Serological and molecular detection of <Emphasis Type="Italic">Borrelia burgdorferi</Emphasis> sensu lato and <Emphasis Type="Italic">Anaplasmataceae</Emphasis> in rodents

The presence of Anaplasma spp. and Borrelia burgdorferi sensu lato in rodents from Eastern Slovakia were followed by serological and molecular methods. The seroprevalence for Borrelia was detected in 16.6 %, for Anaplasmataceae (APT) in 13.2 % and co-occurrence of Borrelia and APT in 7.5 %. Out of 110 ear biopsies of rodents, 5 were B. afzelii-positive. Five biopsies tested positive with the Ehr521-Ehr747 primers amplifying all the members of the family APT. A. phagocytophilum was detected in 1.8 %, 2.7 % were infected with Anaplasma-like organisms. Co-occurrence of Borrelia and Anaplasma in ear biopsies was found in 1.8 %. The circulation of both Borrelia and Anaplasma in the region of Eastern Slovakia was confirmed.     

Our experience with virtual endoscopy of paranasal sinuses

The main goal of our work was to evaluate advantages and disadvantages of virtual endoscopy (VE) techniques in routinely diagnostic and preoperative management of patients with various sinus diseases or head traumas in our practice. Fly-through algorithm was performed using an Xeon based workstation on data sets created from axial CT images acquired from 320 patients with various paranasal sinus disorders. Images were created using Siemens Somatom Emotion 16 continiously rotating helical CT scanner and archived in DICOM format. In comparison with real endoscopy, the VE has several advantages. It is completely non-invasive. It is possible to repeat the same procedure several times, therefore it may be a valuable tool for training. Interactive control of all virtual camera parameters, including the field-of-view is possible. Endoscopic viewing as opposed to real endoscopy is not restricted to the spaces defined by inner surfaces. The viewer may penetrate the walls and see the extent of lesions within and beyond the wall as well as the adjacent anatomic structures. Virtual endoscopy also has a potential to stage tumors by determining the location and the extent of transmural extension.     

The contribution of dichotomous keys to the quality of biological-botanical knowledge of eighth grade students

The aim of the research is to examine the contribution of applying author-generated dichotomous keys (digital key - DDK and print key - DPK) to the quality and durability of the knowledge of eighth grade students about the Systematic and classifications of plants (Bryophyta, Pteridophyta, Gymnosperms and Angiosperms), as compared to traditional teaching. The study included 180 eighth grade students from Montenegro (12–13 years old) divided into three groups: E₁ (where content was learned through DPK), E₂ (where content was learned through DDK) and K (where content was learned through the verbal-textual method). Dichotomous keys contributed to increasing the quality and durability of the knowledge acquired in comparison to traditional teaching at the cognitive levels of analysis, evaluation and synthesis. DDK contributed to the higher quality and durability of student knowledge in comparison to DPK at the cognitive levels of evaluation and synthesis.     

Evaluation of bacteremia in a pediatric intensive care unit: epidemiology, microbiology, sources sites and risk factors

