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Biomedical subjects

D P O'Leary

Publications and source records attributed to D P O'Leary.

At least 19 recordsLinked to original sources
PubMed2004

The Department of Health's "two week standard" for bowel cancer: is it working?

OBJECTIVE: To determine the effectiveness and efficiency of the Department of Health's new general practitioner referral guidelines for bowel cancer. DESIGN: One year prospective audit. SETTING: District general hospital serving a population of 550 000. SUBJECTS: All patients with bowel cancer; all patients referred on the basis of the two week standard and to a routine colorectal surgical outpatient clinic. MAIN OUTCOME MEASURES: Proportion of cancers referred on the basis of the two week standard and to other colorectal clinics; the proportion with the higher risk criteria and their diagnostic yields; stage of cancers diagnosed in outpatient clinics; and time to treatment. RESULTS: A total of 249 cancers were diagnosed in the index year. Sixty five (26.1%) were referred to two week standard clinics, 40 (16.1%) to routine colorectal surgical outpatient clinics, 54 (22%) to other clinics, and 88 (35.3%) were emergencies. Thirteen patients per week were referred to the two week standard clinics and 85% (54/65) of cancers so referred were seen within two weeks. The diagnostic yield of cancer in the two week standard clinic was 9.4% (65/695) compared with 2.2% (40/1815) in the routine colorectal surgical outpatient clinic (p<0.0001). Eighty five per cent of patients with cancer referred to outpatients matched the guidelines for the two week standard clinics. Only 46% of this group were so referred. Overall, delay to treatment and Dukes' stage were not improved in patients diagnosed in the two week standard clinics. CONCLUSIONS: Most patients with bowel cancer were not referred on the basis of the two week standard although most fulfilled the referral criteria, which had higher diagnostic yields. The two week standard clinics did not shorten the overall time to treatment or improve the stage of disease because the time lags before referral and after the outpatient appointment are the major causes of delay in the bowel cancer patient's journey.

Adult↗
PubMed2002

Intra-operative injection of Patent Blue V dye to facilitate nodal staging in colorectal cancer.

OBJECTIVES: Routine histopathology may understage colorectal cancer by failing to detect involved lymph nodes. This study examined the feasibility of dye staining those lymph nodes most likely to harbour metastases. PATIENTS AND METHODS: Patent Blue V dye 2.5% was injected intra-operatively into left-sided colorectal carcinomas prior to resection in 19 patients. RESULTS: Blue-stained nodes were found in 12/19 patients (63%). Examination of blue-stained nodes alone correctly identified overall nodal status in 11 (92%) of these 12 patients. CONCLUSION: The technique needs to be refined further. Nonetheless, intra-operative lymph node staining using blue dye offers the prospect of improving the ease and accuracy of nodal staging in colorectal cancer.

Journal Article↗
PubMed2001

Approximating the number of monomer-dimer coverings in periodic lattices.

Our starting point is an algorithm of Kenyon, Randall, and Sinclair, which is built upon the ideas of Jerrum and Sinclair, giving an approximation to crucial parameters of the monomer-dimer covering problem in polynomial time. We make two key improvements to their algorithm: we greatly reduce the number of simulations that must be run by estimating good values of the generating function parameter, and we greatly reduce the number of steps that must be taken in each simulation by aggregating to a simulation with at most five states. The result is an algorithm that is computationally feasible for modestly sized meshes. We use our algorithm on two- and three-dimensional problems, computing approximations to the coefficients of the generating function and some limiting values.

Journal Article↗
PubMed2001

Quality of life after low anterior resection with total mesorectal excision and temporary loop ileostomy for rectal carcinoma.

BACKGROUND: Low anterior resection (LAR) with total mesorectal excision (TME) may be the optimal operation for carcinoma of the mid or lower rectum. Routine formation of a temporary defunctioning stoma has been recommended with TME. The impact of this strategy on health-related quality of life (HRQOL) has not been addressed. METHODS: A prospective longitudinal study was conducted among 24 patients undergoing LAR with TME and loop ileostomy for rectal cancer. Clinical outcomes were documented. HRQOL was assessed using Short Form 36 (SF-36). Twenty-three patients undergoing high anterior resection (HAR) for rectosigmoid cancer were studied concurrently to determine the effects of major colorectal resection without a stoma. RESULTS: Time to resume normal diet, length of stay in hospital and time to return to non-work activities were similar after HAR or LAR with TME and loop ileostomy. Twelve weeks after HAR SF-36 scores were stable or improved compared with preoperative levels. In contrast, 12 weeks after LAR + TME patients had a reduction in physical functioning scores on SF-36. SF-36 scores improved after ileostomy closure. Ileostomy closure increased total hospital stay and time off non-work activities. CONCLUSION: LAR with TME and temporary loop ileostomy for rectal cancer results in a long total hospital stay and impairs aspects of HRQOL. Prompt stoma closure should be a priority in these patients.

Aged↗
PubMed2000

Chromosome identification using hidden Markov models: comparison with neural networks, singular value decomposition, principal components analysis, and Fisher discriminant analysis.

