[Diagnosis and antibiotic therapy of nosocomial pneumonia in adults: from recommendations to real practice. A review].

Nosocomial pneumonia is a healthcare-associated infection with significant consequences for the patient and the healthcare system. The efficacy of treatment significantly depends on the timeliness and adequacy of the antibiotic therapy regimen. The growth of resistance of gram-negative pathogens of nosocomial pneumonia to antimicrobial agents increases the risk of prescribing inadequate empirical therapy, which worsens the results of patient treatment. Identification of risk factors for infection with multidrug-resistant microorganisms, careful local microbiological monitoring with detection of resistance mechanisms, implementation of antimicrobial therapy control strategy and use of rational combinations of antibacterial drugs are of great importance. In addition, the importance of using new drugs with activity against carbapenem-resistant strains, including ceftazidime/aviabactam, must be understood. This review outlines the current data on the etiology, features of diagnosis and antibacterial therapy of nosocomial pneumonia.

Identification of risk factors and development of a predictive model for bloodstream infection in intensive care unit COVID-19 patients.

OBJECTIVES: To identify risk factors for nosocomial bloodstream infections (BSIs) in intensive care unit (ICU) patients with COVID-19 and to build a predictive model for BSIs. PATIENTS AND METHODS: The retrospective case-control study included 236 ICU COVID-19 patients with BSIs group and 234 patients in the control group. Demographic and laboratory data, comorbidities, drug use, invasive procedures and identified pathogens were recorded separately for patients directly admitted and transferred to ICU. Fine and Gray's multi-variate competing risk model was used to build a predictive model for patients transferred to ICU. RESULTS: The risk factors were: interleukin inhibitors (HR = 6.1 (95% CI: 2.0-18.5)) and dexamethasone (HR = 3.0 (95% CI: 1.3-7.1)) use in previous hospitalization, glomerular filtration rate <60 mL/min per 1.73 m2 (HR = 4.0 (95% CI: 2.1-7.6)) and blood glucose >9 mmol/L (HR = 2.5 (95% CI: 1.4-4.6)) in patients directly admitted to ICU; and dexamethasone use in previous hospitalization (HR = 4.5 (95% CI: 1.8-11)), the total dexamethasone dose before transfer to ICU (HR = 1.2 (95% CI: 1.06-1.37)), diabetes mellitus (HR = 1.4 (95% CI: 1.1-1.9)), alanine transaminase (ALT) ≥35.5 U/L on hospital admission (HR = 1.5 (95% CI: 1.1-2.1)), and the use of low-flow oxygen versus high-flow oxygen therapy or non-invasive mechanical ventilation on admission to ICU ((HR = 2.7 (95% CI: 5.6-11.1)) in patients transferred to ICU. A predictive model had sensitivity of 63-73% and specificity of 71-83% at different times of ICU stay. CONCLUSIONS: Our findings may help clinicians detect patients at high risk of developing BSIs.

Influence of occupational noise on hearing: systematic review of foreign literature.

The article is aimed to systematically review evidence-based data published in foreign literature on influence of level and characteristics of occupational noise on hearing loss. Search of the literature was based on key words "occupational noise exposure, permissible exposure limit, dose-response relationship, acceptable noise level, noise-induced hearing loss" The authors studied 349 publications, 7 out of which were included into the present systematic review. Findings are that developed countries demonstrate a tendency to decreased prevalence of hearing loss among workers exposed to noise. Occupational groups with increased risk include workers of mining, machinery, light industries and agriculture. Lower occupational risk or no risk of hearing loss is seen in education, transport workers, musicians and other groups. Occupational noise level of 80 dB is a theoretically minimal exposure level resulting in no increase in hearing loss risk. Following normal noise level at 85 dB could decrease prevalence of hearing loss due to noise.

Critical terrace width for two-dimensional nucleation during Si growth on Si(111)-(7×7) surface.

