Biochemical characteristics of clinical and environmental isolates of Burkholderia pseudomallei

The biochemical characteristics of 213 isolates of Burkholderia pseudomallei from patients with melioidosis and 140 isolates from the soil in central and northeastern Thailand were compared. Whereas the biochemical profiles of all the clinical isolates were similar, all soil isolates from the central area and 25% of isolates from northeastern Thailand comprised a different phenotype. This was characterised by the ability to assimilate L-arabinose (100%), adonitol (100%), 5-keto-gluconate (90%) and D-xylose (84%), but failure to assimilate dulcitol (0%), erythritol (0%) and trehalose (10%). Compared with clinical isolates, these organisms had similar antibiotic susceptibility profiles and were also recognised by a specific polyclonal antibody against B. pseudomallei. As melioidosis is rare in central Thailand, but common in the northeast, this raises the possibility that this biochemical phenotype may be less virulent, or may even represent a different species.

Effects of pulse methylprednisolone on cell adhesion molecules in the synovial membrane in rheumatoid arthritis. Reduced E-selectin and intercellular adhesion molecule 1 expression

OBJECTIVE

To investigate the effects of a 1,000-mg intravenous pulse of methylprednisolone succinate (MP) on cell adhesion molecule expression on the synovial vascular endothelium in patients with rheumatoid arthritis (RA).

METHODS

Sequential arthroscopic biopsy samples were taken before and 24 hours after MP administration (10 patients) and at the time of RA flare (2 patients) and after retreatment with MP (1 patient). Immunoperoxidase staining for E-selectin (CD62E), P-selectin (CD62P), intercellular adhesion molecule 1 (ICAM-1; CD54) and platelet-endothelial cell adhesion molecule (PECAM; CD31) was performed, and the staining was quantified by color video image analysis.

RESULTS

MP caused a rapid (within 24 hours) and substantial decrease in the expression of E-selectin on the synovial vascular endothelium, with a smaller reduction in ICAM-1 expression on synovial vascular endothelium and the synovial lining. There were no similar effects on synovial membrane P-selectin or PECAM expression.

CONCLUSION

A potential mechanism by which MP impairs neutrophil trafficking into inflamed RA joints might be by reducing E-selectin, and possibly, ICAM-1, expression in the synovial membrane.

Consideration of potential immunological problems in the application of xenogenic hybrid liver support

Hybrid liver support systems (LSS) for the use of pig liver cells are under development for extracorporeal therapy of acute liver failure and for bridging to liver transplantation. A literature overview about possible immunological side effects of a clinical application is given. The data summarised from experimental studies and those clinical applications of porcine cells reported so far, suggest that clinical use of LSS utilising porcine cells and an immuno-isolation membrane should not be compromised by severe immunological complications. The reported data suggest that clinical application should be conducted in conjunction with carefully planned immunological monitoring. Only after such applications of LSS have been carried out and further data have been evaluated, might one be able to judge the immunological consequences of broader application of hybrid liver support.

An uncommon cause of finger drop in a patient with rheumatoid arthritis

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The functionally antagonistic POU family transcription factors Brn-3a and Brn-3b show opposite changes in expression during the growth arrest and differentiation of human neuroblastoma cells

The Brn-3a and Brn-3b POU family transcription factors have previously been shown to have functionally antagonistic effects, with Brn-3a activating specific gene promoters which are repressed by Brn-3b. We show here that proliferating cell lines of human neuroblastoma origin have a high ratio of Brn-3b to Brn-3a compared with other cell lines derived from related tumours. Moreover, the level of Brn-3a rises and that of Brn-3b falls when neuroblastoma cell lines are exposed to treatments which induce a cessation of proliferation. Such treatments also result in the activation of a test promoter which is normally stimulated by Brn-3a and repressed by Brn-3b. Our findings suggest that these antagonistic factors may play a key role in regulation of gene expression during human neuroblastoma differentiation and could thus represent a potential therapeutic target for treatments designed to induce such differentiation.

