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Biomedical subjects

K Jones

Publications and source records attributed to K Jones.

At least 91 records · Page 5Linked to original sources
PubMed2001

Identification of a possible biomarker for colophony exposure.

Colophony is known to cause occupational asthma and dermatitis. Biological monitoring may be useful in assessing exposure. This paper describes a method for the analysis of dehydroabietic acid in urine and its potential use as a marker of colophony exposure. The method involves hydrolysis, solvent extraction, derivatization and analysis by gas chromatography-mass spectrometry. Twenty-eight workers from a soldering factory in South Africa were monitored. Results showed that levels of dehydroabietic acid in urine may be correlated with a subjective assessment of exposure.

Abietanes↗
PubMed2001

Effect of rodent diets on the sexual development of the rat.

Five rodent diets have been evaluated for their possible effect on the sexual development of the rat. Groups of 12 pregnant Alpk rats were fed one of the following combinations of diets during pregnancy and postnatally: RM3/RM1, AIN-76A/AIN-76A, RM3/AIN-76A, Teklad Global 2016 (Global)/Global and Purina 5001/Purina 5001. AIN-76A is phytoestrogen-free while the other diets contained varying amounts of phytoestrogens. The phytoestrogens genistein and daidzein were determined in the diets studied, and the concentrations found agreed with earlier estimates. RM3/RM1 was selected as the control group, as this has been used routinely in this laboratory for the past decade. Determinations were made in offspring of the times of vaginal opening and first estrus among the females, and of prepuce separation and testes descent among the males. At postnatal day (PND) 26 the females from 6 of the 12 litters were terminated and tissue weights measured. Males from 6 of the 12 litters were similarly studied at PND 68. Animals from the remaining litters were transferred to RM1 diet at PND 70. Termination of the study was at PND 128 (males) and PND 140 (females) when body weights and tissue weights were determined. Marked differences in body weight, sexual development, and reproductive tissue weights were observed for rats maintained on AIN-76A or Purina 5001, with only minimal effects among rats maintained on the Global diet. These comparisons were against RM3/RM1 as the reference diet. However, using Purina 5001 as the reference diet reversed the direction of the differences seen when using RM3/RM1 as the reference diet. The differences observed when using RM3/RM1 as reference diet occurred mainly postnatally. In addition, the fact that similar differences were seen for the phytoestrogen-free diet, AIN-76A, and the phytoestrogen-rich diet, Purina 5001, indicate that these effects are more likely to be caused by nutritional differences between the diets that then have centrally mediated effects on rodent sexual development, rather than individual dietary components affecting peripheral estrogen receptors (ER). This proposal is supported by abolition of the uterotrophic activity of AIN-76A and Purina 5001 (relative to RM3/RM1) in the immature rat by coadministration of the gonadotrophin-releasing hormone (GnRH) antagonist ANTARELIX: The present data indicate that choice of diet may influence the timing of sexual development in the rat, and consequently, that when evaluating the potential endocrine toxicity of chemicals, the components of rodent diets used should be known, and as far as is possible, controlled.

Age Factors↗
PubMed2001

Endometrial laser intrauterine thermotherapy for the treatment of dysfunctional uterine bleeding: the first British experience.

Forty patients due to undergo endometrial ablation as a treatment for dysfunctional uterine bleeding were recruited to assess the efficacy and safety of endometrial laser intrauterine thermo-therapy using the gynelase. At 12 months the average menstrual score reduction was 88%, the amenorrhoea rate was 70%, and the hypomenorrhoea rate 16%. Four women (10%) have had a hysterectomy for persistent menorrhagia, and one (3%) for pelvic pain. One patient (3%) has had a further endometrial laser ablation. There were no major complications. and 34 patients (85%) were most satisfied with the treatment. The system is easy to use and has a short learning curve.

Adult↗
PubMed2001

An economic evaluation of community water fluoridation.

