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Biomedical subjects

G C Jones

Publications and source records attributed to G C Jones.

At least 19 recordsLinked to original sources
PubMed2006

Biogeochemical signatures in the lichen Hypogymnia physodes in the mid Urals.

Multi-element content and uranium (U) isotopes were investigated in the lichen Hypogymnia physodes (native and transplants) sampled across a 60-km transect, centred on Karabash smelter town, from Turgoyak Lake (SW) to Kyshtym (NE) to investigate the origin of U. Kyshtym was the site of a major nuclear accident in 1957. (234)U/(238)U activity ratios in native thalli sampled during July 2001 were within the natural isotopic ratio in minerals. Uranium/thorium (U/Th) ratios were higher in native thalli towards the NE (average 0.73) than those in the SW (average 0.57). Element signatures in native thalli and transplants suggest U was derived from fossil fuel combustion from Karabash and sources lying further to the east. Systematic and significant U enrichment indicative of a nuclear fuel cycle source was not detected in any sample. Element signatures in epiphytic lichen transplants and native thalli provide a powerful method to evaluate U deposition.

Cluster Analysis↗
PubMed2005

Biomonitoring using the lichen Hypogymnia physodes and bark samples near Zlatna, Romania immediately following closure of a copper ore-processing plant.

Lichen transplants were established along a 40km transect centred on a large mine waste dump close to Zlatna town centre, two weeks after closure of a major industrial source, to compare spatial patterns of element concentrations in lichen and bark samples. After 3 months of exposure, spatial patterns of 4 element concentrations (Pb, Cu, Zn and Fe) in transplants confirmed deposition due to a point source 'Zlatna influence'. Cu and Pb reached concentrations 8 and 4 times, respectively, higher than samples transplanted in the 'background' site, and over 200 (Cu) and 2000 (Pb) times higher relative to 'background' bark. Ten out of 15 elements analysed reached highest concentrations in bark. Spatial patterns confirmed long-term pollution for 6 elements (Pb, S, Fe, Cu, Zn and Ba). The study provides a model baseline to monitor recovery following closure of major industrial sources and highlights the importance of considering biogeochemical processes when interpreting metal concentrations.

Betulaceae↗
PubMed2004

Characterisation of airborne particulate pollution in the Cu smelter and former mining town of Karabash, South Ural Mountains of Russia.

Airborne total suspended particulates (TSP), dusts from smelter blast furnace and converter stacks, and filtrates of snow melt waters have been characterised in the Cu smelter and former mining town of Karabash, Russia. TSP was collected at sites up- and downwind of the smelter and large waste and tailings dumps (Oct. 2000 and July 2001). Methods for particle size, mineralogical and elemental determinations have been tested and described, and a new PSD-MicroSOURCE XRD technique developed for the mineralogical analysis of microsamples on filter substrates. TSP in downwind samples has a mean equivalent spherical diameter of 0.5 microm (s.d. = 0.2) and was found to be 100% respirable. The main element of human health/environmental concern, above Russian maximum permitted levels (1 microg m(-3), average over any time period), was Pb which was measured at 16-30 microg m(-3) in downwind samples. Individual particulates mainly consisted of complex mixtures of anglesite (PbSO4), Zn2SnO4 and poorly ordered Zn sulphates. From experimental and theoretical considerations, a high proportion of contained Pb, Zn, Cd and As in this material is considered to be in a readily bioavailable form. Chemical and mineralogical differences between the TSP, stack dusts and snow samples are discussed, as well as the implications for human and regional environmental health.

Air Pollutants↗
PubMed2003

Which factors are responsible for the changing lichen floras of London?

SO(2) is no longer the principal factor influencing the vitality and composition of lichen assemblages in London. We provide direct evidence for an impact on lichen growth during episodic high exhaust emissions coupled with unusual climatic conditions. This suggests a combination of particles and nitrogen plays a major role in influencing lichen growth. Nitrogen from traffic emissions may be at least as important as agriculture in influencing the composition of lichen assemblages.

Agriculture↗
PubMed2001

Endothelium-derived hyperpolarizing factor and potassium use different mechanisms to induce relaxation of human subcutaneous resistance arteries.

