Antibiograms of resistant Gram-negative bacteria from Scottish CF patients.

BACKGROUND: Over a 19-month pilot phase, 93 multiply resistant Gram-negative isolates from Scottish cystic fibrosis patients were sent to a referral laboratory for further investigation. METHODS: In common with the referring diagnostic laboratories, disc diffusion testing was carried out. Antibiotic susceptibility testing was also established by MIC methodology. NCCLS methods were used throughout. Twenty antibiotics were tested. RESULTS: Comparing disc diffusion results against MIC results, there were 167 (14%) major errors. By MIC, Pseudomonas aeruginosa (n = 59), Stenotrophomonas maltophilia (n = 16), Burkholderia cepacia (n = 10) and Alcaligenes xylosoxidans (n = 7) were susceptible to 18%, 11%, 4% and 35% of the antibiotics tested, respectively. Colistin and tobramycin were the most active agents against P. aeruginosa with 60% and 49%, respectively, testing susceptible. Minocycline and gentamicin were most active against S. maltophilia with 58% and 18%, respectively, testing susceptible. B. cepacia were most susceptible to co-trimoxazole (10%) and ciprofloxacin (10%). Five and six of the seven A. xylosoxidans isolates were susceptible to piperacillin and imipenem, respectively. CONCLUSIONS: Improved methods for susceptibility testing of such clinical isolates need to be employed in routine diagnostic laboratories. Levels of resistance in referred isolates were very high and similar to those described in the USA.     

Differential class III and glibenclamide effects on action potential duration in guinea-pig papillary muscle during normoxia and hypoxia/ischaemia.

1. Microelectrode recording techniques were used to study the effects of several potassium channel blockers which are considered to be Class III antiarrhythmic compounds. The effects of (+)-sotalol, UK-66,914, UK-68,798 and E-4031 on action potential duration (APD) were determined in guinea-pig isolated papillary muscles. The compounds were evaluated under normoxic or hypoxic/ischaemic conditions at 36.5 degrees C and compared to glibenclamide, which is considered to be a blocker of ATP-dependent potassium channels. Prolongation of action potential duration at 90% repolarization (APD90) was taken as an indirect measure of potassium channel blockade. 2. Under normoxic conditions, the Class III compounds prolonged APD in a concentration-dependent manner. According to EC15 values, the order of potency of the Class III compounds was found to be UK-68,798 > E-4031 > UK-66,914 > (+)-sotalol. Glibenclamide did not significantly prolong APD90 under normoxic conditions. 3. Perfusion with an experimental hypoxic or ischaemic bathing solution produced qualitatively similar effects on action potentials. Over a period of 20-25 min in either of the experimental solutions, there was a small decrease in action potential amplitude (APA) and a prominent shortening of APD. The ischaemic solution also depolarized the resting membrane potential by about 15 mV. 4. (+)-Sotalol and UK-66,914 did not reverse the shortening of APD induced by perfusion with hypoxic Krebs solution. High concentrations of glibenclamide (10 microM) and UK-68,798 (30 and 60 microM) partially reversed the hypoxia-shortened APD. Glibenclamide was more potent and exhibited a greater time-dependent action than UK-68,798.(ABSTRACT TRUNCATED AT 250 WORDS)     

Enterocutaneous fistula: A reconstructive dilemma

Summary  Surgical repair of enterocutaneous fistulae in Crohn’s disease may result in large skin defects of the anterior abdominal wall. We present a case in which a large defect was managed with reconstruction using a pedicled rectus abdominis mycocutaneous flap in a single procedure. The case highlights the technical challenge of such a case and the value of a joint surgical approach between plastic and colorectal services.     

Differential effects of kindling and kindled seizures on place learning in the morris water maze

There is some controversy about the role of long-term potentiation (LTP) in spatial learning. The authors have found that triggering generalized kindled seizures with stimulation of the perforant path disrupts spatial learning in the Morris water maze but that kindling per se does not affect spatial learning. It is suggested that abnormal electrical activity induced by high-frequency stimulation of the perforant path may have been responsible for the disruption of spatial learning previously attributed to LTP saturation.     

Management of patients supported on the Hemopump cardiac assist system

The Hemopump Cardiac Assist System is a relatively new intraarterial, axial-flow circulatory assist device that offers temporary left ventricular support to patients in refractory cardiogenic shock, without requiring major surgery for insertion. Use of the Hemopump is associated with a low complication rate. Device-related morbidity is extremely rare. Because the Hemopump is safe for use in community hospitals, the number of patients supported by this device is expected to increase. In this report, we present general guidelines for the care of patients supported by the Hemopump. We describe techniques for the management of afterload reduction, supravalvular dislodgement, device malfunction, ventricular ectopy, intracardiac shunting, and inflow cannula obstruction.     

Mode and speed specificity of eccentric and concentric exercise training

This research was supported by a Duke University Research Council Grant. The purpose of this study was to examine mode and speed specificity of strength training by comparing concentric and eccentric isokinetic exercise of the quadriceps. Forty-eight healthy men (mean age = 23.9 years) were randomly assigned to one of three groups: concentric training (C), eccentric training (E), or control (K). Average force (in Newtons) of 3 concentric and of 3 eccentric quadriceps contractions on the KIN-COM(R) dynamometer at 60, 120, and 180 degrees /sec was evaluated prior to and following a 6 week period during which only the C and E groups trained. Training sessions (3/week) included 4 submaximal and 1 maximal warm-up followed by 10 maximal effort isokinetic contractions of the quadriceps at 120 degrees /sec for each leg. Group C subjects trained concentrically only while Group E subjects trained eccentrically only. A t-test for independent means showed no significant right/left differences. ANOVA and Scheffe's F-tests were then used to assess the differences in training effects among the 3 groups for the left leg only. Results showed that although Group C increased slightly in both concentric and eccentric force at all speeds, the gains were significant only for concentric force at 180 degrees /sec. Group E showed significant gains (p < 0.05) in eccentric force at all speeds but not in concentric force. The K group had no significant change in concentric or eccentric force at any speed. We conclude that the eccentric mode of isokinetic exercise has highly specific strength training effects while the concentric mode has less specific training effects. In addition, speed of exercise does not appear to have specific training effects. J Orthop Sports Phys Ther 1989;11(2):70-75.     

