Smaqnr, a new chromosome-encoded quinolone resistance determinant in Serratia marcescens

OBJECTIVES

A new pentapeptide repeat (PRP) protein, named SmaQnr, from the clinically relevant species Serratia marcescens, which decreased susceptibility to quinolones when expressed in Escherichia coli, is reported herein.

METHODS

In silico analysis revealed the presence of a gene encoding a Qnr-like protein that shares 80% amino acid identity with QnrB1 in the S. marcescens strain Db11. Fragments carrying the coding region and the upstream non-coding sequences of eight clinical isolates were cloned and expressed in E. coli. MIC values of quinolones were determined. RT-PCR was used to study expression of these genes in their natural host. Southern hybridization was used to explore the presence of the gene in the genus Serratia.

RESULTS

Recombinant plasmids encoding SmaQnr reduced susceptibility to fluoroquinolones and nalidixic acid in both E. coli ATCC 25922 and DH10B. Sequences upstream of these genes contain a LexA box. Conventional RT-PCR showed transcription of the analysed Smaqnr genes in their natural hosts. Southern blot analysis suggests the presence of similar genes in several species of the genus Serratia.

CONCLUSIONS

SmaQnr conferred a reduced susceptibility phenotype against fluoroquinolones in E. coli. These data provide evidence of its possible role in quinolone resistance in S. marcescens. This Gram-negative species may constitute a reservoir for qnr-like quinolone resistance genes.

Energy density of sub-Antarctic fishes from the Beagle Channel

The energy density (ED) of nine species of sub-Antarctic fishes was estimated by calorimetry. The fish, seven notothenioids, one atherinopsid and one galaxiid, represents some of the more abundant species in the ichthyofauna of the Beagle Channel. Principal-components analysis (PCA) of the ED of the different organs/tissues indicated that PC(1) and PC(2) accounted for 87% of the variability. Separation along PC(1) corresponded to differences in muscle and liver energy densities whereas separation along PC(2) corresponded to differences in the ED of the gonads. Differences between species were significant except for P. sima. Inclusion of the gonadosomatic index (GSI) as an explanatory variable enabled us to establish the existence of energy transfer from muscle and liver to the gonads in ripe P. tessellata females. Total ED values varied between 4.21 and 6.26 kJ g(-1), the pelagic Odontesthes sp. being the species with the highest ED. A significant relationship between ED and muscle dry weight (DW(M)) was found for all the species except P. tessellata. These data are the first direct estimates of ED of fishes from the Beagle Channel.

Interleukin-12 gene polymorphisim in patients with giant cell arteritis, polymyalgia rheumatica and elderly-onset rheumatoid arthritis

OBJECTIVE

The cytokine profile suggests that giant cell arteritis (GCA) is a Th1-driven disease, in which local IFN-gamma plays a critical role in the development of a systemic arteritis. IL-12 is a potent inducer of IFN-gamma and is critically involved in biasing an immune response towards a Th1 pathway. The purpose of this study was to investigate whether there was an association between an IL-12 gene polymorphism (-1188 A/C 3UTR) and disease susceptibility for GCA and two other age-related inflammatory conditions, such as polymyalgia rheumatica (PMR) and elderly-onset rheumatoid arthritis (EORA). Furthermore, we attempted to correlate such polymorphism with in vitro IL-12 production.

MATERIALS AND METHODS

We analyzed genotypes at -1188 in the 3UTR of the IL-12 promoter by PCR-RFLP in 68 GCA, 138 PMR, and 72 EORA patients as well as in 465 healthy controls (HC). IL-12p70 levels in culture supernatants after stimulation with PMA+Ionomycin was assessed by ELISA.

RESULTS

All groups were in Hardy-Weinberg equilibrium. Allelic and gen-omic distribution was not significantly different among the study groups. None of the genetic variants was associated with disease severity. Although the differences were not statistically significant, HC genotypes were associated with distinct IL-12 p70 production.

CONCLUSIONS

The IL-12 (-1188 A/C 3UTR) gene polymorphism is not associated with disease susceptibility or severity in three age-related chronic inflammatory syndromes. The production of IL-12 p70 is dependent on the genetic background in HC, although in patients such association may be biased by other unknown factors.

Globally dispersed Y chromosomal haplotypes in wild and domestic sheep

To date, investigations of genetic diversity and the origins of domestication in sheep have utilised autosomal microsatellites and variation in the mitochondrial genome. We present the first analysis of both domestic and wild sheep using genetic markers residing on the ovine Y chromosome. Analysis of a single nucleotide polymorphism (oY1) in the SRY promoter region revealed that allele A-oY1 was present in all wild bighorn sheep (Ovis canadensis), two subspecies of thinhorn sheep (Ovis dalli), European Mouflon (Ovis musimon) and the Barbary (Ammontragis lervia). A-oY1 also had the highest frequency (71.4%) within 458 domestic sheep drawn from 65 breeds sampled from Africa, Asia, Australia, the Caribbean, Europe, the Middle East and Central Asia. Sequence analysis of a second locus, microsatellite SRYM18, revealed a compound repeat array displaying fixed differences, which identified bighorn and thinhorn sheep as distinct from the European Mouflon and domestic animals. Combined genotypic data identified 11 male-specific haplotypes that represented at least two separate lineages. Investigation of the geographical distribution of each haplotype revealed that one (H6) was both very common and widespread in the global sample of domestic breeds. The remaining haplotypes each displayed more restricted and informative distributions. For example, H5 was likely founded following the domestication of European breeds and was used to trace the recent transportation of animals to both the Caribbean and Australia. A high rate of Y chromosomal dispersal appears to have taken place during the development of domestic sheep as only 12.9% of the total observed variation was partitioned between major geographical regions.