The critical terrace width λ for 2D island nucleation and growth (2DNG) on large-scale atomically flat terraces of a step-bunched Si(111)-(7×7) surface has been studied by in situ ultrahigh vacuum reflection electron microscopy as a function of the substrate temperature T and Si deposition rate R. The dependence of λ(2)(R) is characterized by a power law with scaling exponent χ=1.36-1.46, validating an attachment limited (AL) growth kinetics up to 720 °C. At this temperature, the Arrhenius dependencies lnλ(2)(1/T) change their slope, so that the effective 2DNG activation energy E(2D) drops from 2.4 eV down to 0.5 eV at T>720 °C. We first show that the E(2D) change is caused by a transition between AL and DL (diffusion limited) growth kinetics accompanied by a step shape transformation. The AL growth mode is characterized by kinetic length d(-)~10(5)a and the preferential step-down attachment of atoms to steps limited by an energy barrier E(ES)(-)≈0.9 eV.

Crystallization of amorphous Si nanoclusters in SiO(x) films using femtosecond laser pulse annealings.

The SiO(x) films of various stoichiometries deposited on Si substrates with the use of the co-sputtering from two separate Si and SiO2 targets were annealed by femtosecond laser pulses. Femtosecond laser treatments were applied for crystallization of amorphous silicon nanoclusters in the silicon-rich oxide films. The treatments were carried out with the use of Ti-Sapphire laser with wavelength 800 nm and pulse duration about 30 fs. Regimes of crystallization of amorphous Si nanoclusters in the initial films were found. Ablation thresholds for SiO(x) films of various stoichiometries were discovered. The effect of laser assisted formation of a-Si nanoclusters in the non-stoichiometric dielectric films with relatively low concentration of additional Si atoms was also observed. This approach is applicable for the creation of dielectric films with semiconductor nanoclusters on non-refractory substrates.

[Influence of auxiliary materials on the proportion of effective particle size of metered-dose suspension type aerosols]. / Segédanyagok hatása szuszpenziós inhlációs aeroszolok hatékony szemcseméret-tartományának dózisonkénti mennyiségére.

The aim of the present study was to formulate suspension type inhalation aerosols by various types of auxiliary materials, and to select the formulation with the highest proportion of the effective particle size. The examined suspension type aerosol contained sodium cromoglycate as an active compound. For the stabilization of the suspension, the applied surface active ingredients were oleic acid and oleyl oleate, and dimethyl siloxane polymer was selected as hydrophobizing agent. Factorial design was used for the optimization of the experimental results. On the basis of our results, the correct types and amounts of auxiliary materials can be selected to obtain the therapeutically effective formulation.

Comparative evaluation of surfactant and hydrophobizing agent concentration in relation to the optimal particle size of metered-dose inhalers.

The aim of the present study was to formulate stabilized suspension-type metered-dose inhalation aerosols, and to examine the connection between the stabilizing additives and the optimal particle size. For the stabilization of the suspended particles, hydrophilic- and hydrophobic-type additives were applied. Oleil oleate was selected as a hydrophilic anionic surfactant, and the hydrophobizing agent was dimethyl siloxane polymer. The effect of the amount of the applied hydrophilic and hydrophobic additives on the optimal particle size was modeled by a second-order polynomial equation fitted to the data gathered by a face-centered central composite statistical design. We found that if the proper type and amount of additives are selected, it is possible to acquire the therapeutically best composition.

The effect of surfactant and suspending agent concentration on the effective particle size of metered-dose inhalers.

The aim of this study was to examine the influence of the concentrations of surfactant and suspending agent on the quantity of effective particles (size < 10 microm) delivered by metered-dose inhalers. A 2-factor, 3-level, face-centred central composite design was used to construct a second-order polynomial model which describes the effect of formulation factors (suspending agent, surface-active ingredient) on the therapeutically important characteristic (effective particle size) delivered by metered-dose inhalers. Oleic acid was selected as the surface-active ingredient, and the suspending agent was anhydrous alcohol. A non-linear model demonstrated with good correlation the effect of the amounts of surfactant and suspending agent on the quantity of particles of effective size. The results obtained enable determination of the correct amount of surface-active ingredient and the optimum quantity of the suspending agent, thus enabling formulation of a therapeutically effective formulation.

