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Biomedical subjects

P J Chapman

Publications and source records attributed to P J Chapman.

At least 19 recordsLinked to original sources
PubMed2006

Spatial variation in concentrations of dissolved nitrogen species in an upland blanket peat catchment.

The concentration of nitrogen (N), particularly as nitrate (NO3-N), in upland streams, lakes and rivers is frequently used as a diagnostic of the vulnerability of upland ecosystems to increased atmospheric nitrogen deposition and N saturation. The N content of running waters, however, is generally assessed on the basis of sampling at a limited number of points in space and time within the catchment under investigation. The current study was conducted at Trout Beck, an 11.5 km2 blanket peat-dominated catchment in the North Pennine uplands of the UK. Results from sampling at 33 sites within this catchment demonstrated that the concentrations of all dissolved N species were highly variable, even over short distances. Statistical relationships between the concentrations of NO3-N and dissolved organic nitrogen (DON) and percentage catchment cover of Calluna/Eriophorum and Eriophorum vegetation were found. However, it was also noted that in catchments containing limestone outcrops, NO3-N concentration was much higher than in catchments where runoff was sourced directly from the blanket peat surface. It is possible that NH4-N and DON leached from the blanket peat are mineralised and nitrified, providing a source for the NO3-N found in the river channels. Overall, the current study suggests that interpretations of N-saturation based on river water chemistry measurements at a single point must be treated cautiously, and that the influence of catchment-scale physical factors, such as vegetation and geology cover on the concentration of dissolved N species in upland river waters should not be ignored.

Calcium↗
PubMed2003

An overview of drugs and ancillary equipment for the dentist's emergency kit.

The concept of a basic (i.e., essential) medical emergency kit suitable for a general dental practitioner varies somewhat between different authorities. A practitioner's choice is also dependant on the proximity of medical aid and the nature of the dental practice. Over recent years the trend has been to restrict the items to a minimum, in the interest of both common sense and safety, for example, just oxygen, adrenaline 1:1000, an oral carbohydrate source, glyceryl trinitrate and aspirin as first options. Ancillary equipment should include an oxygen therapy facemask, a pocket mask and a set of oral (Guedel) airways. Two further medication options for consideration are an aerosol bronchodilator and, in certain circumstances, an injectable antihypoglycaemic agent. This paper provides a selective overview of the subject. An absolute necessity is for dentists to be competent in Basic Life Support skills, and to maintain a complete and current medical history for all patients.

Adrenergic Agents↗
PubMed2002

Effects of fractions from biodegraded Alaska North Slope crude oil on embryonic inland silversides, Menidia beryllina.

Embryonic inland silversides, Meinida beryllina, were exposed to neutral, water-soluble fractions (WSFs) resulting from microbial degradation of artificially weathered Alaska North Slope (ANS) crude oil. Three individual microbes obtained from Prince William Sound, Alaska, and designated Phe#6 (enriched on phenanthrene), Hexaco#2 (enriched on the straight-chain alkane, hexacosane), and EI2V (grown by enrichment on Bushnell-Haas medium containing 0.2% pristane, a branched alkane) were used to individually biodegrade weathered ANS crude oil for 14 days in darkness in 20-L glass carboys containing nutrient enriched, sterilized 20% salinity sea water at 20 +/- 1 degrees C. Neutral WSFs resulting from biodegradation of ANS (lot 521) by each microbe were recovered and weighted. Neutral WSFs recovered were: 1.76 mg/L for Phe#6, 1.85 mg/L for Hexaco#2, and 13.02 mg/L for the EI2V microbe. Embryo toxicity and teratogenicity tests revealed that exposure of embryos to the WSFs from the EI2V incubation (with a total recovered neutral fraction approximately seven times greater than the Phe#6 and Hexaco#2 incubations) resulted in the most severe responses in craniofacial, cardiovascular, and skeletal organ systems. The total neutral WSFs recovered from the EI2V biodegradation of weathered ANS 521 were subfractionated into saturated (eluted with hexane), aromatic (eluted with CH2Cl2), polar (eluted with ethyl ether), and recombined (saturated + aromatic + polar) fractions. Developing fish embryos were then exposed to each subfraction and the recombined subfractions. The polar subfraction and recombined subfractions proved to be the most embryo toxic and teratogenic. They resulted in statistically significant (p < or = 0.05) responses (compared to controls) for craniofacial, cardiovascular, skeletal, and total severity effects in one or both tests with these subfractions.

Animals↗
PubMed2002

A case report of acute heart failure caused by a patient delaying taking his diuretic medication.

