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Biomedical subjects

H Hossain

Publications and source records attributed to H Hossain.

9 recordsLinked to original sources

[Microarray-based transcriptome analyses in infectious diseases. A new diagnostic method].

The complex interaction between a pathogen and a host is the molecular basis of infectious diseases. Microarray technology is a powerful tool to investigate the crosstalk between pathogen and the host as it assesses whole genome expression profiles in response to disease. Deciphering the molecular details on both sides of the host-pathogen interaction will increase our understanding of the pathogenesis of infectious diseases and offer improvements in their diagnosis, treatment, prognosis, and prevention.

Biomarkers↗

Clonal identity of Candida albicans in the oral cavity and the gastrointestinal tract of pre-school children.

The clonal relationship between oral and fecal Candida albicans isolated from children of pre-school age was examined using RAPD analysis. Significantly higher levels of C. albicans were found in saliva, dental plaque, carious specimens and stools of 56 patients with severe caries as compared to 52 healthy control subjects. The highest prevalence was found in carious specimens and a strong correlation was observed between its presence in saliva, dental plaque, carious specimen and feces. RAPD analysis of isolates from 23 patients with simultaneous oral and fecal C. albicans revealed clonal counterparts present in both oral and stool samples in 15 cases; five patients harbored closely related strains; and three patients harbored unrelated strains. Our results demonstrate a strong correlation between oral and gastrointestinal C. albicans colonization. We assume that carious teeth may constitute an ecologic niche for C. albicans potentially responsible for recurrent oral and non-oral candidiasis.

Abscess↗

Structural analysis of glycolipids from Borrelia burgdorferi.

In this study the lipids of Borrelia burgdorferi, the causative agent of Lyme disease, were analyzed. Lipids comprise about 25-30% of the cell dry weight. The lipid fraction could be separated by HPTLC into 11 components. Staining of these components revealed two glycolipids and two phospholipids. The glycolipids represented about 50% of the total lipids and comprised only galactose as monosaccharide constituents. By means of mass spectrometric and gas chromatographic analysis both glycolipids could be identified as alpha-galactosyl-diacylglycerolipids with different fatty acid compositions. The phospholipids were identified as phosphatidylcholine and phosphatidylglycerol. Immunoassays with sera from patients with Lyme disease showed antibody reactivity only to the glycolipids, which was present in all stages of the disease. Other lipid components seemed to be non-immunogenic in Lyme disease. The glycolipids of B. burgdorferi may be, thus, considered promising candidates for diagnosis and possibly also for vaccination.

Blotting, Western↗

Bioinformatics in medical practice: what is necessary for a hospital?

Building bioinformatic facilities for a university hospital is pretty similar to using standardized building blocks to construct a house. Starting with the intention to built a dwelling house, a factory or just a shelter the architect draws a construction plan and determines the material to be used. In general, the building is then constructed by the workmen following exactly the plan. However, for particular reasons, minor alterations may be needed to improve the construction of the building. Here we use the metaphor of constructing a "bio-informatics building" to describe the steps needed to support the daily tasks of a university hospital medical microbiology department which uses genomic methods quite extensively for pathogen identification. Today the Giessen "bioinformatics building" is not yet complete but we have been able to lay solid foundations and erect the ground floor which is functional already. Using a combination of standard tools, internet accessible genomic databases and some own software tools we can support genome sequencing from the raw sequence to pathogen identification.

Computational Biology↗

[Rapid and reliable detection of multiresistent Staphylococcus aureus (MRSA) by multiplex PCR].

BACKGROUND AND OBJECTIVE: Staphylococci are widespread pathogens and are frequently associated with nosocomial infections. Many hospitals struggle with increasing amounts of methicillin-resistant Staphylococcus aureus (MRSA) which are "multiresistant" against all betalactam antibiotics. Often, applicable antibiotics for treatment are only glycopeptides like vancomycin and teicoplanin. In addition, MRSA infected patients require expensive intensive isolation measures and strict hygiene. To efficiently prevent dissemination of these pathogens rapid and reliable identification and a close collaboration between clinicians and microbiologists are required. The purpose of our study was to set up a rapid and reliable identification procedure for MRSA by the amplification of specific gene determinants by PCR in order to to efficiently support therapy and eradication of the pathogen. METHODS: 153 strains of staphylococci isolated from in-patients of the hospital of the Justus-Liebig University of Giessen were examined. The femB gene was used to differentiate between Staphylococcus aureus (S. aureus) and coagulase-negative staphylococci (CNS), a gene which allows the species-specific identification of methicillin-resistant (MRSA) and -susceptible S. aureus (MSSA). Additionally, MRSA harbor the mecA gene encoding methicillin-resistance, which is absent in MSSA strains. RESULTS: Using a multiplex PCR with femB and mecA gene-specific oligonucleotides MRSA strains were unequivocally detected within 3 hours. The femB gene was detected in all 102 strains of S. aureus but in none of the 51 CNS. The mecA determinant was detected in 12 S. aureus. Among these, 11 strains were phenotypically methicillin-resistant and one strain was susceptible. The methicillin-resistance of this particular mecA-positive/methicillin-susceptible strain (cryptic MRSA) was inducible by cultivation on agar plates supplemented with flucloxacillin. CONCLUSIONS: The described method specifically detects S. aureus and identifies phenotypical and cryptic MRSA. These cryptic MRSA are of particular relevance since they are undetectable using common phenotypically based detection methods. It is conceivable that the methicillin resistance of these strains is induced under antibiotic therapy with flucloxacillin and that the mec-encoded feature of methicillin-resistance can be transferred to previously methicillin-susceptible strains. Using the reliable detection of these strains by PCR, failure of flucloxacillin therapy is avoidable.

