. The aim of the present study was to analyse the possible association between jugular venous bulb pressure (JVBP) and jugular venous bulb saturation (SjO2) to IAP in critically ill patients. METHODS: Adult septic shock patients with acute kidney injury were studied just after the admission to Intensive Care Unit and after 24 and 48 hours of treatment. Patients were divided into: CVVH group (patients treated with continuous veno-venous haemofiltration) and furosemide group (patients treated with furosemide infusion). The IAP was measured via the bladder. The right jugular vein was retrogradely cannulated for JVBP and SjO2 measurement. Intra-abdominal hypertension was defined as a sustained increase of IAP equal to or above 12 mmHg. RESULTS: Forty patients (25 male and 15 female patients) were studied. In all participants, IAP strongly correlated with JVBP (P<0.001, r=0.73). This correlation was stronger in the furosemide group than the CVVH group. Moreover, an increase in IAP was related to an increase in JVBP and a decrease in SjO2. There was an inverse correlation between IAP and SjO2 (P<0.001, r=-0.55). This correlation was stronger in furosemide group than CVVH group. CONCLUSION: IAP is correlated to JVBP and inversely correlated to SjO2. Increase in IAP leads to elevation in JVBP and decrease in SjO2. Renal replacement therapy disturbs the correlation between IAP, JVBP and SjO2.

Dense arrays of micro-needles for recording and electrical stimulation of neural activity in acute brain slices.

OBJECTIVE: This paper describes the design, microfabrication, electrical characterization and biological evaluation of a high-density micro-needle array. The array records from and electrically stimulates individual neurons simultaneously in acute slices of brain tissue. APPROACH: Acute slices, arguably the closest in-vitro model of the brain, have a damaged surface layer. Since electrophysiological recording methods rely heavily on electrode-cell proximity, this layer significantly attenuates the signal amplitude making the use of traditional planar electrodes unsuitable. To penetrate into the tissue, bypassing the tissue surface, and to record and stimulate neural activity in the healthy interior volume of the slice, an array of 61 micro-needles was fabricated. MAIN RESULTS: This device is shown to record extracellular action potentials from individual neurons in acute cortical slices with a signal to noise ratio of up to ∼15:1. Electrical stimulation of individual neurons is achieved with stimulation thresholds of 1.1-2.9 µA. SIGNIFICANCE: The novelty of this system is the combination of close needle spacing (60 µm), needle heights of up to 250 µm and small (5-10 µm diameter) electrodes allowing the recording of single unit activity. The array is coupled to a custom-designed readout system forming a powerful electrophysiological tool that permits two-way electrode-cell communication with populations of neurons in acute brain slices.

Intra-abdominal and abdominal perfusion pressure in patients undergoing coronary artery bypass graft surgery.

BACKGROUND: In 2006, the International Conference of Experts on Intra-abdominal Hypertension defined abdominal perfusion pressure (APP) as the difference between mean arterial pressure (MAP) and intra-abdominal pressure (IAP).The aim of the study was to analyse changes in IAP and APP in patients undergoing elective coronary artery bypass grafting (CABG). PATIENTS AND METHODS: Fifty patients undergoing CABG with extracorporeal circulation (ECC) and normovolemic haemodilution (NH) under general anaesthesia were studied. IAP and APP were measured during CABG and in the early postoperative period. Changes in IAP and APP were analysed according to degree of normovolemic haemodilution, age, body weight, body mass index (BMI), duration of anaesthesia, surgery, ECC, aorta clamping and other haemodynamic parameters. RESULTS: The induction of anaesthesia decreased IAP. Extracorporeal circulation resulted in IAP elevation, which was dependent on the degree of blood dilution. At any time point of the postoperative period IAP higher than 12 mmHg was noted in 22 patients (44%). Abdominal perfusion pressure decreased during ECC and on the morning of the first postoperative day. Intra-abdominal pressure strongly correlated with BMI and central venous pressure. The correlation between IAP and APP and other haemodynamic parameters was poor. CONCLUSIONS: 1) The induction of anaesthesia decreased IAP. 2) ECC resulted in an increase in IAP. 3) IAP increased in 44% of patients. 4) IAP strongly correlated with BMI and central venous pressure. 5) CABG with ECC resulted in a decrease in APP. 6) Changes in APP strongly correlated with MAP and poorly correlated with other haemodynamic parameters. 7) The changes in APP demonstrated a double-phase character.

