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Biomedical subjects

C Hayes

Publications and source records attributed to C Hayes.

At least 37 records · Page 2Linked to original sources
PubMed2001

PCA ketamine and morphine after abdominal hysterectomy.

Following a standardized general anaesthetic for total abdominal hysterectomy, patients received either patient controlled analgesia (PCA) with morphine 1 mg/ml (group M, n = 33) or morphine 1 mg/ml plus ketamine 2 mg/ml (group K, n = 37) for 48 hours in a randomized, double-blind fashion. In 43 women the area of allodynia around the scar was mapped as a measure of the degree of central sensitization. A significant reduction in the area of allodynia was found in those receiving ketamine with morphine (42 cm2 [interquartile range (IQR) 57] compared with 57 cm2 [IQR 82] z = -2.0, P = 0.04) in those receiving morphine alone. There were no significant differences between the two groups with respect to age, or weight, or between the subgroups within which the area of allodynia was measured with respect to length of incision. No significant differences were found between the groups with respect to pain scores, total or hourly drug consumption, patient satisfaction, nausea scores or antiemetic use. Patients in group K were more likely to require PCA for a shorter period than those in group M (median 40 hours, IQR 26 versus 48 hours IQR 7). Ten patients in group K were withdrawn because of side-effects (dysphoria n = 4, nausea n = 2, pruritus n = 4) compared with one in group M (nausea n = 1) (P = 0.006). The potential usefulness of ketamine after hysterectomy was offset by a high incidence of adverse effects and a lack of opioid-sparing effects, such that combined intravenous ketamine and morphine PCA as used in this study cannot be recommended for routine care.

Adult↗
PubMed2001

Food refusal and dysphagia in older people with dementia: ethical and practical issues.

Food refusal poses difficulties for nurses and care staff and can place older patients with dementia at risk of undernutrition. The dangers of and reasons for food refusal in these patients are explored and the fundamental ethical and legal issues raised in caring for these patients are examined. Practical guidance and solutions are offered through dietetics and speech and language therapy with the aim of helping nurses and care staff, as well as professional carers in palliative care, and explore ways of critically examining and coping with these dilemmas.

Aged↗
PubMed2001

Hypodontia in hemifacial microsomia.

OBJECTIVE: The purpose of this study was twofold: (1) to describe the patterns of missing teeth in patients with hemifacial microsomia (HFM) and (2) to compare the prevalence of missing teeth in subjects with HFM with a group of unaffected subjects. STUDY DESIGN: A descriptive study was conducted comparing HFM subjects with a group of patients selected from an orthodontic clinic. METHODS: The prevalence of missing teeth was assessed by evaluation of panoramic radiographs. At the time of the study, records of 125 patients with HFM were available from the Craniofacial Center at Boston's Children's Hospital. Seventy-six met inclusion criteria for radiographic analysis of hypodontia. Fifty-two patients met inclusion criteria into the comparison study in which the prevalence of hypodontia was compared with a group of patients from the Department of Orthodontics at Harvard School of Dental Medicine. A Fisher's exact test was conducted to test the hypothesis that HFM patients have a greater prevalence of missing teeth than individuals without the anomaly. A chi-square test for trend was conducted to determine whether hypodontia was more prevalent with increasing severity of the mandibular deformity in HFM. RESULTS: Hypodontia was more common among HFM patients (26.9%) versus the comparison group in which no missing teeth were recorded (p < .0001). Additionally, the degree of hypodontia was correlated with the grade of mandibular hypoplasia (p = .024). CONCLUSION: Hypodontia was found to be more prevalent in patients with HFM than in comparison subjects, possibly indicating an etiologic link between the two conditions.

Adolescent↗
PubMed2001

The effect of non-cariogenic sweeteners on the prevention of dental caries: a review of the evidence.

The role of sugar substitutes such as xylitol and sorbitol in the prevention of dental caries has been investigated in several clinical studies. The purpose of this report is to review the current published evidence regarding the relationship between sugar substitutes and dental caries. A literature search was conducted using MEDLINE and EMBASE and included studies published from 1966 to 2001. Studies that included human subjects and were published in English were included in this review. A total of fourteen clinical studies were reviewed that evaluated the effect of sorbitol or xylitol or the combination of both sugar substitutes on the incidence of dental caries. Most of the reports were of studies conducted with children outside of the United States. These studies demonstrated a consistent decrease in dental caries, ranging from 30 to 60 percent, among subjects using sugar substitutes as compared to subjects in a control group. These caries rate reductions were observed in subjects using xylitol or sorbitol as the sugar substitute in chewing gum or toothpaste. The highest caries reductions were observed in subjects using xylitol. These findings suggest that the replacement of sucrose with sorbitol and xylitol may significantly decrease the incidence of dental caries.