[Usage modeling test in aerosols formulations]. / Hasznlatot modellezó vizsgálatok gyógyszeres aeroszol készítményekkel.

Authors emphasize the importance of "usage-modelling" test concerning the uniformity of doses in the case of aerosol formulations, containing propellants or supplied with atomising devices. Weight measurement was carried out to identify the uniformity of doses per actuation keeping non-use periods in the case of water-based solutions with different density and suspension containing HFC propellants. It can be concluded that uniformity of doses--applying non-use periods during the testing time--significantly depends on the composition, the density of the formulation and the spraying mechanism of the atomising device.

Differential sympathetic reactions during cerebral ischaemia in cats: the role of desynchronized nerve discharge.

1. Sympathetic nerve discharge (SND) of three postganglionic nerves with different functions and anatomical locations was simultaneously recorded at rest and during severe cerebral ischaemia (Cushing reaction). The three nerves, controlling the heart (inferior cardiac nerve), visceral (renal nerve) and skeletal muscle circulation (vertebral nerve), were selected with the assumption that their activity pattern will represent the differential central autonomic command to the major players of the circulatory response to cerebral ischaemia. 2. Changes in the power density spectra of the nerve signals, and in the pairwise coherence functions, elicited by the cerebral ischaemia, were evaluated separately for the rhythmic (R-SND, i.e. between 0 and 6 Hz) and high-frequency (HF-SND, i.e. between 12 and 100 Hz) components of the nerve signals. 3. The sympathetic nerve response to cerebral ischaemia developed in two phases. Phase 1 was a massive R-SND reaction and phase 2 was characterized by SND desynchronization and by the emergence of HF-SND. The power of HF-SND occupied a wide band between 12 and 80 Hz with maximum between 20 and 30 Hz. All three nerves were involved in the Cushing response but the magnitude and character of the reactions were specific for each nerve. In the cardiac nerve, the power of the rhythmic component of the discharge increased almost twice the control and remained dominant during the whole reaction, strongly modulating HF-SND during the second phase. In the vasomotor nerves, R-SND was suppressed during phase 2 and HF-SND occupied 65% of the total power of the signal. Near equal R- to HF-SND proportions, however, were reached on different activity levels in renal and vertebral nerves. Whereas total renal SND did not change, the power of the vertebral SND increased more than twice. In addition, desynchronization in the vertebral SND was preceded by a massive R-SND reaction during phase 1, which was missing in the renal nerve. 4. For all possible nerve pairs, R-SND was highly coherent before the reaction and remained so during intracranial pressure elevation, regardless of the direction and magnitude of the changes in absolute and/or relative power of this component in different nerves. On the other hand, HF-SND never correlated between any of the nerve pairs indicating that this component in each nerve originated from specific sources of regional sympathetic activity.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of preexisting brain ischemia on sympathetic nerve response to intracranial hypertension.

The performance of the sympathetic nervous system during sustained moderate cerebral ischemia (CI) was examined in the present study. For this purpose, a Cushing response was elicited repeatedly during incomplete global CI in anesthetized artificially ventilated cats after vagotomy and baroreceptor denervation. In control animals without CI, sympathetic activity in response to brief elevation of intracranial pressure (ICP) showed a well-repeatable two-phase reaction. During CI there was a progressive deterioration of background sympathetic nerve discharge (SND) over a period of 30 min. SND response to repeated elevation of ICP was initially similar to control response but later with progression of CI was seriously changed. 1) Instead of the usual hyperactivation, sympathetic nerve activity was depressed during intracranial hypertension. 2) The characteristic desynchronized activity either appeared later during the reperfusion period or remained absent. The progressive loss of SND response to raised ICP in developed CI was compared with the changes seen in experiments in which repeated ICP elevations were superimposed on asphyxia. These findings suggest that the sympathetic component of the Cushing reaction strongly depends on the actual state of brain stem autonomic circuits and may be seriously altered in pathological situations involving ischemic brain injury.

