RESUMEN
Chitosan was extracted from the oriental hornet, Vespa orientalis [L.], Vespinae, Order; Hymenoptera, as a new source of insect chitosan, using chemical methods. We assessed the physical properties of the wasp's chitosan using different approaches including: preliminary color-change identification, Fourier Transform Infrared spectroscopy [FTIR], X-ray diffraction and Nuclear Magnetic Resonance spectroscopy [1H-NMR]. The results showed that it gave a
higher purity, solubility and Degree of Deacetylation [DD] compared to crustacean chitosan. Also, it is soluble in a very low concentration of acetic acid from 0.25% to 0.5% while that of Crustacea was soluble in more than 1% acetic acid, so the oriental hornet could be a novel alternative source of higher pure and more soluble chitosan
RESUMEN
Multidrug-resistant tuberculosis [MDR-TB] is an emerging problem with high mortality rate where recently developed molecular techniques represent potential tools for its early detection. The aim of this study is to detect drug resisting mutants of Mycobacterium tuberculosis [M.TB] in 15 patients with active pulmonary tuberculosis, who were non responding to 1[st] line multi-drug therapy [refampicin [ RIF] and isoniazid [INH]]. This was performed using the Chain Termination method of manual Gene Sequencing for the following Mycobacterial genes: rpoB gene [involved in sensitivity to RIF], katG and inhA genes [involved in sensitivity to INH]. Missence point mutations in rpoB gene were found in 93.3 % [14/15], which involved codon 184 in 80% [12/15] with Histidine-Tyrosine substitution, and codon 174 in only 13 .3% [2/15] with Aspartate-Valine substitution. Missence mutations in katG gene were detected in all cases [100%], which involved codon 315 in 80% [12/15] with Serine- Threonine substitution and codon 444 in 13.3 % [2/15] with Valine - Alanine substitution, while only 6.7 %[1/15] involved codon 315 and 444 together. Inh-A gene revealed missence mutantion in 86.7% [13/15], where 60 % [9/15] involved codon 94 with Serine - Valine substitution, 20 %[3/15] involved codon 99 with proline - Arginine substitution and 6.7% [1/15] involved codon 69 with Glutamate - Alanine substitution. It could be concluded that, missence point mutations found in the examined genes could explain the resistance of 14 patients to both drugs and resistance of only one patient to INH alone. The missence point mutation was found at a common codon position among each gene, in addition to some other involved codons. It could be also concluded that, manual gene sequencing is a rapid, non expensive and accurate technique for early detection of MDR-TB, which helps early starting of proper treatment and inhibits spreading of such strains. Although it is difficult to be performed as a routine test, facilities should be available in order to perform it for at least some selected cases, as it does not need the expensive automated DNA sequencer
RESUMEN
Metallo- beta lactamases [MBLs] have been increasingly recognized from bacterial isolates worldwide where they are considered to be one of the most worrisome antibiotic resistance mechanisms. They differ from other beta-lactamases in their need of metallic cofactor for enzymatic activity which could be inhibited by metallic chelators, in their ability to resist beta-lactamase inhibitors and in being able to hydrolyze all beta lactams including carbapenems. In the present study, the most common MBLs- genes [the VIM and IMP genes] were detected using multiplex polymerase chain reaction [PCR] in nosocomial isolates of 40 Imipenem [IPM] resistant and 20 Imipenem sensitive Pseudomonas aeruginosa. The results revealed that none of the Imipenem sensitive isolates had any MBLs-gene while 16/40 [40%] of the Imipenem resistant isolates were positive for MBL-VIM gene and none of them had MBL-IMP gene. So, MBL-VIM gene was found to be significantly associated with IPM resisting than IPM sensitive isolates [P<0.001]. Among the IPM resisting P. aeruginosa, isolates which had the VIM gene were found to be more prevalent in blood [87.5 %] and sputum [60 %] than urine [20 %] and infected post operative wounds or burns [8.3 %]. It was also found that VIM positive isolates were more resistant to Amikacin [75% versus 66.7%, P 1.000], Ceftazidime [93.8% versus 45.8 %, P 0.034], Ciprofloxacin [100% versus 29.2%, P 0.000], Gentamycin [87.5% versus 50%, P 0.020] and Tobramycin [81.3% versus 41.7%, P 0.022], and less resistant to Piperacillin [50% versus 75%, P 0.205] than VIM negative isolates. Moreover, case fatality rate was found to be significantly higher in patients infected with VIM positive isolates than those infected with VIM negative isolates [50 % versus 8.4 %, P 0.005]. It could be concluded that isolates of IPM - resistant P. aeruginosa which had MBL-gene [MBL-producers] were more resistant to antibiotics and more associated with serious infections and higher mortality rate than those which have other mechanisms of beta lactam resistance. So, as it is thought that emergence of such enzymes could bring us to feared end of antibiotics, it has to be recommended that all IPM-resistant isolates should be tested for MBLs production. This will ensure the early recognition of an outbreak and introduction of appropriate infection control measures to prevent further nosocomial spreading of such multiresistant highly virulent strains
RESUMEN
To describe incidence of Down syndrome in Dubai, United Arab Emirates [UAE]. A total of 63,398 newborn babies in Dubai [24,250 UAE nationals and 39,148 non-UAE] during a 5-year period of 1999-2003 were routinely examined by experienced nurses, neonatologists, pediatricians and/or general practitioners for symptoms of Down syndrome. Those suspected with Down syndrome were referred to the cytogenetic laboratory for karyotyping. A total of 141 cases were confirmed cytogenetically as Down syndrome. Of these, 139 were trisomy 21 and of the remaining 2, 1 was a translocation and the other a mosaic. Theoverall incidence of Down syndrome in Dubai was 1/449 live births [2.2 per 1,000]; 1/319 live births [3.13 per 1,000] among UAE nationals and 1/602 live births [1.66 per 1,000] among non-UAE nationals. The mean maternal age of UAE national mothers was 33.48 ' 8.08, with 41.66% of the mothers being in the advanced maternal age group [>35 years]. The higher incidence of Down syndrome among UAE nationals is comparable to incidences reported for other Arab populations in the Middle Eastern region. Advanced maternal age, with mothers bearing children until their 50s and higher parity, appear to be the major contributing factors for the increased incidence. The study indicates the need to provide efficient genetic counseling and to introduce an effective antenatal screening program and prenatal diagnostic services to reduce the psychological and genetic burden on the families and community