Comparative analysis of PCR versus culture for diagnosis of ulceroglandular tularemia

PCR and culture were comparatively evaluated for their abilities to demonstrate Francisella tularensis in wound specimens from tularemia patients during an outbreak in Sweden in 1998. For transport of the specimens used for PCR, a buffer solution containing a nuclease inhibitor was used, and for transport of the specimens used for culture, a commercial transport system was selected after experimental comparison of various systems. Of 40 patients with culture- and/or serology-verified ulceroglandular tularemia, PCR detected F. tularensis DNA in 30 (75%) patients, whereas culture detected bacterial growth in 25 (62%) patients. Compared to data from a previous study, the present inclusion of a nuclease inhibitor in the transport medium did not improve the sensitivity of the PCR, whereas the sensitivity of the culture procedure was significantly increased by selection of the system used for transport. Among eight patients with clinically suspected tularemia but with negative serology and culture, specimens from four patients showed detectable DNA. In three of these patients the diagnosis was verified by the demonstration of an F. tularensis-specific T-cell response in vitro. In conclusion, PCR was more sensitive than culture for demonstration of F. tularensis in wound specimens. Besides, we showed that tularemia may proceed without development of serum antibodies, and in these patients, PCR may be of special importance for verification of the diagnosis.

Material and design in haematogenous implant-associated infections in a rabbit model

We used 111 rabbits to study the susceptibility to intravenously injected bacteria of conventional stainless steel plates, and titanium plates of either traditional design or of the PC-FIX concept, that is less traumatic to bone. After plating, the animals were given between 1 x 10(8) and 2 x 10(9) colony forming units of Staphylococcus aureus Wood 46 intravenously. Significant differences in infection rates (positive cultures) were found between conventional stainless steel plates (36-67% infected, depending on inoculum size) and titanium PC-FIX plates (6-7% infected). In fact, the infection rate at the PC-FIX plate did not differ from sham operated animals. Since conventionally designed titanium plates had an intermediate infection rate, it appears that design and material both are important for the risk of infection.

Monitoring of heart and respiratory rates in newborn infants using a new photoplethysmographic technique

OBJECTIVE

A new photoplethysmographic (PPG) device for respiratory and heart rate monitoring has been evaluated in the neonatal care units at the University Children's Hospital of Uppsala, Sweden. The purpose of this study was to compare this new device with more established techniques, i.e., transthoracic impedance plethysmography (TTI) for monitoring of respiratory rate and ECG for heart rate monitoring.

METHODS

Data were acquired continuously for 8-hours in each of 6 neonates. The signals were analysed for periods of 30 seconds, in which the heart and respiratory signals from the PPG device were compared with the ECG and the impedance plethysmogram.

RESULTS

The ECG recordings were of high quality in 77% of the analysed periods. In these periods, excluding periods (6%) disturbed by offset-adjustement of the PPG signal, the PPG heart signal included 1.1% (+/- 0.7% SD) false negative beats and 0.9% (+/- 0.6%) false positive beats. In periods with an impedance signal of high quality (29% of total time), the part of the PPG signal synchronous with respiration included 2.7% (+/- 1.1%) false negative breaths and 1.5% (+/- 0.4%) false positive breaths. Here, 2% of the periods were discarded because of offset-adjustment. From the periods of low signal quality, two other conclusions were drawn: 1) The impedance signal contains more power in the respiratory range than the corresponding PPG respiratory signal. 2) The breaths are easier to identify in the PPG respiratory signal than in the impedance signal (subjective measure).

CONCLUSIONS

Electrode and motion artefacts seem to disturb the ECG signals and, particularly, the impedance signals. During periods of high quality ECG and impedance signals, the new optical device produces signals of equal quality to these traditional methods, and is in some cases even better. The new device is non-invasive and has a small optical probe. These factors indicate further advantages of the photoplethysmographic method.

