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Biomedical subjects

C Hayes

Publications and source records attributed to C Hayes.

At least 91 records · Page 5Linked to original sources
PubMed1996

The epidemiology of Down syndrome in four counties in Ireland 1981-1990.

BACKGROUND: We conducted a descriptive epidemiological study of Down syndrome (DS) in the four Irish counties (Dublin, Kildare, Wicklow and Galway) covered by EUROCAT registries of congenital malformations for the years 1981-1990. METHODS: EUROCAT registries, which cover defined populations, use multiple sources for case ascertainment. All DS cases born between 1 January 1981 and 31 December 1990 to mothers resident in the four counties were identified. Crude birth prevalence rates and maternal age-standardized rates (SPRs) were calculated for each county and for each year in the study period. The prevalence of DS by maternal age grouped in five-year periods and the risk for each five-year group were also estimated. RESULTS: The crude birth prevalence for the four counties was 18.5/10 000 for all births and 18.3 for live births. There was a fall in the total number of DS births over the decade, but less change in the crude birth prevalence owing to an increase in the proportion of mothers aged 35+. Galway had the highest crude birth prevalence of DS (23.5/10 000) but the SPR was within average for the four counties as a whole - 110.3, 95 per cent confidence interval (CI) 86.7-139. The risk of having a DS child increased 70-fold from 1:1841 at age 15-19 to 1:26 at 45 years or older. Nearly half of all DS cases (47.4 per cent) had at least one additional anomaly. CONCLUSIONS: The parts of Ireland covered by EUROCAT have a high birth prevalence of DS births as compared with some other countries, but the maternal age-specific rates are not substantially different from those in large international studies.

Adolescent↗
PubMed1996

Intensive care unit admissions following laparoscopic surgery: what lessons can be learned?

BACKGROUND: Laparoscopic surgery has been widely embraced, often without adequate data concerning the range and incidence of complications. In the present series, our experience of complications requiring Intensive Care Unit (ICU) admission following laparoscopic surgery is described. METHODS: The records of patients requiring ICU admission at John Hunter Hospital (JHH) following laparoscopic surgery over a 39 month period were retrospectively reviewed by an independent multidisciplinary panel. RESULTS: Twenty-three ICU admissions were identified. Twenty-one followed general surgical laparoscopic procedures and two followed gynaecological laparoscopies. Ten cases were operated on initially at JHH and 13 were transferred from other hospitals. During the study period, 2444 laparoscopic surgical cases were performed at JHH; 725 general surgical procedures (1.37% admitted to ICU) and 1719 gynaecological procedures (no ICU admissions). Twelve cases suffered surgical complications (including five gastrointestinal tract perforations and three biliary tract injuries) and 11 cases were admitted for non-surgical problems. In 75% of surgical complications there was delay in diagnosis of more than 24 h. The duration of ICU stay for surgical complications (16.4 days) was significantly longer than for the non-surgical group (3.9 days). CONCLUSION: There was a greater likelihood of ICU admission following general surgical rather than gynaecological laparoscopy. Fifty-two per cent of the admissions were for surgical complications. Surgical complications are characterized by delay in diagnosis and longer ICU admission periods. Strategies to prevent some of these complications are discussed.

APACHE↗
PubMed1996

Comparison of outdoor and classroom ozone exposures for school children in Mexico City.

To evaluate methods of reducing exposure of school children in southwest Mexico City to ambient ozone, outdoor ozone levels were compared to indoor levels under three distinct classroom conditions: windows/doors open, air cleaner off; windows/doors closed, air cleaner off; windows/doors closed, air cleaner on. Repeated two-minute average measurements of ozone were made within five minutes of each other inside and outside of six different school classrooms while children were in the room. Outdoor ozone two-minute average levels varied between 64 and 361 ppb; mean outdoor levels were above 160 ppb for each of the three conditions. Adjusting for outdoor relative humidity, for a mean outdoor ozone concentration of 170 ppb, the mean predicted indoor ozone concentrations were 125.3 (+/- 5.7) ppb with windows/doors open; 35.4 (+/- 4.6) ppb with windows/doors closed, air cleaner on. The mean predicted ratios of indoor to outdoor ozone concentrations were 0.71 (+/- 0.03) with windows/doors open; 0.18 (+/- 0.02) ppb with windows/doors closed, air cleaner off; and 0.15 (+/- 0.02) ppb with windows/doors closed, air cleaner on. As outdoor ozone concentrations increased, indoor ozone concentrations increased more rapidly with windows and doors open than with windows and doors closed. Ozone exposure in Mexican schools may be significantly reduced, and can usually be kept below the World Health Organization (WHO) guideline of 80 ppb, by closing windows and doors even when ambient ozone levels reach 300 ppb or more.