Acute heart failure is a life-threatening medical emergency, most commonly occurring as an immediate or delayed complication of acute myocardial infarction (AMI), or resulting from severe hypertension or valvular defects (stenosis or incompetence). Occasionally it is caused by patients' non-compliance with medication orders. In this case the patient had a history of three previous AMIs, controlled hypertension, and controlled congestive heart failure (CHF) for which he took two 40 mg frusemide tablets (a very potent oral diuretic) each morning. Because he had experienced bladder discomfort during the latter stages of previous appointments he decided to delay taking the diuretic until after his appointment and acute heart failure ensued.

Acute Disease↗
PubMed2002

Successful defibrillation of a dental patient in cardiac arrest.

Cardiac arrest is a very rare event in a dental patient. However, practitioners have a duty of care to their patients if ever such an event occurs. The cardiac arrest discussed in this case report occurred in an elderly person with an implanted pacemaker whilst undergoing restorative dental treatment. Cardiac arrest was diagnosed and cardiopulmonary resuscitation instituted immediately, followed within three minutes by successful defibrillation using the School's semi-automatic defibrillator.

Aged↗
PubMed2002

Chest pain in the dental surgery: a brief review and practical points in diagnosis and management.

If a dental patient develops chest pain it must always be managed promptly and properly, i.e., the practitioner immediately stops the procedure and, being aware of the patient's medical history, questions the patient regarding the nature of the pain to help determine the likely diagnosis. It will most likely be a manifestation of coronary artery disease (synonymous with ischaemic heart disease), i.e., angina pectoris or acute myocardial infarction, most usually the former. Angina will usually resolve with proper intervention whereas up to about one-half of myocardial infarction cases will develop cardiac arrest, mostly in the first few hours, and this will be fatal in up to two-thirds of cases. As health care professionals, dental practitioners have an inherent duty of care to be able to initiate appropriate care if such a medical emergency occurs.

Angina Pectoris↗
PubMed2001

Merging nitrogen management and renewable energy needs.

The ARBRE (ARable Biomass Renewable Energy) project, the first large-scale wood-fueled electricity generating plant in the U.K., represents a significant development in realising British and European policy objectives on renewable energy. The plant is fueled by a mix of wood from short rotation coppice (SRC) and forest residues. Where feasible, composted/conditioned sewage sludge is applied to coppice sites to increase yields and improve soil structure. In the Yorkshire Water region, typical total N:P:K composition of composted/conditioned sludge is 2.9:3.8:0.3, respectively. Sludge application is calculated on the basis of total nitrogen (N) content to achieve 750 kg N ha(-1), for 3 years" requirement. Willow coppice forms a dense, widely spaced, root network, which, with its long growing season, makes it an effective user of nutrients. This, in combination with willow"s use as a nonfood, nonfodder crop, makes it an attractive route for the recycling of sewage sludge in the absence of sea disposal, banned under the EC Urban Waste Water Treatment Directive (UWWTD). Further work is required on the nutritional requirements of SRC in order to understand better the quantities of sludge that can be applied to SRC without having a detrimental impact on the environment. This paper suggests the source of N rerouting under the UWWTD and suggests the likely expansion of SRC as an alternative recycling pathway.

Biomass↗
PubMed2001

Inorganic and organic losses of nitrogen from upland regions of Britain: concentrations and fluxes.

The nitrogen (N) composition of streams draining eight upland regions of Britain was compared using monthly samples collected between April 1997 and April 1998. Stream samples were analysed for total N (TN), particulate N (PN), nitrate (NO3), ammonium (NH4), and dissolved organic nitrogen (DON). Concentrations of TN were small, generally less than 1.5 mg N l(-1), were dominated by dissolved forms of N, and varied significantly between regions. NO3 accounted for the majority of variability. Concentrations of DON also varied between regions but to a smaller extent than those of NO3. There were considerable variations in TN fluxes between upland regions, which ranged between 3.8 and 16.1 kg N ha(-1) year(-1). The majority of the variation was due to NO3 fluxes, which were largest in regions receiving largest inputs of atmospheric N deposition and ranged between 1.4 and 13.5 kg N ha(-1) year(-1). Fluxes of DON ranged between 1 and 3.5 kg N ha(-1) year( -1), while fluxes of PN were generally less than 0.5 kg N ha(-1) year(-1) , and NH4 fluxes ranged between 0.1 and 0.4 kg N ha(-1) year(-1). NO3 was the dominant fraction (47-84%) of N exported from all upland regions except the Highlands, where DON accounted for 52% of the TN flux. This study has shown that the DON fraction is an important component of the total N transported by upland streams in Britain.