Local plate infections in a rabbit model

We used 30 New Zealand white rabbits to compare the susceptibility to bacterial challenge of two different orthopaedic implants: a standard-design stainless steel plate, or a PC-FIX titanium plate applied on the right tibia were compared with sham operated animals. Directly after surgery Staphylococcus aureus (10(8)-10(9) colony forming units) were inoculated close to the plate. The infection rate in the group of plated animals was 11/20 (stainless steel plates 6/10, PC-FIX titanium plates 5/10) and in sham operated animals only 1/10. Thus, a foreign body increased the risk for infection (p = 0.02). However, the implant type did not appear to be of major importance when the bacteria were inoculated locally. In experimental haematogenous infections, by contrast, implant design and material are considered to be important. This may either indicate different pathogenic mechanisms in locally and haematogenously induced infections, or simply that the large number of microorganisms in local inoculation 'overload' the normal defence systems.

Ingested aggregates of ultrafine carbon particles and interferon-gamma impair rat alveolar macrophage function

Alveolar macrophages (AM), obtained by lavage from the rat lung, were allowed to ingest aggregated ultrafine carbon particles, about 1 microgram/10(6) AM, which is a realistic result of long-term exposure to ambient air. The effects of the ingested carbon on the phagocytosis of test particles and oxidative metabolism of the AM were studied. In addition, the effects of short-term (40 min or 2 h) and long-term (28 or 44 h) incubation with interferon gamma (IFN-gamma) on AM loaded and unloaded with carbon were investigated. Phagocytic activity was studied using fluorescein-labeled 3.2-microgram silica particles. The attachment and ingestion processes were evaluated separately. The ingested carbon markedly impaired the phagocytosis of silica particles; the accumulated attachment (sum of attached and ingested particles per AM) decreased from 5.0 to 4.2 particles/AM and the ingested fraction (number of ingested particles per AM divided with accumulated attachment) from 0.42 to 0.27. The short-term incubation with IFN-gamma tended to increase the accumulated attachment (from 5.0 to 5.7 particles/AM) and decreased the ingested fraction (from 0.42 to 0.34) in unloaded AM. Long-term incubation with IFN-gamma markedly impaired both the accumulated attachment (to 3.8 particles/AM) and the ingested fraction (to 0.24) in unloaded AM and the carbon load further decreased the accumulated attachment to 2.8 particles/AM, and the ingested fraction to 0.21. The oxidative metabolism was not effected by the ingested carbon or the short-term incubation with IFN-gamma, but the long-term incubation with IFN-gamma increased it with a factor of almost 3. Our results suggest that ingested environmental particles in AM may markedly impair their phagocytic capacity, especially during long-term exposure to IFN-gamma as after infections, and there might be an increased risk for additional infections. Moreover, during an episode of high ambient particle concentration the inhaled particles will not be efficiently phagocytized and may thereby damage the Lung tissue.

Idiotypic-anti-idiotypic antibody interactions in experimental radioimmunotargeting

Idiotypic-anti-idiotypic antibody interactions can be used in vivo to regulate the serum levels of specific radiolabeled antibodies. Anti-idiotypic antibodies can also be used as clearing agents for radiolabeled antibodies in radioimmunolocalization and radioimmunotherapy. The present study describes the immunochemical interactions between the monoclonal idiotype (H7) and three generated monoclonal anti-idiotypic antibodies (alphaH7:1, alphaH7:35, and alphaH7:38). An unexpected variability in complex formation could be demonstrated in vitro, revealing three different stable complex patterns, i.e., low molecular weight 1:1 complexes, ladder formation with oligomeric, consecutively added constituents, and large linear polymeric complexes of high molecular weight. Within 24 h, the anti-idiotypes were able to cause a significant decrease in total body radioactivity, and the antibody generating a ladder formation (alphaH7:38) was found to be the most efficient at removing radiolabeled idiotypes from the circulation. It is concluded that monoclonal anti-idiotypic antibodies may be valuable tools in improving radioimmunolocalization and radioimmunotargeting.

Tissue and intracellular pH in normal periarticular soft tissue and during different phases of antigen induced arthritis in the rat

OBJECTIVE

To measure intracellular and tissue pH in periarticular soft tissue during different phases of antigen induced arthritis in the rat.

