Biomedical subjects

K O'Sullivan

Publications and source records attributed to K O'Sullivan.

At least 19 recordsLinked to original sources

PubMed2006

Rapid intraoperative parathyroid hormone assay--more than just a comfort measure.

BACKGROUND: Minimally invasive radio-guided parathyroidectomy (MIRP) has been embraced as an acceptable therapeutic approach to primary hyperparathyroidism. Preoperative sestamibi scanning has facilitated this technique. Here we evaluate the addition of a rapid intraoperative parathyroid hormone (iPTH) assay for patients undergoing MIRP. METHODS: A series of 51 patients underwent sestamibi localization of parathyroid glands followed by MIRP for primary hyperparathyroidism. Using peripheral venous samples, iPTH levels were measured prior to gland excision, as well as post-excision at 5, 10, and 15 minutes, taking a 50% reduction in iPTH level as indicative of complete excision. Next, changes in serum iPTH were compared with preoperative and postoperative changes in serum calcium, as well as levels of intraoperative ex-vivo radiation counts taken by hand-held gamma probe. RESULTS: In this series, a drop of greater than 50% in iPTH levels was observed in 94% of patients (n=48). Moreover, a significant drop in iPTH occurred within 10 minutes of excision in the majority (n=42) of cases (P<0.004). Changes in iPTH were comparable with the therapeutic reduction in calcium levels, as well as with the change in intraoperative ex-vivo gamma counts. CONCLUSIONS: This study demonstrates that the addition of an iPTH assay to MIRP provides a quick and reliable intraoperative diagnostic modality in confirming correct adenoma removal. Moreover, it precludes the requirement of frozen section.

Adult↗

PubMed2006

Surveillance in Barrett's oesophagus: will a strategy focused on a high-risk group reduce mortality from oesophageal adenocarcinoma?

BACKGROUND AND STUDY AIMS: The incidence of oesophageal adenocarcinoma has increased significantly in recent years. While surveillance of people with Barrett's oesophagus, its usual precursor, has been advocated in order to detect dysplasia and early cancer in those considered to be at greatest risk, the impact of such a strategy on survival from oesophageal adenocarcinoma is unclear. This study aimed to determine the effect of surveillance on mortality from oesophageal adenocarcinoma in a group of patients considered to be at high risk of developing Barrett's oesophagus and adenocarcinoma. PATIENTS AND METHODS: After performing a Medline search of the literature published between 1985 and 2004 for studies on gastro-oesophageal reflux disease, Barrett's oesophagus and adenocarcinoma, we examined the impact of surveillance on mortality from oesophageal adenocarcinoma in a hypothetical sample of 100 high-risk patients (men aged over 50 with Barrett's oesophagus but without high-grade dysplasia at entry). RESULTS: Four patients in this high-risk group developed adenocarcinoma during surveillance, with survival rates of 78.9% (95%CI 64.9%-88.5%) at 2 years and 78.6% (95%CI 62.8%-89.2%) at 5 years. Meanwhile, between 515 and 2060 patients with Barrett's oesophagus were not detected or surveyed by this strategy and between 16 and 61 of these developed adenocarcinoma, with much lower survival rates of 37.1% (95%CI 25.4%-50.3%) at 2 years and 16.7% (95%CI 9%-28.3%) at 5 years. Although surveillance in the high-risk group resulted in the long-term survival of three patients who would not otherwise have survived, this gain was dramatically offset by the 13 to 51 patients, excluded from surveillance by this strategy, who died from oesophageal adenocarcinoma. CONCLUSIONS: A surveillance programme based on current concepts of risk cannot have an impact on mortality from oesophageal adenocarcinoma. To be effective, it will be necessary for surveillance programmes to utilise more precise methods for the identification of those who are most at risk of progression to adenocarcinoma.

Adenocarcinoma↗

PubMed2005

Fluctuations in the occurrence of Escherichia coli O157:H7 on a Norwegian farm*.