Air Pollution↗
PubMed1995

Morphological and molecular response of the MOCH-1 oligodendrocyte cell line to serum and interferon-gamma: possible implications for demyelinating disorders.

The regional loss of oligodendrocytes is thought to be an important pathological event in a variety of demyelinating diseases of the central nervous system (CNS). Various components of serum, which are normally excluded from the CNS by the blood-brain barrier, have been implicated as mediators of demyelinating disorders. We have examined the effects of high concentrations of serum (10% fetal bovine serum, FBS), as well as the cytokine interferon-gamma (IFN-gamma), on an oligodendrocyte cell line, MOCH-1 cells. These cells changed from phase-bright, small round cells with multiple thin, branched processes in 1% FBS medium to flat, fibroblast-like cells with large cell bodies when cultured in 10% FBS medium or 1% FBS medium containing IFN-gamma. These morphological changes were accompanied by a large increase in expression of the astrocyte marker, glial fibrillary acidic protein (GFAP), as detected by Northern and Western blot analyses. In addition, Northern blot and fluorescence-activated cell sorting analyses revealed that IFN-gamma induced a very large increase in major histocompatibility complex (MHC) class I expression in MOCH-1 cells. MHC class II mRNA induction by IFN-gamma was also seen. In contrast, 10% FBS did not elevate either MHC class I or class II mRNA levels in MOCH-1 cells. The morphological and molecular effects of 10% FBS and IFN-gamma were reversible. We suggest that the response of MOCH-1 cells to high concentrations of serum and IFN-gamma may reflect an important in vivo response to oligodendrocytes to perturbations that occur in demyelinating disorders.

Animals↗
PubMed1995

The risk of hepatitis A from sewage contamination of a water supply.

The drinking water supply of a town became contaminated with sewage. The town's population was surveyed to determine the baseline prevalence of hepatitis A antibodies and to establish whether an associated outbreak of hepatitis A had occurred. Samples of saliva were obtained from 540 people in 200 randomly selected households, and tested for IgG and IgM antibodies to hepatitis A. Fifty-six per cent (279/495) were susceptible to hepatitis A and 43% (213/495) immune as a result of previous infection. Immunity was directly related to age; those who were immune were significantly older than those who were susceptible (mean ages: 43.5 years and 19.0 years; p < 0.0001). Six people were found to have had a recent infection with hepatitis A, but exposure to hepatitis A during the water pollution incident was possible in only one case. The results offer no evidence that this incident caused an outbreak of hepatitis A, but the study has provided useful epidemiological data on hepatitis A.

Adolescent↗
PubMed1995

Presentation of comparative audit data.

The Royal College of Surgeons of England organizes a voluntary comparative audit service for its general surgical fellows. To date, the information from the audit has been presented purely descriptively, which does not take account of statistical variability and the effects of differences in case mix between the participants. A new approach to the presentation of these data, based on statistical modelling of the effects of case mix, is presented. The approach is illustrated in an application based on data relating to 136203 admissions reported by 110 surgeons. The result of adjusting for case mix is a substantial change in the relative performance of the participating surgeons, which demonstrates the folly of attempting to compare surgical performance on the basis of a measure as crude as the unadjusted mortality rate. Further development of the statistical modelling is required, but this new statistical approach appears to enhance greatly the credibility of the audit data, by quantifying its strengths and limitations.

Age Distribution↗
PubMed1995

Illness in a community associated with an episode of water contamination with sewage.

