Biomedical subjects

D N Adams

Publications and source records attributed to D N Adams.

5 recordsLinked to original sources

PubMed2006

Shortcut detection of the vanB gene cluster in enterococci by a duplex real-time PCR assay.

AIM: To develop a robust, simple and rapid method for detection of vanB in enterococci. METHODS: A real-time duplex PCR assay for the simultaneous detection of Enterococcus faecium and vanB resistance genotype in enterococci was developed in conjunction with a simple method for DNA extraction. The assay was tested on 130 fresh plate cultures of clinical isolates of enterococci and other Gram-positive bacteria. RESULTS: Forty-eight isolates of vanB E. faecium from 32 different patients and three isolates of vanB E. faecalis were detected within 1 hour. All isolates of E. faecium were identified correctly. CONCLUSION: This simple method for the detection of resistance mediated by vanB is a potentially useful method that is suitable for use in the diagnostic microbiology laboratory.

Anti-Bacterial Agents↗

PubMed2006

Profound lymphopenia and bacteraemia.

Bacteraemia often carries a poor prognosis despite prompt antibiotic therapy and is associated with late morbidity and mortality that is difficult to explain. Here, we describe perisistent B- and T- cell lymphopenia in a cohort of patients with Gram-positive and Gram-negative bacteraemia. This suggests previously unrecognized mechanisms of subversion of immunity by pathogens and might explain the comorbidity of blood stream infection with bacteria.

Anti-Bacterial Agents↗

PubMed1997

Micropatterning gradients and controlling surface densities of photoactivatable biomolecules on self-assembled monolayers of oligo(ethylene glycol) alkanethiolates.

BACKGROUND: Bioactive molecules that are covalently immobilized in patterns on surfaces have previously been used to control or study cell behavior such as adhesion, spreading, movement or differentiation. Photoimmobilization techniques can be used, however, to control not only the spatial pattern of molecular immobilization, termed the micropattern, but also the surface density of the molecules--a characteristic that has not been previously exploited. RESULTS: Oligopeptides containing the bioactive Arg-Gly-Asp cell-adhesion sequence were immobilized upon self-assembled monolayers of an oligo(ethylene glycol) alkanethiolate in patterns that were visualized and quantified by autoradiography. The amount and pattern of immobilized peptide were controlled by manipulating the exposure of the sample to a UV lamp or a laser beam. Patterns of peptides, including a density gradient, were used to control the location and number of adherent cells and also the cell shape. CONCLUSIONS: A photoimmobilization technique for decorating surfaces with micropatterns that consist of variable densities of bioactive molecules is described. The efficacy of the patterns for controlling cell adhesion and shape has been demonstrated. This technique is useful for the study of cell behavior on micropatterns.

3T3 Cells↗

PubMed1982

Cervical thymic cyst.

Various types of cysts that originate in embryonal remnants may be observed in the neck. Among these, branchial cleft and thyroglossal duct cysts are more commonly observed, whereas thymic cysts are rare. Most patients with a cervical thymic cyst complain of a painless, enlarging mass in the neck. The histopathologic features of thymic cysts are diagnostic. Cystic thymomas, which seem to have a more aggressive clinical behavior in children, should be differentiated from the benign cervical thymic cyst. Thymic cysts most probably arise from embryonic remnants of the thymopharyngeal duct. Our patient had a cervical thymic cyst with neurofibromatosis.

Child↗

PubMedDate not supplied

Formation of microscale gradients of protein using heterobifunctional photolinkers.

Gradients of biological molecules on a microscale have been postulated to elicit cellular responses, such as migration. However, it has been difficult to prepare such gradients for experimental testing. A means for producing such gradients has been developed using a heterobifunctional photolinking agent with laser light activation. The photolinking agent synthesized includes an N-hydroxysuccinimide group and a photoreactive benzophenone (BP) separated by a tetraethylene glycol (TEG) spacer. The presence of the tetraethylene glycol spacer renders the photolinker hydrophilic, a desirable trait for conjugation in aqueous solutions. The linker was then conjugated to R-phycoerythrin (R-PE), a fluorescent protein. The resulting photolinker-R-phycoerythrin conjugate (BP-TEG-PE) was then immobilized onto a polystyrene surface by laser irradiation on a motorized stage. By varying exposure time of the sample to the beam, the amount of BP-TEG-PE immobilized on the surface was changed over an order of magnitude over a distance of 250 microns. This method can be applied to prepare gradients of proteins that elicit biological responses, such as extracellular matrix proteins or growth factors, and to study the biological effects of such gradients.

Alanine↗