AIM: To describe the distribution of Escherichia coli O157:H7 on a sporadically positive dairy farm and on possible contact farms over a one-year period. METHODS AND RESULTS: Environmental and faecal samples from all animals at the farm, and faecal samples from animals at contact farms were analysed for E. coli O157:H7 by immunomagnetic separation methods or VIDAS. Confirmed isolates were tested for cytotoxicity in the Vero cell assay and typed by PFGE. Escherichia coli O157:H7 (stx2 and eae) of the same PFGE type were isolated from cattle, sheep, hens and environmental samples at variable levels during summer and fall 2002, but were not detected in 2003. CONCLUSIONS: Escherichia coli O157:H7 had a widespread distribution on the farm investigated, but the original source of contamination could not be identified. The occurrence of this bacterium on the farm did not result in any detectable increase in gastrointestinal disease in the associated population. SIGNIFICANCE AND IMPACT OF THE STUDY: Despite a low endemic level of E. coli O157:H7 in the Norwegian cattle population, the growth and spread of this potentially important bacterium may occur.

Agriculture↗

PubMed2004

Cytotoxic Bacillus spp. belonging to the B. cereus and B. subtilis groups in Norwegian surface waters.

AIMS: To investigate the presence and numbers of Bacillus spp. spores in surface waters and examine isolates belonging to the B. cereus and B. subtilis groups for cytotoxicity, and to discuss the presence of cytotoxic Bacillus spp. in surface water as hazard identification in a risk assessment approach in the food industry. METHODS AND RESULTS: Samples from eight different rivers with variable degree of faecal pollution, and two drinking water sources, were heat shocked and examined for the presence of Bacillus spp. spores using membrane filtration followed by cultivation on bovine blood agar plates. Bacillus spp. was present in all samples. The numbers varied from 15 to 1400 CFU 100 ml(-1). Pure cultures of 86 Bacillus spp. isolates representing all sampling sites were characterized using colony morphology, atmospheric requirements, spore and sporangium morphology, and API 50 CHB and API 20E. Bacillus spp. representing the B. cereus and B. subtilis groups were isolated from all samples. Twenty-one isolates belonging to the B. cereus and B. subtilis groups, representing eight samples, were screened for cytotoxicity. Nine strains of B. cereus and five strains belonging to the B. subtilis group were cytotoxic. CONCLUSIONS: The presence of cytotoxic Bacillus spp. in surface water represents a possible source for food contamination. Filtration and chlorination of surface water, the most common drinking water treatment in Norway, do not remove Bacillus spores efficiently. This was confirmed by isolation of spores from tap water samples. SIGNIFICANCE AND IMPACT OF THE STUDY: Contamination of food with water containing low numbers of Bacillus spores implies a risk for bacterial growth in foods. Consequently, high numbers of Bacillus spp. may occur after growth in some products. High numbers of cytotoxic Bacillus spp. in foods may represent a risk for food poisoning.

Bacillus↗

PubMed2004

Influence of concentrate composition and forage type on retail packaged beef quality.

The objective of this study was to determine the effect of type of conserved forage and concentrate composition on the quality of beef held in overwrapped (aerobic) or modified atmosphere packaging under simulated retail display for 17 d. Friesian steers (n = 45) were assigned randomly to one of five dietary treatments: 1) extensively fermented grass silage plus silage concentrate (EFS); 2) restricted fermented grass silage plus silage concentrate (RFS); 3) starch-based concentrate plus wheat straw (SC); 4) nonstarch-based concentrate plus wheat straw (NSC); or 5) zero-grazed perennial ryegrass plus grass concentrate (RYE). Meat quality was determined by measuring color, lipid oxidation (TBARS), alpha-tocopherol concentrations, and fatty acid composition. In aerobically packaged beef, there was a display x diet interactive effect (P < 0.001) on Hunter a* values, with steaks from the EFS group having higher (P < 0.05) a* values than all other dietary groups from d 6 through d 17. Moreover, during the last 12 d of display, beef from the EFS group had the lowest (P < 0.01) proportion of metmyoglobin (display day x diet; P < 0.001). Under aerobic packaging, the SC and NSC groups produced steaks with higher (P < 0.05) TBARS values than RFS, EFS, and RYE groups, which did not differ from each other (display day x diet; P < 0.01). The SC and NSC groups had higher (P < 0.05) oxidation levels than RFS, EFS, and RYE groups, which did not differ from each other. Beef from the EFS group had (P < 0.05) higher concentrations of alpha-tocopherol than from the SC, NSC, and RYE groups. Beef from EFS-fed steers had a higher (P < 0.05) proportion of saturated fatty acids than the SC and NSC groups. It was concluded that the method of grass conservation influenced beef color, whereas concentrate composition did not. Color of aerobically packaged beef was improved by feeding animals silage that had undergone extensive fermentation. Conversely, oxidative stability was decreased by feeding animals starch- and nonstarch-based concentrate diets.

