Transposon content of nonconjugative plasmids ofEscherichia coli

Department of Biology and General Genetics, Patrice Lumumba Peoples' Friendship University, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR S. V. Prozorovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 106, No. 12, 711–714, December, 1988.     

Antimicrobial susceptibilities and plasmid contents of Neisseria gonorrhoeae isolates from commercial sex workers in Dhaka, Bangladesh: emergence of high-level resistance to ciprofloxacin

Commercial sex workers (CSWs) serve as the most important reservoir of sexually transmitted diseases (STD), including gonorrhea. Periodic monitoring of the antimicrobial susceptibility profile of Neisseria gonorrhoeae in a high-risk population provides essential clues regarding the rapidly changing pattern of antimicrobial susceptibilities. A study concerning the prevalence of gonococcal infection among CSWs was conducted in Bangladesh. The isolates were examined with regards to their antimicrobial susceptibility to, and the MICs of, penicillin, tetracycline, ciprofloxacin, cefuroxime, ceftriaxone, and spectinomycin by disk diffusion and agar dilution methods. The total plasmid profile of the isolates was also analyzed. Of the 224 CSWs, 94 (42%) were culture positive for N. gonorrhoeae. There was a good correlation between the results of the disk diffusion and agar dilution methods. Some 66% of the isolates were resistant to penicillin, and 34% were moderately susceptible to penicillin. Among the resistant isolates, 23.4% were penicillinase-producing N. gonorrhoeae (PPNG). 60.6% of the isolates were resistant and 38.3% were moderately susceptible to tetracycline, 17.5% were tetracycline-resistant N. gonorrhoeae, 11.7% were resistant and 26.6% had reduced susceptibility to ciprofloxacin, 2.1% were resistant and 11.7% had reduced susceptibility to cefuroxime, and 1% were resistant to ceftriaxone. All PPNG isolates contained a 3.2-MDa African type of plasmid, and a 24.2-MDa conjugative plasmid was present in 34.1% of the isolates. Since quinolones such as ciprofloxacin are recommended as the first line of therapy for gonorrhea, the emergence of significant resistance to ciprofloxacin will limit the usefulness of this drug for treatment of gonorrhea in Bangladesh.     

Circulating immune complexes in patients with cryptogenic fibrosing alveolitis.

Increased Clq binding levels have been obtained in serum from twenty-one (50%) of forty-two patients with cryptogenic fibrosing alveolitis (CFA) suggesting the presence of circulating immune complexes. There was a low frequency of positive results using a number of other tests for circulating immune complexes. The increased Clq binding levels were observed in six (35%) out of seventeen patients with lone lung involvement and in fifteen (60%) out of twenty-five patients with extrapulmonary connective tissue disorders. There was an especially close correlation between arthritis and elevated Clq binding. A strong correlation between Clq binding levels and levels of circulating rheumatoid factor (RF) and IgG, and enhancement in macrophage radiobioassay tests using RF-containing sera, suggested that RF might be involved in the circulating immune complexes in these patients. DNAase pre-treatment of sera did not influence the findings, and there was no correlation between Clq binding and levels of immunofluorescent ANA, C-reactive protein levels, or platelet counts. A weak correlation between Clq binding and erythrocyte sedimentation rates, and slightly lower binding levels in treated than untreated patients with 'lone' CFA suggested that binding levels may give some indication of disease activity and may in some instances be influenced by treatment.     

Cowden syndrome and Lhermitte-Duclos disease in a family: a single genetic syndrome with pleiotropy?

Cowden syndrome is an autosomal dominant condition of multiple hamartomas. Patients with this phakomatosis have an increased risk of breast cancer and thyroid tumours. Lhermitte-Duclos disease is usually a sporadic condition of cerebellar ganglion cell hypertrophy, ataxia, mental retardation, and self-limited seizure disorder. We describe a three generation family with Cowden syndrome and Lhermitte-Duclos disease. Karyotyping performed on the peripheral lymphocytes of the proband and her affected mother showed a 46,XX complement. Single strand conformational polymorphism analysis failed to show any germline p53 mutations as a cause of the syndrome in this family.     

