In-vitro activity of tigecycline against multidrug-resistant Gram negative bacteria: The experience of a university hospital.

The emergence of multidrug-resistant Gram negative bacteria has given rise to significant therapeutic challenges. These pathogens may have developed resistance to tigecycline, which is an alternative antibiotic used empirically in the treatment of serious infections. The objectives of this study were to identify the in-vitro activity of tigecycline against multidrug-resistant Gram negative strains isolated from clinical specimens and their related genes, at a university hospital. For this, 150 clinical isolates of multidrug-resistant Gram negative cultures from various clinical specimens were collected. Bacterial isolates were cultured, identified and their antibiotic susceptibilities were determined. Polymerase chain reaction was performed to amplify AcrB, AmpC, RamR, MexR, AdeB, TetA genes. Results revealed that all isolates were multidrug-resistant. The resistance of isolates was 91.4% to aztreonam, 94.6% to piperacillin, 34% to imipenem, 38.7% to meropenem, 71.3% to levofloxacin, 97.3% to ceftriaxone, 94.7% to cefepime, 9.3% to colistin, 78% to tetracycline, 21.4% to tigecycline and 68% to trimethoprim. AcrB, AmpC, RamR, MexR, AdeB, TetA genes were present in multidrug-resistant Gram negative bacteria. AcrB, RamR, TetA genes were related to tigecycline resistance. It is concluded that infections caused by multidrug-resistant Gram negative bacteria occur at a high rate. Most isolates were multi drug resistant, with 21.4% being resistant to tigecycline.

Beta-defensin-2 genomic copy number variation and chronic periodontitis.

Chronic periodontitis (ChP) is a multifactorial disease influenced by microbial and host genetic variability; however, the role of beta-defensin-2 genomic (DEFB4) copy number (CN) variation (V) in ChP remains unknown. The association of the occurrence and severity of ChP and DEFB4 CNV was analyzed. Our study included 227 unrelated Caucasians, that is, 136 ChP patients (combined ChP) and 91 control individuals. The combined ChP group was subdivided into the severe ChP and slight-to-moderate ChP subgroups. To determine DEFB4 CNV, we isolated genomic DNA samples and analyzed them by relative quantitation using the comparative CT method. The serum beta-defensin-2 (hBD-2) level was determined via ELISA. The distribution pattern and mean DEFB4 CN did not differ significantly in combined ChP cases vs. the controls; however, the mean DEFB4 CN in the severe ChP group differed significantly from those for the control and slight-to-moderate ChP groups. Low DEFB4 CN increased the risk of severe ChP by about 3-fold. DEFB4 CN was inversely associated with average attachment loss. Mean serum hBD-2 levels were highest in the controls, followed by the slight-to-moderate ChP group and the severe ChP group. The results suggested an association between decreased DEFB4 CN and serum hBD-2 levels and periodontitis severity.

Prevalence and distribution of high-risk human papillomavirus genotypes in cervical carcinoma, low-grade, and high-grade squamous intraepithelial lesions in Jordanian women.

PURPOSE: To assess high-risk human papillomavirus (HR-HPV) prevalence, and genotype distribution in invasive cervical cancer (CC) and its precursors in Jordanian patients. MATERIALS AND METHODS: A total of 124 different specimens of formalin-fixed, paraffin embedded samples, including 18 low-grade squamous intraepithelial lesions (LSILs), 28 high grade squamous intraepithelial lesions (HSILs), and 78 CCs were included in this study. HPV detection and typing was done using HPV High Risk Typing Real-TM Kit that enables the concomitant detection of the 12 most common HR-HPVs. RESULTS: Overall, HR-HPV prevalence was 87.2%, 78.6%, and 72.2% in CC, HSIL, and LSIL respectively. Genotype 16 was the most predominant in all cervical lesions, detected in 53.8%, 46.4%, and 38.9% of CC, HSIL, and LSIL, respectively. Among all HPV genotypes, HPV-16 and HPV-18 were found separately or together in 50% of LSILs, 60.7% of HSILs, and 76.9% of CC specimens. HPV-31 was the second most common type detected in LSILs (22.2%) and HSILs (21.4%). HPV-45 was the third most common type detected in CC (11.5%). CONCLUSION: The prevalence and genotypes distribution patterns of HR-HPV types among patients with CC and its precursors in Jordan are similar to known international patterns. The results of this study provide baseline information on the HPV type distribution, which may guide the development of CC prevention and control programs in Jordan.

