Dielectric Properties of Materials Used for Microwave-Based NOx Gas Dosimeters

Nitrogen oxides (NOx), primarily generated from combustion processes, pose significant health and environmental risks. To improve the coordination of measures against excessive NOx emissions, it is necessary to effectively monitor ambient NOx concentrations, which requires the development of precise and cost-efficient detection methods. This study focuses on developing a microwave- or radio frequency (RF)-based gas dosimeter for NOx detection and addresses the optimization of the dosimeter design by examining the dielectric properties of LTCC-based (Low-Temperature Co-fired Ceramics) sensor substrates and barium-based NOx storage materials. The measurements taken utilizing the Microwave Cavity Perturbation (MCP) method revealed that these materials exhibit more pronounced changes in dielectric losses when storing NOx at elevated temperatures. Consequently, operating such a dosimeter at high temperatures (above 300 °C) is recommended to maximize the sensor signal. To evaluate their high-temperature applicability, LTCC substrates were analyzed by measuring their dielectric losses at temperatures up to 600 °C. In terms of NOx storage materials, coating barium on high-surface-area alumina resolved issues related to limited NOx adsorption in pure barium carbonate powders. Additionally, the adsorption of both NO and NO2 was enabled by the application of a platinum catalyst. The change in dielectric losses, which provides the main signal for an RF-based gas dosimeter, only depends on the stored amount of NOx and not on the specific type of nitrogen oxide. Although the change in dielectric losses increases with the temperature, the maximum storage capacity of the material decreases significantly. In addition, at temperatures above 350 °C, NOx is mostly weakly bound, so it will desorb in the absence of NOx. Therefore, in the future development of a reliable RF-based NOx dosimeter, the trade-off between the sensor signal strength and adsorption behavior must be addressed.

Revealing the Deposition Mechanism of the Powder Aerosol Deposition Method Using Ceramic Oxide Core-Shell Particles

The powder aerosol deposition (PAD) method is a process to manufacture ceramic films completely at room temperature. Since the first reports by Akedo in the late 1990s, much research has been conducted to reveal the exact mechanism of the deposition process. However, it is still not fully understood. This work tackles this challenge using core-shell particles. Two coated oxides, Al2 O3 core with a SiO2 shell and LiNi0.6 Mn0.2 Co0.2 O2 core with a LiNbO3 shell, are investigated. Initially, the element ratios Al:Si and Ni:Nb of the powder are determined by energy-dispersive X-ray spectroscopy (EDX). In a second step, the change in the element ratios of Al:Si and Ni:Nb after deposition is investigated. The element ratios from powder to film strongly shift toward the shell elements, indicating that the particles fracture and only the outer parts of the particles are deposited. In the last step, this work investigates cross-sections of the deposited films with scanning transmission electron microscopy (STEM combined with EDX and an energy-selective back-scattered electron (EsB) detector to unveil the element distribution within the film itself. Therefore, the following overall picture emerges: particles impact on the substrate or on previously deposited particle, fracture, and only a small part of the impacting particles that originate from the outer part of the impacting particle gets deposited.

Resistive Multi-Gas Sensor for Simultaneously Measuring the Oxygen Stoichiometry (λ) and the NOx Concentration in Exhausts: Engine Tests under Dynamic Conditions

Due to increasingly stringent limits for NO_x emissions, there is now more interest than ever in cost-effective, precise, and durable exhaust gas sensor technology for combustion processes. This study presents a novel multi-gas sensor with resistive sensing principles for the determination of oxygen stoichiometry and NO_x concentration in the exhaust gas of a diesel engine (OM 651). A screen-printed porous KMnO₄/La-Al₂O₃ film is used as the NO_x sensitive film, while a dense ceramic BFAT (BaFe_0.74Ta_0.25Al_0.01O_3-δ) film prepared by the PAD method is used for λ-measurement in real exhaust gas. The latter is also used to correct the O₂ cross-sensitivity of the NO_x sensitive film. This study presents results under dynamic conditions during an NEDC (new European driving cycle) based on a prior characterization of the sensor films in an isolated sensor chamber with static engine operation. The low-cost sensor is analyzed in a wide operation field and its potential for real exhaust gas applications is evaluated. The results are promising and, all in all, comparable with established, but usually more expensive, exhaust gas sensors.