Comparison of methods eliciting cerebral ischaemic pressor response in the cat.

Three methods of intercepting the blood supply to the brain were tested by means of X-ray angiography and by monitoring the pressor response following cerebral ischaemia. The methods were: (1) occlusion of carotid and basilar artery; (2) occlusion of carotids and vertebral arteries in the cervical canal of the third vertebra; (3) occlusion of carotid and subclavian arteries. The X-ray angiographs showed that in most cases we could close the accessory sources of the cerebral circulation and drastically reduce the blood supply to the brain of the cat. With all three methods the cerebral ischaemia evoked strong blood pressor elevation, which was weaker however when the carotid and basilar artery were clamped, in comparison with the other two methods. This may be explained by the existence of small arteries supplying the lower brain stem and originating intracranially from the vertebral artery near to the junction of the vertebral and anterior spinal artery.

Transplantation of cultured embryonic spinal cord grafts into the hemisected spinal cord of adult rabbits.

Spinal cord fragments from 20-day-old rabbit embryos cultivated for 1 week were transplanted into the hemisected and intact spinal cord of adult rabbits. The morphological changes at the site of intervention were investigated by light and electron microscopy 3, 12, and 29 weeks following implantation. In 80% of the animals the procedure was successful. The implants grew in volume, the cells matured, and many new neural processes with myelinization and synapse formation appeared. The histological findings indicate the survival, maturation, and integration of transplanted cultured embryonic spinal cord tissue in the lesioned adult spinal cord.

Two-phase change of sympathetic rhythms in brain ischemia, Cushing reaction, and asphyxia.

The present study was designed to determine the extent to which the brain stem neural networks, normally capable of synchronizing the sympathetic nerve discharge (SND) into 2- to 6- and 10-Hz rhythmic fluctuations, contribute to the control of autonomic reactions during brain hypoxia and/or hypercapnia. Vertebral, cardiac, and renal nerve discharges were recorded electrophysiologically in 34 anesthetized, curarized, and artificially ventilated cats. The sympathetic nerve responses to cerebral ischemia (elicited by reducing the blood supply to the brain), intracranial pressure elevation (Cushing reaction), and systemic asphyxia were tested with special focus on the rhythmic structure of the SND. It has been found that there are two phases of SND changes during cerebral ischemia differing mainly in the frequency content of the signals and less in the compound action potential amplitude. During the first phase the rhythmic generators controlling the tonic sympathetic outflow are more strongly activated, which is reflected in a stronger, more regular, and more widespread manifestation of these rhythms on the efferent neurograms. After some time the normal SND structure abruptly changes to a desynchronized activity with loss of the three main sympathetic rhythms and responsiveness to baroreceptor reflex activation. The same stereotyped changes can be observed regardless of the way in which the brain hypoxia and/or hypercapnia has been produced. Nor does the denervation of peripheral baro- and chemoreceptors substantially alter the general pattern of the responses.

In vitro assessment of MR relaxation properties of pituitary adenomas.

Proton magnetic relaxation times (T1 and T2) and bound water content were measured in vitro in pituitary adenomas from 15 patients using 90 MHz radiofrequency excitation. These data were compared with those measured in normal pituitary glands obtained from four cats and seven fresh human cadavers. The T1 and T2 measured at 24 degrees C in the tumors (mean +/- SD: 1,170 +/- 80 and 123 +/- 35 ms, respectively) were significantly higher than those of cadaver pituitary (830 +/- 200 and 76 +/- 12 ms) and cat pituitary gland (790 +/- 120 and 69 +/- 10 ms). Although the absolute values were lower, similar differences were present in T1 measured at 4 degrees C. Two-dimensional T2 versus T1 plot was particularly helpful in distinguishing tumor from the normal gland. When tumors were grouped according to density on CT, histology or previous treatment (e.g., irradiation or bromocriptine), there were no significant differences in T1 values between the groups. Bound water content was not found to correlate with T1 or T2 values. We concluded that pituitary adenomas can be distinguished from normal pituitary glands by their different relaxation properties when measured at high frequency in vitro MR.