Altitude↗
PubMed2001

The nitrogen composition of streams in upland Scotland: some regional and seasonal differences.

The nitrogen (N) composition of streams draining four upland regions of Scotland was compared in samples collected monthly between April 1997 and April 1998. Stream samples were analysed for total N (TN), particulate N (PN), nitrate (NO3), ammonium (NH4), dissolved organic N (DON) and dissolved organic carbon (DOC). Concentrations of TN were small, generally less than 1 mg l(-1) , dominated by dissolved forms of N, and varied significantly between upland regions. Nitrate accounted for most of the variability in TN; largest concentrations were observed in the Southern Uplands and smallest concentrations were observed in the Highlands. Nitrate concentrations were positively correlated with the percentage cover of improved grasslands and brown forest soils and negatively correlated with the percentage cover of peat. Concentrations of DON also varied between regions, but to a lesser extent than those of NO3. Largest concentrations occurred in SW Scotland and smallest concentrations in the Cairngorms. Although a significant positive correlation between DON and DOC was observed, stream water DON content was not related to the percentage cover of peat in the catchment, as was the case for DOC. The average DOC:DON ratio was narrower for streams in the Southern Uplands than for those in the Cairngorms and Highlands. Nitrate and DON displayed contrasting seasonal trends; NO3 concentrations were larger in the winter while DON concentrations were larger in the summer. Only a small proportion, < 8% and < 7%, of TN was PN and NH4, respectively, the majority of N was present as either NO3 or DON. Nitrate was the dominant fraction (58-65%) in all regions except the Highlands where DON accounted for 57% of TN. However, the relative importance of the DON component increased in the summer in all regions. This study has demonstrated that the DON fraction is an important component of the total N transported by streams from upland catchments in Scotland. Thus, assessments of anthropogenic impacts on N losses from upland ecosystems need to consider not only the dissolved inorganic species but also DON.

Agriculture↗
PubMed1999

Degradation of weathered oil by mixed marine bacteria and the toxicity of accumulated water-soluble material to two marine crustacea.

Artificially weathered crude oil was degraded by four diverse cultures of mixed marine bacteria under optimized conditions for 7 and 14 days. Loss in total weight of starting oil (30 g) ranged from 6.8-17.3% in biologically active incubations compared with only 0. 9-1.1% in sterile and nutrient-limited controls. In all incubations, both neutral and acidic water-soluble fractions (WSF) were accumulated. In biologically active systems, 50.9-249.0 mg neutral and 63.3-406.8 mg acidic WSF were accumulated whereas only 6.5-11.1 mg neutral and 1.7-2.2 mg acidic WSF were accumulated in control incubations. Analysis by gas chromatography demonstrated that accumulated WSF in biologically active systems contained compounds different from those washed from the starting crude oil. Exposure of grass shrimp (Palaemonetes pugio) embryos to neutral WSF from each of the biologically active cultures resulted in high embryo mortalities relative to sterile and nutrient-limited controls which exhibited >90% hatching success and larval survival. Toxicity of neutral WSF was also demonstrated on larvae of mysids (Mysidopsis bahia). In both cases, toxicity occurred only on exposure to neutral material accumulated by active, oil-degrading cultures and not with material washed from the weathered crude oil. These results imply that unique compounds were accumulated during degradation that may have been responsible for increased toxicity.

Animals↗
PubMed1998

Preliminary observations on responses of embryonic and larval Pacific herring, Clupea pallasi, to neutral fraction biodegradation products of weathered Alaska North Slope oil.

Weathered Alaska North Slope crude oil (ANS 521) was subjected to biodegradation in vigorously stirred incubations for 14 days at 15 +/- 1 degrees C in 20/1000 salinity sterilized seawater, amended with nutrients and inoculated with a hydrocarbon-degrading microorganism (EI2V) isolated from an oil-contaminated beach in Prince William Sound, Alaska. A total of 13.7 mg/L water-soluble neutral fraction (WSF) was recovered from the incubation of weathered ANS 521. Toxicity/ teratogenicity tests were conducted with WSF recovered from the biodegradation system using embryonic and larval Pacific herring, Clupea pallasi. Exposures were begun at 4, 48, and 96 h postfertilization of herring eggs. Exposure concentrations were 1, 10, and 100% of the original concentration of WSF recovered from incubations (redissolved in 20/1000 salinity sterile seawater at 15 +/- 1 degrees C). Sterile 20/1000 salinity seawater without the addition of redissolved neutral fraction was used as a control. Significant (p < or = 0.05) embryo mortality or teratogenic responses were observed at WSF concentrations of 10 and 100%. On days 5 through 8 of embryogenesis, counts of heart contraction rates were significantly lower (p < or = 0.05) at the 100% WSF concentration for embryos exposed beginning at 4 and 48 h postfertilization. Grow-out of larvae from selected exposures was conducted. High mortality was noted in larvae exposed to the 10% WSF concentration beginning at 4 and 48 h postfertilization. Most of these larvae died 5 to 8 days after hatching when they elicited vertebral displacements at a time concurrent with the onset of feeding behavior.