Chewing Gum↗
PubMed2000

Effectiveness of dentist-prescribed, home-applied tooth whitening. A meta analysis.

INTRODUCTION: Common clinical experience suggests that tooth whitening agents are 100% effective. This study uses meta-analysis of data from published randomized controlled clinical trials to determine the efficacy of tooth whitening agents. METHODS: A MEDLINE search strategy was developed and implemented to systematically identify clinical trials on dentist-prescribed, home-applied tooth whitening agents, using 10% carbamide peroxide, published between 1989-1999. Inclusion criteria (e.g., in English, human clinical trials) and exclusion criteria (e.g., not placebo controlled) were established and clinical trials that met these criteria were critically appraised for validity and clinical applicability. Meta-analysis was then used to quantitatively integrate the findings. RESULTS: Seven studies were identified that met the inclusion and validity criteria. These studies indicated that: Whitening results in a significant mean change of 6 4 shade guide units (p < 0.01), while the placebo control group exhibited little change (0.7 0.6, p > 0.05). 93% of the bleached patients exhibited 2 shade guide unit change, while 20% of the placebo control group exhibited this change. The brand of bleaching agent had a significant effect on tooth whitening, but the daily application time and duration of treatment did not. Whitening is maintained for 6 months for 1/2 of the people treated. Neither gingival indices nor plaque indices were adversely or favorably affected by bleaching. CLINICAL APPLICABILITY: The data from the reviewed studies indicate that rather than being 100% effective, on average: 73% (93% for bleached group minus 20% placebo group) of people who whiten their teeth will exhibit a whitening that is 2 shade guide units greater than the placebo. 20% of the people who use dentist-prescribed, home-applied bleaching will achieve a mean whitening effect of 5 shade guide units. Re-treatment for 50% of people may be necessary to maintain this effect longer than 6 months. The methods used here are Internet applicable for other clinical topics.

Adult↗
PubMed2000

Genetic analysis of vitamin D related genes in Canadian multiple sclerosis patients. Canadian Collaborative Study Group.

The objective of this study was to investigate genes involved in the metabolism and function of vitamin D as candidate genes for genetic susceptibility to MS. Restriction fragment length polymorphisms and highly polymorphic microsatellite markers within or very close to the 1,25(OH)2D3 receptor (VDR) [12q14], the vitamin D binding protein (DBP) [4q12], and the 25(OH)D2 1alpha-hydroxylase [12q13] loci were analyzed for linkage or association with MS. We found no evidence for linkage or association of these candidate genes with MS in the Canadian population.

Alleles↗
PubMed2000

Magnetic resonance imaging screening in women at genetic risk of breast cancer: imaging and analysis protocol for the UK multicentre study. UK MRI Breast Screening Study Advisory Group.

The imaging and analysis protocol of the UK multicentre study of magnetic resonance imaging (MRI) as a method of screening for breast cancer in women at genetic risk is described. The study will compare the sensitivity and specificity of contrast-enhanced MRI with two-view x-ray mammography. Approximately 500 women below the age of 50 at high genetic risk of breast cancer will be recruited per year for three years, with annual MRI and x-ray mammography continuing for up to 5 years. A symptomatic cohort will be measured in the first year to ensure consistent reporting between centres. The MRI examination comprises a high-sensitivity three-dimensional contrast-enhanced assessment, followed by a high-specificity contrast-enhanced study in equivocal cases. Multiparametric analysis will encompass morphological assessment, the kinetics of contrast agent uptake and determination of quantitative pharmacokinetic parameters. Retrospective analysis will identify the most specific indicators of malignancy. Sensitivity and specificity, together with diagnostic performance, diagnostic impact and therapeutic impact will be assessed with reference to pathology, follow-up and changes in diagnostic certainty and therapeutic decisions. Mammography, lesion localisation, pathology and cytology will be performed in accordance with the UK NHS Breast Screening Programme quality assurance standards. Similar standards of quality assurance will be applied for MR measurements and evaluation.

Adult↗
PubMed2000

Expression of murine adenosine deaminase (ADA) in transgenic maize.