What Happens during Thermal Post-Treatment of Powder Aerosol Deposited Functional Ceramic Films? Explanations Based on an Experiment-Enhanced Literature Survey

Powder aerosol deposition (PAD) is a unique ceramic spray coating method that produces dense and well-adhering thick-films directly at room temperature, without requiring any heating or sintering. After the successful film formation, mechanical film properties like hardness or plasma resistance are remarkably good. However, when it comes to electrical properties like permittivity or electrical conductivity, the nanocrystalline structure of PAD films combined with high internal strains deteriorates partly the characteristic properties. The electrical conductivity may already be present within the as-deposited films. However, it is mostly lowered by several orders of magnitude. Therefore, a thermal post-deposition annealing is oftentimes required. In this work, electrically conducting films produced by powder aerosol deposition are surveyed based on published data. Their microstructural and electrical behavior during the post-deposition annealing treatment is summarized and reasons for the lowered electrical conductivity are identified. Additionally, the processes taking place during annealing, which eventually allow to regain bulk-like functional properties, are examined. A universal annealing behavior is found that leads to a quantitative recommendation for the suitable film annealing temperatures to regain the electrical conductivities.

Novel Method for NTC Thermistor Production by Aerosol Co-Deposition and Combined Sintering

A novel three-stage process to produce NTCR sensors is presented. In this process, an uncalcined powder mixture of NiO and Mn₂O₃ was deposited onto an alumina substrate via aerosol co-deposition (AcD). Then, an electrode structure was screen-printed onto the surface and the composite film was sintered in a multifunctional temperature treatment. Thereby, the sintering of the electrode, the formation of the NiMn₂O₄ spinel and the removal of film strains took place simultaneously. This enabled a significant reduction in energy demand and workload. The manufactured sensors, both as first prototypes, as well as miniaturized chip components, were characterized by a single-phase cubic NiMn₂O₄ spinel structure, mechanical stability and electrical properties that were similar to those of classical NiMn₂O₄ bulk ceramics or tempered aerosol deposited (AD) NiMn₂O₄ films. Particularly noteworthy was the high reproducibility and low variation of the NTCR parameters, such as the specific resistivity at 25 °C ρ₂₅, the electrical resistance at 25 °C R₂₅ and the thermistor constant B. The NTCR parameters were as aging-stable as for NiMn₂O₄ bulk ceramics or tempered NiMn₂O₄ AD-films and could even be further improved by thermal post-treatment.

Manufacturing Dense Thick Films of Lunar Regolith Simulant EAC-1 at Room Temperature

The Aerosol Deposition (AD, also known as gas kinetic spraying or vacuum deposition) method is a rather novel coating process to produce dense thick films directly from dry ceramic (or metal) powders on a variety of substrates without any heat treatment. Because of the similarity of the up to now used powders and lunar regolith, it is imaginable to use AD systems for future in situ resource utilization missions on the Moon planned by several space agencies. To test the feasibility of such an endeavor, the processability of lunar mare simulant EAC-1 by the AD method has been examined in this study. Three regolith films with an area of 25 × 10 mm², and thicknesses between 2.50 µm and 5.36 µm have been deposited on steel substrates using a standard AD setup. Deposited films have been investigated by Laser Scanning Microscopy (LSM) and Scanning Electron Microscopy (SEM). Moreover, the roughness and Vickers hardness of the deposited films and the underlying substrates have been measured. It has been shown that dense consolidated films of regolith simulant can be produced within minutes by AD. The deposited films show a higher roughness and, on average, a higher hardness than the steel substrates. Since on the Moon, naturally available regolith powders are abundant and very dry, and since the required process vacuum is available, AD appears to be a very promising method for producing dense coatings in future Moon exploration and utilization missions.

Planar Microstrip Ring Resonators for Microwave-Based Gas Sensing: Design Aspects and Initial Transducers for Humidity and Ammonia Sensing

A planar microstrip ring resonator structure on alumina was developed using the commercial FEM software COMSOL. Design parameters were evaluated, eventually leading to an optimized design of a miniaturized microwave gas sensor. The sensor was covered with a zeolite film. The device was successfully operated at around 8.5 GHz at room temperature as a humidity sensor. In the next step, an additional planar heater will be included on the reverse side of the resonator structure to allow for testing of gas-sensitive materials under sensor conditions.