METHODS

pH was calculated using the following values: (1) the distribution of [14C]-dimethyl-oxazolidinedione; (2) the total tissue water and the extracellular space water volume, which was measured as [14C]-sucrose distribution in nephrectomized rats. Experiments were performed during both maximal inflammation (Day 3) and the restorative phase (Day 14).

RESULTS

In all animals both tissue (pHt) and intracellular (pHi) pH were lower in arthritic joints than in the contralateral control. Mean pHt in control joints was 7.37+/-0.03. In arthritic rats it was 7.30+/-0.05 on Day 3 after challenge and 7.27+/-0.03 on Day 14. The pHi ranges were 6.86-7.81 for controls, 6.65-7.28 for arthritis Day 3, and 5.66-6.91 for arthritis Day 14.

CONCLUSION

In this model there is a reduction in pH in the periarticular tissue of arthritic joints. The magnitude is, however, relatively small and the pannus tissue is not uniquely acidic in comparison with other compartments. There does not seem to be a correlation between pH and changes in metabolic balance, pannus formation, or healing.

Gap junction intercellular communication in gliomas is inversely related to cell motility

Gliomas are lethal because of local invasion into brain parenchyma. Glioma cells were isolated from different regions (white matter, gray matter and tumor core) of a glioma-bearing dog brain. Individual clonal cell lines were established from each area, and characterized for growth, migration and gap junctions. The regional clonal cell lines differed in rates and preferred substrate for migration. Cell lines generated from invaded white matter showed stimulated migration on collagen and variable migration on merosin, whereas migration of cell lines derived from invaded gray matter showed the reciprocal responses: stimulation on merosin and inhibition on collagen. Gap junctional communication showed significant degrees of variation between the different clones. A direct inverse relationship between the number of cells demonstrating gap junctional communication and migration rate of cells away from multicellular spheroids was evident. Glioma cells which have a reduced capacity to connect to each other have an accelerated migration rate onto autologous, glioma-derived matrix. These results suggest that invasive glioma cells suppress autologous cell-to-cell cohesion, partly evident as reduced formation of gap junctions. In addition, glioma cells were stimulated to migrate in a dose-dependant manner in response to epidermal growth factor (EGF) coincident with the reduction of Cx43 levels and increased serine phosphorylation. We speculate that in order for glioma cells to invade locally into brain parenchyma they must first detach from neighboring cells ("let go...let's go" paradigm of invasion).

Prevalence of the 985A>G mutation in the medium-chain acyl-CoA dehydrogenase (MCAD) gene in Sweden

The prevalence of the 985A>G mutation in the medium-chain acyl-CoA dehydrogenase gene was determined in the Swedish population. A heterozygote frequency of 1:127 was observed. Morbidity data indicate that most of the homozygotes with this mutation are not diagnosed and probably remain asymptomatic.

An independent association between obstructive sleep apnoea and coronary artery disease

Previous studies of sleep and breathing suggest an independent association between coronary artery disease (CAD) and obstructive sleep apnoea (OSA) in middle-aged males and females. These studies, however, were criticized because they did not properly adjust for all important confounding factors. In order to better control for the impact of these confounders, a case-control study was performed, matching for age, sex and body mass index (BMI), and additionally adjusting for hypertension, hypercholesterolemia, diabetes mellitus and current smoking. A consecutive selection of 62 patients (44 males and 18 females, mean age 69 yrs, range 44-88 yrs) requiring intensive care for angina pectoris or myocardial infarction at the County Hospital of Skaraborg, Skövde, Sweden, as well as 62 age-, sex- and BMI- matched control subjects without history or signs of heart disease underwent an overnight sleep/ventilatory monitoring study. The time interval between discharge from the intensive care unit and the overnight study ranged between 4 and 21 months. OSA, defined as a Respiratory Disturbance Index (RDI) of > or =10 x h(-1), was present in 19 CAD patients but only in eight control subjects (p=0.017). Using a univariate logistic regression analysis, current smoking (odds ratio (OR) 8.1, 95% confidence interval (CI) 2.2-29.0), diabetes mellitus (OR 4.2, 95% CI 1.1-16.1) and OSA (OR 3.0, 95% CI 1.2-7.5), but not hypertension (OR 1.5, 95% CI 0.7-3.2) and hypercholesterolaemia (OR 1.8, 95% CI 0.7-4.1) were significantly correlated with CAD. In a multiple logistic regression model, current smoking (OR 9.8, 95% CI 2.6-36.5), diabetes mellitus (OR 4.2, 95% CI 1.1-17.1) and OSA (OR 3.1, 95% CI 1.2-8.3) all remained independently associated with CAD. In summary, these data suggest a high occurrence of obstructive sleep apnoea in middle-aged and elderly patients with coronary artery disease requiring intensive care, which should be taken into account when considering risk factors for coronary artery disease.