Animal Feed↗

PubMed2003

Screening for asymptomatic celiac disease among patients referred for bone densitometry measurement.

Celiac disease (CD) is a relatively common gastrointestinal disorder that can be asymptomatic. An increased prevalence of subclinical CD has been reported in many populations. Even among asymptomatic patients a reduction in bone mineral density (BMD) has been observed. The aim of this study was to evaluate the prevalence of silent CD in a cohort of consecutive individuals referred for bone densitometry measurement. Serum samples were taken from 454 women attending for bone densitometry (mean age: 56 +/- 11 years). Of the individuals evaluated, 89 had normal BMD and 365 had low BMD (T score < -1.0). Subjects were screened for the presence of serum IgA anti-endomysial antibodies (EMA) and IgA tissue transglutaminase (tTG) antibodies by indirect immunofluorescence and enzyme-linked immunosorbent assay (ELISA), respectively. BMD was measured by dual X-ray absorptiometry (DEXA) at the lumbar spine and femoral neck. Eight EMA tTG-positive individuals were identified in this population (1.8% or 1:57). Serologically positive women had a lower mean Z score at both the lumbar spine and femoral neck than EMA tTG-negative women. But this did not approach significance. There was no significant difference in the incidence of CD between the normal- and low-BMD groups in this dataset (P = 0.365). In conclusion, our study indicates that the prevalence of CD in our dataset is high. However, the frequency of asymptomatic CD among low-BMD individuals is similar to that among normal-BMD individuals in our population. These observations do not support the hypothesis that serological testing for CD may be a good accompaniment to DEXA scanning.

Absorptiometry, Photon↗

PubMed2003

MRI directed bilateral stimulation of the subthalamic nucleus in patients with Parkinson's disease.

OBJECTIVE: Bilateral chronic high frequency deep brain stimulation (DBS) of the subthalamic nucleus (STN) has emerged as an appropriate therapy for patients with advanced Parkinson's disease refractory to medical therapy. Advances in neuroimaging and neurophysiology have led to the development of varied targeting methods for the delivery of this treatment. Intraoperative neurophysiological and clinical monitoring is regarded by many to be mandatory for accurate STN localisation. We have examined efficacy of bilateral STN stimulation using a predominantly magnetic resonance imaging (MRI)-directed technique. METHODS: DBS leads were stereotactically implanted into the STN using an MRI directed method, with intraoperative macrostimulation used purely for adjustment. The effects of DBS were evaluated in 16 patients followed up to 12 months, and compared with baseline assessments. Assessments were performed in both off and on medication states, and were based on the Unified Parkinson's Disease Rating Scale (UPDRS) and timed motor tests. Functional status outcomes were examined using the PDQ-39 quality of life questionnaire. A battery of psychometric tests was used to assess cognition. RESULTS: After 12 months, stimulation in the off medication state resulted in significant improvements in Activities of Daily Living and Motor scores (UPDRS parts II and III) by 62% and 61% respectively. Timed motor tests were significantly improved in the off medication state. Motor scores (UPDRS part III) were significantly improved by 40% in the on medication state. Dyskinesias and off duration were significantly reduced and the mean dose of L-dopa equivalents was reduced by half. Psychometric test scores were mostly unchanged or improved. Adverse events were few. CONCLUSIONS: An MRI directed targeting method for implantation of DBS leads into the STN can be used safely and effectively, and results are comparable with studies using intraoperative microelectrode neurophysiological targeting. In addition, our method was associated with an efficient use of operating time, and without the necessary costs of microelectrode recording.