Following an episode of water contamination with sewage in a rural Irish town, a community-wide survey of gastrointestinal-associated illness and health service utilization was conducted. Random sampling of households yielded residents who were surveyed using a self-administered questionnaire. Of 560 respondents from 167 (84%) households, equal proportions lived in areas known to have been exposed and unexposed to the contaminated water, although 65% of subjects reported using contaminated water. Sixty-one percent of subjects met the case definition. The most common symptoms among cases were abdominal cramps (80%), diarrhoea (75%), appetite loss (69%), nausea (68%) and tiredness (66%). Mean duration of illness was 7.4 days. Only 22% of cases attended their general practitioner. Drinking unboiled water from the exposed area was strongly associated with being a case. A substantial degree of community illness associated with exposure to contaminated water was observed. The episode ranks as one of the largest reported water-borne outbreaks causing gastrointestinal illness in recent times.

Disease Outbreaks↗
PubMed1995

Case mix adjustment in comparative audit.

There is increasing pressure to measure and publicize the quality of health care, with, for example, hospital 'league tables' appearing regularly in the lay press. Equally, there is increasing recognition that such simplistic presentations of data can be seriously misleading, as differences in case mix mean that they do not compare like with like. We discuss what is required of a statistical model if it si to be used to make comparisons of clinical performance which are adjusted for case mix. Outcome measures must be well defined and relevant, and the risk factors used in the model must reflect the patients' potential prognosis rather than aspects of his or her clinical care. In addition, the calibration of the statistical model is crucial. We review a number of established clinical scoring systems and demonstrate that they fail to meet all of the required criteria. Of particular concern is the fact that these scoring systems are susceptible to biases which could actually mask differences in performance. We highlight areas where further research is required, with the aim of stimulating progress in this field.

Bias↗
PubMed1995

Acute effects of ozone on the pulmonary function of exercising schoolchildren from Mexico City.

The acute effects of ozone (O3) on the change in lung function before and after exercise was assessed in 22 boys and 18 girls from 7 1/2 to 11 yr of age tested up to eight times over a 1 1/2-yr period outdoors (under a tarpaulin) at a school in Mexico City. Ozone and particulates were monitored at an adjacent government station, in the school yard, and under the tarp. Subjects were selected to oversample children with chronic respiratory symptoms, although children with active asthma under regular medication or FEV1 < 80% predicted were excluded. Of the participants, 21 had chronic cough, chronic phlegm, or ever wheeze with colds or apart from colds. Children performed two cycles of treadmill exercise (15 min) and rest (15 min) for a total of 1 h of intermittent exercise. Most subjects attained the target minute ventilation of 35 L/min/m2. Subjects exercised alternately during low ozone hours (8:00-10:00 A.M.) and during peak O3 hours (12:00-2:00 P.M.), to assure a range of exposures. On 85% of exercise days, the maximum daily 1-h average for ambient O3 exceeded the Mexican guideline of 110 parts per billion (ppb). O3 exposure during the hour of exercise was divided into quintiles, and the response was adjusted for repeated measures, subject having a cold, and prior outdoor exercise. Ambient O3 in the fifth quintile (mean = 229 ppb) was associated with a percentage change in FVC (-1.43% +/- 0.70), FEV1 (-2.85% +/- 0.79), FEF25-75% (-6.32 +/- 1.87) and FEV1 (-1.41% +/- 0.46).(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants↗
PubMed1995

An experimental evaluation of residential and nonresidential treatment for dually diagnosed homeless adults.

Homeless adults with both a serious mental illness and substance dependence (N = 276) were randomly assigned to: (1) a social model residential program providing integrated mental health and substance abuse treatment; (2) a community-based nonresidential program using the same social model approach; or (3) a control group receiving no intervention but free to access other community services. Interventions were designed to provide 3 months of intensive treatment, followed by 3 months of nonresidential maintenance. Subjects completed baseline interviews prior to randomization and reinterviews 3, 6, and 9 months later. Results showed that, while substance use, mental health, and housing outcomes improved from baseline, subjects assigned to treatment conditions differed little from control subjects. Examination of the relationship between length of treatment exposure and outcomes suggested that residential treatment had positive effects on outcomes at 3 months, but that these effects were eroded by 6 months.

Adult↗
PubMed1994

Enhanced chemiluminescence as a means of increasing the sensitivity of western blot assays for HIV antibody.