A murine adenosine deaminase (ADA) gene, driven by the maize ubi-1 promoter and intron region, was transformed into embryogenic maize callus, along with a bar and gusA gene-containing plasmid, using microparticle bombardment. Selection in the presence of either the herbicide Basta or the adenosine analogue 2'-deoxyadenosine resulted in transgenic cultures that expressed GUS and accumulated a 41-kD protein that immunoprecipated with an ADA-specific polyclonal antibody. ADA enzyme activity was observed in extracts from transgenic callus as well as regenerated plants and progeny. Culltures expressing ADA grew in the presence of 200 mg/l 2'-deoxyadenosine, a concentration which completely inhibited the growth of non-transgenic cultures. ADA activity appeared to segregate in progency of regenerated plants as a single, dominant Mendelian trait. These results suggest that ADA, in combination with adenosine analogue selection, represents a potentially viable selectable marker system for transgenic maize production.

Adenosine↗
PubMed2000

Optimized MR imaging for polyacrylamide gel dosimetry.

Polyacrylamide gels are a powerful tool to measure radiation dose by quantifying the NMR T2 relaxation times of the irradiated gel. The exploitation of these radiation sensitive gels in clinical radiotherapy requires accurate mapping of T2 values. This paper describes the optimization strategy used to identify accurate and practical methods of measuring the range of T2 values typical of gel dosimeters (140-700 ms). The MR imaging techniques used to measure T2 values and the choice of image acquisition parameters are described. Four sequences are compared and the results are analysed in terms of accuracy, signal-to-noise ratio and acquisition time. A multiple spin echo sequence was found to yield the most accurate results (98.9%). Single spin echo sequences, such as Hahn spin echo and EPI spin echo, were found to measure gel T2 values with an accuracy of 90.1%. This paper reports the importance of careful selection and optimization of the MR imaging sequences for accurate and reliable polyacrylamide gel dosimetry.

Echo-Planar Imaging↗
PubMed2000

Localization of breast lesions shown only on MRI--a review for the UK Study of MRI Screening for Breast Cancer. Advisory Group of MARIBS.

The UK study of screening for breast cancer compares mammography and dynamic contrast enhanced MRI of the breast in women at high genetic risk of developing cancer. Owing to the high sensitivity of MR in the breast, it is anticipated that some lesions will be visible only on MR. A key issue for the study is how to localize these lesions for histological verification and removal. This article reviews available methods and describes the current UK expertise and recent European developments. The use of MR compatible wires and markers has been explored in a phantom. The use of these markers in vivo is demonstrated in a case imaged by MR and mammography and further discussed. The susceptibility artefacts produced on MRI, and technical properties associated with these needles, wires and markers are discussed. The clinical pathway by which these lesions will be worked up for the study, and the quality control procedures for keeping the number of such biopsies to a minimum, are described. There is an urgent need for further centres in the UK to become proficient at removing lesions found only on MRI in support of this study and other breast MRI applications. The management of these lesions must be resolved in order to realize the full potential of MRI for screening for breast cancer in women at genetic risk, and for other diagnostic applications.

Algorithms↗
PubMed2000

Width of keratinized tissue after gingivoplasty of healed subepithelial connective tissue grafts.

BACKGROUND: The subepithelial connective tissue graft has markedly broadened clinicians' abilities to treat gingival recession. Frequently, however, bulky soft tissue contours are sequelae of this procedure, and post-healing gingivoplasty is often performed to improve esthetics of the grafted site. As a secondary benefit, it is believed that the zone of keratinized tissue is additionally increased after gingivoplasty. METHODS: To further investigate this clinical impression, 16 bilateral pairs of sites with recession in 6 consecutive patients (mean age = 38 +/- 9 years) were studied. At the time of initial grafting, one site in each pair was randomly assigned to receive either gingivoplasty 2 months later (GP+) or no further treatment (GP-). Clinical measurement of recession and keratinized tissue width was standardized using customized acrylic stents and Schiller iodine solution, which stains epithelia; values were recorded at baseline (day of graft) and at 2, 3, and 5 months after grafting. Mean clinical gingival widths over time between GP+ and GP- sites, as well as within GP+ sites, were analyzed by t test. RESULTS: At 5 months, both the GP+ and GP- sites demonstrated a mean root coverage of 87.4% and increased keratinized tissue width (1.2 mm) when compared to their respective baseline measures. No differences in recession depth and width of keratinized tissue were seen at 5 months between the GP+ and GP- groups. In addition, no differences in recession or gingival width were found between 2- and 5-month observations for either the GP+ or GP- groups. CONCLUSIONS: These data suggest that the observed clinical improvements are the outcome of the initial graft surgery and that the gingivoplasty procedure does not result in additional (or "rebound") increases in keratinized tissue width.

Adult↗
PubMed2000

The epidemiology of pathogenic mitochondrial DNA mutations.