Collagen-induced arthritis development requires alpha beta T cells but not gamma delta T cells: studies with T cell-deficient (TCR mutant) mice

Collagen type II (CII)-induced arthritis (CIA) in mice is a model for rheumatoid arthritis (RA) in which the role of T lymphocytes remains controversial. To clarify this, we have bred a targeted gene deletion of TCR beta or delta loci into two mouse strains susceptible to CIA, the B10.Q and DBA/1 strains. The TCRbeta-/- mice lacked alphabeta T cells, which was compensated by an expansion of B cells, gammadelta T cells and NK cells. The beta-/- mice, but not control beta+/- littermates, were completely resistant to CIA. The production of anti-CII IgG antibodies was also abolished in beta-/- mice, revealing a strict alphabeta T cell dependency. In contrast, beta-/- mice produced reduced, but significant, anti-CII IgM titers after immunization with either CII or ovalbumin, indicating a multispecificity for these alphabeta T cell-independent IgM antibodies. The TCRdelta-/- mice lacked gammadelta T cells but had no other significant changes in lymphocyte or monocyte subsets. The cytokine response (IL-2, IL-4, IL-10 and IFN-gamma) in delta-/- mice, quantified by flow cytometry staining of mitogen-stimulated lymphocytes, was indistinguishable from normal mice. Likewise, no statistically significant differences were observed in CIA between mice lacking gammadelta T cells and control littermates, considering arthritis incidence, day of disease onset, maximum arthritic score, anti-CII IgG titers and disease course. We conclude that alphabeta T cells are necessary for CIA development and for an IgG response towards CII, whereas gammadelta T cells are neither necessary nor sufficient for development of CIA.

Stability and immunoreactivity of the monoclonal anticytokeratin antibody TS1 after different degrees of iodination

The immunoreactivity, stability and in vivo kinetics of an anticytokeratin 8 monoclonal antibody, TS1, were investigated following different degrees of labeling with 125I (0.2, 1 and 2-3 125I/TS1 MAb). By testing with ELISA, it was demonstrated that a high degree of iodination, i.e. > 2 125I/TS1, caused a rapid decrease in immunoreactivity to almost zero within 10 days. Furthermore, a complete degradation to low molecular weight fragments and free iodine was seen, as shown by SDS PAGE and autoradiography. The differently labeled radionuclide conjugates were injected into nude mice inoculated with HeLa Hep2 cells and tumor doses (estimated by MIRD formalism), tumor:non-tumor dose ratios, % I.D./gram tissue, Gy/MBq and in vivo kinetics of the differently labeled MAbs were determined. Despite the in vitro instability of the highest iodinated radionuclide conjugate, it was possible to deliver high doses to the tumors if the conjugate was injected into the animal immediately after completion of the iodination procedure. Increases from 1.4 Gy to 15.2 Gy delivered tumor dose were obtained with a tenfold increase in the specific activity, without alterations in the tumor:non-tumor tissue dose ratios. There is room for significant improvements in efficacy at radioimmunotherapy, which can be gained by optimizing the degree of iodination. For therapeutical applications a high degree of iodination may be an advantage.