This investigation examined the hypothesis that release of K(+) accounts for EDHF activity by comparing relaxant responses produced by ACh and KCl in human subcutaneous resistance arteries. Resistance arteries (internal diameter 244+/-12 microm, n=48) from human subcutaneous fat biopsies were suspended in a wire myograph. Cumulative concentration-response curves were obtained for ACh (10(-9) - 3x10(-5) M) and KCl (2.5 - 25 mM) following contraction with noradrenaline (NA; 0.1 - 3 microM). ACh (E(max) 99.07+/-9.61%; -LogIC(50) 7.03+/-0.22; n=9) and KCl (E(max) 74.14+/-5.61%; -LogIC(50) 2.12+/-0.07; n=10)-induced relaxations were attenuated (P<0.0001) by removal of the endothelium (E(max) 8.21+/-5.39% and 11.56+/-8.49%, respectively; n=6 - 7). Indomethacin (10 microM) did not alter ACh-induced relaxation whereas L-NOARG (100 microM) reduced this response (E(max) 61.7+/-3.4%, P<0.0001; n=6). The combination of ChTx (50 nM) and apamin (30 nM) attenuated the L-NOARG-insensitive component of ACh-induced relaxation (E(max): 15.2+/-10.5%, P<0.002, n=6) although these arteries retained the ability to relax in response to 100 microM SIN-1 (E(max) 127.6+/-13.0%, n=3). Exposure to BaCl(2) (30 microM) and Ouabain (1 mM) did not attenuate the L-NOARG resistant component of ACh-mediated relaxation (E(max), 76.09+/-8.92, P=0.16; n=5). KCl-mediated relaxation was unaffected by L-NOARG+indomethacin (E(max); 68.1+/-5.6%, P=0.33; n=5) or the combination of L-NOARG/indomethacin/ChTx/apamin (E(max); 86.61+/-14.02%, P=0.35; n=6). In contrast, the combination of L-NOARG, indomethacin, ouabain and BaCl(2) abolished this response (E(max), 5.67+/-2.59%, P<0.0001, n=6). The characteristics of KCl-mediated relaxation differed from those of the nitric oxide/prostaglandin-independent component of the response to ACh, and were endothelium-dependent, indicating that K(+) does not act as an EDHF in human subcutaneous resistance arteries.

Acetylcholine↗
PubMed2000

Understanding the role of glucocorticoids in obesity: tissue-specific alterations of corticosterone metabolism in obese Zucker rats.

The role of glucocorticoids in obesity is poorly understood. Observations in obese men suggest enhanced inactivation of cortisol by 5alpha-reductase and altered reactivation of cortisone to cortisol by 11betahydroxysteroid dehydrogenase type 1 (11betaHSD1). These changes in glucocorticoid metabolism may influence corticosteroid receptor activation and feedback regulation of the hypothalamic-pituitary-adrenal axis (HPA). We have compared corticosterone metabolism in vivo and in vitro in male obese and lean Zucker rats, aged 9 weeks (n = 8/group). Steroids were measured in 72-h urine and 0900 h trunk blood samples. 5alpha-Reductase type 1 and 11betaHSD activities were assessed in dissected tissues. Obese animals were hypercorticosteronemic and excreted more total corticosterone metabolites (2264+/-623 vs. 388+/-144 ng/72 h; P = 0.003), with a greater proportion being 5alpha-reduced or 11-oxidized. 11-Dehydrocorticosterone was also elevated in plasma (73+/-9 vs. 18+/-2 nM; P = 0.001) and urine (408+/-111 vs. <28 ng/72 h; P = 0.01). In liver of obese rats, 5alpha-reductase type 1 activity was greater (20.6+/-2.7% vs. 14.1+/-1.5%; P<0.04), but 11betaHSD1 activity (maximum velocity, 3.43+/-0.56 vs. 6.57+/-1.13 nmol/min/mg protein; P = 0.01) and messenger RNA levels (0.56+/-0.08 vs. 1.03+/-0.15; P = 0.02) were lower. In contrast, in obese rats, 11betaHSD1 activity was not different in skeletal muscle and sc fat and was higher in omental fat(36.4+/-6.2 vs. 19.2+/-6.6; P = 0.01), whereas 11betaHSD2 activity was higher in kidney (16.7+/-0.6% vs. 11.3+/-1.5%; p = 0.01). We conclude that greater inactivation of glucocorticoids by 5alpha-reductase in liver and 11betaHSD2 in kidney combined with impaired reactivation of glucocorticoids by 11betaHSD1 in liver may increase the MCR of glucocorticoids and decrease local glucocorticoid concentrations at these sites. By contrast, enhanced 11betaHSD1 in omental adipose tissue may increase local glucocorticoid receptor activation and promote obesity.