Animals↗
PubMed1998

Use of 13C nuclear magnetic resonance to assess fossil fuel biodegradation: fate of [1-13C]acenaphthene in creosote polycyclic aromatic compound mixtures degraded by bacteria.

[1-13C]acenaphthene, a tracer compound with a nuclear magnetic resonance (NMR)-active nucleus at the C-1 position, has been employed in conjunction with a standard broad-band-decoupled 13C-NMR spectroscopy technique to study the biodegradation of acenaphthene by various bacterial cultures degrading aromatic hydrocarbons of creosote. Site-specific labeling at the benzylic position of acenaphthene allows 13C-NMR detection of chemical changes due to initial oxidations catalyzed by bacterial enzymes of aromatic hydrocarbon catabolism. Biodegradation of [1-13C]acenaphthene in the presence of naphthalene or creosote polycyclic aromatic compounds (PACs) was examined with an undefined mixed bacterial culture (established by enrichment on creosote PACs) and with isolates of individual naphthalene- and phenanthrene-degrading strains from this culture. From 13C-NMR spectra of extractable materials obtained in time course biodegradation experiments under optimized conditions, a number of signals were assigned to accumulated products such as 1-acenaphthenol, 1-acenaphthenone, acenaphthene-1,2-diol and naphthalene 1,8-dicarboxylic acid, formed by benzylic oxidation of acenaphthene and subsequent reactions. Limited degradation of acenaphthene could be attributed to its oxidation by naphthalene 1,2-dioxygenase or related dioxygenases, indicative of certain limitations of the undefined mixed culture with respect to acenaphthene catabolism. Coinoculation of the mixed culture with cells of acenaphthene-grown strain Pseudomonas sp. strain A2279 mitigated the accumulation of partial transformation products and resulted in more complete degradation of acenaphthene. This study demonstrates the value of the stable isotope labeling approach and its ability to reveal incomplete mineralization even when as little as 2 to 3% of the substrate is incompletely oxidized, yielding products of partial transformation. The approach outlined may prove useful in assessing bioremediation performance.

Acenaphthenes↗
PubMed1997

Medical emergencies in dental practice and choice of emergency drugs and equipment: a survey of Australian dentists.

This is a report of a postal questionnaire survey of 1250 general dental practitioners regarding occurrence of medical emergencies and their choice of emergency drugs and equipment. The response rate was 65 per cent and the results showed that about one in seven practitioners had had to resuscitate a patient. The most common medical emergencies were adverse reactions to local anaesthetics, grand mal seizures, angina pectoris and hypoglycaemia (insulin shock). Nearly all respondents (96 per cent) believed that dentists need to be competent in cardiopulmonary resuscitation, just over a half (55 per cent) felt they were competent in CPR on graduation and a similar figure (57 per cent) felt they could perform effective single person CPR for five minutes. Almost two-thirds (64 per cent) had undertaken CPR courses since graduation. Additionally, the most commonly kept emergency drugs were oxygen (63 per cent) and adrenaline (22 per cent), while the most commonly kept emergency equipment was a manual resuscitator (recoil bag-valve-mask type) which was kept by 27 per cent of the practitioners.

Anesthetics, Local↗
PubMed1996

Responses of embryonic and larval inland silversides, Menidia beryllina, to a water-soluble fraction formed during biodegradation of artificially weathered Alaska North Slope crude oil.

