Comparison of rates of fecal colonization with extended‐spectrum beta‐lactamase‐producing enterobacteria among patients in different wards,outpatients and medical students

Because asymptomatic carriage of extended‐spectrum beta‐lactamase (ESBL) producers is a risk factor for infection, data on colonization dynamics are important when planning infection control. This study investigated fecal colonization with ESBL producers among inpatients, outpatients and medical students and compares the characteristics of ESBL producers among these groups. Carriage rates were investigated in 5581 fecal samples; 4343 from inpatients (330, 1397, 619 and 1864 from adult ICUs [intensive care units], adult non‐ICUs, pediatric ICUs and pediatric non‐ICUs, respectively), 814 from outpatients and 424 from screening of medical students. ESBL producers were characterized by co‐resistance, integrons carried, and aminoglycoside resistance and ESBL genes. Dynamic regression models were built to identify relationships between combinations of time series of monthly antibiotic consumption, prevalence of carriers and infected subjects. Inpatients, ICU patients and adults showed higher prevalence than outpatients, non‐ICU patients or children (7.4%, 9.3% and 12.0% vs. 3.1%, 6.1% and 4.1%, respectively). Klebsiella pneumoniae was more frequent in ICU patients; dominance of CTX‐M‐15 producers was more marked in adult than in pediatric inpatients. ESBL carriage was shown to be a consequence of infection in adults in the time‐series analysis; antibiotic consumption had little effect. The epidemiology of colonization with ESBL producers differed between pediatric ICU, adult ICU and adult non‐ICU patients. In adults, carriage of ESBL producers seems to be the consequence of infection, especially in ICU patients; the main source of colonization is nosocomial acquisition. In contrast, children are less likely to acquire colonizer strains in hospitals; importation of ESBL producers by colonized children seems to be significant.     

Emulsifying activities of purified Alasan proteins from Acinetobacter radioresistens KA53

The bioemulsifier of Acinetobacter radioresistens KA53, referred to as alasan, is a high-molecular-weight complex of polysaccharide and protein. The emulsifying activity of the purified polysaccharide (apo-alasan) is very low. Three of the alasan proteins were purified by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and had apparent molecular masses of 16, 31, and 45 kDa. Emulsification assays using the isolated alasan proteins demonstrated that the active components of the alasan complex are the proteins. The 45-kDa protein had the highest specific emulsifying activity, 11% higher than the intact alasan complex. The 16- and 31-kDa proteins gave relatively low emulsifying activities, but they were significantly higher than that of apo-alasan. The addition of the purified 16- and 31-kDa proteins to the 45-kDa protein resulted in a 1.8-fold increase in the specific emulsifying activity and increased stability of the oil-in-water emulsion. Fast-performance liquid chromatography analysis indicated that the 45-kDa protein forms a dimer in nondenaturing conditions and interacts with the 16- and 31-kDa proteins to form a high-molecular-mass complex. The 45-kDa protein and the three-protein complex had substrate specificities for emulsification and a range of pH activities similar to that of alasan. The fact that the purified proteins are active emulsifiers should simplify structure-function studies and advance our understanding of their biological roles.     

A common ancestral origin of the frequent and widespread 2299delG USH2A mutation

Usher syndrome type IIa is an autosomal recessive disorder characterized by mild-to-severe hearing loss and progressive visual loss due to retinitis pigmentosa. The mutation that most commonly causes Usher syndrome type IIa is a 1-bp deletion, described as "2299delG," in the USH2A gene. The mutation has been identified in several patients from northern and southern Europe and from North America, and it has been found in single patients from South America, South Africa, and China. Various studies have reported a range of frequencies (.16-.44) among patients with Usher syndrome, depending on the geographic origin of the patients. The 2299delG mutation may be the one that most frequently causes retinitis pigmentosa in humans. Given the high frequencies and the wide geographic distribution of the mutation, it was of interest to determine whether the mutation resulted from an ancestral mutational event or represented a mutational hotspot in the USH2A gene. Haplotype analysis was performed on DNA samples from 116 unrelated patients with Usher syndrome type IIa; the patients were from 14 countries and represented 148 2299delG alleles. On the basis of six single-nucleotide polymorphisms within the USH2A gene, 12 core haplotypes were observed in a panel of normal chromosomes. However, in our analysis, only one core haplotype was found to be associated with the 2299delG mutation. The data indicate that the widespread geographic distribution of the 2299delG mutation is the result of an ancestral mutation that has spread throughout Europe and into the New World as a result of migration.     