11-beta-Hydroxysteroid Dehydrogenase Type 1↗
PubMed1998

Perceived symptoms of hypoglycaemia in elderly type 2 diabetic patients treated with insulin.

Elderly insulin-treated diabetic patients have a high risk of severe hypoglycaemia, yet their hypoglycaemic symptom profile has attracted little research. In this study, the frequency and intensity of symptoms of hypoglycaemia were recorded using a validated questionnaire in 132 insulin-treated diabetic patients, aged 70 years or more. Principal components analysis (PCA) was used to discover the factorial structure of the symptoms. Lightheadedness and unsteadiness were prominent symptoms in the elderly patients. PCA suggested three separate groups of symptoms: (1) those related specifically to impairment of co-ordination and articulation; (2) more general neuroglycopenic symptoms, and (3) autonomic symptoms. The frequency and classification of hypoglycaemic symptoms in this elderly population is different from those seen in younger diabetic patients treated with insulin. Neurological symptoms of hypoglycaemia were more commonly reported and may be misinterpreted as features of cerebrovascular disease. Health professionals and carers involved in the treatment and education of diabetic patients should be aware of the age-specific differences in hypoglycaemic symptoms.

Aged↗
PubMed1997

Medical assessment for licensing of taxi drivers by Scottish local authorities.

In the UK, licensing of taxi drivers is dealt with by local government authorities. In Scotland, before the recent reorganization of local government, taxi licensing was under the jurisdiction of District Councils, so a telephone survey was conducted of all 52 mainland Scottish District Councils to ascertain the procedures which were being employed in assessing medical fitness to drive a taxi, for which there is no national standard. Medical enquiries relevant to fitness to drive were being made by 41 (79%) of local authorities, but in 38 (73%) this was limited to a single question about health. No enquiry regarding health status was being made by 11 (21%) District Councils (all serving < 100,000 population size). Only three Scottish District Councils conducted a routine medical examination of all applicants. Thirteen of the 15 large (> 100,000 population size), and 20 of the 21 medium-sized (50,000-100,000) Scottish District Councils carried out medical examinations either when a relevant medical disorder was declared by the applicant, or when the applicant was above a defined age (which varied between local authorities). The small local authorities (population < 50,000) examined only those applicants who declared medical disorders. This survey has shown considerable variation and limitations in the approach of the previously existing Scottish District Councils to the assessment of medical fitness to drive of applicants for taxi licences. It is suggested that national standards and guidelines are required for medical fitness to drive in relation to taxi licensing.

Automobile Driving↗
PubMed1997

Planning the 2001 census: only four years to go.

The first key stage in the build-up to the 2001 Census was reached with the 1997 Census Test on 15 June. As 2001 approaches, Population Trends will carry articles describing the detailed work and analyses that underpin preparations and decisions affecting the Census. In this inaugural article Graham Jones, Director of Census, ONS, explains the principles and issues which underpin the planning process, and the work in hand. A second article, from Dr David Martin, on the geographical information system planned for use in the 1997 Census Test appears later in this issue.

Bias↗
PubMed1994

Socializing culturally diverse students: a historically black university's nursing education program.

A convenience sample (N = 83) of RN and non-RN students enrolled at a historically Black university in North Carolina responded to a self-report culturally-relevant socialization questionnaire. The University has a long-standing commitment to the development and socialization of culturally diverse students. As such, the educational plan in both the lower division (general college studies) and the upper division nursing major is culturally sensitive. With the assumption that the process of socialization can be assessed during the course of professional development, the authors designed a culturally relevant socialization model. Using variables from the model, a 19-item questionnaire was administered to determine its efficacy in assessing the level of socialization engendered by the nursing program via the Likert scale. While the results were mixed, the non-RN students reported more socialization than the RNs, and all students perceived themselves as culturally diverse.