Pulsed Polarization-Based NOx Sensors of YSZ Films Produced by the Aerosol Deposition Method and by Screen-Printing

The pulsed polarization technique on solid electrolytes is based on alternating potential pulses interrupted by self-discharge pauses. Since even small concentrations of nitrogen oxides (NO_x) in the ppm range significantly change the polarization and discharge behavior, pulsed polarization sensors are well suited to measure low amounts of NO_x. In contrast to all previous investigations, planar pulsed polarization sensors were built using an electrolyte thick film and platinum interdigital electrodes on alumina substrates. Two different sensor layouts were investigated, the first with buried Pt electrodes under the electrolyte and the second one with conventional overlying Pt electrodes. Electrolyte thick films were either formed by aerosol deposition or by screen-printing, therefore exhibiting a dense or porous microstructure, respectively. For screen-printed electrolytes, the influence of the electrolyte resistance on the NO_x sensing ability was investigated as well. Sensors with buried electrodes showed little to no response even at higher NO_x concentrations, in good agreement with the intended sensor mechanism. Electrolyte films with overlying electrodes, however, allowed the quantitative detection of NO_x. In particular, aerosol deposited electrolytes exhibited high sensitivities with a sensor output signal ΔU of 50 mV and 75 mV for 3 ppm of NO and NO₂, respectively. For screen-printed electrolytes, a clear trend indicated a decrease in sensitivity with increased electrolyte resistance.

Duration of hepatic vascular inflow clamping and survival after liver resection for hepatocellular carcinoma

BACKGROUND

The aim of this study was to evaluate the influence of the duration of hepatic vascular inflow clamping (Pringle time) on the survival of patients with any type of liver background (not only cirrhosis) undergoing liver resection for hepatocellular carcinoma (HCC).

METHODS

Patients who underwent liver resection between April 2000 and December 2008 for HCC using the Pringle manoeuvre were identified retrospectively from an institutional database and divided into two groups: group 1 had a Pringle time of 60 min or less, and group 2 a Pringle time of more than 60 min. Univariable and multivariable analyses were performed to identify predictors of postoperative survival. Kaplan-Meier analysis was used to compare overall survival between the groups.

RESULTS

A total of 357 patients were enrolled; 242 patients had a Pringle time of 60 min or less (group 1), and 115 patients had a Pringle time of more than 60 min (group 2). Patients in group 2 had a shorter overall survival than those in group 1 (P = 0·010). Univariable analyses showed that type of HCC (primary versus recurrent), maximum tumour diameter, hepatic venous infiltration, platelet count, serum protein induced by vitamin K absence or antagonist II level, blood loss (700 ml or less versus more than 700 ml), duration of operation (300 min or less versus more than 300 min) and Pringle time (60 min or less versus more than 60 min) were predictive of postoperative survival. Multivariable analysis indicated that only Pringle time was associated with postoperative survival (odds ratio 1·83, 95 per cent confidence interval 1·08 to 3·10; P = 0·024).

CONCLUSION

Longer Pringle time is an important predictor of shorter postoperative survival in patients undergoing liver resection for HCC.

The effect of heterotypic infections of older horses with equine influenza virus type-2 on some clinical and immunological parameters

Twelve horses, all of them 10 years old, were vaccinated intramuscularly on 0 and 28 days of the experiment with inactivated vaccine containing only antigens of A-equi-2/Miami/63. Another three unvaccinated horses, each at the age of 10 years, were the negative control group. One, ten-year-old horse was vaccinated with commercial inactivated vaccine containing both antigens of A-equi-2/Miami/63 as well as A-equi-1/Praha/56 as positive control. Three horses were challenged intranasally with homotypic strain of Miami/63, while six other were challenged with heterotypic strains--three with Suffolk/89 and three with Kentucky/86. Three horses vaccinated with vaccine containing only strain A-equi-2/Miami/63 were not challenged. In the group of three unvaccinated horses, each one was challenged intranasally with different strains studied in this experiment. The horse vaccinated with commercial vaccine was not challenged. Replication of each strain was done in chick embryos. During the experiment blood from horses was collected for hematological and immunological examinations (antigen-specific and antigen-nonspecific lymphocyte transformation tests, lymphocyte immunophenotyping, antigen-specific leukocyte migration inhibition test and hemagglutination inhibition test). The statistical analysis showed that the dynamics of lymphocyte immunological reactivity in horses vaccinated with inactivated vaccine containing antigens of A-equi-2/Miami/63 in response to further antigen stimulation (in vitro) was different comparing the homotypic or nearly homotypic challenging with Miami/63 and Suffolk/89 respectively, to the more heterotypic one with the strain Kentucky/86. In horses challenged with classical homotypic strain of Miami/63 no clinical signs were observed. These results confirm that the vaccine shall consist of the strains currently circulating in the horse population.