Adrenal steroid dysregulation in dystrophia myotonica

OBJECTIVE

To evaluate circulating adrenal steroid hormones, cortisol diurnal rhythm and the negative feedback function of the cortisol axis in patients with dystrophia myotonica (DyM), a disease where metabolic disturbances, peripheral insulin insensitivity and cognitive dysfunction are common features.

DESIGN

Morning serum levels of dehydroepiandrosterone sulphate, androstenedione, 17 alpha-hydroxy progesterone and cortisol; morning serum levels of testosterone and insulin; diurnal rhythm of saliva cortisol; and an overnight dexamethasone suppression test, together with a cognitive screening test in men with DyM and in controls.

SETTING

Outpatient clinic in co-operation with Umeå University Hospital.

SUBJECTS

Fifteen men with DyM and 13 age-matched controls.

MAIN OUTCOME MEASURES

Adrenal steroid hormone levels, diurnal rhythm of saliva cortisol, dexamethasone suppression test and Mini Mental State Examination scores.

RESULTS

Morning serum levels of dehydroepiandrosterone sulphate, androstenedione and 17 alpha-hydroxy progesterone were significantly decreased in DyM after inclusion of age and body mass index in multiple regression analyses (48, 26 and 32% decreases, respectively). An abnormal diurnal rhythm of saliva cortisol was present in all patients, mean saliva cortisol levels being significantly increased (33%) in DyM patients. Dexamethasone suppressibility did not differ between groups. DyM patients scored significantly lower on the Mini Mental State Examination (P < 0.001).

CONCLUSIONS

These results indicate an abnormal adrenal steroid hormone secretion in DyM, which may contribute to peripheral insulin sensitivity as well as cognitive impairment in these patients.

Pharmacokinetics of latanoprost in the cynomolgus monkey. 3rd communication: tissue distribution after topical administration on the eye studied by whole body autoradiography. Glaucoma Research Laboratories

Latanoprost (13,14-dihydro-15(R)-17-phenyl-18,19,20-trinor-PGF2 alpha-isopropyl ester, CAS 130209-82-4, PhXA41, Xalatan), an antiglaucoma drug, labelled with tritium at carbon 13 and 14 (4.8 micrograms, 20.8 MBq/eye) was administered topically on the eyes of cynomolgus monkeys. After 0.5 h the concentration of radioactivity in the cornea was estimated to be about 0.6 ng eq/mg tissue. The elimination half-life of total radioactivity in the cornea was about 4 h. The corneal epithelium contained a higher concentration of radioactivity than the stroma. Cornea seemed to act as a slow release depot to the anterior part of the eye. In the iris, anterior chamber and ciliary body the maximal concentrations were 217.0 +/- 12.9 pg eq/mg, 99.8 +/- 7.4 pg eq/mg and 54.0 +/- 4.9 pg eq/mg, respectively, 1 h after administration. The elimination half-life of total radioactivity from these tissues was 3-4 h. Trace amounts (0.4-9 pg eq/mg) remained in these tissues 24 h after administration. Initially the radioactivity was present in the conjunctiva, sclera and choroid as well as in the general circulation. Radioactivity passed through the lachrymal ducts and high concentrations were observed in the oesophagus, stomach content, small intestine, bile and urine of a monkey administered latanoprost topical on the eye 0.5 and 1 h before sacrifice. In this animal concentrations of radioactivity were found in the kidney, liver, wall of the small intestine and blood. All other tissues in this animal contained lower concentrations of radioiactivity than the blood. In an animal sacrificed 2 h after administration of tritium labelled latanoprost on one eye and 6 h after administration on the other eye the highest concentrations of radioactivity were found in urine, bile and in the stomach content. Low concentration of radioactivity remained in the kidney and the liver. In a monkey administered latanoprost 12 and 24 h before death low concentrations remained in the colon, bile and urine. The anterior parts of the eyes from the monkey sacrificed 0.5 and 1 h after administration of latanoprost were cut out from the tissue sections for HPLC analysis. The predominating peak present corresponded to acid of latanoprost (PhXA85). In the stomach the radioactivity chromatographed as latanoprost and the acid of latanoprost. In the small intestine and in bile the main radioactive peak corresponded to 1,2-dinor-acid of latanoprost and in addition several more polar metabolites were present. In conclusion, latanoprost penetrated the cornea, was hydrolysed and slowly released into the anterior parts of the eye the site of action. The maximum concentration in the eye was reached after 1 h with an elimination half-life of 3-4 h. In the body the distribution was limited mainly to the gastro-intestinal tract, the kidney, the gall- and urinary bladder.