During the past decade, there have been many descriptions of patients with neurological disorders due to mitochondrial DNA (mtDNA) mutations, but the extent and spectrum of mtDNA disease in the general population have not yet been defined. Adults with suspected mtDNA disease in the North East of England were referred to a single neurology center for investigation over the 10-year period from 1990 to 1999 inclusive. We defined the genetic defect in these individuals. For the midyear period of 1997, we calculated the minimum point prevalence of mtDNA disease in the adults of working age (> 16-<60 years old for female subjects and <65 years old for male subjects) and the minimum prevalence of adults and children (<60 years for female subjects, <65 years for male subjects) at risk of developing mtDNA disease. mtDNA defects caused disease in 6.57 per 100,000 individuals in the adult population of working age, and 7.59 per 100,000 unaffected adults and children were at risk of developing mtDNA disease. Overall, 12.48 per 100,000 individuals in the adult and child population either had mtDNA disease or were at risk of developing mtDNA disease. These results reflect the minimum prevalence of mtDNA disease and pathogenic mtDNA mutations and demonstrate that pathogenic mtDNA mutations are a common cause of chronic morbidity. These findings have resource implications, particularly for supportive care and genetic counseling.

Adolescent↗
PubMed1999

Multivitamin supplementation and risk of birth defects.

It is widely accepted that supplementation with folic acid, a B vitamin, reduces the risk of neural tube defects (NTDs). This case-control study tested the hypothesis that multivitamins reduce risks of selected birth defects other than NTDs. Infants with and without birth defects and aborted fetuses with birth defects were ascertained in the greater metropolitan areas of Boston, Philadelphia, and Toronto during 1993-1996. Mothers were interviewed within 6 months after delivery about a variety of factors, including details on vitamin use. Eight case groups were included: cleft lip with or without cleft palate, cleft palate only, conotruncal defects, ventricular septal defects, urinary tract defects, limb reduction defects, congenital hydrocephaly, and pyloric stenosis (n's ranged from 31 to 186). Controls were 521 infants without birth defects (nonmalformed controls) and 442 infants with defects other than those of the cases (malformed controls). Daily multivitamin supplementation was evaluated according to gestational timing categories, including periconceptional use (28 days before through 28 days after the last menstrual period). Odds ratios (ORs) below 1.0 were observed for all case groups except cardiac defects, regardless of control type. For periconceptional use, ORs with 95% confidence intervals that excluded 1.0 were estimated for limb reduction defects using both nonmalformed controls (OR = 0.3) and malformed controls (OR = 0.2) and for urinary tract defects using both nonmalformed controls (OR = 0.6) and malformed controls (OR = 0.5). Statistically significant ORs for use that began after the periconceptional period were observed for cleft palate only and urinary tract defects. These data support the hypothesis that periconceptional vitamin supplementation may extend benefits beyond a reduction in NTD risk. However, other than folic acid's protecting against NTDs, it is not clear what nutrient or combination of nutrients might affect risk of other specific defects.

Adult↗
PubMed1999

Two-dimensional proton echo-planar spectroscopic imaging of brain metabolic changes during lactate-induced panic.

BACKGROUND: A fast, proton echo-planar spectroscopic imaging (PEPSI) technique, capable of simultaneously measuring metabolites from multiple brain regions, was used to investigate the anatomical distribution and magnitude of brain lactate responses to intravenous lactate infusion among subjects with panic disorder and control subjects. METHODS: Fifteen subjects with panic disorder and 10 control subjects were studied. All subjects were medication free and met DSM-IV criteria for panic disorder, or, for controls, no Axis I psychiatric disorder. Two-dimensional axial metabolite images having 1-cm3 spatial resolution were acquired at 61/2-minute intervals during 3 conditions: a 20-minute baseline, 20-minute 0.5-mol/L sodium lactate infusion, and 15-minute postinfusion period. RESULTS: Intravenous lactate infusion increased brain lactate levels throughout the axial brain section studied in all subjects. Panic-disordered subjects had significantly greater global brain lactate increases in response to lactate infusion. Lateralization of brain lactate response did not occur, nor were discrete regional loci of elevated lactate observed. Cerebrospinal fluid lactate changes corresponded to lactate changes in brain tissue. Severity of symptoms provoked by lactate infusion did not directly correlate with brain lactate response. CONCLUSIONS: Greater overall rises in brain lactate among subjects with panic disorder compared with controls occurred in response to lactate infusion. We were unable to detect a distinct regional pattern for magnitude differences in brain lactate rise by which to identify a specific neuroanatomical substrate underlying a lactate-induced panic response. The wide anatomical distribution of these brain lactate increases suggest metabolic and/or neurovascular mechanisms for the abnormal rise in subjects with panic disorder.

Adult↗