Effects of benzodiazepine agonist exposure on corticotropin-releasing factor content and hormonal stress responses: divergent responses in male and ovariectomized female rats

Benzodiazepine agonists affect endocrine responses of the hypothalamic-pituitary-adrenal axis and can antagonize many of the actions of corticotropin-releasing factor (CRF). Gender and gonad-related factors can influence both the development of tolerance to the benzodiazepines in rats and the concomitant neural adaptations associated with chronic benzodiazepine agonist exposure. This study compared changes in CRF content, corticosterone release and ACTH levels after diazepam exposure in ovariectomized female (OVX) and male rats. After treatment with diazepam for 3 days (acute) or 3 weeks (chronic), content of CRF immunoreactivity in eight brain areas and serum corticosterone were determined by radioimmunoassay in handling-habituated rats. The effects of acute and chronic benzodiazepine exposure on swim stress-induced corticosterone and ACTH release were also examined. Chronic diazepam exposure reduced stress-induced corticosterone and ACTH release in OVX, but not male, rats. Acute diazepam exposure similarly attenuated stress-induced corticosterone release in OVX rats, but did not affect ACTH release. OVX control groups had greater levels of CRF than males in several brain regions. Gender-specific alterations in CRF content after chronic diazepam exposure were observed in amygdala, locus ceruleus and median eminence. Chronic benzodiazepine agonist exposure increased CRF levels in the amygdala of OVX rats, but not males. Both chronic and acute diazepam exposure increased CRF content in the locus ceruleus of male, but not OVX, rats. These results indicate that the effects of benzodiazepine exposure on neural CRF systems are region specific and influenced by gender-related factors.

Three year follow-up of a case of giant cell arteritis presenting with a chronic cough and upper limb ischaemic symptoms

A case of giant cell arteritis presenting in an atypical fashion with respiratory and upper limb ischaemic symptoms is described. The subclavian and axillary arterial involvement is demonstrated in this case, and followed up with repeated angiographic examinations over the next 3 yr. Despite resolution of all symptoms and return of pulses and a recordable blood pressure in the ischaemic upper limb, there was no angiographic evidence of resolution of the axillary artery stenoses.

Is a clinical application of hybrid liver support systems limited by an initial disorder in cellular amino acid and alpha-keto acid metabolism, rather than by later gradual loss of primary hepatocyte function?

The in-vitro amino acid (AA) and alpha-keto acid (KA) metabolism of bioreactors initially seeded with 2.5 x 10(9) pig hepatocytes was investigated with a perfusion technique. Considerable changes in the culture medium concentrations of AA and KA were measured during the first days in culture. This is indicative of dynamic cellular metabolism in the initial phase. While the concentration of pyruvate decreased starting on the first day, alpha-ketoglutarate, alpha-ketoisocaproate, alpha-ketoisovalerate, and alpha-keto-beta-methyl-n-valerate were synthesized. The long term use of hepatocyte cultures in bioreactors and thus a desirable clinical hybrid liver support therapy appears to be possible since the hepatocytes switched, after 15 days in culture, to steady-state conditions with a stable amino acid turnover featuring general AA uptake accompanied by KA release. The release of branched chain KA, in particular that of alpha-ketoisocaproate, reflects an effective transamination activity in the bioreactor system. Primary pig hepatocytes cultivated in hybrid liver support systems for therapy of acute liver failure or as devices for bridging to liver transplantation can sustain amino acid metabolism for at least 30 days in vitro. However, an initial disorder following the cell isolation that is demonstrated may limit immediate utilization of the systems prior to the reorganisation of the cells to tissue-like structures in bioreactors.