Epitope specificity of the monoclonal anticytokeratin antibody TS1

Due to their abundance in epithelial cells and deposition in necrotic regions intratumorally, cytokeratins (CKs) have been established as valuable targets for both radioimmunolocalization and radioimmunotherapy. The target epitope for the monoclonal anti-CK8 antibody, TS1, used for both experimental radioimmunolocalization and radioimmunotherapy, was determined by means of synthesis of 96 overlapping peptides that covered the entire CK8 molecule. A highly conserved peptide sequence, spanning amino acids (aa) 343-357 and covering the discontinuous epitope in the helical 2B domain, was identified. The epitope retains its helical structure, as shown with circular dichroism spectroscopy, although the length of the peptide (ie., >20 aa) is crucial for maintenance of immunoreactivity. To determine which aa residues are crucial for binding to the monoclonal antibody, alanine scanning was performed on a 26-mer covering aa 340-365, with the sequence QRGELAIKDANAKLSELEAALQRAKQ. The 26 modified peptides were evaluated using ELISA and BIAcore technology. The uniqueness of this epitope has been established by data base sequence comparisons.

Estimation of respiratory volumes from the photoplethysmographic signal. Part I: Experimental results

To evaluate the possibility of respiratory-volume measurement using photoplethysmography (PPG), PPG signals from 16 normal volunteers are collected, and the respiratory-induced intensity variations (RIIV) are digitally extracted. The RIIV signals are studied while respiratory volume is varied. Furthermore, respiratory rate, body posture and type of respiration are varied. A Fleisch pneumotachograph is used as the inspired volume reference. The RIIV and pneumotachograph signals are compared, and a statistical analysis is performed (linear regression and t-tests). The key idea is that the amplitude of the RIIV signal is related to the respiratory volume. The conclusion from the measurements is that there exists a relationship between the amplitude of the RIIV signal and the respiratory volume (R = 0.842, s = 0.428, p < 0.005). Absolute measurements of the respiratory volume are not possible from the RIIV signal with the present set-up. The RIIV signal also seems to be affected by respiratory rate and type. More knowledge about respiratory parameters and improved sensor and filter design are required to make absolute measurements of volumes possible.

Estimation of respiratory volumes from the photoplethysmographic signal. Part 2: A model study

A Windkessel model has been constructed with the aim of investigating the respiratory-volume dependence of the photoplethysmographic (PPG) signal. Experimental studies show a correlation between respiratory volume and the peak-to-peak value of the respiratory-induced intensity variations (RIIV) in the PPG signal. The model compartments are organised in two closed chambers, representing the thorax and the abdomen, and in a peripheral part not directly influenced by respiration. Cardiac pulse and respiration are created by continuous adjustment of the pressures in the affected compartments. Together with the criteria for heart and venous valves, the model is based on a set of 17 differential equations. These equations are solved for varying thoracic and abdominal pressures corresponding to different respiratory volumes. Furthermore, a sensitivity analysis is performed to evaluate the properties of the model. The PPG signals are created as a combination of peripheral blood flow and pressure. From these signals, the respiratory synchronous parts are extracted and analysed. To study some important limitations of the model, respiratory type and rate are varied. From the simulations, it is possible to verify our earlier experimental results concerning the relationship between respiratory volume and the peak-to-peak value of the RIIV signal. An expected decrease in the amplitude of the respiratory signal with increased respiratory rate is also found, which is due to the lowpass characteristics of the vessel system. Variations in the relationship between thoracic and abdominal respiration also affect the RIIV signal. The simulations explain and verify what has been found previously in experimental studies.