Preliminary study of choledochocholedochostomy without T tube in liver transplantation: a comparative study

INTRODUCTION

Biliary anastomosis during liver transplantation can be safely performed using an end-to-end choledochocholedochostomy, with or without a T tube. The objective of this study was to determine whether the insertion of a T tube was related to more postoperative complications.

METHODS

Between April 1986 and September 2004, we performed a retrospective, longitudinal, and comparative study of 1012 liver transplantations, including 50 adult recipients with a T tube and a control group with a choledochocholedochostomy without a T tube.

RESULTS

T tube insertion was associated with more postoperative complications and worse actuarial survival of both the recipient and graft, though these differences did not reach statistical significance.

CONCLUSION

The duct-to-duct biliary anastomosis stented with a T tube tends to be associated with more postoperative complications. Based on this analysis, we recommend the performance of a nonstented anastomosis.

Comparative analysis of the results of orthotopic liver transplantation in patients with and without portal vein thrombosis

INTRODUCTION

Portal vein thrombosis (PVT), which had been considered an absolute contraindication to orthotopic liver transplantation (OLT), is currently considered a risk factor that increases morbi-mortality. The objective of this study was to compare OLT outcomes in patients with vs without PVT.

MATERIALS AND METHODS

Between April 1986 and December 2003, a sample of 83 patients with PVT was compared with another sample of 83 patients without PVT among 962 OLT performed in our department.

RESULTS

Both groups were homogeneous in terms of epidemiological variables, surgical technique, immunosuppression, and donor-related variables. There were no differences with respect to graft function during the first week following surgery. Surgical time and anhepatic phase duration was longer in the PVT group, albeit the differences were not significant. PVT patients also required more transfusions; a strong statistical association was observed with respect to blood (P = .12) and plasma (P = .11) transfusions and statistically significant differences regarding platelet transfusions (P = .02). Time on mechanical ventilation and the length of stay in the ICU were longer but not significant among PVT patients. The only statistically significant difference was the incidence of portal rethrombosis (P = .02). With respect to mean and global patient and graft actuarial survivals after 1, 3, 5, and 10 years, we have observed no significant intergroup differences, although both patient (P = .48; NS) and graft (P = .96, NS) survivals were lower among PVT cases.

CONCLUSIONS

PVT should not only cease to be considered a contraindication for OLT, but there were no significant differences between the outcomes despite this finding.

Modulation of hepatocyte growth factor plasma levels in relation to the dose of exogenous heparin administered: an experimental study in rats

INTRODUCTION

Partial liver transplantation has been consolidated to be a valid treatment option. We sought to understand the factors that modulate and may be harnessed to accelerate hepatocyte regeneration. We sought to determine the impact of heparin on m-hepatocyte growth factor (HGF) plasma concentrations.

MATERIALS AND METHODS

Sixteen rats were assigned to four groups of four animals each: group A, without heparin; group B, 600 IU/kg; group C, 1000 IU/kg, group D, 1400 IU/kg. Blood samples (0.5 mL) were obtained from each rat at baseline and at 30, 60, 120, and 240 minutes. After the samples were centrifuged to separate supernates from the cell phase they were stored at -20 degrees C in the m-HGF reagent and subsequently tested using enzyme-linked immunosorbent assay. Results were analyzed using SPSS 11.5 statistical software.

RESULTS

Among the 16 rats, one died at 110 minutes, just prior to the last extraction. The remaining rats were sacrificed. Mean weight was: 466 +/- 64.24 g with no intergroup differences (P = .149). The comparative results (using Student t test) were: baseline A(1-4) versus A(1-4) 30 minutes: P < .05; baseline A(1-4) versus A(1-4) 60 minutes: P < .05; baseline A(1-4) versus A(1-4) 120 minutes: P = .10 (NS); baseline A(1-4) versus A(1-4) 240 minutes: P = .15 (NS). No significant differences were found among group B: baseline C(1-4) versus C(1-4) 30 minutes and 60 minutes: NS; baseline C(1-4) versus C(1-4) 120 minutes: P < .001; baseline C(1-4) versus C(1-4) 240 minutes: P < .10 (NS). Finally, the results in group D were: baseline D(1-4) versus D(1-4) 30 minutes: NS; baseline D(1-4) versus D(1-4) 60 minutes and 120 minutes: P < .05; baseline D(1-4) versus D(1-4) 240 minutes: P < .0005. When we compared group A to C and D, we detected differences (albeit not when compared to B) with P values = .01. Peak values were obtained at 120 and 240 minutes (225.21 pg/mL and 221.78 pg/mL) among groups C and D.