Systemic liberation of interleukin-1 beta and interleukin-1 receptor antagonist in the perioperative phase of liver transplantation

We measured systemic serum levels of interleukin-1 receptor antagonist (IL-1ra), interleukin-1 beta (IL-1 beta), tumor necrosis factor alpha (TNF-alpha), and interleukin-6 (IL-6) during the preoperative, anhepatic, and postreperfusional phases up to the 7th postoperative day in 60 patients undergoing orthotopic liver transplantation (LTx). In contrast to IL-1 beta, IL-1ra, TNF-alpha, and IL-6 showed a significant elevation in relation to the early phase after reperfusion, while TNF-alpha displayed a high grade of scatter. In addition, IL-1ra levels were significantly elevated during the anhepatic phase. Maximum serum levels were found at 15 min after reperfusion, 120 min after reperfusion, and on the 1st postoperative day, respectively. Serum levels decreased considerably at 24 h and 7 days after reperfusion. The comparative monitoring of systemic cytokine and cytokine antagonist levels, in particular the liberation of IL-1ra and IL-6 may provide useful parameters for the development of new liver preservation theories for LTx.

Bioelectric response of human nasal epithelial cells to polycationic protein

Polycationic proteins alter electrolyte transport by epithelium and endothelium, and in asthma are thought to disrupt the airway epithelium and contribute to hyperresponsiveness and airway plugging. In the present study, we used primary cultures of human nasal epithelial cells to investigate the response of respiratory tract epithelium to luminal presentation of a polycationic protein, protamine. Protamine (100 micrograms/ml) in the apical bathing solution had no significant effect on basal transepithelial resistance (Rt) but decreased short-circuit current (Isc) and hyperpolarized the apical membrane, indicating that Na+ absorption had been inhibited. Pretreating with amiloride inverted the response to protamine, resulting in an increase in Isc, depolarization of the apical membrane, and decrease in the fractional resistance of the apical membrane (fRa). The increase in Isc was inhibited by pretreatment with bumetanide. These results indicated that protamine augmented amiloride-induced Cl- secretion. Induction of Cl- secretion by bathing the apical surface in 3 mM Cl(-)-Ringer solution similarly resulted in protamine-induced depolarization of the apical membrane. Heparin precipitated protamine from solution and reversed the Isc responses. In summary, low concentrations of polycationic protein can alter electrolyte transport by human airway epithelium without desquamation, and the response is dependent on the secretory state of the tissue.

Validation of three-dimensional echocardiography for quantifying the extent of dyssynergy in canine acute myocardial infarction: comparison with two-dimensional echocardiography

OBJECTIVES

This study was designed to compare the accuracy of three- and two-dimensional echocardiography for quantifying the extent of abnormal wall motion in experimental acute myocardial infarction, as correlated with the pathologic determination of infarct size.

BACKGROUND

Two-dimensional echocardiographic estimations of the fraction of myocardium showing abnormal wall motion are often used as an index of infarct size even though they rely on image plane positioning and geometric assumptions that may not be valid. Three-dimensional echocardiographic reconstruction of the endocardial surface eliminates the need for these assumptions and may improve echocardiographic estimates of infarct size.

METHODS

Coronary ligation was performed in 14 open chest dogs, and echocardiographic imaging of the ventricle was performed 6 h later. Three-dimensional echocardiography used seven or eight spatially registered short-axis images to measure percent of endocardial surface and mass showing abnormal wall motion. Three two-dimensional echocardiographic methods using multiple, nonpatially registered images were evaluated. One method used seven or eight-axis slices and a summation of discs algorithm for computing surface area. The second method used the same images and a conical model for the left ventricle. The third used basal, middle and apical short-axis plus apical four- and two-chamber views comparing summed endocardial lengths showing abnormal wall motion with the total of the endocardial dimensions, expressed as percent. The percent of left ventricular mass and surface area infarcted was determined by staining with triphenyltetrazolium chloride.