Integrating signals from T-cell receptor and serum by T cells enhance translation of tumour necrosis factor-alpha

Tumour necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine produced by several cell types, including T cells upon antigen stimulation. Its production is crucial for the development of an early defence against many pathogens, but its beneficial effects are dependent on the strength and duration of its expression. In this paper we present evidence indicating that serum increases translational efficiency of TNF-alpha in human peripheral blood mononuclear cells stimulated with superantigen. The increase in translation of TNF-alpha due to serum could be inhibited by the phosphatidylinositol (PI) 3-K inhibitors, wortmannin and LY294002, suggesting that PI 3-K is involved in the translational control of TNF-alpha by serum. Similarly to primary T cells, stimulation of Jurkat T cells with superantigen led to TNF-alpha secretion and this was up-regulated by serum. Transfection of Jurkat cells with a constitutively active form of PI 3-Kalpha increased the production of TNF-alpha in cells stimulated with superantigen. Additionally, we used the specific inhibitors targeting ERK kinase and p38 mitogen-activated protein kinase (MAPK), potentially downstream of PI 3-kinase, PD98059 and SB203580. Differently from with PI 3-K inhibitors, the accumulation of TNF-alpha mRNA was inhibited by PD98059 or SB203580. These results suggest that, in T cells, activation of PI 3-K is an important step in controlling TNF-alpha protein synthesis in response to growth factors.     

Characterization of enterotoxin purified from Clostridium perfringens type C.

Enterotoxin produced by a sporulating culture of Clostridium perfringens type C, which had been isolated from a case of severe necrotic enteritis, was purified. The molecular weight was estimated to be 36,000 by gel chromatography on Sephadex G-100 and 33,400 by ultracentrifugation. The sedimentation coefficient S20,W was 2.92. The toxin protein exhibited unusual behavior on sodium dodecyl sulfate gels, and toxin aggregates having molecular weights of 68,000, 85,000, 105,000, and 140,000 were obtained. The purified enterotoxin often separated, apparently due to slight charge differences, into two protein bands on 7% polyacrylamide gels. Electrofocusing of enterotoxin on polyacrylamide gels gave an approximate isoelectric point of 4.3, with the enterotoxin being fractionated into four distinct protein bands. The specific toxicity of the enterotoxin was about 1,900 mouse mean lethal doses per mg of calculated nitrogen. The data obtained indicate that the enterotoxin from C. perfringens type C is identical in most respects to that obtained from type A strains. Whether or not this toxin plays a role in the necrotic enteritis caused by type C strains is unknown at present.     

C3d binding to the circumsporozoite protein carboxy-terminus deviates immunity against malaria

The immunogenicity of recombinant protein or anti-viral DNA vaccines can be significantly improved by the addition of tandem copies of the complement fragment C3d. We sought to determine if the efficacy of a circumsporozoite protein (CSP)-based DNA vaccine delivered to mouse skin by gene gun was improved by using this strategy. Instead, we found that C3d suppressed the protective immunity against Plasmodium berghei malaria infection and deviated immunity, most notably by suppressing the induction of antibodies specific for the CSP C-terminal flanking sequence and by suppressing the induction of CSP-specific IL-4-producing spleen cells. We further showed that C3d bound to the C-terminal flanking sequence of the CSP, which may explain the immune deviation observed in CS/C3d chimeric antigen. We have thus identified C3d-mediated epitope masking and shifting of both the humoral and cellular immune responses as a potential novel escape mechanism, which plasmodia may use to divert the induction of protective immunity.     

Birnavirus VP1 proteins form a distinct subgroup of RNA-dependent RNA polymerases lacking a GDD motif

We have cloned and characterized the Drosophila X virus (DXV) genome segment B and its encoded VP1, the putative RNA-dependent RNA polymerase (RdRp) present in the virion. The 2991-bp open reading frame encodes the largest birnavirus VP1 at 977 aa, with a calculated M(r) of 112.8 kDa. As with the VP1 proteins of the type species of the other two genera in the family Birnaviridae, namely, infectious pancreatic necrosis virus (genus Aquabirnavirus) and infectious bursal disease virus (genus Avibirnavirus), the DXV (genus Entomobirnavirus) VP1 protein contains a consensus GTP-binding site and appears to possess self-guanylylation activity. All of the birnavirus VP1 proteins contain conserved RdRp motifs that reside in the catalytic "palm" domain of all classes of polymerases. However, the birnavirus RdRps lack the highly conserved Gly-Asp-Asp (GDD) sequence, a component of the proposed catalytic site of this enzyme family that exists in the conserved motif VI of the palm domain of other RdRps. All three birnavirus RdRps do contain downstream DD motifs that could function as part of the catalytic triad. These motifs are, however, located in spatially distinct regions of the various birnavirus VP1 proteins. These results suggest that the VP1 proteins of birnaviruses form a defined subgroup of polymerases that either are lacking the conserved RdRp motif VI or have repositioned this motif to different structural regions.