Changes of blood magnesium concentration in patients undergoing surgical myocardial revascularisation.

BACKGROUND: Magnesium (Mg) is the second most relevant intracellular element, which plays an important role in many physiological processes. Magnesium disorders are particularly important in haemodynamically unstable patients, such as patients after extracorporeal circulation. The aim of this study was to analyze the changes in blood Mg levels in patients undergoing coronary artery bypass procedures with extracorporeal circulation. PATIENTS AND METHODS: Twenty male patients, aged 50-69, undergoing CABG with ECC under general anaesthesia, were included in the study. All of them were operated on due to Io and IIo degree coronary disease (according to CCS). The blood concentrations of Mg were examined in five stages: 1) before the induction of anaesthesia; 2) during extracorporeal circulation; 3) after surgery; 4) in the morning of the first postoperative day; 5) in the morning of the second postoperative day. The blood Mg concentrations were determined by spectrophotometric methods. RESULTS: The blood concentration of Mg decreased during extracorporeal circulation and immediately after surgery and increased in the morning of the first and second postoperative days. CONCLUSION: The CABG with extracorporeal circulation resulted in a significant decrease in blood Mg concentration.

The effect of preoperative magnesium supplementation on blood catecholamine concentrations in patients undergoing CABG.

BACKGROUND: It is well known that magnesium (Mg) plays an important role in many physiological processes such as regulation of blood catecholamine concentrations, particularly epinephrine (E) and norepinephrine (NE). The complex character of extracorporeal circulation (ECC) with intraoperative normovolemic haemodilution (NH) may alter blood Mg levels, which is likely to result in disorders of E and NE. The aim of this study was to analyze the influence of preoperative Mg supplementation on E and NE in patients undergoing CABG. PATIENTS AND METHODS: Forty male patients undergoing CABG under general anaesthesia were included. Patients were randomly divided into two groups: A--the patients receiving pre-operative magnesium supplementation and B--patients without pre-operative magnesium supplementation. The Mg, E and NE blood concentrations were measured in five stages: 1) before anesthesia after the radial artery cannulation, 2) during NH and ECC, 3) immediately after surgery, 4) in the morning of the 1st postoperative day, 5) in the morning of the 2nd postoperative day. The Mg levels were determined by spectrophotometric methods, E and NE were measured by radioimmunoassay methods. RESULTS: The CABG caused a decrease of Mg and an increase of E and NE in both groups, but the changes were significantly higher in group B. CONCLUSIONS: 1) CABG causes a decrease of Mg and an increase of E and NE; 2) Preoperative, oral supplementation of Mg substantially reduces intra- and postoperative disorders.

Blood magnesium concentration and dopamine or dobutamine infusion demand in patients during CABG (coronary artery bypass grafting) with normovolemic haemodilution.