RESULTS

Three-dimensional echocardiographic measurements of endocardial surface and correlated more closely with infarct mass (r = 0.94, SEE +/- 3.6%) than did the two-dimensional method using the summation of discs algorithm (r = 0.85, SEE +/- 6.6%), he summation of conical sections algorithm (r = 0.82, SEE +/- 5.4%) or the method using summed endocardial lengths (r = 0.79, SEE +/- 7.4%). Limits of agreement analysis comparing mass showing abnormal wall motion with anatomic infarct mass surface area showing abnormal wall motion with anatomic infarct surface area showed the smallest limits for three-dimensional echocardiography.

CONCLUSIONS

Three-dimensional echocardiography is a more accurate means of noninvasively estimating myocardial infarct size in this canine model than two-dimensional echocardiography.

Three-dimensional echocardiography compared to two-dimensional echocardiography for measurement of left ventricular mass anatomic validation in an open chest canine model

A three-dimensional echocardiographic system has been developed that can accurately compute left ventricular mass in vitro. This study was designed to validate the new echocardiographic system for the measurement of left ventricular mass in vivo and to compare the accuracy of three-dimensional echocardiography to the accuracy of conventional two-dimensional echocardiography for measuring left ventricular mass. Echocardiographic imaging was performed 6 h following coronary ligation in 20 open chest dogs, at which time the heart was excised and the left ventricle weighed. Three-dimensional echocardiography used multiple short axis sections and polyhedral surface reconstruction to compute myocardial volume. The two dimensional methods employed the truncated ellipsoid model and the area-length model. Myocardial volume was multiplied by 1.05 g/cc and echocardiographic mass estimates were compared to the true left ventricular weight. Three-dimensional echocardiography provided the best correlation (r = 0.96, upsilon r = 0.88 and r = 0.83 for the truncated-ellipsoid and area-length methods, respectively), and the lowest standard error of the estimate for the regression equation (+/- 5.5 g upsilon +/- 11.0 and +/- 14.6 g, respectively). Three dimensional echocardiography also had the lowest standard deviation for the echo-true mass differences (+/- 5.8 g upsilon +/- 10.7 g and +/- 14.2 g) and a lower root mean square percent error (6.8%) upsilon 12.6% and 12.7%). In this open chest canine model, three-dimensional echocardiography is more accurate than standard two-dimensional echocardiographic methods for measuring left ventricular mass.

Relation of Doppler transmitral flow patterns to functional status in congestive heart failure

We analyzed the relation of Doppler transmitral flow patterns and New York Heart Association (NYHA) classification in 60 consecutive patients with heart failure (44 men and 16 women; mean age 58 +/- 13 years) with left ventricular ejection fraction of < 40 percent. Of the study population, 40 patients with mild to moderate heart failure underwent symptom-limited exercise testing. The relation of transmitral flow pattern and exercise tolerance was also analyzed. Doppler echocardiography was performed in all patients. The patients were subdivided into nonrestrictive and restrictive groups according to the pattern. The univariate analysis showed a relation for left ventricular ejection fraction (p = 0.01 by analysis of variance testing) and transmitral flow pattern (p = 0.0003 by chi-squared test) with NYHA classification. When the multivariate regression analysis was performed, only the restrictive pattern by Doppler emerged as an independent determinant of the advanced NYHA class (p = 0.005). In mild to moderate congestive heart failure, patients with nonrestrictive pattern exercised significantly longer than those with the restrictive pattern by an average of 133 seconds (p = 0.003) despite comparable reductions in ejection fraction. Thus the restrictive transmitral flow pattern by Doppler is a noninvasive marker for severe symptoms and diminished exercise tolerance in heart failure patients.

In-vitro activity of carbapenem antibiotics against beta-lactam susceptible and resistant strains of Burkholderia pseudomallei

Four carbapenem antibiotics were tested for their in-vitro activities (MICs, MBCs and time-kill studies) against Burkholderia pseudomallei. The carbapenems were all more active than either ceftazidime or co-amoxiclav against strains of B. pseudomallei with a normal susceptibility pattern. Biapenem was the most active antibiotic tested. All four carbapenems retained bactericidal activity against 24 strains of B. pseudomallei with reduced susceptibility to ceftazidime and/or co-amoxiclav.