OBJECTIVE: The purpose of this research was to assess the local cost savings resulting from community water fluoridation, given current exposure levels to other fluoride sources. METHODS: Adopting a societal perspective and using a discount rate of 4 percent, we compared the annual per person cost of fluoridation with the cost of averted disease and productivity losses. The latter was the product of annual dental caries increment in nonfluoridated communities, fluoridation effectiveness, and the discounted lifetime cost of treating a carious tooth surface. We obtained or imputed all parameters from published studies and national surveys. We conducted one-way and three-way sensitivity analyses. RESULTS: With base-case assumptions, the annual per person cost savings resulting from fluoridation ranged from $15.95 in very small communities to $18.62 in large communities. Fluoridation was still cost saving for communities of any size if we allowed increment, effectiveness, or the discount rate to take on their worst-case values, individually. For simultaneous variation of variables, fluoridation was cost saving for all but very small communities. There, fluoridation was cost saving if the reduction in carious surfaces attributable to one year of fluoridation was at least 0.046. CONCLUSION: On the basis of the most current data available on the effectiveness and cost of fluoridation, caries increment, and the cost and longevity of dental restorations, we find that water fluoridation offers significant cost savings.

Adolescent↗
PubMed2001

Use of pulsed-field gel electrophoresis and flagellin gene typing in identifying clonal groups of Campylobacter jejuni and Campylobacter coli in farm and clinical environments.

Although campylobacters have been isolated from a wide range of animal hosts, the association between campylobacters isolated from humans and animals in the farm environment is unclear. We used flagellin gene typing and pulsed-field gel electrophoresis (PFGE) to investigate the genetic diversity among isolates from animals (cattle, sheep, and turkey) in farm environments and sporadic cases of campylobacteriosis in the same geographical area. Forty-eight combined fla types were seen among the 315 Campylobacter isolates studied. Six were found in isolates from all four hosts and represented 50% of the total number of isolates. Seventy-one different SmaI PFGE macrorestriction profiles (mrps) were observed, with 86% of isolates assigned to one of 29 different mrps. Fifty-seven isolates from diverse hosts, times, and sources had an identical SmaI mrp and combined fla type. Conversely, a number of genotypes were unique to a particular host. We provide molecular evidence which suggests a link between campylobacters in the farm environment with those causing disease in the community.

Animals↗
PubMed2001

Children and road safety: increasing knowledge does not improve behaviour.

BACKGROUND: Programmes designed to teach children about road safety have often failed to assess their effectiveness in terms of either an increase in children's knowledge or an improvement in children's behaviour. AIM: The two studies reported here sought to address both issues, by focusing on the abilities of Primary 1 children (5 years old). SAMPLE: A total of 120 Primary 1 children within the age range 4-5 years old participated in this study, drawn from three different primary schools within an educational district of Scotland. METHODS: In the first study the effects of three different road safety interventions were tested, all of which employed commercially marketed products: 1) a three-dimensional model of the traffic environment; 2) a road safety board game; and 3) illustrated posters and flip-chart materials. In the second study the transfer of knowledge to children's behaviour in a real-life traffic environment was tested, using a subsample of 47 children who had taken part in the first study. RESULTS: Results from the first study showed, surprisingly, that all three interventions were effective in increasing children's knowledge about safe and dangerous locations at which to cross the street, and that this knowledge was retained for a period of six months. Study 2, however, showed that increased knowledge did not result in improved traffic behaviour. Children who had received training performed no better than children in a control group. CONCLUSION: These findings highlight the need to distinguish between children's road safety knowledge and their behaviour, particularly for teachers and parents, who may mistakenly believe that children who know more will be safer on the road.

Accident Prevention↗
PubMed2001

The effects of varying resistance-training loads on intermediate- and high-velocity-specific adaptations.

The purpose of this study was to compare changes in velocity-specific adaptations in moderately resistance-trained athletes who trained with either low or high resistances. The study used tests of sport-specific skills across an intermediate- to high-velocity spectrum. Thirty NCAA Division I baseball players were randomly assigned to either a low-resistance (40-60% 1 repetition maximum [1RM]) training group or a high-resistance (70-90% 1RM) training group. Both of the training groups intended to maximallv accelerate each repetition during the concentric phase (IMCA). The 10 weeks of training consisted of 4 training sessions a week using basic core exercises. Peak force, velocity, and power were evaluated during set angle and depth jumps as well as weighted jumps using 30 and 50% 1RM. Squat 1RMs were also tested. Although no interactions for any of the jump tests were found, trends supported the hypothesis of velocity-specific training. Percentage gains suggest that the combined use of heavier training loads (70-90% 1RM) and IMCA tend to increase peak force in the lower-body leg and hip extensors. Trends also show that the combined use of lighter training loads (40-60% 1RM) and IMCA tend to increase peak power and peak velocity in the lower-body leg and hip extensors. The high-resistance group improved squats more than the low-resistance group (p < 0.05; +22.7 vs. + 16.1 kg). The results of this study support the use of a combination of heavier training loads and IMCA to increase 1RM strength in the lower bodies of resistance-trained athletes.