Husbands' involvement in abortion in Vietnam

This study analyzes the involvement of men in abortion in Vietnam, where induced abortion is legal and abortion rates are among the highest in the world. Twenty men were interviewed in 1996 about the role they played in their wives' abortions and about their feelings and ethical views concerning the procedure. The results showed that both husbands and wives considered the husband to be the main decisionmaker regarding family size, which included the decision to have an abortion, but that, in fact, some women had undergone an abortion without consulting their husbands in advance. Parents and in-laws were usually not consulted; the couples thought they might object to the decision on moral grounds. Respondents' ethical perspectives on abortion are discussed. When faced with an unwanted pregnancy, the husbands adopted an ethics of care and responsibility toward family and children, although some felt that abortion was immoral. The study highlights the importance of understanding husbands' perspectives on their responsibilities and rights in reproductive decisionmaking and their ethical and other concerns related to abortion.

Physiological characterization of mBSA antigen induced arthritis in the rat. II. Joint blood flow, glucose metabolism, and cell proliferation

OBJECTIVE

Based on the hypothesis that blood flow in the inflamed joint is inadequate to maintain aerobic glycolysis, we sought to estimate the correlation between blood flow, glucose metabolism, and cellular proliferation rate in the arthritic joint.

METHODS

Experiments were performed on rats with antigen induced arthritis (AIA). Regional blood flows (RBF) were measured with the microsphere technique, glucose metabolism by determination of [14C]2-deoxy-D-glucose (2-DG) uptake, and the proliferative response as the incorporation of [3H]-thymidine.

RESULTS

In periarticular soft tissue of the arthritic knee the only significant change in the weight related RBF was an approximate 70% rise on Day 14 after arthritis onset. The RBF was lowest on Day 3 and the time course for the changes was inversely related to intensity of vascular inflammation. Weight related 2-DG uptake was more elevated than the RBF and peaked on Day 3. [3H]-thymidine incorporation in the soft tissue was only markedly enhanced on Day 3. Neither 2-DG nor [3H]-thymidine uptake was affected by treatment with methotrexate or indomethacin. In epiphyseal bone RBF was reduced on the first day of arthritis, but steadily increased thereafter.

CONCLUSION

In AIA an intense vascular leakiness negatively affects the synovial blood. There is a marked enhancement of glucose metabolism, but only a minor part of this increase seems to be induced by increased cellular proliferation.

Inhomogeneity in planar ventilation scintigraphy of emphysematous patients

The aim of this study was to develop and evaluate a method for the quantification of inhomogeneity in ventilation scintigraphy. Ten healthy volunteers and 10 emphysematous patients were investigated. Anteroposterior (AP) and Posteroanterior (PA) images of planar ventilation scintigraphy were acquired. Lung regions of interest (ROI) were obtained by manual delineation of the lung contours and then divided into several 10-pixel-high horizontal-stripe regions. By allowing for the statistical noise of the pixel count rate, the biological coefficient of variation (CVB) of the pixel counts in each stripe region was calculated. The apex-to-base distribution of the CVB in the emphysematous lungs dispersed largely and with higher values than the corresponding distribution in the healthy lungs. The mean values of the CVB (MCVB), the ranges of the CVB (RCVB) and the maximum values of the CVB (MAXCVB) in the stripe regions in emphysematous lungs were significantly higher than the corresponding ones in the healthy lungs (all P < 0.001). The intraobserver variations of the MCVB, RCVB and MAXCVB (calculated using the standard deviations of the differences) were less than 2.3% units, 5.2% units and 3.9% units respectively. The corresponding values for interobserver variation were 5.7% units, 6.1% units and 6.4% units. A systematic decrease in lung ROI size, i.e. inclusion of successively less of the lung edge, resulted in a linear decrease of 1.7% units in the MCVB and MAXCVB of both emphysematous and normal lungs. In conclusion, the stripe-region method is a reliable tool for the quantification of inhomogeneity in the planar ventilation scintigraphy.