Cytogenetic and morphological analysis of de novo acute myeloid leukemia in adults: a single center study in jordan.

Acute myeloid leukemia (AML) in adults is known to be a heterogeneous disease with diverse chromosomal abnormalities. Some of these abnormalities are found with a high incidence in specific ethnic groups and in certain geographical areas. We report the results of cytogenetic studies of 35 adult Jordanian Arab patients with de novo AML diagnosed according to the French-American-British (FAB) criteria. Four patients did not have meta-phases secondary to hypocellular bone marrow. The most common morphological subtype was M5 (55%) followed by M3 (19%). Cytogenetic abnormalities were present in 20 patients (65%); t(15;17) translocation in six patients (19%), inv(16) in four patients (13%), t(11;17) in two patients (4%), and the t(8;21) translocation was not present in any patient. Trisomy 8 was the most common numerical chromosomal abnormality [four patients (13%)]. There were variations and similarities with similar ethninc Arab populations. The most common chromosomal abnormalities were t(15;17), +8 and inv(16). Further and larger crossborder studies are needed.

Association of interleukin-10 gene promoter polymorphisms with chronic and aggressive periodontitis.

OBJECTIVE: Interleukin-10 gene promoter polymorphisms have been associated with interleukin-10 decreased production, thereby playing a role in the pathogenesis of periodontitis. This study aimed to investigate whether interleukin-10 single nucleotide polymorphisms at positions -1087(G/A) and -597(C/A) are associated with generalised chronic periodontitis and localised aggressive periodontitis. METHODS: Genomic DNA samples were isolated from 276 unrelated Jordanian participants. Subjects were categorised into 86 periodontally healthy controls, 105 chronic periodontitis patients and 85 localised aggressive periodontitis patients. Genotype frequencies were calculated, and differences were determined using Pearson chi-squared test, and odds ratio and 95% confidence intervals were included. RESULTS: The frequencies of the -1087A and -597A alleles were significantly more common in chronic periodontitis patients than controls. The A-positive allele genotypes (GA, AA) at position -1087 and A-positive allele genotypes (CA, AA) at position -597 appeared to increase the risk of having chronic periodontitis. No significant differences were observed in the genotype frequencies between localised aggressive periodontitis patients and controls. CONCLUSIONS: These findings indicate the possible use of interleukin-10 single nucleotide polymorphisms as genetic markers in chronic periodontitis patients and further emphasise the molecular differences between chronic periodontitis and aggressive periodontitis.

Time-resolved x-ray studies of the dynamics of smectic- A layer realignment by magnetic fields.

While the rotation of smectic layers under an applied field may at first appear to be a relatively simple problem, the dynamic processes involved are rather complex. An applied field produces a torque on the liquid crystal director, but has no direct influence on the smectic layers. If the director is reoriented significantly, however, the layers must also reorient in order to accommodate this (the layered structure is produced by short-range molecular interactions). Indeed, if the liquid crystalline order is not maintained during the realignment then matters become even more complex. In this paper we use time-resolved x-ray scattering to investigate the realignment of smectic- A layers in thin-film devices using a magnetic field. No evidence is found for continuous rotation of the smectic layers under any circumstances in such devices, a result that is not found when using bulk samples. No evidence indicating the formation of the nematic phase is observed during realignment. A molecular-dynamics technique is used to model the system which indicates that the sample becomes significantly disorganized during the realignment process when large angular rotations are induced.