UNLABELLED: It is well known that magnesium (Mg) plays an essential role in cardiac protection. Mg has many beneficial effects on the myocardium and cardiac function, e.g. it improves contractility and reduces the number of cardiac arrhythmia episodes. The inotropically positive effects of Mg are interesting and worth stressing. High blood Mg concentration may result in an increase in cardiac contraction strength, which may be important for haemodynamic stabilization, and thus it is likely to decrease the demand for dopamine and dobutamine infusions. However, the exact determination of correlation between blood Mg concentrations and dopamine or dobutamine infusion demand is still unknown. The aim of the study was to assess the demand for dopamine or dobutamine infusion in relation to changes in blood magnesium concentrations in patients undergoing CABG (Coronary artery bypass graft) with extracorporeal circulation and normovolemic haemodilution. The study included 20 male patients, aged 53-70 (61.1 +/- 6.9) who underwent general anaesthesia and coronary artery bypass grafting (CABG) with extracorporeal circulation (ECC) and normovolemic haemodilution (NH) due to stable angina pectoris. The patients were retrospectively divided into three groups: A--patients who did not receive dopamine or dobutamine infusion, B--those receiving only D infusion in the doses dependent on their clinical state and C--those receiving DB infusion in the doses dependent on their clinical state. Mg was measured in 7 stages: 1) just before anaesthesia after the radial artery cannulation, 2) during normovolemic haemodilution and ECC, 3) immediately after surgery, 4) in the evening of the surgery day, 5) in the morning of the lst postoperative day, 6) in the evening of 1st postoperative day, 7) in the morning of the 2nd postoperative day. The spectrophotometric methods were used to determine Mg. The CABG procedure resulted in a decrease in Mg. Its level returned to normal in the evening of surgery day. The NH caused a similar Mg decrease in groups A, B and C, but these significantly low values of Mg were observed only in stage 2. There was no correlation between blood Mg concentrations and dopamine or dobutamine infusion demand. IN CONCLUSION: 1) The CABG procedure resulted in decreased blood magnesium concentrations. 2) The Mg changes do not correlate with dopamine or dobutamine infusion demand.

The relationship between magnesium, epinephrine and norepinephrine blood concentrations during CABG with normovolemic hemodilution.

The effects of procedures with extracorporeal circulation on the disturbance of relationships between blood magnesium (Mg), epinephrine, and norepinephrine levels have not been explicitly explained. It is assumed that both hypomagnesemia and increased concentration of the above mentioned hormones exert adverse effects on the myocardium often causing life threatening disorders. This problem is particularly important in cases of stunned myocardium, observed after extracorporeal circulation procedures. The complex nature of the procedures and the intraoperative normovolemic hemodilution (NH) employed are likely to alter Mg, epinephrine, and norepinephrine concentrations, as well as the above mentioned relations. The aim of the study was to evaluate the changes in blood Mg, epinephrine and norepinephrine concentrations in patients undergoing extracorporeal circulation and normovolemic hemodilution. The study encompassed 16 men operated on for stable coronary disease (I or II degrees according to the Canadian Scale). The patients were divided into two groups according to body weight: A) patients weighing less than 75 kg and B) patients weighing more than 75 kg. The degree of NH caused by constant volume of priming (1800 mL) was determined on the basis of hematocrit measurements and in relation to body weight. The examinations were conducted in 5 stages: 1) after radial artery cannulation before anaesthesia and surgery, 2) during hemodilution and deepest hypothermia, 3) after surgery before sending the patient to Intensive Postoperative care Unit, 4) in the first postoperative day, 5) in the second postoperative day. The observations showed an increase in epinephrine levels in group A in the second stage and of norepinephrine levels in stage 4. Decreased blood Mg levels were noted in all the patients in the second stage, however in group A significantly lower values were also observed in stage 3. Moreover, the correlation between Mg level changes and blood epinephrine and norepinephrine levels were observed. The study revealed significant effects of extracorporeal circulation procedures on adrenergic reactions as well as blood magnesium concentrations. It seems that the degree of NH is the main factor determining blood levels of Mg, epinephrine and norepinephrine during the use of a heart-lung apparatus, which may be particularly relevant in patients with impaired heart function and low body weight.

The degree of lymphocytic mitochondrial transmembrane potential and blood magnesium concentrations during coronary artery bypass grafting.