Ocular measurements in fetal alcohol spectrum disorders

Fetal alcohol spectrum disorders (FASD) describe a range of physical, behavioral, and neurologic deficits in individuals exposed to alcohol prenatally. Reduced palpebral fissure length is one of the cardinal facial features of FASD. However, other ocular measurements have not been studied extensively in FASD. Using the Fetal Alcohol Syndrome Epidemiologic Research (FASER) database, we investigated how inner canthal distance (ICD), interpupillary distance (IPD), and outer canthal distance (OCD) centiles differed between FASD and non‐FASD individuals. We compared ocular measurement centiles in children with FASD to non‐FASD individuals and observed reductions in all three centiles for ICD, IPD, and OCD. However, when our non‐FASD children who had various forms of growth deficiency (microcephaly, short‐stature, or underweight) were compared to controls, we did not observe a similar reduction in ocular measurements. This suggests that reductions in ocular measurements are a direct effect of alcohol on ocular development independent of its effect on growth parameters, which is consistent with animal models showing a negative effect of alcohol on developing neural crest cells. Interpupillary distance centile appeared to be the most significantly reduced ocular measure we evaluated, suggesting it may be a useful measure to be considered in the diagnosis of FASD.     

Differentiating molecular etiologies of Angelman syndrome through facial phenotyping using deep learning

Angelman syndrome (AS) is caused by several genetic mechanisms that impair the expression of maternally‐inherited UBE3A through deletions, paternal uniparental disomy (UPD), UBE3A pathogenic variants, or imprinting defects. Current methods of differentiating the etiology require molecular testing, which is sometimes difficult to obtain. Recently, computer‐based facial analysis systems have been used to assist in identifying genetic conditions based on facial phenotypes. We sought to understand if the facial‐recognition system DeepGestalt could find differences in phenotype between molecular subtypes of AS. Images and molecular data on 261 individuals with AS ranging from 10 months through 32 years were analyzed by DeepGestalt in a cross‐validation model with receiver operating characteristic (ROC) curves generated. The area under the curve (AUC) of the ROC for each molecular subtype was compared and ranked from least to greatest differentiable phenotype. We determined that DeepGestalt demonstrated a high degree of discrimination between the deletion subtype and UPD or imprinting defects, and a lower degree of discrimination with the UBE3A pathogenic variants subtype. Our findings suggest that DeepGestalt can recognize subclinical differences in phenotype based on etiology and may provide decision support for testing.     

Ability of laboratories to detect emerging antimicrobial resistance: proficiency testing and quality control results from the World Health Organization's external quality assurance system for antimicrobial susceptibility testing

The accuracy of antimicrobial susceptibility data submitted by microbiology laboratories to national and international surveillance systems has been debated for a number of years. To assess the accuracy of data submitted to the World Health Organization by users of the WHONET software, the Centers for Disease Control and Prevention distributed six bacterial isolates representing key antimicrobial-resistance phenotypes to approximately 130 laboratories, all but one of which were outside of the United States, for antimicrobial susceptibility testing as part of the World Health Organization's External Quality Assurance System for Antimicrobial Susceptibility Testing. Each laboratory also was asked to submit 10 consecutive quality control values for several key organism-drug combinations. Most laboratories were able to detect methicillin (oxacillin) resistance in Staphylococcus aureus, high-level vancomycin resistance in Enterococcus faecium, and resistance to extended-spectrum cephalosporins in Klebsiella pneumoniae. Many laboratories, particularly those using disk diffusion tests, had difficulty in recognizing reduced susceptibility to penicillin in an isolate of Streptococcus pneumoniae. The most difficult phenotype for laboratories to detect was reduced susceptibility to vancomycin in an isolate of Staphylococcus epidermidis. The proficiency testing challenge also included a request for biochemical identification of a gram-negative bacillus, which most laboratories recognized as Enterobacter cloacae. Although only a small subset of laboratories have submitted their quality control data, it is clear that many of these laboratories generate disk diffusion results for oxacillin when testing S. aureus ATCC 25923 and S. pneumoniae ATCC 49619 that are outside of the acceptable quality control range. The narrow quality control range for vancomycin also proved to be a challenge for many of the laboratories submitting data; approximately 27% of results were out of range. Thus, it is important to establish the proficiency of laboratories submitting data to surveillance systems in which the organisms are tested locally, particularly for penicillin resistance in pneumococci and glycopeptide resistance in staphylococci.     