Unexpected field-induced phase transitions between ferrielectric and antiferroelectric liquid crystal structures.

Liquid crystals are intriguing electrically responsive soft matter systems. We report previously unexplored field-induced changes in the structures of some frustrated liquid crystal phases and describe them theoretically. Specifically, we have discovered using resonant x-ray scattering that the four-layer intermediate smectic phase can undergo either a transition to the ferrielectric (three-layer) phase or to the ferroelectric phase, depending on temperature. Our studies of intermediate phases using electric fields offer a way to test theories that describe ferroelectricity in self-assembling fluids.

Molecular models for ferroelectric liquid crystals with conventional and anomalously weak layer contraction.

A molecular theory of the ferroelectric smectic C* phase has been developed using the simple model of a chiral molecule composed of a uniaxial core and a pair of off-center nonparallel dipoles which determine molecular chirality and polarity. The interaction between uniaxial cores is modeled by a rather general effective potential which can be used to describe smectic materials with both conventional and anomalously weak layer contraction in the smectic C* phase. Spontaneous polarization, tilt, and layer spacing are calculated numerically as functions of temperature, and it is shown that the variation of the polarization generally deviates from that of the tilt angle. It is shown that this deviation is more pronounced in smectic materials tilting with low layer contraction which corresponds to existing experimental data. The model has been used to reproduce qualitatively the experimental data for polarization, tilt and layer spacing for two similar mixtures exhibiting conventional and anomalously weak layer contraction. The polarization and the tilt are also calculated in the case when the smectic A-smectic C* transition is characterized by the biaxial primary order parameter.

Deduction of the temperature-dependent structure of the four-layer intermediate smectic phase using resonant X-ray scattering.

A binary mixture of an antiferroelectric liquid-crystal material containing a selenium atom and a highly chiral dopant is investigated using resonant X-ray scattering. This mixture exhibits a remarkably wide four-layer intermediate smectic phase, the structure of which is investigated over a temperature range of 16K. Analysis of the resonant X-ray scattering data allows accurate measurement of both the helicoidal pitch and the distortion angle as a function of temperature. The former decreases rapidly as the SmC* phase is approached, whilst the latter remains constant over the temperature range studied at 8 degrees +/-3 degrees. We also observe that the senses of the helicoidal pitch and the unit cell of the repeating four-layer structure are opposite in this mixture and that there is no pitch inversion over the temperature range studied.

Genome-wide expression profiling of mid-gestation placenta and embryo using a 15,000 mouse developmental cDNA microarray.

cDNA microarray technology has been increasingly used to monitor global gene expression patterns in various tissues and cell types. However, applications to mammalian development have been hampered by the lack of appropriate cDNA collections, particularly for early developmental stages. To overcome this problem, a PCR-based cDNA library construction method was used to derive 52,374 expressed sequence tags from pre- and peri-implantation embryos, embryonic day (E) 12.5 female gonad/mesonephros, and newborn ovary. From these cDNA collections, a microarray representing 15,264 unique genes (78% novel and 22% known) was assembled. In initial applications, the divergence of placental and embryonic gene expression profiles was assessed. At stage E12.5 of development, based on triplicate experiments, 720 genes (6.5%) displayed statistically significant differences in expression between placenta and embryo. Among 289 more highly expressed in placenta, 61 placenta-specific genes encoded, for example, a novel prolactin-like protein. The number of genes highly expressed (and frequently specific) for placenta has thereby been increased 5-fold over the total previously reported, illustrating the potential of the microarrays for tissue-specific gene discovery and analysis of mammalian developmental programs.

Transcriptional regulation of mammalian cytochrome c oxidase genes.