UNLABELLED: Magnesium (Mg) plays an important role in lymphocyte function. Low blood concentration of Mg may result in intralymphocyte imbalance and in turn may be associated with intensified apoptosis of peripheral blood lymphocytes. Due to its multistage character; extracorporeal circulation (ECC) may augment Mg disorders adding to the above mentioned pathology. The aim of this study was to assess the correlation between lymphocyte apoptosis and Mg concentration in the blood during the course of coronary artery bypass grafting (CABG) and in the early postoperative period. METHOD: Twenty male patients undergoing CABG with ECC under general anaesthesia were included in the study. For detection of apoptotic lymphocytes in the circulation, inner mitochondrial transmembrane potential (deltapsim) was measured with the use of chloromethyl-X-rosamine (CMXRos) and flow cytometry. Spectrophotometry was used for Mg blood concentration measurements. Peripheral blood samples were obtained in seven stages: 1) just before anaesthesia, 2) 2 hours after the beginning of surgery, 3) immediately after surgery, 4) 12 hours after the beginning of surgery, 5) 24 hours after the beginning of surgery, 6) 36 hours after the beginning of surgery, 7) 54 hours after the beginning of surgery. RESULTS: The statistically significant increases of lymphocyte apoptosis were noted in stages from 2 to 7. Blood Mg concentrations decreased in stages 2 and 3. There was negative correlation between Mg blood concentration in stages 2 and 3 and the intensity of lymphocyte apoptosis in the stage 5. CONCLUSIONS: 1) CABG with extracorporeal circulation was associated with a decrease of magnesium concentration in the blood and an increase of lymphocyte apoptosis intensity. 2) The decrease of magnesium blood concentration may increase the degree of lymphocyte apoptosis. 3) Lymphocyte apoptosis after extracorporeal circulation has a two-phase course.

A low noise multichannel integrated circuit for recording neuronal signals using microelectrode arrays.

This paper reports on the development of a fully integrated 32-channel integrated circuit (IC) for recording neuronal signals in neurophysiological experiments using microelectrode arrays. The IC consists of 32 channels of low-noise preamplifiers and bandpass filters, and an output analog multiplexer. The continuous-time RC active filters have a typical passband of 20-2000 Hz; the low and the high cut-off frequencies can be separately controlled by external reference currents. This chip provides a satisfactory signal-to-noise ratio for neuronal signals with amplitudes greater than 50 microV. For the nominal passband setting, an equivalent input noise of 3 microV rms has been achieved. A single channel occupies 0.35 mm(2) of silicon area and dissipates 1.7 mW of power. The chip was fabricated in a 0.7 microm CMOS process.

The seasonal variability of yeasts and yeast-like organisms in water and bottom sediment of the Szczecin Lagoon.

Qualitative and quantitative analysis of samples of water and bottom sediment from the Szczecin Lagoon were carried out from May, 1996 to December, 1997. Isolates of yeasts and yeast-like fungi from water samples reached maximum counts in July whereas sediment samples revealed highest counts in May. Qualitative analysis showed that Candida famata and Rhodothorula rubra were dominant species. As they are typical of strongly eutrophic water their presence indicates that the Szczecin Lagoon is significantly polluted by industrial and municipal sewage.

A real vessel phantom for flow imaging: 3-D Doppler ultrasound of steady flow.

Vascular phantoms are used to assess the capabilities of various imaging techniques, such as x-ray CT and angiography, and B-mode, power Doppler, and colour Doppler ultrasound (US). They should, therefore, accurately mimic the vasculature, blood, and surrounding tissue, in regard to both imaging properties and vessel geometry. In the past, a variety of walled and wall-less vessel models have been used. However, these models only approximate the true vessel geometry, and generally lack pathologic features such as plaques or calcifications. To amend these deficiencies, we have developed a real vessel phantom for US and x-ray studies, which comprises a fixed human vessel specimen, cannulated onto two acrylic tubes, and embedded in agar in an acrylic box. Earlier, we demonstrated a good overall correlation between x-ray angiography, CT, and 3-D B-mode US images of this phantom. Here, we extend its use to flow imaging with 3-D power and 3-D colour Doppler US.