Weathered Alaska North Slope crude oil (ANS 521) was stirred for 2 and 14 days in 20 per thousand salinity sterile seawater or for 14 days in seawater with nutrients and a group of three (GO3) microorganisms from Prince William Sound, Alaska, that were capable of biodegrading hydrocarbons. A total of 0.65 and 0.69 mg/L water soluble fraction (WSF) of neutral fraction hydrocarbons was recovered from the 2- and 14-day stirred sterile systems, respectively. In comparison, a total of 7.5 mg/L WSF neutral fraction hydrocarbons was recovered from systems containing ANS 521 that were stirred and biodegraded by the GO3 microbes for 14 days. Toxicity/teratogenicity tests were conducted with neutral fraction hydrocarbons recovered from the sterile and biodegraded systems using embryonic inland silversides, Menidia beryllina. Hydrocarbons from the sterile systems did not cause statistically significant teratogenic responses at concentrations of 1%, 10%, and 100% (w/v) of recovered fractions (redissolved in 20 per thousand salinity sterile seawater). Counts of heart contraction rates were significantly lower (alpha</=0.05) at the 100% WSF concentration of hydrocarbons on days 5 and 6 of embryogenesis. In contrast, recovered and redissolved neutral fraction hydrocarbons from ANS 521, that were biodegraded for 14 days, caused statistically significant (alpha</=0.05) teratogenic responses at the 1, 10, and 100% WSF concentrations. Measurement of heart contraction rates showed statistically significant (alpha</=0.05) reductions at the 100% WSF concentration on days 2 through 6 of embryogenesis, compared to controls.

Analysis of Variance↗
PubMed1996

Prevalence of orofacial injuries and use of mouthguards in high school Rugby Union.

In Australia there is a tradition of early involvement of children in contact sports. Mouthguards are known to reduce the risk of dental and associated injuries--however, Australian studies of the use of mouthguards in contact sports and the prevalence of dental and associated injuries have only focused on adult participants. Previous studies of high school Rugby Union players in New Zealand have shown that between 13 and 15 per cent had previously sustained dental injury while between 30 and 37 per cent wore mouthguards regularly. One hundred and thirty Rugby Union football players attending a large high school in Brisbane participated in this survey. All believed in the safety value of mouthguards in football. All of the players in the four open teams and the majority of players in the four under-age teams wore mouthguards, and the incidence of dental injury was very low, approximately 4 per cent. These and other results will be presented and compared with previous similar studies.

Adolescent↗
PubMed1996

Oxidation of naphthenoaromatic and methyl-substituted aromatic compounds by naphthalene 1,2-dioxygenase.

Oxidation of acenaphthene, acenaphthylene, and fluorene was examined with recombinant strain Pseudomonas aeruginosa PAO1(pRE695) expressing naphthalene dioxygenase genes cloned from plasmid NAH7. Acenaphthene underwent monooxygenation to 1-acenaphthenol with subsequent conversion to 1-acenaphthenone and cis- and trans-acenaphthene-1,2-diols, while acenaphthylene was dioxygenated to give cis-acenaphthene-1,2-diol. Nonspecific dehydrogenase activities present in the host strain led to the conversion of both of the acenaphthene-1,2-diols to 1,2-acenaphthoquinone. The latter was oxidized spontaneously to naphthalene-1,8-dicarboxylic acid. No aromatic ring dioxygenation products were detected from acenaphthene and acenaphthylene. Mixed monooxygenase and dioxygenase actions of naphthalene dioxygenase on fluorene yielded products of benzylic 9-monooxygenation, aromatic ring dioxygenation, or both. The action of naphthalene dioxygenase on a variety of methyl-substituted aromatic compounds, including 1,2,4-trimethylbenzene and isomers of dimethylnaphthalene, resulted in the formation of benzylic alcohols, i.e., methyl group monooxygenation products, which were subsequently converted to the corresponding carboxylic acids by dehydrogenase(s) in the host strain. Benzylic monooxygenation of methyl groups was strongly predominant over aromatic ring dioxygenation and essentially nonspecific with respect to the substitution pattern of the aromatic substrates. In addition to monooxygenating benzylic methyl and methylene groups, naphthalene dioxygenase behaved as a sulfoxygenase, catalyzing monooxygenation of the sulfur heteroatom of 3-methylbenzothiophene.

Journal Article↗
PubMed1995

A questionnaire survey of dentists regarding knowledge and perceived competence in resuscitation and occurrence of resuscitation emergencies.

Little information has been published on the knowledge and perceived competence of dentists in resuscitation or the occurrence of resuscitation emergencies in dental practice. Further, no such surveys have been done in Australia. A postal survey was therefore devised and the names of 350 dentists were randomly selected from the Australian Dental Association national membership registry. The response rate was approximately 45 per cent and the main results included: just under half of the respondents felt they were competent in basic resuscitation at the time of graduation, that is, in expired air resuscitation (EAR) and cardiopulmonary resuscitation (CPR); just less than two-thirds had undertaken resuscitation training since graduation; about three-quarters felt they would be able to perform EAR and almost two-thirds felt they would be able to perform CPR; almost 90 per cent gained a satisfactory score in a Resuscitation Quiz included in the survey; and just over 5 per cent had had to resuscitate a patient.

Adult↗