Clinical assessment of oral malodor intensity expressed as absolute value using an electronic nose

OBJECTIVES

In our previous study, scores determined via a multiple linear regression method (EN-MLR) involving an electronic nose provided objective halitosis-related measurements; however, this model afforded only relative expression exclusively. The objective of this investigation was to assess clinically oral malodor intensity expressed as an absolute value using an electronic nose.

SUBJECTS AND METHODS

Sixty-six subjects were evaluated based on results of an actual organoleptic test (OLT), measurements of volatile sulfur compound (VSC) concentrations, a score representing malodor intensity (EN-MI) as the absolute value and EN-MLR measured with an electronic nose system. Oral health parameters were also examined.

RESULTS

The OLT score served as a benchmark. The area under the receiver-operating characteristic (ROC) plots of EN-MI score (0.975) was significantly larger than that of log VSC (0.896) (P = 0.036); however, the area did not differ significantly from that of EN-MLR score (0.932). Percentage of teeth with pocket depth greater than or equal to 4 mm, tongue coating score and plaque control record displayed meaningful association with EN-MI score in multiple logistic regression analyses.

CONCLUSION

Oral malodor intensity expressed as an absolute value employing an electronic nose may be a suitable method for clinical evaluation of oral malodor.

Some morphological, biochemical and immunological blood parameters in European bison with or without lesions in the digestive, respiratory, urinary and reproductive tracts

Ninety-seven bison (39 males and 58 females) were culled out during three successive winter seasons. No infection with BHV-1 and BHV-5 or other viruses was detected by PCR and SN methods. Advanced pathological lesions observed in males exhibiting symptoms of posthitis/balanoposthitis are probably due to secondary infection by microorganisms present in the prepuce (Corynebacterium spp., Bacillus spp., Fusobacterium necrophorum, Staphylococcus spp. (coagulase negative) and Staphylococcus hyicus). Histopathological examinations of sections from prepuce and lips of pudendum showed the presence of Onchocercinae nematode (Onchocerca sp.). A comparison of biochemical and morphological blood parameters in the bison with or without lesions in the digestive (presence of parasites), respiratory, urinary and reproductive tracts revealed that the most variable parameter during reproductive organ disorder is the leukocyte count, while disorders in the urinary and digestive tracts coincided with the age of animals. In cases of digestive disorder most changes were observed in the number of neutrophils and concentration of urea. The number of red blood cells, monocytes, the level of alkaline phosphatase (AP) and hematocrit negatively correlated with age. Negative correlation was also observed between the number of neutrophils, level of creatinine and lymphocyte proliferation index. However, positive correlation was seen between erythrocyte sedimentation rate (Spearman's correlation coefficient), level of alanine aminotransferase (ALT) and protein, and age of the bison. Positive correlation was also observed between the lymphocyte count and lymphocyte proliferation index. The attempt to determine the reference values for blood biochemical and morphological parameters showed similarities to those of cattle.

Seroprevalence of selected viral and bacterial pathogens in free-ranging European bison from the Białowieza Primeval Forest (Poland)

Blood was collected from bison that were selected between 1991 and 2001 for poor body condition, cachexia, lameness and balanoposthitis. Sera were tested for antibodies to bovine herpes virus type 1 (BHV-1), bovine viral diarrhoea virus (BVDV), foot-and-mouth disease virus (FMDV), parainfluenza virus type 3 (PI-3), Brucella abortus, Chlamydophila abortus, Coxiella burnetti, and Leptospira interrogans. The results of serological tests showed a prevalence of low titers of a serological reaction to Chlamydophila abortus (45.1%), bovine viral diarrhoea virus (29.5%), Leptospira interrogans (21.3%) and parainfluenza virus type 3 (13.9%). There were differences in the prevalence of antibodies to Ch. abortus between female and male bison. Futhermore, a relationship between age and antibodies to BVDV was observed in older bison. These results suggest that there is some transmission of bacterial and viral pathogens occurring between domestic and wild ruminants grazing in the same pastures in the peripherial areas of Bialowieza Primeval Forest.