Adult↗
PubMed2000

Interaction of the U3-55k protein with U3 snoRNA is mediated by the box B/C motif of U3 and the WD repeats of U3-55k.

U3 small nucleolar RNA (snoRNA) is a member of the Box C/D family of snoRNAs which functions in ribosomal RNA processing. U3-55k is a protein that has been found to interact with U3 but not other members of the Box C/D snoRNA family. We have found that interaction of the U3-55k protein with U3 RNA in vivo is mediated by the conserved Box B/C motif which is unique to U3 snoRNA. Mutation of Box B and Box C, but not of other conserved sequence elements, disrupted interaction of U3-55k with U3 RNA. Furthermore, a fragment of U3 containing only these two conserved elements was bound by U3-55k in vivo. RNA binding assays performed in vitro indicate that Box C may be the primary determinant of the interaction. We have cloned the cDNA encoding the Xenopus laevis U3-55k protein and find strong homology to the human sequence, including six WD repeats. Deletion of WD repeats or sequences near the C-terminus of U3-55k resulted in loss of association with U3 RNA and also loss of localization of U3-55k to the nucleolus, suggesting that protein-protein interactions contribute to the localization and RNA binding of U3-55k in vivo.

Amino Acid Motifs↗
PubMed2000

Impact of synthetic pyrethroid-sheep dip on the indigenous microflora of animal slurries.

The chemical constituents of sheep dip in the UK are currently changing from organophosphate-based to synthetic pyrethroid-based insecticides. As a result, changes are also being made to the methods of disposal of these chemicals in the environment, such that pyrethroid sheep dips must now be diluted in animal slurry or water. To date, there is a lack of quantitative information on the impact of the insecticide on the indigenous microflora of animal slurries. This paper investigated the impact of Bayticol (synthetic pyrethroid sheep dip) over a range of concentrations on selected populations of bacteria within animal slurry. It was found that, with increasing pesticide concentration, there was up to a four orders of magnitude increase in the numbers of faecal coliforms and pathogens, such as putative Salmonella spp. These findings have implications for the disposal of sheep dip-amended animal slurries to land from several aspects: (i) the longevity of putative pathogens in the field may require re-evaluation of the time required before the return of grazing livestock to a slurry-amended field; (ii) the potential for the transfer of pathogenic bacteria and faecal coliforms into human and animal foodchains, and (iii) the increased potential for faecal coliforms being washed into streams, rivers and coastal bathing waters.

Animals↗
PubMed2000

A new route to spirooxindoles.

[reaction: see text]Reaction of indole amides 5 with tributylstannane gave spiroindolenines 9 which are readily converted into spiropyrrolidinyloxindoles. This tricyclic system is found in a number of interesting natural products.

Cyclization↗
PubMed2000

Formation of a full complement of cranial proprioceptors requires multiple neurotrophins.

Inactivation of neurotrophin-3 (NT3) completely blocks the development of limb proprioceptive neurons and their end organs, the muscle spindles. We examined whether cranial proprioceptive neurons of the trigeminal mesencephalic nucleus (TMN) require NT3, brain-derived neurotrophic factor (BDNF) or neurotrophin-4 (NT4) for their development. Complements of TMN neurons and masticatory muscle spindles were decreased by 62% in NT3 null mutants, 33% in BDNF null mutants, and 10% in NT4 null mutant mice at birth. The extent of proprioceptive deficiencies differed among different masticatory muscles, particularly in NT3 null mice. Masticatory muscles of embryonic mice heterozygous for the NT3(lacZneo) or BDNF(lacZ) reporter genes expressed both NT3 and BDNF, consistent with target-derived neurotrophin support of TMN neurons. Although more than 90% of TMN neurons expressed TrkB as well as TrkC receptor proteins by immunocytochemistry in wild-type newborns, TrkC or TrkB null mice exhibited only partial proprioceptive deficiencies similar to those present in NT3 or BDNF;NT4 null mice. Thus, in terms of the survival outcome, two main subpopulations of TMN neurons may exist during embryogenesis, one dependent on TrkC/NT3 functioning and the other utilizing TrkB/BDNF signaling. The differential dependence of TMN neurons on neurotrophins may reflect differential accessibility of the neurons to limiting amounts of NT3, BDNF, or NT4 in target tissues, especially if the tissue distribution or levels of BDNF, NT3, and NT4 were dynamically regulated both spatially and temporally.

