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Biomedical subjects

P Floyd

Publications and source records attributed to P Floyd.

12 recordsLinked to original sources
PubMed2000

Mass spectrometric survey of peptides in cephalopods with an emphasis on the FMRFamide-related peptides.

A matrix-assisted laser desorption/ionization (MALDI) mass spectrometric (MS) survey of the major peptides in the stellar, fin and pallial nerves and the posterior chromatophore lobe of the cephalopods Sepia officinalis, Loligo opalescens and Dosidicus gigas has been performed. Although a large number of putative peptides are distinct among the three species, several molecular masses are conserved. In addition to peptides, characterization of the lipid content of the nerves is reported, and these lipid peaks account for many of the lower molecular masses observed. One conserved set of peaks corresponds to the FMRFamide-related peptides (FRPs). The Loligo opalescens FMRFa gene has been sequenced. It encodes a 331 amino acid residue prohormone that is processed into 14 FRPs, which are both predicted by the nucleotide sequence and confirmed by MALDI MS. The FRPs predicted by this gene (FMRFa, FLRFa/FIRFa and ALSGDAFLRFa) are observed in all three species, indicating that members of this peptide family are highly conserved across cephalopods.

Amino Acid Sequence↗
PubMed1999

Basic implant surgery.

Implant surgery protocols differ slightly with individual systems. However, basic surgical principles are required to ensure successful osseointegration of the implant in the correct location which allows good aesthetics and loading.

Anesthesia, Dental↗
PubMed1992

HIV prevention among psychiatric inpatients: a pilot risk reduction study.

An HIV prevention program was piloted on an acute inpatient admission ward. Patients who volunteered to participate had significantly higher rates of histories of substance use than non-participants, suggesting that patients participated based on rational concerns about past HIV risk behavior. The program consisted of 75 minute sessions once a week for seven weeks and was co-led by an HIV counselor and the ward's social worker. Each session focused on a specific topic and included a short presentation of informational material, viewing of an educational videotape, a discussion, and role play and other educational games. In spite of a wide range in functioning among the participants, discussion was lively and participation was good. The pilot program demonstrates that chronic mentally ill patients can engage in, and benefit from, risk reduction programs and that frank and explicit discussion of sexual issues is well tolerated. Recommendations for improvement in the program are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Monitoring untreated periodontal disease.

The purpose of this study was to monitor clinical attachment levels, using a constant force probe, in patients with untreated periodontal disease, and to use darkfield microscopy to monitor changes in subgingival plaque. 10 patients with untreated disease were studied over 12 weeks. The parameters measured at baseline and every 4 weeks were probing depth, attachment level and bleeding. The subgingival microflora of the deepest site in each quadrant was examined by darkfield microscopy, using a Hellber counting chamber, at baseline and 12 weeks. The subgingival plaque from any site which lost more than 2 mm clinical attachment was also sampled and the microflora examined. Analysis of the results shows that 91% of probing depths and attachment levels remained the same or within +/- 1 mm. 3.5% of probing depths and 3.7% of attachment levels became deeper by 2 mm. 6.9% of probing depths and 4.5% of attachment levels became shallower by 2 mm. Only 6 sites out of 1029 showed loss of clinical attachment greater than 2 mm. Darkfield microscopy showed no differences in the proportion of microorganisms at the 6 sites which lost more than 2 mm of clinical attachment, compared with the baseline value. A surprising result was the tendency for probing depths and attachment levels to decrease, especially in deeper pockets. This study showed that none of the parameters monitored, i.e., probing depth, attachment level, bleeding or subgingival microflora, indicated which sites would lose attachment over a 12-week period.

Adult↗
PubMed1986

A prophylactic bolus of thiopentone does not protect against prolonged focal cerebral ischaemia.

