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Biomedical subjects

D E Holmes

Publications and source records attributed to D E Holmes.

13 recordsLinked to original sources
PubMed2006

Molecular analysis of a sulphate-reducing consortium used to treat metal-containing effluents.

A sulphate-reducing consortium used in a bioprocess to remove toxic metals from solution as insoluble sulphides, was characterised using molecular (PCR-based) and traditional culturing techniques. After prolonged cultivation under anoxic biofilm-forming conditions, the mixed culture contained a low diversity of sulphate-reducing bacteria, dominated by one strain closely related to Desulfomicrobium norvegicum, identified by three independent PCR-based analyses. The genetic targets used were the 16S rRNA gene, the 16S-23S rRNA gene intergenic spacer region and the disulfite reductase (dsr) gene, which is conserved amongst all known sulphate-reducing bacteria. This organism was also isolated by conventional anaerobic techniques, confirming its presence in the mixed culture. A surprising diversity of other non-sulphate-reducing facultative and obligate anaerobes were detected, supporting a model of the symbiotic/commensal nature of carbon and energy fluxes in such a mixed culture while suggesting the physiological capacity for a wide range of biotransformations by this stable microbial consortium.

Bacteria↗
PubMed2004

Microbial communities associated with electrodes harvesting electricity from a variety of aquatic sediments.

The microbial communities associated with electrodes from underwater fuel cells harvesting electricity from five different aquatic sediments were investigated. Three fuel cells were constructed with marine, salt-marsh, or freshwater sediments incubated in the laboratory. Fuel cells were also deployed in the field in salt marsh sediments in New Jersey and estuarine sediments in Oregon, USA. All of the sediments produced comparable amounts of power. Analysis of 16S rRNA gene sequences after 3-7 months of incubation demonstrated that all of the energy-harvesting anodes were highly enriched in microorganisms in the delta-Proteobacteria when compared with control electrodes not connected to a cathode. Geobacteraceae accounted for the majority of delta-Proteobacterial sequences or all of the energy-harvesting anodes, except the one deployed at the Oregon estuarine site. Quantitative PCR analysis of 16S rRNA genes and culturing studies indicated that Geobacteraceae were 100-fold more abundant on the marine-deployed anodes versus controls. Sequences most similar to microorganisms in the family Desulfobulbaceae predominated on the anode deployed in the estuarine sediments, and a significant proportion of the sequences recovered from the freshwater anodes were closely related to the Fe(III)-reducing isolate, Geothrix fermentans. There was also a specific enrichment of microorganisms on energy harvesting cathodes, but the enriched populations varied with the sediment/water source. Thus, future studies designed to help optimize the harvesting of electricity from aquatic sediments or waste organic matter should focus on the electrode interactions of these microorganisms which are most competitive in colonizing anodes and cathodes.

Base Sequence↗
PubMed1996

Emerging indicators of ego growth and associated resistances.

In this paper the technique of resistance analysis is extended beyond a focus on defenses against aggressive drive derivatives to include a focus on resistances based on libidinal conflicts and resistances which stem from defenses against accessing and using autonomous ego functions. For example, patients may resist progress by forming primary defenses against expression of joyful affects, increased capacity to think, and/or new possibilities for effective action. This expanded focus for analysis of resistance permits us to build a technique bridge between drive-defense perspectives and ego psychology, it highlights the need to analyze the sense of danger involved in autonomous ego functioning, and it points to a way of freeing such functioning from the influences of resistance.

Adult↗
PubMed1992

Race and transference in psychoanalysis and psychotherapy.

Given the enduring primacy of race in western cultures, it is always a factor in any psychotherapeutic situation. In this paper, the role of race in elucidating transference manifestations is explored. Vignettes and clinical narratives are used to illustrate the point that race can be a useful vehicle for the expression and elaboration of transferences of defence, of drive derivative and of object ties. Several factors are discussed which influence whether and to what degree race serves as a point of engagement for transference reactions.

Adaptation, Psychological↗
PubMed1988

Prefrontal stimulus-produced hypotension in rat.

In 41 rats, bipolar electrical stimulation was administered to various regions of the frontal cortex, including the medial prefrontal cortex (MPFC), lateral prefrontal cortex (LPFC), infralimbic cortex, and convexity cortex. Resulting alterations of blood pressure and heart rate were noted. It was observed that hypotension resulted from stimulation administered to either LPFC, infralimbic cortex or ventral portion of MPFC (i.e. prelimbic cortex). Furthermore, stimulation of the LPFC typically produced bradycardia, whereas stimulation of the MPFC or infralimbic cortex had little or no effect on heart rate. Pharmacological and surgical blocks of the vagus nerves failed to attenuate the stimulus produced hypotension (SPH), as elicited from the prefrontal or infralimbic cortices, thus demonstrating that SPH in rats is not mediated by the vagus nerves. However, intraperitoneal injections of norepinephrine, which mimicked a state of increased sympathetic tone, were observed to completely block SPH. Accordingly, it is suggested that SPH may occur as the result of sympathetic inhibition. Furthermore, intravenous injections of naloxone were also observed to also completely block SPH, thus demonstrating that SPH may be mediated via opioid pathways.

Adrenergic Fibers↗