[Anaesthesia for thyroid surgery in the patient suffering from myasthenia gravis]. / Znieczulenie chorej z miastenia do operacji tarczycy.

The preparation and perioperative treatment of patients with myasthenia gravis and hyperthyreosis constitutes a serious problem for a surgeon as well as an anaesthetist. The need of anticholinesterase therapy application makes it difficult to achieve euthyreosis in the patients. The aim of this case report is to present perioperative management and the methods used in anaesthesia in 41-year-old woman suffering from both illnesses.

Evaluation of the API test, phosphatidylinositol-specific phospholipase C activity and PCR method in identification of Listeria monocytogenes in meat foods.

The aim of this work was to compare the possibility of identifying Listeria monocytogenes strains isolated from meat and sausage on the basis of the API-Listeria test, production of phosphatidylinositol-specific phospholipase C (PI-PLC) and polymerase chain reaction (PCR) for a DNA fragment of the hlyA gene encoding listeriolysin O. Forty-six strains were isolated and examined. The lethality of some Listeria isolates for BALB/c mice was also determined. In this study, all isolates identified as L. monocytogenes in the API test gave a positive signal in the PCR. Listeriae identified as L. innocua or L. welshimeri in the API test were negative in the PCR conducted with the primers for listeriolysin O. All strains identified as L. monocytogenes on the basis of the API test and the PCR produced PI-PLC. However, this activity was not limited to the bacteria of this species. Four out of 17 L. innocua and three out of 10 L. welshimeri isolates were PI-PLC-positive. None of the L. innocua or L. welshimeri isolates (neither PI-PLC+ or PI-PLC-) showed lethality for BALB/c mice. In contrast, two L. monocytogenes isolates as well as a reference L. monocytogenes strain killed all mice used for the experiment.

[Hemodynamic changes during cholecystectomy with the use of laparolift method]. / Zmiany hemodynamiczne podczas operacji cholecystektomii metoda laparoliftu.

The study was carried out in 17 randomly chosen patients who were subjected to cholecystectomy under general anesthesia with the use of laparolift method. Heart rate, systolic and diastolic blood pressure, wedge pressure, mean pulmonary artery pressure, central venous pressure and stroke volume were analyzed in the five following stages of the procedure. The performed examinations showed the transient increase of the pressures in peripheral and pulmonary vascular system as well as heart rate acceleration--during the operation and the increase of cardiac output in postoperative period. The observed changes did not need therapeutic interventions in any case. The obtained results prove that applied operative technique caused no dangerous side effects.

A real vessel phantom for imaging experimentation.

Vascular phantoms are used to evaluate imaging techniques such as ultrasound (US), CT, and angiography. They are expected to mimic the vasculature, surrounding tissue, and blood, and therefore must meet specific requirements on the mimicking materials, with respect to x-ray attenuation and acoustic properties (velocity, attenuation). In the past, researchers have used a variety of vessel models, including walled (typically latex tube) and wall-less phantoms (obtained by moulding a lumen in a block of agar). These models lacked the exact geometry of human vessels as well as pathologic features such as plaques and calcifications. To overcome these disadvantages, this paper describes a real vessel phantom for US and x-ray studies. The phantom consists of an agar-filled acrylic box containing a formaldehyde fixed section of a real human vessel (obtained at autopsy) cannulated onto two acrylic tubes. This phantom was evaluated by comparing the images obtained with x-ray angiography, CT, and 3-D B-mode US. The images show good overall correlation based on the location of the geometrical features within the phantom, such as lumen, plaques, and calcifications. Discrepancies, artifacts, and difficulties were minor, and are discussed. The use of a real vessel, with its natural geometry and pathology, makes this phantom attractive for evaluation of imaging techniques including projection radiography, CT and US, and for extending its use to MR and US based flow studies.