Chemiluminescence indicator systems offer several advantages for diagnostic assays and have been used successfully to increase the sensitivity of antibody and antigen assays. A technique of enhanced chemiluminescence (ECL) was applied as a replacement for routine chromogenic substrates on HIV-1 Western blots. The results indicated that the enhanced chemiluminescence detection system increased the sensitivity by greater than 10-fold over routine chromogenic indicator systems when testing diluted, reactive sera. When testing 9 seroconversion panels, the use of ECL indicated that early detection of HIV infection was elicited in six panels up to 31 days (average 11.4 days) prior to detection by routine FDA-licensed Western blots, and could be detected in all panels up to 43 days (average 18.8 days) prior to detection by in-house Western blots. In no case was the ECL Western blot system less sensitive than any of the chromogenic Western blots, and in several cases the maximum potential of the ECL system for early detection of antibody could not be determined. The ECL system was capable of detecting antibodies to envelope antigens at a 20-fold increase over chromogenic Western blots. The time of detection of seropositivity by the ECL Western blot was equal to that of most ELISAs in 5 panels and was 31 days earlier than ELISA in one panel. Permanent documentation of Western blot profiles was accomplished using a simple instamatic camera system capable of detecting the chemiluminescence signal, and blots could be re-probed using a second sample.(ABSTRACT TRUNCATED AT 250 WORDS)

Blotting, Western↗
PubMed1994

Audit of guidelines for effective control of chemotherapy and radiotherapy induced emesis.

A system was devised to establish the optimum treatment for emesis for each individual child receiving cytotoxic treatment. Cytotoxic drugs were ranked on a scale (1-5), with antiemetic regimens correspondingly graded. An age division (< or = 5 years, > 5 years) was included. Cytotoxic treatment was given with co-administration of the parallel antiemetic regimen. Failure to control emesis required administration of a stronger regimen as defined in the guidelines. A prospective clinical audit was performed to monitor the efficacy and utility of the system using diary cards to record episodes of nausea or vomiting, or both, completed by the patient or a parent and the nursing staff. The following audit criteria were set: (a) 80% control with first courses of chemotherapy; (b) 85% control with subsequent courses of similar chemotherapy; and (c) 90% lack of anticipatory nausea. Sixty children (< 18 years) received emetogenic cytotoxic drugs from February-June 1993. The criteria were satisfied in two of three categories, with 82% control for first courses of chemotherapy, 83% control for subsequent courses of chemotherapy, and 90% lack of anticipatory nausea. The guidelines were workable and acceptable overall. Minor modifications have been made subsequent to the audit to improve their efficacy further.

Adolescent↗
PubMed1994

Jugular venous desaturation and outcome after head injury.

Early experience with continuous monitoring of jugular venous oxygen saturation (SjvO2) suggested that this technology might allow early identification of global cerebral ischaemia in patients with severe head injury. The purpose of the present study was to examine the relationship between episodes of jugular venous desaturation and neurological outcome. One hundred and sixteen severely head-injured patients had continuous monitoring of SjvO2 during days 1-5 after injury. Episodes of jugular venous desaturation (SjvO2 < 50% for more than 10 minutes) were prospectively identified, and the incidence of desaturation was correlated with neurological outcome: 77 episodes of desaturation occurred in 46 of the 116 patients; 27 had one episode and 19 had multiple episodes of desaturation. The causes of these episodes were systemic (n = 36), cerebral (n = 35), or both (n = 6). Most of the episodes were less than 1 hour in duration, and it is probable that many of them would not have been detected without continuous measurement of SjvO2. Episodes of desaturation were most common on day 1 after injury, and were twice as common in patients with a reduced cerebral blood flow as in patients with a normal or elevated cerebral blood flow. The occurrence of jugular venous desaturation was strongly associated with a poor neurological outcome. The percentage of patients with a poor neurological outcome was 90% with multiple episodes of desaturation and 74% in patients with one desaturation, compared to 55% in patients with no episodes of desaturation. When adjusted for all co-variates that were found to be significant, including age, Glasgow coma score, papillary reactivity, type of injury, lowest recorded cerebral perfusion pressure, and highest recorded temperature, the incidence of desaturation remained significantly associated with a poor outcome. Although a cause and effect relationship with outcome cannot be established in this study, the data suggest that monitoring SvO2 might allow early identification and therefore treatment of many types of secondary injury to the brain.

Adolescent↗
PubMed1993

Detection of immunoglobulin A in urine specimens from children with Campylobacter-associated diarrhea by a chemiluminescent indicator-based western immunoblot assay.