Bacteremia is a common cause of morbidity and mortality in children treated in pediatric intensive care unit (PICU). We have investigated the causative agents of bacteremia in our PICU over a one-year period, to determine mortality associated with such infection and identify the dependent predictors for morbidity and mortality. From 1 January till 31 December 2006, 479 patients were admitted in the PICU and 379 blood culture samples were taken. Samples were incubated in the BACTEC 9050 System, and isolates identified by routine microbiological methods. A pair of samples taken for aerobic and anaerobic culture were statistically regarded as one sample. Data collected from the medical records of each patient were recorded onto standardized collections sheets and included demographic information, predisposing conditions, source(s) of infection, important clinical and laboratory parameters at the time of infection, and microbiological data. Based on these data, positive blood cultures were classified as either contaminants or true bacteremias. During a year period, 117 episodes of bacteremia were documented in 72 patients. The most frequent isolates were the coagulase-negative staphylococci 32.2% (39), followed by Candida spp. 30.5% (36). The mean white blood cell count (WBC) on the day of bacteremia was 15.2 x 10(9)/L (range 0.1-48.0 x 10(9)/L), and 3.3% of episodes occurred in neutropenic (WBC count < 1 x 10(9)/L) children. The mean temperature on the day of infection was 38.2 +/- 1.1 degrees C (range, 34-41 degrees C). Some newborns 23% (n = 5) had a significantly lower mean temperature (p < 0.02) and lower mean WBC count (p < 0.05) than older children. Hemodynamic instability was noted in 11% of bacteremic episodes. Among all bacteremias, intravascular catheters were implicated in 22.6%, pneumonia in 20.4%, genitourinary tract in 14.2%, surgical wounds in 11.7% and, gastrointestinal tract in 9.8%. Seven patients died because of sepsis. Early diagnosis, prompt blood culture reports, followed by appropriate antibiotic treatment is essential in reducing mortality in such patients. Short hospital stay and restricted use of invasive devices should be the aims to reduce the risk of bacteremia during the stay in the PICU.     

Hormonally regulated programmed cell death in barley aleurone cells

Cell death was studied in barley (cv Himalaya) aleurone cells treated with abscisic acid and gibberellin. Aleurone protoplasts incubated in abscisic acid remained viable in culture for at least 3 weeks, but exposure to gibberellin initiated a series of events that resulted in death. Between 4 and 8 days after incubation in gibberellin, >70% of all protoplasts died. Death, which occurred after cells became highly vacuolated, was manifest by an abrupt loss of plasma membrane integrity followed by rapid shrinkage of the cell corpse. Hydrolysis of DNA began before death and occurred as protoplasts ceased production of alpha-amylase. DNA degradation did not result in the accumulation of discrete low molecular weight fragments. DNA degradation and cell death were prevented by LY83583, an inhibitor of gibberellin signaling in barley aleurone. We conclude that cell death in aleurone cells is hormonally regulated and is the final step of a developmental program that promotes successful seedling establishment.     

Expression of the alpha 1-proteinase inhibitor gene family during evolution of the genus Mus

alpha 1-Proteinase inhibitors (alpha 1-PIs) are members of the serpin superfamily of proteinase inhibitors, and are important in the maintenance of homeostasis in a wide variety of animal taxa. Previous studies have shown that in mice (genus Mus), evolution of alpha 1-PIs is characterized by gene amplification, region-specific concerted evolution, and rapid accumulation of amino acid substitutions. The latter occurs primarily in the reactive center, which is the region of the alpha 1-PI molecule that determines the inhibitor's specificity for target proteinases. The P1 residue within the reactive center, which is methionine in so-called orthodox alpha 1-PIs and an amino acid other than methionine in unorthodox alpha 1-PIs, is a primary determinant of inhibitor specificity. In the present study, we find that the expression of mRNAs encoding unorthodox alpha 1-PIs is polymorphic within Mus species, i.e., among individuals or inbred strains. This is in striking contrast to mRNAs that encode orthodox alpha 1-PIs, whose concentrations are relatively invariant. The intraspecies variations in mRNA expression represent polymorphisms in the structure of the alpha 1- PI gene family. The results, taken together with previously described aspects of alpha 1-PI evolution, indicate that the dissimilar levels of polymorphism exhibited by orthodox and unorthodox alpha 1-PIs, which likely have distinct physiological functions, may reflect different levels of selective constraint. The significance of this finding to the evolution of gene families is discussed.      