Development and evaluation of NucliSens basic kit NASBA for diagnosis of parainfluenza virus infection with 'end-point' and 'real-time' detection

New methods for the detection of human parainfluenza viruses (HPIVs) were developed. These were based on nucleic acid sequence-based amplification (NASBA) and utilised the NucliSens Basic Kit. Primers and probes were selected from the haemagglutinin neuraminidase (HN) gene of HPIV1, HPIV2 and HPIV3, and from the phosphoprotein (P) of HPIV4a and -4b. Synthetic RNA, titrated control virus stocks and respiratory specimens (n=44) were utilised to evaluate performance of the assays. Detection of NASBA products was by probe hybridisation and electrochemiluminescence (ECL) ('end-point' detection) or using molecular beacons ('real-time' detection). The assays using ECL detection proved to be both sensitive and specific. Typically, less than or equal to 100 RNA copies or one TCID(50) input was detectable with no cross-reaction between the specific HPIV assays and other respiratory viruses. Results for clinical samples were concordant with those obtained by 'conventional' procedures by classical viral diagnostic methods. 'Real-time' detection utilised probes specific for either HPIV1 or HPIV3 with similar performance characteristics to the assays with 'end-point' detection. The feasibility of multiplexing targets together was confirmed using a combined HPIV1 and HPIV3 assay with good results for ECL and molecular beacon detection on control material and clinical samples.     

Synthesis and characterization of α-hydroxy, α-thiol and α-chloroformyl oligomers of poly(butylene terephthalate)

α-Hydroxy and α-chloroformyl oligomers of poly(butylene terephthalate) (PBT) were prepared in 1,1,2,2-tetrachloroethane by condensing terephthaloyl chloride and 1,4-butanediol and using benzoyl chloride and 4-hydroxybutyl benzoate as chain limitator. The average molecular weight was determined by ¹H NMR analysis, and thermal properties were assessed by differential scanning calorimetry (DSC). Preparation of α-thiol oligomers of PBT was also investigated by esterification of α-hydroxy oligomers with thioglycolic acid and using p-toluenesulfonic acid as catalyst. The DSC and TGA analyses pointed out that the introduction of a thiol group by esterification has no influence on the thermal properties of the PBT oligomers.     

Cigarette smoke prevents apoptosis through inhibition of caspase activation and induces necrosis

Emphysema is characterized by enlargement of the distal airspaces in the lungs due to destruction of alveolar walls. Alveolar endothelial and epithelial cell apoptosis induced by cigarette smoke is thought to be a possible mechanism for this cell loss. In contrast, our studies show that cigarette smoke condensate (CSC) induces necrosis in alveolar epithelial cells and human umbilical vein endothelial cells. Furthermore, study of the cell death pathway in a model system using Jurkat cells revealed that in addition to inducing necrosis, CSC inhibited apoptosis induced by staurosporine or Fas ligation, with both effects prevented by the antioxidants glutathione and dithiothreitol. Time course experiments revealed that CSC inhibited an early step in the caspase cascade, whereby caspase-3 was not activated. Moreover, cell-free reconstitution of the apoptosome in cytoplasmic extracts from CSC-treated cells, by addition of cytochrome-c and dATP, did not result in activation of caspases-3 or -9. Thus, smoke treatment may alter the levels of pro- and antiapoptogenic factors downstream of the mitochondria to inhibit active apoptosome formation. Therefore, unlike previous studies, cell death in response to cigarette smoke by necrosis and not apoptosis may be responsible for the loss of alveolar walls and inflammation observed in emphysema.