Barbiturate coma is still recommended for brain protection during periods of temporary focal ischaemia such as during carotid endarterectomy. We tested the hypothesis that a single dose of barbiturate given before a period of protracted severe focal ischaemia would protect against focal cerebral infarction. Sixteen cats had the proximal left middle cerebral artery (MCA) occluded. Eight cats received halothane alone titrated to keep their pulse and blood pressure within the normal range. Eight cats received, in addition to halothane, a bolus of thiopentone sufficient to produce an isoelectric EEG immediately prior to MCA occlusion. Six hours after the occlusions the animals were sacrificed and the brains scored histologically to assess both size and severity of ischaemia. There was no statistically significant difference in the size or severity of the infarcts between the groups. We conclude from this study that the extent of the histological injury was not reduced by a single prophylactic bolus of thiopentone given before prolonged focal cerebral ischaemia.

Animals↗
PubMed1986

Metronidazole: a double-blind trial in untreated human periodontal disease.

The effect of metronidazole was assessed in 20 subjects with untreated periodontitis, in a double-blind trial. Subjects received a 1-week course of drug or placebo immediately after baseline examination, and were reassessed 1 month and 3 months later. A 0.25 N constant force probe and darkfield microscopy were used. At 1 month, a difference was observed between the deepest individual pockets in experimental and control groups, with regard to change in probing depth and the proportions of non-motile organisms. At 3 months, differences were observed in 1-3 mm baseline pockets, where a greater proportion of control pockets increased in probing depth, and in 4-6 mm pockets, where a greater proportion of baseline bleeding pockets had ceased to bleed in the experimental group. The differences were of limited clinical significance when compared to studies where metronidazole was used as an adjunct to other therapy, and the results were equivocal with regard to the specific plaque hypothesis, since inhibition of connective tissue attachment loss was not unambiguously demonstrable.

Adult↗
PubMedDate not supplied

An evaluation of the effect of lidocaine in experimental focal cerebral ischemia.

In order to determine the effect of lidocaine in focal cerebral ischemia, the left middle cerebral artery was transorbitally occluded in twenty cats. Eleven received lidocaine hydrochloride intravenously. The infusion was begun half an hour prior to clip occlusion and the rate was adjusted to maintain an isoelectric EEG. Nine cats served as controls, receiving an equivalent volume of 5% dextrose 0.2% saline. Thirteen animals (7 lidocaine-treated and 6 control) were sacrificed after six hours of left middle cerebral artery occlusion without reperfusion. In the remaining seven cats, the vessel was occluded for four hours prior to sacrifice. Ischemic neuronal alteration was assessed by both histochemical (2'3'5' triphenyl-2H-tetrazolium hydrochloride reaction) and histological examination. With both durations of ischemia, there was no significant difference in the extent and severity of neuronal alterations between the lidocaine-treated and control groups of animals.

Animals↗
PubMedDate not supplied

Correlation between somatosensory evoked potentials and neuronal ischemic changes following middle cerebral artery occlusion.

In an attempt to determine the usefulness of evoked potentials as a measure of focal cerebral ischemia, we examined somatosensory evoked potentials (SEP's) and morphological neuronal changes in cats following unilateral middle cerebral artery (MCA) occlusion. Fifteen adult cats underwent transorbital occlusion of the MCA under halothane anesthesia. In seven cats the ipsilateral SEP's were abolished after middle cerebral artery occlusion, and did not show any recovery after 6 hours. The same seven cats showed the greatest area of moderate and severe ischemic neuronal changes, ranging from 21 to 64% (mean 39 +/- 14%) of the total ipsilateral cortical area. The remaining eight cats showed a complete flattening or decreased amplitude of the SEP after occlusion, but demonstrated a considerable recovery in the amplitude of the primary cortical potential during the six hours of the study. All these cats had ischemic areas of less than 15% (mean 9 +/- 3%) of the total ipsilateral cortex. These results demonstrate that the disappearance of the SEP and their failure to recover correlate with the extent and degree of histological cerebral ischemia.

Animals↗