The analysis of G-banded chromosomes remains the most important tool available to the clinical cytogeneticist. The analysis is laborious when performed manually, and the utility of automated chromosome identification algorithms has been limited by the fact that classification accuracy of these methods seldom exceeds about 80% in routine practice. In this study, we use four new approaches to automated chromosome identification--singular value decomposition (SVD), principal components analysis (PCA), Fisher discriminant analysis (FDA), and hidden Markov models (HMM)--to classify three well-known chromosome data sets (Philadelphia, Edinburgh, and Copenhagen), comparing these approaches with the use of neural networks (NN). We show that the HMM is a particularly robust approach to identification that attains classification accuracies of up to 97% for normal chromosomes and retains classification accuracies of up to 95% when chromosome telomeres are truncated or small portions of the chromosome are inverted. This represents a substantial improvement of the classification accuracy for normal chromosomes, and a doubling in classification accuracy for truncated chromosomes and those with inversions, as compared with NN-based methods. HMMs thus appear to be a promising approach for the automated identification of both normal and abnormal G-banded chromosomes.

Chromosome Mapping↗
PubMed1999

Use of the greater omentum in colorectal surgery.

INTRODUCTION: Complications related to impaired healing remain a major challenge in colorectal surgery. This review examines the potentially protective role of the greater omentum in colorectal operations. METHODS: Review of all reports concerning applications of the greater omentum in colorectal surgery identified through MEDLINE (1966-1997) and other sources. RESULTS: Clinical case studies indicate that an interposition flap of omentum is beneficial in the management of complex rectal fistulas. Pelvic omentoplasty or an omental hammock appears to reduce the incidence of radiation enteropathy in patients receiving pelvic radiotherapy after rectal resection. However, recent research demonstrates that omental wrapping does not "protect" colonic or rectal anastomoses. Nor is there convincing evidence that pelvic omentoplasty promotes primary perineal healing after abdominoperineal resection for cancer, although it may reduce the incidence of perineal wound breakdown. CONCLUSIONS: Previous assumptions concerning the omentum are now being rigorously investigated with the aim of defining its true value in colorectal applications. This must be encouraged, especially where use of the omentum increases the magnitude or duration of operations significantly.

Colon↗
PubMed1998

Tube caecostomy to protect rectal anastomoses.

BACKGROUND: Low rectal anastomoses are associated with a substantial risk of anastomotic leakage. Tube caecostomy offers a potentially simple method of anastomotic protection. METHODS: Some 226 patients undergoing restorative rectal resection with on-table colonic lavage and tube caecostomy over an 11-year period were reviewed. Endpoints selected included clinical anastomotic leakage, requirement for a subsequent formal stoma and complications of tube caecostomy. RESULTS: Overall, clinical anastomotic leakage occurred in 25 patients with a caecostomy (11.1 per cent). All leaks were noted among patients in whom caecostomy protection had been used after low anterior resection, giving a leak rate of 14.9 per cent (25 of 168) for this group of whom 17 (10.1 per cent) required reoperation and a formal stoma, and five (3.0 per cent) died. Complications of caecostomy or prolonged drainage after tube removal occurred in ten (4.4 per cent) and 15 (6.6 per cent) patients respectively. There were two cases of life-threatening invasive infection. CONCLUSION: Tube caecostomy provides inadequate protection of rectal anastomoses; complications are common and may be life threatening.

Anastomosis, Surgical↗
PubMed1998

Definitive repair of anovaginal fistula in Crohn's disease.

Anovaginal fistula may be a very distressing complication of Crohn's disease. We review the definitive repair of such fistulas in ten patients. The objectives were to cure the fistula, maintain continence and avoid proctectomy. The fistula was low trans-sphincteric in five patients, high trans-sphincteric in three and suprasphincteric in two. Loop ileostomies were formed in nine patients. Overall, after 14 repair procedures 8/10 fistulas are healed. Seven remain healed at a mean of 38 months (range 10-66 months) after ileostomy closure (six) or repair without ileostomy (one). All of the patients are continent. Definitive repair is effective and worthwhile in selected patients with Crohn's anovaginal fistula.

Adult↗
PubMed1997

Does hospital mortality rate reflect quality of care on a surgical unit?

All deaths occurring in 1 year in the surgical unit of a district general hospital were analysed to determine to what extent crude mortality rates reflect the quality of care. There were 166 deaths, 70% of patients were aged 75 years and older, and 87.3% were emergency admissions. Almost one-half (46.4%) of the deaths were inevitable. This high proportion of inevitable deaths means that crude hospital mortality rates are a poor indicator of the quality of surgical care. Factors such as the nature of the catchment area served, the proportion of emergency versus elective admissions, the numbers of complex operations performed and the availability of convalescent or hospice facilities are a greater influence on surgical mortality rates than variations in the standard of surgical care. The use of crude hospital mortality rates to compare the quality of care given by surgical units should be discontinued as it is unreliable and misleading.

Adult↗
PubMed1996

Management of varicose veins according to reason for presentation.