Aged↗

PubMed2003

Relationships among milk yield, body condition, cow weight, and reproduction in spring-calved Holstein-Friesians.

Relationships among milk production, body condition score (BCS), body weight (BW), and reproduction were studied using logistic regression on data from 6433 spring-calving Holstein-Friesian dairy cows in 74 commercial herds. Multivariate models were adjusted for herd, breeding value for milk yield, proportion of Holstein-Friesian genes, lactation number, calving period, and degree of calving assistance. Significant associations between reproductive measures and components of energy balance were identified. Higher 200-d milk protein content and higher protein-to-fat ratio at start of breeding were associated with increased likelihood of submission for breeding in the first 21 d of the breeding season (SR21). High 100-d cumulative milk yield as a proportion of estimated 305-d milk yield (low persistency) was associated with a lower likelihood of pregnancy to first service (PREG1), whereas cows reaching peak milk yields earlier tended to have higher PREG1. Cows that reached nadir milk protein content relatively late in lactation had lower PREG1. Milk yield at first service and 305-d milk protein content were positively associated with the likelihood of pregnancy after 42 d of breeding (PR42). Higher 305-d milk lactose content was associated with increased PREG1 and PR42. Mean BCS at 60 to 100 d of lactation was positively associated with both SR21 and PR42, whereas nadir BCS was positively associated with PREG1. Cows with precalving BCS > 3.0 that also lost > 0.5 BCS unit by first service had lower PR42. More BW gain for 90 d after start of breeding was associated with higher SR21 and PREG1; more BW gain for 90 d after first service was associated with higher PR42. Milk protein and lactose content, BCS, and BW changes are important tools to identify cows at risk of poor reproduction.

Animals↗

PubMed2002

The effect of feeding and management practices on calving rate in dairy herds.

The objective of this study was to examine the effects of nutrition and management practices on reproductive performance in 31 Irish dairy herds participating in the Moorepark Dairy Management Information System (DairyMIS) during the period 1991-1998. Fifty variables relating to herd reproductive indices, calving events, stocking rate, disease, concentrate feeding, fertiliser usage, milk production and economic performance were studied using factor analysis. A factor analysis, followed by varimax rotation, identified 13 factors, which accounted for 83% of the total variance of the original variables. A regression model was used to predict calving rate from the orthogonal factor scores identified by factor analysis. Calving rate was defined as the proportion of services, for which an outcome was known, which resulted in a subsequent calving. Year, farm code and factor 3 (labelled herd size) together accounted for 40% of the observed variation in calving rate. The factor scores for factor 3 (herd size) were plotted against calving rate and because the plot was not linear, it was decided that dividing the factor scores into quartiles would produce a better fitting model. The factor scores for herd size were sorted and assigned to four equal categories (n = 47 per category), from lowest to highest. The ranges in herd size according to category were as follows: category 1 (34-96), category 2 (47-103), category 3 (66-152) and category 4 (108-359). The calving rate (%), (+/-S.E.) was 67.0 +/- 2.5 for category 1, 61.8 +/- 1.8 for category 2, 56.9 +/- 1.5 for category 3 and 53.2 +/- 2.85 for category 4. Using pair-wise comparisons, calving rates differed significantly (P < 0.05) between all categories except between categories 3 and 4 (P > 0.05). Herd-level milk production was not associated with calving rate indicating that good management may overcome any adverse effects of high milk production on reproductive performance. Larger herds, in combination with other associated herd characteristics, are likely to have poorer calving rates than medium or small herds.

Animal Husbandry↗

PubMed2002

Investigation of the genetic influence of the OPG, VDR (Fok1), and COLIA1 Sp1 polymorphisms on BMD in the Irish population.