A case of symptomatic Morgagni's hernia and a review of Morgagni's hernia in Japan (263 reported cases)

An 81-year-old female patient was admitted to the emergency room of our hospital with complaints of respiratory distress, abdominal ache, nausea, and intermittent vomiting. A plain X-ray of the abdomen and chest revealed air-fluid levels on the abdomen and the right side of the chest. Laboratory tests showed severe acidemia with a blood base excess level of -24.9 mmol/L. Since the patient was considered to have acute intestinal obstruction due to transverse colon herniation into the thorax through a foramen of Morgagni, emergency surgery was performed. Operative findings revealed that the retrosternal diaphragm had a defect of 5 cm in diameter and 20 cm in length with the transverse colon herniated into the thorax. The diaphragm defect was sutured first, and partial resection of the transverse colon was performed. After the operation, the patient had no symptoms and no recurrence has been observed during the 1-year follow-up. There have been 263 reported cases of Morgagani hernia in Japan. The case of the Morgagni hernia is reported here with some bibliographical comments.

Changes in structure of lymphatic organs in foals died due to Rhodococcus equi infection

The aim of this study was to investigate the structure of lymphatic organs in foals which died due to Rhodococcus equi infection. The material for this study consisted of 9 foals, of both genders, various breeds, 6-14 weeks old. The routine histopathological examination and immunocytochemical reaction for cytokeratine-3 receptors revealed the disturbances in the thymus epithelial cells development. This was manifested by a complete lack of cells expressing cytokeratine-3 receptors, as well as absence of normal thymocytes differentiation. The supposed thymus epithelial cells were very few, expressing faint reaction of cytokeratine-3 receptors. The relative deficiencies in the lymphatic tissue development in peripheral lymphatic organs were observed. It was concluded, that the observed pathological changes may indicate the inherited, not described yet gene failure, which was responsible for the thymus epithelial cells developmental disturbances, and was expressed with various intensity in examined foals. The causes of the fatal course of rhodococcosis in foals were primary disturbances in the immune competence.

Prevalence of the suilysin gene in Streptococcus suis strains isolated from diseased and healthy carrier pigs

Knowledge of virulence factors of Streptococcus suis is limited. Several virulence factor candidates have been proposed, among them suilysin, which is responsible for a toxic effect on epithelial cells. The aim of this study was to detect the suilysin gene sequence in Streptococcus suis strains of various origin. In total 63 Streptococcus suis isolates were investigated. Forty four of them originated from tissues of streptococcosis affected animals. The remaining 19 strains were isolated from tonsils of healthy carrier pigs. Suilysin gene specific sequence was detected in 79% of the strains tested. In isolates obtained from pigs with signs of streptococcosis this gene sequence was recorded in 85% of cases. In Streptococcus suis strains isolated from healthy carrier pigs the suilysin gene was detected in 63% of the isolates. It seems that suilysin toxic activity is only one of the many steps involved in the pathogenesis of Streptococcus suis infection and that strain's virulence cannot be stated only on the basis of suilysin gene sequence presence.

The occurrence of pulmonary hypertension in patients with systemic sclerosis hospitalized in the Department of Rheumatology and Internal Diseases Medical University of Białystok in years 2003-2004

Pulmonary hypertension (PH) is one the most fatal complications of systemic sclerosis (SSc). The aim of the present study was to investigate the occurrence of PH in SSc patients hospitalized in Department of Rheumatology and Internal Diseases University Hospital of Bialystok in years 2003-2004. PH was defined as pulmonary artery systolic pressure (PASP) higher than 35 mmHg as evaluated by ECHO-Doppler. We found PH in 23 out of 53 (43%) SSc patients included in the study. In the majority of patients 20/23 (87%) PH coexisted with the presence of scleroderma lung disease as evaluated by high resolution computed tomography of the lungs. In the remaining 3/23 (13%) patients isolated (arterial) PH was detected. Patients with isolated PH tend to have higher values of PASP (82 +/- 39.0 mmHg) than those with PH and interstitial lung disease (42.5 +/- 6.4 mmHg). The results of our study indicate that PH is a frequent complication of SSc.