Evidence for dissociation of histone mRNA expression from cellular proliferation in cutaneous human papillomavirus infection

Replication of human papillomavirus (HPV) is thought to require the expression of components of the host cell DNA replication apparatus. The expression of the mRNA encoding the DNA replication-dependent histones H2B, H3, and H4 was investigated in a series of verrucae using an FITC-labelled oligonucleotide cocktail for in situ hybridization, to explore the possibility of HPV inducing the transcription of host cell histones. In contrast to normal epidermis, in which the majority of histone mRNA labelling was confined to basal cells, a bimodal distribution of histone positivity was observed in all verrucae. In addition to basal hyperproliferation-associated labelling, numerous positive suprabasal cells were found within the stratum spinosum. By contrast, in another hyperproliferative lesion, psoriasis, the labelling pattern was similar to that found in the normal controls, with characteristic basal hyperproliferation but no evidence of suprabasal labelling. The presence of HPV replication in every verruca and its absence from all controls of normal and psoriatic skin were demonstrated immunohistochemically, using a polyclonal antibody to the viral capsid proteins. It is proposed that the presence of histone mRNAs in differentiated suprabasal keratinocytes of verrucae is due to the virus turning on parts of the cellular apparatus in order for it to replicate in the absence of cellular proliferation. The results also emphasize that when assessing proliferation with in situ hybridization for histone mRNA, the possibility of HPV causing the labelling of non-proliferating cells should be considered.

Neutrophil trafficking into inflamed joints in patients with rheumatoid arthritis, and the effects of methylprednisolone

OBJECTIVE

To investigate the trafficking of circulating blood neutrophils and synovial fluid neutrophils in rheumatoid arthritis (RA) patients and the influence of a 1,000-mg intravenous pulse of methylprednisolone succinate (MP).

METHODS

Neutrophils were isolated from the circulation and from the knee synovial compartments of subjects with RA. Circulating neutrophils were labeled with technetium-99 hexametazime (99mTc-HMPAO) and reinjected intravenously. Synovial fluid neutrophils were labeled from indium-111 oxine and reinjected into the knee from which they were isolated. Gamma camera images were obtained at intervals up to 24 hours post MP. Each patient had a baseline study (no MP) and a study in which MP was administered either 4 hours before (2 patients), 10 minutes before (1 patient), or 30 minutes to 1.5 hours after (6 patients) injection of the radiolabeled neutrophils. Subsequent analysis allowed quantitation of the neutrophil uptake into and clearance from the knee as a function of time.

RESULTS

Nine patients who had not received glucocorticoids in the previous 3 months were studied. MP significantly decreased neutrophil ingress in 13 of the 16 knees studied (almost total inhibition in 5 knees), and this occurred within 1.5 hours of MP administration in all except 1 knee. At 24 hours after MP administration, there was a significant increase in visual analog scale (VAS) scores for well-being and significant decreases in scores on the modified Health Assessment Questionnaire (P<0.05), tender joints (P<0.005), VAS for pain (p<0.005), and generalized stiffness (P<0.005), as well as a decrease in the C-reactive protein level (P<0.05). MP had no effect on neutrophil egress (2 patients). Two additional patients who were receiving oral glucocorticoids were studied. One of them was clinically unresponsive to oral prednisolone, and MP had no effect on neutrophil ingress. The other patient showed no neutrophil ingress during the baseline study. This was confirmed by the presence of a noninflammatory synovial fluid at arthrocentesis.

CONCLUSION

Neutrophil ingress into and egress from inflamed joints can be accurately monitored using radiolabeled neutrophils and quantitative gamma camera imaging. MP rapidly and substantially decreases neutrophil ingress into inflamed joints. In contrast, MP has no effect on neutrophil egress from the joint.