Activity of peripheral sympathetic efferent nerves in experimental subarachnoid haemorrhage. Part II: Observations during the "early vasospasm" period.

The efferent activity of the vertebral, cardiac and renal sympathetic nerves was recorded during the so-called "early vasospasm" period, 25-30 minutes after experimentally induced subarachnoid haemorrhage. Experiments were performed on 51 cats with methods described in Part I of our publication. The animals were held either in a sphynx-like position (Pos. I), or in head-down position (Pos. II), when the level of the cisterna magna was 2-3 cm below the level of the spinal cord, facilitating the injected blood to flow in to, and remain at the base of the brain. According to our results during the "early vasospasm" period, we could not observe such changes in the sympathetic efferent activity, which could be specific for this period. With the gradual decrease in the intracranial pressure, the sympathetic overactivity ceased, and in most cases the level of activity was similar to that of the preinjection period. Our results also indicate that because of the remarkable variability of the activity of the renal sympathetic nerve during the intracranial pressure elevation, recording the activity of one sympathetic nerve only may give misleading results concerning the activity of the whole sympathetic system.

Activity of peripheral sympathetic efferent nerves in experimental subarachnoid haemorrhage. Part I: Observations at the time of intracranial hypertension.

The origin and pathomechanism of vegetative disturbances in patients suffering from subarachnoid haemorrhage are not completely clarified. Since some of these alterations in vegetative functions may well be attributed to acute changes in sympathetic activity, we initiated a study to investigate this modality in experimentally induced subarachnoid haemorrhage. Experiments were performed on 51 cats, anaesthetized with alpha-chloralose and urethane, immobilized and artificially ventilated. Compound electrical discharges of the left vertebral, cardiac and renal sympathetic nerves, ECG, EEG, end-tidal CO2, systemic arterial blood pressure and intracranial pressure were recorded on a polygraph. Subarachnoid haemorrhage was simulated by the injection of 1-5 ml of fresh, autologous blood into the cisterna magna. Mock cerebrospinal fluid was also injected as a control. Our results showed that in induced subarachnoid haemorrhage, not the blood itself but the intracranial pressure elevation might be responsible for the strong increase in sympathetic efferent activity. With the direct recording of the electrical activity of the three sympathetic nerves, we were able to verify the sympathetic overactivity underlying the cardiovascular disturbances during intracranial pressure elevation. Regarding the mechanism of the overactivity, most probably not the ischaemia or hypoxia, but the mechanical distortion of the medulla could be the adequate stimulus of the sympathetic overactivity and the Cushing response during intracranial pressure elevation.

[Comparative study of different strains of the dwarf tapeworm, Hymenolepis nana in the process of adapting to the body of a new host, the white mouse]. / Sravnitel'noe izuchenie razlichnykh shtammov karlikovogo tsepnia Hymenolepis nana v protsesse adaptatsii k organizmu novogo khoziania--beloi myshi

Different strains of H. nana from man, Norway and white rats were studied in regards to their adaptability. Strains obtained from spontaneously infected white mice and those passaged for several years on white mice served as control. In the course of successive passages the infectivity of these strains, developmental rates of tissue larvae, localization of cystocercoids in the small intestine and mesenteric lymph glands were compared. The strains were found to possess different adaptability to white mice. The strain from white rats had the highest rate of adaptation, the strains from Norway rats and man showed lower adaptation rates, respectively.