Hepatic and extrahepatic clearance of circulating human lactoferrin: an experimental study in rat

Lactoferrin, unlabelled or 125I-labelled by 2 different methods, was given intravenously to rats. Blood, tissue and liver cell radioactivity was measured. Both of the radiolabelled preparations were eliminated by the liver, and some deposited extrahepatically. One preparation formed large aggregates--here 90% of the hepatic uptake occurred in the Kupffer cells. The other preparation, consisting mostly of protein monomers but also dimers/oligomers/microaggregates, was taken up by hepatocytes (63% of total liver uptake), liver endothelial cells (22%) and Kupffer cells (15%). On a per cell volume basis, lactoferrin uptake was much more efficient by nonparenchymal cells compared to hepatocytes, which explains why immunomorphological staining only revealed lactoferrin in the nonparenchymal liver cells. The study demonstrates that radio-iodination of lactoferrin can affect its properties and handling, which may be important regarding contradictory reports on hepatic lactoferrin uptake. We conclude that both hepatocytes and nonparenchymal liver cells are involved in the blood clearance of lactoferrin, probably to a great extent owing to nonspecific mechanisms. Extrahepatic deposition and exposure (for instance on vessel walls/glomeruli) suggests that lactoferrin can be available to circulating anti-lactoferrin autoantibodies in autoimmune disease.

Evaluation of attenuation corrections using Monte Carlo simulated lung SPECT

SPECT (single photon emission computed tomography) images are distorted by photon attenuation. The effect is complex in the thoracic region due to different tissue densities. This study compares the effect on the image homogeneity of two different methods of attenuation correction in lung SPECT; one pre-processing and one post-processing method. This study also investigates the impact of attenuation correction parameters such as lung contour, body contour, density of the lung tissue and effective attenuation coefficient. The Monte Carlo technique was used to simulate SPECT studies of a digital thorax phantom containing a homogeneous activity distribution in the lung. Homogeneity in reconstructed images was calculated as the coefficient of variation (CV). The isolated effect of the attenuation correction was assessed by normalizing pixel values from the attenuation corrected lung by pixel values from the lung with no attenuation effects. Results show that the CV decreased from 12.8% with no attenuation correction to 4.4% using the post-processing method and true densities in the thoracic region. The impact of variations in the definition of the body contour was found to be marginal while the corresponding effect of variations in the lung contour was substantial.

Evaluation of a workplace redesign of a grocery checkout system

The aim of this study was to evaluate the effects on the working postures and movements of a cashier when two different locations of the scales (one to the left of the cashier, the other under the conveyer belt in front of the cashier) were used in a grocery checkout system. Two cashiers (of average stature and short stature) were videotaped while working, in both sitting and standing working positions. Analysis of the video tapes was performed using the WOPALAS method and video observations. The results of the study show that the design of the checkout system with the scales under the conveyer belt provides a more favourable working position for both the taller and the shorter cashier. Additionally, the results indicate that a standing position is more favourable than a sitting one for the taller cashier while for the shorter cashier the sitting position is better.

Characterization of the proteinase-dependent cytotoxicity of Porphyromonas gingivalis

Cytotoxicity of proteins from Porphyromonas gingivalis towards gingival fibroblasts and epithelial cells was studied by methods measuring vital dye uptake, DNA synthesis, release of cytoplasmic components, and apoptosis. Microscopic examination of the cells was also performed for detection of morphological changes. Experiments were made with dialyzed culture supernatants of P. gingivalis as well as supernatant fractions obtained by isoelectric focusing. The main cell damage observed was rounding of the cells and detachment from each other and the underlying surface. The cell-damaging activity correlated with the cystein-dependent proteolytic activity of the various supernatant preparations as well as with the occurrence of gelatinolytic protein bands with molecular weights previously reported for the cysteine proteinases gingipains R and K of P. gingivalis. The activity was abolished by heat treatment or by the addition of cysteine proteinase inhibitors. The results indicate that the main cytotoxic effect towards fibroblasts and epithelial cells is degradation of the intercellular matrix. The gingipains released in P. gingivalis culture supernatants are the responsible factors for this degradation.