Synthesis of 1H-pyridin-2-one derivatives as potent and selective farnesyltransferase inhibitors

Two novel series of potent and selective FTase inhibitors have been synthesized using structure-based design. Medicinal chemistry efforts led to the discovery of compound 4e with potent cellular activity and good oral bioavailability in dog. A synthetic route toward novel heterocycles 1,5-dimethyl-6-oxo-4-aryl-1,6-dihydro-pyridine-2-carbonitrile was established. The structure of compound 5c was confirmed by X-ray crystallography.     

Correlation between CAG Repeat Length and Clinical Features in Machado-Joseph Disease

Machado-Joseph disease (MJD) is associated with the expansion of a CAG trinucleotide repeat in a novel gene on 14q32.1. We confirmed the presence of this expansion in 156 MJD patients from 33 families of different geographic origins: 15 Portuguese Azorean, 2 Brazilian, and 16 North American of Portuguese Azorean descent. Normal chromosomes contain between 12 and 37 CAG repeats in the MJD gene, whereas MJD gene carriers have alleles within the expanded range of 62–84 CAG units. The distribution of expanded alleles and the gap between normal and expanded allele sizes is either inconsistent with a premutation hypothesis or most (if not all) of the alleles we studied descend from a common ancestor. There is a strong correlation between the expanded repeat size and the age at onset of the disease as well as the clinical presentation. There is mild instability of the CAG tract length with transmission of the expanded alleles; both increase and decrease in size between parents and progeny occur, with larger variations in male than in female transmissions. Together, these effects can partly explain the variability of age at onset and of phenotypic features in MJD; however, other modifying factors must exist.     

The absence of Msh2 alters abelson virus pre-B-cell transformation by influencing p53 mutation

Defects in DNA mismatch repair predispose cells to the development of several types of malignant disease. The absence of Msh2 or Mlh1, two key molecules that mediate mismatch repair in eukaryotic cells, increases the frequency of mutation and also alters the response of some cells to apoptosis and cell cycle arrest. To understand the way these changes contribute to cancer predisposition, we examined the effects of defective mismatch repair on the multistep process of pre-B-cell transformation by Abelson murine leukemia virus. In this model, primary transformants undergo a prolonged apoptotic crisis followed by the emergence of fully transformed cell lines. The latter event is correlated to a loss of function of the p53 tumor suppressor protein and down-modulation of the p53 regulatory protein p19Arf. Analyses of primary transformants from Msh2 null mice and their wild-type littermates revealed that both types of cells undergo crisis. However, primary transformants from Msh2 null animals recover with accelerated kinetics, a phenomenon that is strongly correlated to the appearance of cells that have lost p53 function. Analysis of the kinetics with which p53 function is lost revealed that this change provides the dominant stimulus for emergence from crisis. Therefore, the absence of mismatch repair alters the molecular mechanisms involved in transformation by affecting a gene that controls apoptosis and cell cycle progression, rather than by affecting these processes directly.     

Efficient transfer of a tumor antigen-reactive TCR to human peripheral blood lymphocytes confers anti-tumor reactivity.