Bacterial Proteins↗

A randomised controlled trial of an oral solution of prostaglandin E2 and oral oxytocin used immediately after low amniotomy for induction of labour in the presence of a favourable cervix.

A randomised controlled trial was carried out in 50 primigravidae and 50 multigravidae to compare the effectiveness in induction of labour after low amniotomy of prostaglandin E2, given as an oral solution, and oxytocin, given as buccal tablets. The results showed that in dosages recommended by the manufacturers, both oxytocic preparations were almost equally effective. With oral oxytocin, once labour had been established and dosage was left to the discretion of the staff, there appeared to be a potentially dangerous tendency to continue giving large doses despite adequate uterine contractions. The authors comment that this was probably the reason why oxytocin-treated multigravidae having normal deliveries within 24 hours had labours significantly shorter on average than those of other successfully induced patients.

Administration, Oral↗

[Infection diagnosis after knee-TEP-implantation].

AIM: In this study, the accuracy of antigranulocyte scintigraphy as a diagnostic means prior to revision in infected total knee replacement was compared to that of preoperative joint aspiration and laboratory parameters. The most efficient combination of all diagnostic methods was calculated and thus a diagnostic algorithm recommended. The value of PCR was compared to commonly used techniques of microbiological culturing. METHODS: Preoperative diagnostic means for infection of 50 total knee replacements in 45 patients requiring revision surgery, were retrospectively analyzed. Inclusion criteria were the intraoperative microbiological and histological verification of infection. Sensitivity, specificity, negative and positive prediction value of C-reactive protein (CRP) and leukocytes, antigranulocyte scintigraphy with (99m)Tc-labeled antibodies, and preoperative joint aspiration were calculated. Furthermore, the accuracy of the different techniques of culturing was compared to that of the polymerase chain reaction (PCR) based on the intraoperative histological findings. Two blinded examiners evaluated specimens taken intraoperatively according to the criteria of Mirra. RESULTS: We observed a sensitivity of 1.0, a specificity of 0.82, a positive prediction value of 0.83 and a negative prediction value of 1.0 for the antigranulocyte scintigraphy. The sensitivity of preoperative joint aspiration was 0.5, the specificity 1.0, and the positive and negative prediction values were 1.0 and 0.5. Correlated to the intraoperative histological findings the accuracy of PCR and culturing was comparable. The highest accuracy was obtained for blood culture samples. CONCLUSION: Compared to preoperative joint aspiration the antigranulocyte scintigraphy proved to be more sensitive in the diagnosis an infected knee replacement while having a high specificity. An advantage of PCR compared to the common microbiological culturing techniques was not observed.

Aged↗

[Usefulness of 16S rDNA polymerase-chain-reaction (PCR) in the intraoperative detection of infection in revision of failed arthroplasties].

AIM: In this study the accuracy of the 16S DNA polymerase chain reaction (PCR) in revision arthroplasties was compared to that of conventional bacterial culture when correlated to intraoperative histological findings. Furthermore, the influence of antibiotic treatment and different ways of collecting samples was evaluated. METHOD: In a prospective study we collected samples of tissues, aspiration fluids and swabs during revision arthroplasty surgery and examined them with PCR as well as conventional bacterial culturing methods. Also, we correlated these two methods with the histological findings of intraoperative tissue samples. Two independent examiners evaluated the samples according to the criteria of Mirra et al. Sensitivity, specificity, positive and negative prediction value and the accuracy were calculated for the molecular biological and culture methods. Three groups were defined to evaluate the influence of accompanying antibiotic treatment and the way of collecting the microbiological samples. RESULTS: Nine periprosthetic infections could be detected by PCR as well as by conventional bacterial culturing. Correlated with the 25 positive histological findings this resulted in a sensitivity of 0.36, a specificity of 1.0, a negative prediction value of 0.61, a positive prediction value of 1.0 and an accuracy of 0.68 for both methods. Swabs compared to aspiration fluids and tissues samples showed the highest sensitivity with both methods. No higher sensitivity of PCR compared to conventional bacterial culturing could be observed in patients with accompanying antibiotic treatment. CONCLUSION: Although PCR is more rapidly available for the diagnosis of periprosthetic infection, a definite advantage of this more expensive method could not be demonstrated in view of the same low sensitivity of PCR and conventional bacterial culturing.

Arthroplasty↗