Clinical assessment of oral malodor by the electronic nose system

A recently developed electronic nose has not yet been clinically applied to evaluations of oral malodor. This investigation sought to determine whether an electronic nose could clinically assess oral malodor. Twenty-nine healthy adults and 49 patients were assessed by results of an actual organoleptic test, a score representing malodor strength with an electronic nose in "top-note" mode (top-note score), and measurements of volatile sulfur compound (VSC) concentrations. The correlation coefficient between top-note and actual organoleptic scores (r = 0.71) was comparable with the log VSC and actual organoleptic scores (r = 0.63). However, the area under the receiver-operating characteristic plots for top-note score was significantly larger than that for log VSC. In logistic regression analyses with top-note score as a dependent variable, probing depth, tongue coating, and plaque control record each had independent associations. Our findings suggest that the top-note score from an electronic nose examination may be useful for the clinical evaluation of oral malodor.

Acute CO2 tolerance during the early developmental stages of four marine teleosts

Ocean sequestration of CO2 is proposed as a possible measure to mitigate climate changes caused by increasing atmospheric concentrations of the gas, but its impact on the marine ecosystem is unknown. We investigated the acute lethal effect of CO2 during the early developmental stages of four marine teleosts: red sea bream (Pagrus major), Japanese whiting (Sillago japonica), Japanese flounder (Paralichthys olivaceus), and eastern little tuna (Euthynnus affinis). The percentages of larvae that hatched and survived were not affected by exposure to water with a PCO2 of 1.0 kPa (= 7.5 mmHg) within 24 h. Median lethal PCO2 values for a 360-min exposure were 1.4 kPa (cleavage), 5.1 kPa (embryo), 7.3 kPa (preflexion), 4.2 kPa (flexion), 4.6 kPa (postflexion), and 2.5 kPa (juvenile) for red sea bream; 2.4 kPa (cleavage), 4.9 kPa (embryo), 5.9 kPa (preflexion), 6.1 kPa (flexion), 4.1 kPa (postflexion), and 2.7 kPa (juvenile) for Japanese whiting; 2.8 kPa (cleavage) and > 7.0 kPa (young) for Japanese flounder; and 11.8 kPa (cleavage) for eastern little tuna. Red sea bream and Japanese whiting of all ontogenetic stages had similar susceptibilities to CO2: the most susceptible stages were cleavage and juvenile, whereas the most tolerant stages were preflexion and flexion.

The use of chosen serological diagnostic methods in Lyme disease in horses. Part II. Western blot

In this investigation the Western blot test was treated as a method verifying results of the IFA, commercial ELISA and standardized ELISA tests (described in Part I). The verifying investigations were performed on 82 serum samples, which in the commercial ELISA were positive in 36 cases, dubious in 31 cases and negative in 15 cases as well as on 5 serum samples obtained from horses infected with Leptospira spp., which in the ELISA commercial were dubious (total of 87 sera samples). The antigens, against which the immunological response in horses was directed, were also established. The Milenia--Blot--Borrelia IgG test (MIDBO IgG-Kit 30 TESTS: DPC Bierman GmbH) was used in the investigation. In view of species differences, rabbit anti-horse IgG (whole molecule) alkaline phosphatase conjugate, no A6063 SIGMA-ALDRICH was used interchangeably. Also the control sera were substituted with the horse control sera. It was demonstrated that the Western blot test is the most reliable in the serological diagnosis of B. burgdorferi infection in horses. The commercial ELISA and standardized ELISA tests represent a lower diagnostic value than the Western blot test, although similar to each other, while the value of the IFA is minimal. In the Western blot test antigens were established against which the immunological response in horses in mostly directed. In the sera evaluated in this test as positive the presence of antibodies, mainly against antigens with the following molecular weights: 41 kDa, 62/60 kDa, 93 kDa, 72 kDa, 34 kDa (OspB), 66 kDa was noted. At the same time, antibodies contained in the sera accepted as negative, in 55.5% cases also reacted with the antigen of 41 kDa. It points to its minimal specificity. On the basis of the results obtained it is recommended that serological examination of horses should be with the ELISA and that positive or dubious results should be verified with the Western blot test.