The tumor-associated-Ag MART-1 is expressed by most human melanomas. The genes encoding an alphabeta TCR from a MART-1-specific, HLA-A2-restricted, human T cell clone have been efficiently transferred and expressed in human PBL. These retrovirally transduced PBL cultures were MART-1 peptide reactive, and most cultures recognized HLA-A2+ melanoma lines. Limiting dilution clones were generated from three bulk transduced PBL cultures to investigate the function of individual clones within the transduced cultures. Twenty-nine of 29 CD8+ clones specifically secreted IFN-gamma in response to T2 cells pulsed with MART-1(27-35) peptide, and 23 of 29 specifically secreted IFN-gamma in response to HLA-A2+ melanoma lines. Additionally, 23 of 29 CD8+ clones lysed T2 cells pulsed with the MART-1(27-35) peptide and 15 of 29 lysed the HLA-A2+ melanoma line 888. CD4+ clones specifically secreted IFN-gamma in response to T2 cells pulsed with the MART-1(27-35) peptide. TCR gene transfer to patient PBL can produce CTL with anti-tumor reactivity in vitro and could potentially offer a treatment for patients with metastatic melanoma. This approach could also be applied to the treatment of other tumors and viral infections. Additionally, TCR gene transfer offers unique opportunities to study the fate of adoptively transferred T cells in vivo.     

Mapping of QTLs for Oral Alcohol Self-Administration in B6.C and B6.I Quasi-Congenic RQI Strains

One strategy to identify neurochemical pathways of addiction is to map the relevant genes. In the present study we used 43 B6.C and 35 B6.I inbred RQI mouse strains, carrying <3% donor genome on C57BL/6ByJ background, for gene mapping. The strains were phenotyped for consumption of alcohol (12% v/v) in a two-bottle-choice paradigm, and genotyped for 396 microsatellite markers. The current mapping study extends our earlier experiment scanning five mouse chromosomes (Vadasz et al. (2000) Scanning of five chromosomes for alcohol consumption loci. Alcohol 22:25–34) to a whole-genome study, and discusses the differences and limitations. Data were analyzed with composite interval (CIM) and multiple interval (MIM) QTL mapping methods. CIM of B6.C strains detected significant QTLs on chrs. 6 and 12. A suggestive, but not significant, locus was detected in the B6.I strains on chr. 12. The best MIM model for B6.C strains confirmed one QTL on chr. 6 and one QTL on chr. 12, while the MIM model for the B6.I strains confirmed the suggestive locus on chr. 12. Some of the QTLs for alcohol consumption are new, while others confirm previously reported QTLs for alcohol preference, and alcohol acceptance.     

Chondrocalcin is identical with the C-propeptide of type II procollagen.

The primary structure of the cartilage matrix molecule chondrocalcin has been found to be identical with that of the C-propeptide of type II procollagen by comparing sequence analyses of the N-terminal regions and of tryptic peptides derived from chondrocalcin. This implies that in type II collagen the C-propeptide of type II collagen is employed not only in the assembly of the triple helix of type II collagen, as demonstrated previously, but in calcifying cartilage it may also be involved in those events leading to cartilage calcification, as earlier indicated.     

Adoptive immunotherapy of a syngeneic murine leukemia with a tumor-specific cytotoxic T cell clone and recombinant human interleukin 2: correlation with clonal IL 2 receptor expression

The successful adoptive immunotherapy of the syngeneic Friend virus-induced murine leukemia FBL-3 was mediated by a proliferative MHC-restricted, tumor-specific CTL clone in combination with recombinant human IL 2. This clone was previously shown to express the L3T4-, Lyt-1+, Lyt-2+ surface phenotype. Activation of the clone for 48 hr in vitro with irradiated tumor cells induced the expression of IL 2 receptors and markedly increased clonal proliferation in response to recombinant IL 2. Intravenous injection of 2 X 10(7) 48 hr in vitro-activated cloned cells, followed by 6 days of systemic (i.p.) administration of IL 2 resulted in the complete regression of tumors and the cure of 50% of the treated mice. IL 2 alone had no effect on tumor growth, whereas the injection of nonactivated (resting) clone plus IL 2 or activated clone without IL 2 had small but insignificant effects on tumor growth and survival. These results indicated that the in vivo effector functions of cloned T cells may be markedly enhanced by the concurrent systemic administration of recombinant IL 2 and by the induction of optimal IL 2 receptor expression on the cloned T cells at the time of cell administration.