A Western blot (immunoblot) assay was used to detect Campylobacter-specific immunoglobulin A in urine. Acute-phase urine samples from six children with Campylobacter diarrhea had titers ranging from 2 to 8. The highest titer was detected 4 days postonset. Campylobacter-specific immunoglobulin A was undetectable in the paired convalescent-phase specimens and urine samples from three control children.

Adolescent↗
PubMed1992

Expression of the neu oncogene under the transcriptional control of the myelin basic protein gene in transgenic mice: generation of transformed glial cells.

We have taken a transgenic approach in an effort to specifically transform oligodendrocytes, the myelinating glial cells of the central nervous system (CNS). Transgenic mice were generated with a DNA construct that contained the activated neu oncogene under the transcriptional control of the myelin basic protein (MBP) gene. The MBP/c-neu transgenic animals have experienced a low incidence of brain tumors that express molecular markers specific to oligodendrocytes, providing a mouse model to study the formation and progression of oligodendrocyte tumors. A tumor from a transgenic animal has been dispersed in culture, and transformed cells that express properties of oligodendrocytes and astrocytes have been maintained. The degree to which these cells express phenotypic characteristic of oligodendrocytes or astrocytes is influenced by culture conditions. These transformed cells should serve as a valuable resource with which to study various molecular and biochemical aspects of the myelination process, as well as the lineage interrelationship of CNS glial cells.

Animals↗
PubMed1992

Protein increases glomerular eicosanoid production and activity of related enzymes.

We examined the in vitro production of PGE2, 6-keto PGF1 alpha and TxB2 by isolated glomeruli from rats fed a low (6% casein) or a high (40% casein) protein diet for approximately eight weeks. Glomeruli from high protein-fed rats produced significantly greater amounts of PGE2, 6-keto PGF1 alpha and TxB2 under basal conditions and in response to the addition of 100 nM angiotensin II (Ang II) than glomeruli from low protein-fed rats. To elucidate the mechanisms by which greater protein intake enhanced the glomerular production of eicosanoids, we explored phospholipase (A2 and C) and cyclooxygenase activity in glomeruli isolated from low- or high-protein fed rats. PE-specific PLA2 activities were significantly increased in glomeruli from rats fed a high protein diet when compared to a low protein diet. On the other hand, PC-specific PLA2 activities were significantly decreased in glomeruli from rats fed a high protein diet. No significant difference in PIP2-PLC activities was detected between glomeruli of the two dietary groups. The cyclooxygenase content and activity was significantly greater in glomeruli from rats fed a high protein diet than in glomeruli from rats fed a low protein diet. Glomeruli of rats fed a 50/50 mixture of the diets (23% casein) had amounts and activity of cyclooxygenase and activities of PE-specific PLA2 intermediate between those of high and low protein-fed animals. In conclusion, increased synthesis of eicosanoids by glomeruli from rats fed a high protein diet may be mediated by increases in the amount and activity of cyclooxygenase coupled with enhanced activity of PE-specific PLA2.

Angiotensin II↗
PubMed1992

Quality assessment and meta-analysis of systemic tetracycline use in chronic adult periodontitis.

The use of systemic tetracycline in the treatment of periodontal disease has been controversial. To investigate this controversy, we performed a quality assessment and attempted to perform a meta-analysis of 13 published studies. We evaluated the quality of the study protocol and data analysis and presentation for each study. We were unable to combine data from the majority of studies due to heterogeneity of the outcomes evaluated and limitations in data reported in the individual studies. Therefore, only 2 studies were included in the quantitative meta-analysis. On a scale of 0-1, the mean score for this group of studies was 0.27 (+/- 0.19) for study protocol and 0.31 (+/- 0.11) for data analysis and presentation. Mean reduction in probing depth for the group treated with tetracycline plus scaling was 2.45 mm; for the group which received only scaling, 2.02 mm; for the group that received only tetracycline, 1.98 mm; and for the control group, 0.65 mm. We conclude that analysis of data from the published literature does not demonstrate that the use of systemic tetracycline is more beneficial than conventional treatment in the management of adult periodontal disease. More information is needed in order to perform an extensive meta-analysis of this subject.

Adult↗