Animals↗
PubMed2000

Expression of nitric oxide synthase isoforms and arginase in normal human skin and chronic venous leg ulcers.

Chronic venous ulcers, an example of abnormal wound healing, show chronic inflammation with defective matrix deposition which together with the underlying vascular pathology, result in delayed healing. L-arginine is known to be metabolized by one of two pathways: nitric oxide synthase (NOS), producing nitric oxide (NO), or arginase, producing ornithine. NO is involved in many pathological conditions including vascular and inflammatory disorders. This study therefore investigated the distribution, level and activity of NOS and arginase in chronic venous ulcers in comparison with normal skin, using immunocytochemistry, western blotting, and enzyme assays. The results demonstrated an increased distribution of both NOS and arginase in chronic venous ulcer tissue compared with normal skin, with inflammatory cells and vascular endothelial cells as the main sources. These data were confirmed by western blot analysis, which showed increased levels of both enzymes in chronic venous ulcers. Moreover, there was significantly increased activity of both total NOS (p<0.04) and inducible NOS (p<0.05) in chronic venous ulcer tissue compared with normal skin, and significantly increased activity of arginase (p<0.01) in chronic venous ulcer tissue in comparison with normal skin. NO is known to combine with hydroxyl free radicals forming peroxynitrite, a potent free radical which causes tissue destruction. NO overexpression in chronic venous ulcers may be involved directly or indirectly (through production of peroxynitrite) in the pathogenesis and delayed healing of chronic venous ulcers, through its effects on vasculature, inflammation, and collagen deposition. Arginase is known to enhance matrix deposition. Thus, increased levels of arginase in chronic venous ulcers could contribute to the pathogenesis of lipodermatosclerosis associated with chronic venous insufficiency, predisposing to the formation of chronic venous ulcers and also to matrix cuff formation around blood vessels.

Arginase↗
PubMed2000

Feather vs. non-feather bedding for asthma.

BACKGROUND: Two recent epidemiological studies have reported that children using non-feather pillows suffered from more frequent episodes of wheeze than those using feather pillows OBJECTIVES: To evaluate the efficacy of using feather bedding in the control of asthma symptoms. SEARCH STRATEGY: The Cochrane Airways Group asthma clinical trials register, derived from MEDLINE, EMBASE and hand searching of major journals, was searched using the terms: feather OR bed* OR linen* OR pillow SELECTION CRITERIA: Only randomised or controlled clinical trials were to be included. DATA COLLECTION AND ANALYSIS: No trials met the inclusion criteria for the review. MAIN RESULTS: 126 abstracts were identified. Ten of these were identified as possibly meeting the entry criteria, but on review of the full paper not were suitable. The reasons for exclusion were: not a randomised trial (n=6); allocation of bedding type combined with another intervention (n=4). REVIEWER'S CONCLUSIONS: Whilst recent epidemiological studies suggest that feather bedding is associated with less frequent wheeze than man-made fibre fillings, the evidence currently available is insufficient to assess the clinical benefits of feather bedding in the management of asthma.

Asthma↗
PubMed2000

Mental health needs and services for severely troubled and troubling young people including young offenders in an N.H.S. region.

Penal, social services, special education and health agencies in one National Health Service Region were screened for severely troubled and troublesome young people in need of mental health services. One hundred and sixteen detailed assessments were undertaken on young people: 57 in "penal" and 59 in "welfare" establishments. Little difference was found between those in these two types of setting except that the "penal group" were much more likely to have high levels of violent behaviour and to have had more changes of placement. The needs for mental health care greatly outstripped supply. As part of this overall neglect, 11 of 15 young people with serious mental illnesses and all 13 who had suffered sexual abuse in the sample were not receiving appropriate treatment. A tentative estimate of the size of the problem in the region yielded a rate of around 11.4 per million with very severe disorder but this is probably an under estimate. The effectiveness of treatment for the problems of these young people is discussed and a possible structure for a service is explored.

Adolescent↗