The cytochrome c oxidase (COX) holoenzyme is a 13-subunit complex that carries out the terminal step in the electron transport chain. Three of the subunits, which contain the electron transfer function, are coded by mitochondrial DNA and the other ten subunits by nuclear DNA. Since the holoenzyme contains equivalent amounts of each subunit, we and others have examined transcriptional regulation of COX nuclear subunits to explore whether there is a common basis for co-regulation. Each gene is seen to have a unique pattern of recognition by regulatory factors; although some factors bind to more than one gene, not all COX genes seem to be regulated by the same set of factors. Current information about the COX promoters that have been examined is summarized, and the relation of promoter regulation to coordinate gene expression is discussed.

Tissue-specific expression and mapping of the Cox7ah gene in mouse.

We have isolated and examined the gene for the heart isoform of cytochrome c oxidase subunit VIIa (COX VIIa-H) in mouse, an isoform gene previously thought to be lacking in rodents. Interspecies amino acid comparisons indicate that mouse COX VIIa-H protein displays 82.5 and 70.9% identity with the bovine and human heart isoforms of COX VIIa, but only 53.7% identity with the paralogous mouse liver isoform (COX VIIa-L). Expression in adult mouse tissues is limited to heart and skeletal muscle, as found in other species. In the early mouse embryo, Cox7al was the exclusive isoform expressed and Cox7ah mRNA was not detectable until day 17 postcoitum. That the mouse Cox7ah gene characterized in this study is orthologous to the human COX7AH gene was also suggested by its mapping to mouse chromosome 7, to a conserved region syntenic with the human chromosome location of COX7AH, 19q13.1. As a result, all three COX heart isoform genes in mouse group to chromosome 7. Interestingly, mapping of the mouse Cox7al to chromosome 9 suggests a new syntenic region between the mouse and the human genomes.

Molecular evolution of cytochrome c oxidase: rate variation among subunit VIa isoforms.

Cytochrome c oxidase (COX) consists of 13 subunits, 3 encoded in the mitochondrial genome and 10 in the nucleus. Little is known of the role of the nuclear-encoded subunits, some of which exhibit tissue-specific isoforms. Subunit VIa is unique in having tissue-specific isoforms in all mammalian species examined. We examined relative evolutionary rates for the COX6A heart (H) and liver (L) isoform genes along the length of the molecule, specifically in relation to the tissue-specific function(s) of the two isoforms. Nonsynonymous (amino acid replacement) substitutions in the COX6AH gene occurred more frequently than in the ubiquitously expressed COX6AL gene. Maximum-parsimony analysis and sequence divergences from reconstructed ancestral sequences revealed that after the ancestral COX6A gene duplicated to yield the genes for the H and L isoforms, the sequences encoding the mitochondrial matrix region of the COX VIa protein experienced an elevated rate of nonsynonymous substitutions relative to synonymous substitutions. This is expected for relaxed selective constraints after gene duplication followed by purifying selection to preserve the replacements with tissue-specific functions.

The prevalence of hemoglobin S and glucose-6-phosphate dehydrogenase deficiency in Jordanian newborn.

OBJECTIVE: The aim of this study was to determine the incidence of HbS and glucose-6-phosphate dehydrogenase (G6PD) deficiency in Jordanian newborn. STUDY DESIGN: A total of 181 male and female babies born at Princess Basma Teaching Hospital, randomly selected, and cord blood samples were collected, and the erythrocyte G6PD activity was measured, and the hemoglobin electrophoresis for blood lysate was conducted and scanned for HbS scanning. RESULTS: The frequencies of two major red cell genetic defects, sickle hemoglobin (HbS) and deficiency G6PD was determined, of the studied subjects 10 (11%) females and 11 (12%) males were found to be deficient in the G6PD gene. The frequency of HbS carriers among the females was 4% while it was 6% among males. The coincidence of both G6PD deficiency and sickle cell hemoglobin in the samples was 1%. No coincidence was found between G6PD deficiency and hyperbilirubinemia. CONCLUSION: A better understanding of the distributions of these genetic disorders has the potential to aid in the more efficient utilization of health care resources and improved planning.