The use of chosen serological diagnostic methods in Lyme disease in horses. Part I. Indirect immunofluorescence and enzyme-linked immunosorbent assay (ELISA)

The investigations aimed to establish the reliability of the chosen serological tests designed for the diagnosis of Lyme borreliosis in horses. The investigations were carried out in five Horse Breeding Centres (OHK). Statistical analysis methods were used to determine sample size for particular centres: Krasne (Kr)--49, Łack (Ł)--21, Walewice (W)--111, BogusŁawice (B)--17, Kozienice (K)--61. The experimental material comprised the chosen horses from which blood samples were collected in order to obtain sera. The test used for indirect immunofluorescence assay (IFA No 75941, Bio-Mérieux) is commercially designed for the investigation of human sera and thus needed a prior species adaptation and standardization; ELISA (MRL DIAGNOSTICS, No EL0400G) which was also species adapted and stardandized and ELISA commercially assigned for the examination of dog or horse sera (Die System Diagnostica GmbH Borrelia burgdorferi Veterinary ELISA No. 122.00 Genzyme Virotech GmbH). In the IFA test the highest share of positive results was obtained in respect of the sera from OHK in (K)--60.7% and then in (B)--52.9%, (Ł)--42.9%, (W)--40.5%, (Kr)--38.7%. In the standardized ELISA the highest percent of positive results, amounting to 33.3%, was obtained in respect of the sera from (Ł), and then from (W)--20.7%, (K)--11.5%, (Kr)--10.2% and (B)--5.9%. The percent of positive results obtained in the commercial ELISA also agreement on a high level: the sera originating from (W) were positive in 18.9%, from (K)--9.8%, (Ł)--9.5%. (B)--5.9% and (Kr)--4.1%. Both ELISAs showed high agreement although the standardized test was characterized by a greater tendency for suggesting the presence of B. burgdorferi infection and the agreement of these two ELISAs with the IFA was not so strong. The IFA showed the highest tendency for suggesting the presence of the B. burgdorferi infection, being characterized by the highest percent of false positive results.

Relationships among ecology, demography and diseases of European bison (Bison bonasus)

The bison population in the Bialowieza Forest in Poland has now grown to approximately 300, while the herds in the Belarusian part of the forest total about 240 bison. The first signs of a health problem in these herds appeared in 1980, when two cases of balanoposthitis were detected in two bulls (2 and 5 years of age). Since 1980 research has been conducted to explain the cause of diseases, particularly balanoposthitis, and to monitor the health of bison in Bialowieza Forest. A total number of 614 bison (294 male and 320 female) of different ages was eliminated between 1980 and 2000. Not all the culled bison were examined (postmortem analysis, histopathological, bacteriological, virological and toxicological examinations, serological tests, molecular research). Based on the increase in numbers, reproduction in this population for the past 21 years is generally considered successful. Among 182 male bison eliminated during 1990-2000, only 85, or 47%, of the animals had balanoposthitis. Thus, the percentage of balanoposthitis cases went from 100% during the 1980s down to 47% in the past decade. It appears that the culling process has been a major factor leading to this decrease. It can be assumed that a set of factors is involved in the appearance of the disease (Corynebacterium spp., Bacillus sp., Pseudomonas aeruginosa, Escherichia coli, Ureoplasma spp, Fusobacterium necrophorum, Streptoccocus spp., Staphyloccocus spp.) while opportunistic infections including nematodes (Onchocerca spp.) are responsible for the occurrence of secondary lesions.

Laparoscopic intragastric resection of gastric leiomyoma using needlescopic instruments. Case report

Laparoscopic intragastric resection of gastric leiomyoma was performed using needlescopic instruments. The patient was a 71-year-old man who had a 2-year history of gastric submucosal tumor 2 cm in diameter located near the esophagocardiac junction. After getting informed consent, we performed a laparoscopic intragastric tumor resection under an oral endoscope. There were no intra- or postoperative complications. The patient was discharged uneventfully. Histopathologic diagnosis of the tumor was leiomyoma. Laparoscopic intragastric resection of a benign gastric submucosal tumor using needlescopic instruments is technically feasible and as safe as a less invasive procedure.

Flow cytometric examination of DNA ploidy, p53 and bcl-2 expression in primary squamous epithelial pulmonary carcinoma

The aim of this study was answering the question whether cytofluorimetric determining of DNA ploidy, p53 and bcl-2 expression in tumour cells may enhance the diagnosis of squamous epithelial lung carcinoma. Samples of neoplastic tissue were taken from 11 operated patients. DNA staining was performed with propidium iodide. p53 and bcl-2 expression was evaluated by using monoclonal antibodies. By assessing of DNA ploidy we observed increased proliferative activity and, at the same time, high rate of the cell necrosis. In the analysis of p53 protein the presence of antigen was observed on average in 7.1 +/- 2.4, 15.1 +/- 3.9, and 19.8 +/- 4.1% of normal cells of the pulmonary tissue, the peripheral part of the tumour and cells of the central part of the tumour, respectively. bcl-2 was found on average in 7.3 +/- 2.2, 9.9 +/- 3.1, and 12.4 +/- 3.19% of the above cells, respectively. These results show that the technique of cytofluorimetric evaluation of p53 and bcl-2 proteins can be useful in diagnosis of pulmonary cancer in addition to classic histological and immunohistochemical methods.