Adult↗
PubMed1990

Effect of bleomycin on hematoporphyrin derivative phototherapy of solid tumors.

Hematoporphyrin derivative phototherapy (HpD-PT) has been successfully used to localize and treat superficial squamous cell cancers. Bleomycin sulfate is a glycopeptide antibiotic that has antineoplastic properties against squamous cell cancers. Because both HpD-PT and bleomycin chemotherapy are accepted forms of treatment for squamous cell cancer and their cytotoxicity is mediated by singlet oxygen and oxygen radicals, we studied the possibility of enhancing the response of solid tumors to HpD-PT by combining this modality with systemic bleomycin chemotherapy in a murine tumor model. Bleomycin did not enhance HpD-PT significantly. Also, we are not confident that HpD-PT alone or in combination with other agents can eradicate solid tumors; it certainly did not in this syngeneic murine tumor model.

Animals↗
PubMed1986

Juvenile angiofibromas. Behavior and treatment of extensive and residual tumors.

In a 15-year period, 40 juvenile angiofibromas were treated surgically (lateral or extended rhinotomy) at the Mayo Clinic, Rochester, Minn. Tumors were staged according to size and extension by using the Sessions classification. Stage III tumors involved the middle fossa or cavernous sinus or both structures, with or without extension into the orbit. Seven patients had stage I, ten had stage IIA, and six had stage IIB disease. Five tumors extended to the skull base (stage IIC). There were 12 cases that included intracranial extension (stage III), none of which involved the sella. There were eight cases with residual tumor: four (stages IIB [one], IIC [one], and III [two]) were not treated again, and four (stage III) were treated with various methods, including operation, embolization, and irradiation. No patient died. No complications or morbidity was experienced by the four patients who were not treated for residual tumor.

Follow-Up Studies↗
PubMed1986

Angiofibroma: treatment trends in 150 patients during 40 years.

A series of 150 patients with histologically confirmed angiofibroma examined from 1945 through 1983 was studied to contrast treatment methods and surgical approaches. From 1945 to 1955, treatment consisted primarily of radiation. From 1955 through 1971, the primary method of treatment was surgical removal; the lateral rhinotomy approach was used to expose the tumor and its extensions in most cases. From 1971 through 1983, all tumors were removed surgically. Trends in diagnosis, treatment, and adjunctive therapy at a single institution were evaluated. Specifically, the trends considered were operative approaches, blood replacement with and without hypotensive anesthesia, adjunctive measures such as hormonal therapy or tumor embolization, mortality, and morbidity. Lateral rhinotomy provides wide exposure of and access to the nose, nasopharynx, paranasal sinuses, elements of the skull base, temporal fossa, and infratemporal fossa. Surgical treatment, specifically the lateral rhinotomy approach and its extensions, is recommended as the best method of managing angiofibroma in most patients.

Adolescent↗
PubMed1984

The effect of cooling on the photodynamic action of hematoporphyrin derivative during interstitial phototherapy of solid tumors. 1983 Second-Place Resident Research Award: basic category.

Hematoporphyrin derivative (HpD), a mixture of compounds chemically prepared from naturally occurring crude hematoporphyrin, is preferentially concentrated in neoplastic cells and produces red fluorescence when irradiated with blue-violet light. In addition, HpD exhibits other photodynamic properties, which, in the presence of oxygen and visible light, result in cytotoxicity. Preliminary reports indicate that early, superficial carcinomas of the upper aerodigestive tract and tracheobronchial tree can be localized and treated successfully with HpD phototherapy (HpD-PT), in which a fiberoptic bundle transmits laser light to the tumors. To assess this modality's potential for treating solid tumors, the cytotoxic effect of HpD-PT was measured in a murine tumor model. We specifically assessed the effect of cooling on the pure photodynamic action of HpD-PT. Adult female mice with typical mammary tumors received interstitial phototherapy 24 hours after HpD was given intraperitoneally. Light from an argon-dye laser was delivered through an optical fiber, along with simultaneous cooling from a cryosurgical probe, for 15 minutes. After being cooled with a cryosurgical probe, tumors were excised 48 hours after treatment and the necrotic area was measured. The results indicate that cooling enhances the tumoricidal action of HpD-PT.

Adenocarcinoma↗