Of 229 newly referred patients with varicose veins, untoward symptoms were the most frequent reason for presentation (38%). Cosmetic concerns were significantly more common in women than in men (33% vs 8%, P < 0.001). Sclerotherapy was offered to 20 patients (8.7%). Surgical operation was offered in 113 (49.3%), mostly for symptoms. No invasive treatment was indicated in 96 patients (42%), more than half of whom had presented because of inappropriate fears of deterioration or with symptoms unrelated to their veins. We advocate that careful evaluation of the reasons for presentation should be used as a guide to the efficient management of varicose veins.

Adolescent↗
PubMed1995

Comparison of vestibular autorotation and caloric testing.

The two most common stimuli of the vestibular system for diagnostic purposes are caloric and rotational head movements. Caloric stimulation, by delivering thermal energy to the lateral semicircular canal, is a well-studied method of vestibular testing, and its clinical usefulness has been established. Vestibular autorotation testing uses high-frequency (2 to 6 Hz), active head movements to stimulate the horizontal and vertical vestibulo-ocular reflex to produce measurable eye movements that can be used to calculate gain and phase. We compared the alternate bilateral bithermal caloric results with the vestibular autorotation test results obtained from 39 patients with peripheral vestibular disorders and from 10 patients with acoustic neuroma. In the peripheral disorder group, only 2 of 14 patients with equal caloric response (< 20% reduced vestibular response) had a normal vestibular autorotation test result. No patients with a reduced vestibular response greater than 21% had a normal vestibular autorotation test result. In the acoustic neuroma group, four patients had a normal reduced vestibular response, but all patients had an abnormal vestibular autorotation test result. We conclude that testing both the horizontal and vertical vestibulo-ocular reflexes in their physiologic frequency range with the vestibular autorotation test provides additional information that could be missed by conventional caloric testing. Therefore high-frequency rotational testing is a valuable addition to the vestibular test battery.

Adult↗
PubMed1995

Predictive monitoring of high-frequency vestibulo-ocular reflex rehabilitation following gentamicin ototoxicity.

Nine patients exposed to gentamicin ototoxicity were tested with active head movements to determine their high-frequency (2-6 Hz) horizontal and vertical vestibulo-ocular reflex (VOR) responses. Results showed a common pattern documenting patients' reports of oscillopsia during walking: gains of 0.5 or less, and phases less than 180 degrees. A subset of these patients undergoing exercise rehabilitation therapy were tested repeatedly during follow-up visits to monitor changes in their VORs. VOR improvements toward reduced oscillopsia were correlated with patients' reported reduction of symptoms. Each patient's VOR changes over time were monitored with a quantitative least-squares method which predicted results of the next test, based on trends from three or more previous tests. The method was tested by comparing predicted results with actual test results, following the next test. Preliminary results show relatively accurate predictions up to 6 weeks in advance of actual tests, at least when trends of recent, previous tests were in a consistent direction. We conclude that predictive monitoring of changing VOR states can be useful for continuing, or modifying, the course of vestibular rehabilitation therapy, by providing quantitative prediction estimates of future results.

Anti-Bacterial Agents↗
PubMed1995

Parathyroidectomy for hyperparathyroidism associated with renal disease.

Between 1969 and 1993, 123 patients were accepted in this unit for surgery for refractory hyperparathyroidism associated with chronic renal failure. Subtotal parathyroidectomy was the procedure of choice. At operation, four or more parathyroids were identified in 75% of patients. Methylene blue localised additional parathyroids in 32% of initial explorations in which it was used. Coincidental thyroid pathology was found in 8.3%, including papillary carcinoma in 2.4%. No further parathyroid surgery was required in 90% of patients at a mean of 6.6 years after operation. Reoperation (10%) was more likely to be required (14.3%) when less than four glands were found than when four or more were found (8.5%). Patients continuing on dialysis were more likely to need reoperation than those with functioning renal transplants.

Adolescent↗
PubMed1994

Artificial bile inhibits bile salt-induced gallbladder glycoprotein release in vitro.

The more hydrophobic bile salts cause rapid release of preformed gallbladder mucin and other glycoproteins by gallbladder explants in vitro, whereas the less hydrophobic bile salts elicit a lesser response. This study was designed to determine (a) whether this short-term effect was matched by a sustained increase in glycoprotein secretion over 24 hr and (b) whether it occurred when bile salts were presented in model biles rather than aqueous solution. Although 3 mmol/L taurodeoxycholate in aqueous solution increased release of preformed gallbladder glycoprotein to 843% of control values after 30 min incubation (p < 0.001), no significant increase was observed after 24 hr. The more prolonged exposure also reduced precursor uptake by 32% (p < 0.05) and inhibited synthesis of new glycoprotein by 24% (p < 0.05). Moreover, the stimulatory effect of taurodeoxycholate on release of gallbladder glycoprotein was much reduced when it was presented in model biles rather than in aqueous solution. Nor was there any difference between the effects of more hydrophobic vs. less hydrophobic bile salts when presented in model biles. Aqueous solutions of the more hydrophobic bile salts induce a rapid release of gallbladder glycoprotein in vitro but do not produce a sustained increase in glycoprotein secretion. Their effect is liable to be prevented in vivo by interaction between bile salts and the other lipids in gallbladder bile.

Animals↗