CONCLUSION

Heparin has a positive effect to increase serum HGF concentrations among rats. The effect was dependent on the administered dose and the time elapsed.

Activating Notch1 mutations in mouse models of T-ALL

Recent studies have demonstrated that most patients with T-cell acute lymphocytic leukemia (T-ALL) have activating mutations in NOTCH1. We sought to determine whether these mutations are also acquired in mouse models of T-ALL. We sequenced the heterodimerization domain and the PEST domain of Notch1 in our mouse model of TAL1-induced leukemia and found that 74% of the tumors harbor activating mutations in Notch1. Cell lines derived from these tumors undergo G(0)/G(1) arrest and apoptosis when treated with a gamma-secretase inhibitor. In addition, we found activating Notch1 mutations in 31% of thymic lymphomas that occur in mice deficient for various combinations of the H2AX, Tp53, and Rag2 genes. Thus, Notch1 mutations are often acquired as a part of the molecular pathogenesis of T-ALLs that develop in mice with known predisposing genetic alterations.

[Combined intratympanic and intravenous dexomethasone to control vertigo in Meniere disease]

OBJECTIVE

To verify the result in the use of intratympanic corticosteroids, combined with intravenous, in patients with Meniere disease (MD).

MATERIAL AND METHODS

Ten patients with vertigo due to MD in stages 4-5 or 6 were included in the study. Combined intratympanic and intravenous dexamethasone was infiltrated. The number of episodes among the months 18 and 24 of treatment, comparing them with the number of episodes 6 months before treatment (according to the norms of the American committee for the hearing and the equilibrium, 1995) are studied.

RESULTS

All patients improved significantly. In one of them treatment was repeated after 6 months. A number of patients with hearing improvement were observed.

CONCLUSIONS

The use of combined dexamethasone may be useful to control vertigo due to MD, to avoid or to be a prior step to other more aggressive treatments.

Live liver donation: a prospective analysis of exclusion criteria for healthy and potential donors

INTRODUCTION

Living donor liver transplantation represents a controversial option to increase the donor pool.

DESIGN

Prospective and descriptive clinical study.

OBJECTIVE

(1) To identify risk factors (exclusion criteria) for live donation; (2) to determine the rate of recipients that benefit from a living donor.

METHODS

Between May 1995 (first adult-to-adult living donor liver transplantation in Spain) and November 2002, we evaluated 74 healthy volunteers and performed 12 living donor liver transplants (no donor mortality).

RESULTS

All actual donors and volunteers are alive and healthy. After a mean time of 3.2+/-0.5 weeks, 72% of potential donors were considered unsuitable for live donation. Exclusion criteria were grouped in three categories: (primary) donor safety reasons (68%); (secondary): ABO mismatch (17%) and (tertiary): cadaveric graft transplantation (15%). Consequently, just 43.7% of the recipients presenting to us with a potential living donor, did finally benefit from these organs. The mortality rate was 8.3% for 43 recipients presenting with a living donor in comparison to 15% for those who did not (321 recipients between May 1995 and November 2001).

CONCLUSIONS

ALDLT can benefit a significant number of recipients on the waiting list (43.7% of those presenting with a donor). The most frequent exclusion criteria concern donor safety, namely, unsuspected chronic liver diseases and unsuspected thrombophilic disorders.

Results in split liver transplantation

INTRODUCTION

The shortage in cadaveric grafts has prompted the development of alternative surgical techniques to expand the donor pool.

OBJECTIVE

To evaluate the feasibility of split liver transplantation using an observational, retrospective, and longitudinal study.

MATERIALS AND METHODS

Between April 1986 and October 2002 we performed 875 liver transplants. From April 1991 to date, we performed 18 split liver transplantations in patients of mean age 42.27+/-25.65 years; five children and 13 adults; and 83.3% women. Urgent transplants accounted for 38.9%. Mean patient weight was 52.29+/-20.87 kg. Ex situ splitting was performed in 33%. The mean cold ischemia time was 460+/-265.69 minutes with a mean warm time of 64.33+/-11.78 minutes. Mean consumption of packed blood was 5.59+/-4.87 units; of frozen fresh plasma, 11.56+/-7.42 units; and of platelets 4.89+/-4.99 units.

RESULTS

After a mean follow-up of 10.83+/-12.51 months, 55.56% of the recipients are alive. Actuarial patient and graft survival rates at 1 year are 55.6% and 44.12%, respectively. Actuarial patient and graft survival rates at 1 year, excluding operative mortality were 77% and 68%, respectively. Actuarial patient and graft survival rates at 1 year, comparing urgent and elective transplantations are: 14.29 and 14%, respectively, for urgent cases and 90.91 and 90% for elective ones. Operative mortality was 16.6% while mortality during follow-up was 26.6%. The late complications included arterial thrombosis (n=2): of whom the first needed liver retransplantation 4 months after split liver transplantation; chronic rejection (n=2), recurrence of hepatitis (n=1).

CONCLUSIONS

Split liver transplantation is a useful way to expand the graft pool and shows better results in elective liver transplantation.