Cell-Type-Specific Expression Pattern of Proton-Sensing Receptors and Channels in Pituitary Gland

In mammalian cells, extracellular protons act as orthosteric and allosteric ligands for multiple receptors and channels. The aim of this study is to identify proton sensors in the rat pituitary gland. qRT-PCR analysis indicated the expression of G-protein-coupled receptor 68 gene (Gpr68) and acid-sensing ion channel (ASIC) genes Asic1, Asic2, and Asic4 in anterior pituitary cells and Asic1 and Asic2 in immortalized GH3 pituitary cells. Asic1a and Asic2b were the dominant splice isoforms. Single anterior pituitary cell RNA sequencing and immunocytochemical analysis showed that nonexcitable folliculostellate cells express GPR68 gene and protein, whereas excitable secretory cells express ASIC genes and proteins. Asic1 was detected in all secretory cell types, Asic2 in gonadotrophs, thyrotrophs, and somatotrophs, and Asic4 in lactotrophs. Extracellular acidification activated two types of currents in a concentration-dependent manner: a fast-developing, desensitizing current with an estimated EC₅₀-value of pH 6.7 and a slow-developing, non-desensitizing current that required a higher proton concentration for activation. The desensitizing current was abolished by removal of bath sodium and application of amiloride, a blocker of ASIC channels, whereas the non-desensitizing current was amiloride insensitive and voltage dependent. Activation of both currents increased the excitability of secretory pituitary cells, consistent with their potential physiological relevance in control of voltage-gated calcium influx and calcium-dependent cellular functions.     

Ventilatory responses to inspiratory threshold loading in humans

Normal alveolar ventilation tends to be maintained during external mechanical loading. The precise manner by which this occurs is unclear but may involve intrinsic mechanisms related to the muscular pump, neural influences, and chemoreceptor control. Recent observations suggest that submaximal threshold loads may result in hyperventilation. In this study we explicitly examined the respiratory effects of sustained threshold loading in normal subjects. We found that sustained threshold loading resulted in hyperventilation associated with high P100's (mouth pressure 100 ms after the start of an occluded breath) and increased tidal volumes but with little effect on duty cycle or respiratory rate. In addition, this increased respiratory motor output was sustained for 30-60 s after the load was removed. At very high threshold loads, hyperventilation failed to occur, despite increased P100's. We conclude that threshold loading results in increased respiratory motor output and hyperventilation, a response that is different from that observed with either resistive or elastic loads, and that the failure to hyperventilate at the higher loads may be the result of mechanical limitation.     

Enhancement of arm exercise endurance capacity with dihydroxyacetone and pyruvate

The effects of dietary supplementation of dihydroxyacetone and pyruvate (DHAP) on endurance capacity and metabolic responses during arm exercise were determined in 10 untrained males (20-26 yr). Subjects performed arm ergometer exercise (60% peak O2 consumption) to exhaustion after consumption of standard diets (55% carbohydrate, 15% protein, 30% fat; 35 kcal/kg) containing either 100 g of Polycose (placebo, P) or DHAP (3:1, treatment) substituted for a portion of carbohydrate. The two diets were administered in a random order, and each was consumed for a 7-day period. Biopsy of the triceps muscle was obtained immediately before and after exercise. Blood samples were drawn through radial artery and axillary vein catheters at rest, after 60 min of exercise, and at exercise termination. Arm endurance was 133 +/- 20 min after P and 160 +/- 22 min after DHAP (P less than 0.01). Triceps glycogen at rest was 88 +/- 8 (P) and 130 +/- 19 mmol/kg (DHAP) (P less than 0.05). Whole arm arteriovenous glucose difference (mmol/l) was greater (P less than 0.05) for DHAP than P at rest (0.60 +/- 0.12 vs. 0.05 +/- 0.09) and after 60 min of exercise (1.00 +/- 0.12 vs. 0.36 +/- 0.11), but it did not differ at exhaustion. Neither respiratory exchange ratio nor respiratory quotient differed between trials at rest, after 60 min of exercise, or at exhaustion. Plasma free fatty acid, glycerol, beta-hydroxybutyrate, catecholamines, and insulin were similar during rest and exercise for both diets. Feeding DHAP for 7 days increased arm muscle glucose extraction before and during exercise, thereby enhancing submaximal arm endurance capacity.