Low bone mineral density (BMD) is a major risk factor for the development of osteoporosis and there is strong evidence to suggest that the procurement and preservation of peak BMD is genetically determined. In an effort to identify factors responsible for susceptibility to low BMD in the Irish population, we investigated its possible association with polymorphisms in the Osteoprotegerin (OPG) gene, Type I collagen alpha 1 (COLIA1) Sp1 binding site and vitamin D receptor (VDR) start codon. Following a systematic screening of the regulatory and coding regions of the OPG gene, we identified a novel G1181C polymorphism in exon 1 and a T950C polymorphism in the promoter region of the OPG gene. Participants were recruited from the Bone Densitometry Unit of Cork University Hospital, including 381 postmenopausal women aged 61.26 +/- 8.50 (mean +/- SD) and 130 premenopausal women aged 46.30 +/- 6.50 (mean +/- SD). Following association analysis using both the premenopausal and postmenopausal cohorts we found that postmenopausal women carrying one or more C alleles of the G1181C polymorphism had 14.8% lower BMD (P = 0.05) at the lumbar spine and 14.4% lower BMD (P = 0.04) at the FN. However, both were nonsignificant when the Bonferroni correction factor (0.01 significance level) was applied to correct for multiple hypothesis testing. We found no association between alleles of the T950C OPG polymorphism and BMD. Similarly, we have found a lack of association between the VDR (fok1) polymorphism or COLIA1 Sp1 polymorphism and low BMD in either postmenopausal or premenopausal women in this population.

Base Sequence↗

PubMed2002

Bone compression technique for arthrodesis and nonunion in the hand.

We present a simple compression technique for treatment of difficult nonunions and joint fusions in the hand. This technique utilizes only K-wires and small vessel loops. The results of 44 consecutive cases were studied retrospectively. Union was achieved in 37/44 cases. The average time to union was 7 weeks and our results were comparable to those of other studies. We found this technique useful, especially in complicated cases.

Adult↗

PubMed2002

Grass silage versus maize silage effects on retail packaged beef quality.

The effects of three preslaughter diets on heifer beef quality were investigated. Heifers (n = 45) were divided into three groups and fed for ad libitum consumption either maize silage, grass silage, or a 50:50 mixture of maize silage and grass silage. Meat quality was determined by measuring color, lipid oxidation, alpha-tocopherol levels, and fatty acid composition. Beef from the maize silage group had poorest color stability (P < 0.05), whereas beef from the grass silage diet had best (P < 0.05) color stability. The visual panel least preferred the maize silage group after 2 or more days of display, and lipid oxidation was significantly (P < 0.001) higher in this group compared to the 50:50 maize:grass silage and grass silage groups. There was a significant (P < 0.001) difference in the alpha-tocopherol levels detected in the meat from the three dietary groups. Alpha-tocopherol levels increased in the order: maize silage < 50:50 maize:grass silage < grass silage, at levels of 2.08, 2.95, and 3.84 microg/g meat, respectively. Fatty acid analysis indicated 18:3 was significantly (P < 0.001) lower in the maize silage-fed group than in the maize:grass silage and grass silage groups. However, 18:3 was significantly (P < 0.001) higher in the grass silage group than in the other two groups. There were no significant differences in all other fatty acids among the three dietary groups. It was concluded that beef from grass silage-fed animals had better overall quality in terms of color, lipid oxidation, and alpha-tocopherol levels than beef from maize silage fed animals.

Animals↗

PubMed2001

Strategy for the maximization of clinically relevant information from hepatitis C virus, RT-PCR quantification.

BACKGROUND: The increasing clinical application of viral load assays for monitoring viral infections has been an incentive for the development of standardized tests for the hepatitis C virus. OBJECTIVE: To develop a simple model for the prediction of baseline viral load in individuals infected with the hepatitis C virus. METHODOLOGY: Viral load quantification of each patient's first sample was assessed by RT-PCR-ELISA using the Roche MONITOR assay in triplicate. Genotype of the infecting virus was identified by reverse line probe hybridization, using amplicons resulting from the qualitative HCV Roche AMPLICOR assay. RESULTS: Retrospective evaluation of first quantitative values suggested that 82.4% (n=168/204) of individuals had a viral load between 4.3 and 6.7 log(10) viral copies per ml. A few patients (3.4%; n=7/204) have a serum viremia less than the lower limit of the linear range of the RT-PCR assay. Subsequent, prospective evaluation of hepatitis C viral load of all new patients using a model based on the dynamic range of viral load in the retrospective group correctly predicted the dynamic range in 75.9% (n=33/54). CONCLUSION: The dynamic range of hepatitis C viremia extends beyond the linear range of the Roche MONITOR assay. Accurate determination of serum viremia is substantially improved by dilution of specimens prior to quantification.