Epizootic of equine influenza in 1969 in Poland

Epidemiological observations on the course and spread of equine influenza in Poland during the 1969 epizootic were carried out. The dynamics of the spread of the disease in the country are shown graphically by voivodship. The disease incidence and mortality rates for the entire country are also shown. The highest incidence of disease and mortality rates were found to be in November 1969. A/equi-2/Warsaw/69 was identified as the causal virus. It caused the largest epizootic in the country since 1954.

Effectiveness and patient satisfaction with screening flexible sigmoidoscopy performed by registered nurses

BACKGROUND

Our aim was to compare the effectiveness and patient satisfaction with flexible sigmoidoscopy performed by a registered nurse, general surgeons, and gastroenterology fellows.

METHODS

Consecutive outpatients referred for sigmoidoscopy were assigned to have the procedure performed by the first available provider. Depth of insertion of the sigmoidoscope, complications, duration of the procedure, and percentage of patients with adenomas were recorded. After the procedure, patients completed a validated patient satisfaction questionnaire.

RESULTS

Mean depth of insertion was less for general surgeons compared with the nurse and gastroenterology fellows (50 vs 53 vs 54 cm, respectively; p = 0.01). Mean duration of procedure was longer for the nurse compared with general surgeons and gastroenterology fellows (8.3 vs 7.6 vs 6.8 min, respectively; p = 0.0001). Percentage of patients with adenomas was similar among patients who underwent sigmoidoscopy by the endoscopists (7% vs 8% vs 9%; p = 0.81). No differences were detected between endoscopists for overall satisfaction (p = 0.60), technical skills of the endoscopist (p = 0.58), communication skills of the endoscopist (p = 0.61), or interpersonal skills of the endoscopist (p = 0.59).

CONCLUSION

No clinically significant differences in effectiveness or patient satisfaction were detected with flexible sigmoidoscopy performed by a registered nurse, general surgeons, or gastroenterology fellows.

Experience with three-port laparoscopic cholecystectomy

After considerable experience with laparoscopic cholecystectomy (LC) using four ports, we began using three-port LC in October 1993 and have performed 130 LCs with this procedure up to May 1996. The procedure was successful in 119 patients. In 6 patients fourth port was used, and in another 5, the procedure was converted to open laparo-tomy. Cooperative manipulation of the surgical instruments between the operator and assistant is very important for this procedure, for exposing Calot's triangle and dissecting the gallbladder from the gallbladder bed. The use of an ultrasonic aspiration system (Sumisonic ME 2400; Sumitomo Bakelite, Tokyo, Japan) made it easier to identify the cystic duct and artery, especially in patients with chronic inflammation or dense adhesions. We encountered no problems with cannulation into the cystic duct for intraoperative cholangiography, and there were no intra- and postoperative complications in this series. We achieved good results, similar to those achieved with the four-port technique. This technique is technically feasible and safe, and it has esthetic and cost advantages compared with the four-port technique. However, the operator who performs three-port LC should not hesitate to add another port, or to convert to open laparotomy, whenever any difficulties occur during this procedure, to prevent critical complications.

Acute effects of kaolinite suspension on eggs and larvae of some marine teleosts

To evaluate the effects of suspended inert particles on the early life stages of the eggs and larvae of four marine fish species, Pagrus major, Acanthopagrus schlegeli, Oplegnathus fasciatus and Parapristipoma trilineatum were exposed to kaolinite suspensions up to 10,000 mg l-1. Hatching success and developmental rates of eggs all species were not significantly affected by 10,000 mg l-1 suspension over a 24-h exposure period. Exposure of larvae of each species to suspensions ranging from 32 to 10,000 mg l-1 for 1, 3 and 12 h, however, resulted in over 50% mortality at 1000 mg l-1 for 12 h. Larvae were much less tolerant to kaolinite exposure than eggs probably due to their relatively larger and more delicate body surface compared to the tough outer membrane of eggs. Kaolinite particles adhered more readily to eggs and larvae of P. major than to those of the other species.