DNA, Viral↗

PubMed2001

HLA class II genes determine the natural variance of hepatitis C viral load.

The aim of this study was to investigate the relationship between human leukocyte antigen (HLA) class II genes and the natural fluctuations in hepatitis C viral load in a homogeneous patient population. The study group consisted of 57 viremic (hepatitis C virus [HCV] 1b) women for whom HLA class II DRB1 and DQB1 haplotyping, virologic, histologic, and biochemical markers of disease activity were available. All patients were infected with HCV 1b from the same source of hepatitis C-contaminated anti-D immunoglobulin during the period from May 1977 to November 1978. The mean slope of change of viral load was 0.34 (SD +/- 0.73) log(10) viral copies/mL/year, which is significantly different from zero, P < 10(-9). Analysis of the relationship between the slope of change of viral load and HLA class II haplotype indicated a significantly different slope of change of viral load between the alleles of (1) DRB1(*)15 and DRB1(*)0701, and (2) DQB1(*)0602 and DQB1(*)0201, P(c) =.036 and P(c) =.026 after Bonferroni correction for multiple comparisons, respectively. Significant differences for grade and stage of disease at liver biopsy were observed for DQB1(*)0501 and DQB1(*)0201 alleles; P =.019, r(s) =.64, and P =.047, r(s) =.57, respectively. In addition, significant differences in stage of disease were found to exist between DRB1(*)13 and DRB1(*)0701, P =.031, r(s) = -.71. Our results define an association between the slope of change of viral load and HLA class II haplotype in patients infected with genotype 1b of HCV. This suggests a role for host immunogenetic factors in HCV infection in this homogeneous group.

Adult↗

PubMed1999

The sequence of the non-haemolytic enterotoxin operon from Bacillus cereus.

The non-haemolytic enterotoxin from Bacillus cereus has been sequenced. It is composed of three components, non-haemolytic enterotoxin A, B and C of 41.0, 39.8 and 36.5 kDa, respectively. Transcription of the operon seems to be positively regulated by plcR, a gene that also regulates phospholipase C expression. There is substantial similarity between the three proteins of non-haemolytic enterotoxin and between the non-haemolytic enterotoxin and haemolytic enterotoxin proteins.

Amino Acid Sequence↗

PubMed1998

Possible virulence factors of Aeromonas spp. from food and water.

Thirty-one isolates of Aeromonas spp. from food and water in Norway were classified and tested for possible virulence factors including cytotoxins (tissue cultures, PCR), enterotoxins (PCR) and invasion ability (Caco-2 cells). Five different species were recorded, A. caviae (9/31), A. hydrophila (15/31), A. schubertii (3/31), A. trota (3/31) and A. veronii biovar veronii (1/31). One of the A. hydrophila strains was probably responsible for a small outbreak of food poisoning caused by ingestion of raw fermented fish. All the A. hydrophila strains produced and secreted cytotoxins at 37 degrees C, as well as two A. trota strains and the single A. veronii biovar veronii strain. In some cases increased cytotoxin secretion was observed under osmotic stress. The majority of the A. caviae strains which produced cytotoxins at 30 degrees C were unable to produce and/or secrete cytotoxins at 37 degrees C. One A. schubertii strain and one A. caviae strain were invasive.

Aeromonas↗

PubMed1998

Men's business.

Explore the source record for details and available documents.

Career Choice↗

PubMed1998

New horizons.

Nurses have always been great innovators. Whether they have cared for patients in busy city hospitals, or remote rural clinics, they have often had to deal with too few resources, a lack of staff or out-moded clinical practices.

Diffusion of Innovation↗