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Biomedical subjects

D J Leaper

Publications and source records attributed to D J Leaper.

102 records · Page 6Linked to original sources
PubMed1972

Computer-assisted diagnosis of abdominal pain using "estimates" provided by clinicians.

This paper reports a comparison between two modes of computer-aided diagnosis in a real-time prospective trial involving 472 patients with acute abdominal pain. In the first mode the computer-aided system analysed each of the 472 patients by referring to data previously collated from a large series of 600 real-life patients. In the second mode the system used as a basis for its analysis "estimates" of probability provided by a group of six clinicians. The accuracy and reliability of both modes were compared with the performance of unaided clinicians.Using "real-life" data the computer system was significantly more effective than the unaided clinician. By contrast, when using the clinicians' own estimates the computer-aided system was often less effective than the unaided clinician-especially when diagnosing less common disorders. It seems, firstly, that future systems for computer-aided diagnosis should employ data from real-life and not clinicians' estimates, and, secondly, that clinicians themselves cannot analyse cases in a probabilistic fashion, since often they have little idea of what the "true" probabilities are.

Abdomen, Acute↗
PubMed1972

Computer-aided diagnosis: description of an adaptable system, and operational experience with 2,034 cases.

This paper describes a system of computer-aided diagnosis using an English Electric KDF9 computer linked to a terminal in a busy clinical department. Data from a series of patients were recorded, coded, and entered into the computer, which then performed a Bayesian analysis and displayed diagnostic probabilities in an adaptable format. Experience in this setting suggests that computer diagnosis may be a valuable aid to the clinician.

Abdomen↗
PubMed1972

Computer-aided diagnosis of acute abdominal pain.

This paper reports a controlled prospective unselected real-time comparison of human and computer-aided diagnosis in a series of 304 patients suffering from abdominal pain of acute onset.The computing system's overall diagnostic accuracy (91.8%) was significantly higher than that of the most senior member of the clinical team to see each case (79.6%). It is suggested as a result of these studies that the provision of such a system to aid the clinician is both feasible in a real-time clinical setting, and likely to be of practical value, albeit in a small percentage of cases.

Abdomen, Acute↗
PubMedDate not supplied

Falls in hemoglobin saturation during ERCP and upper gastrointestinal endoscopy.

Fiberoptic endoscopy is practiced everyday in the field of gastroenterology and, for diagnostic purposes, carries a risk of complications and an estimated mortality of 1:5,000, which is multiplied several times during interventional procedures. Half of these complications have a cardiopulmonary origin which may be anticipated by the use of pulse oximetry to measure hemoglobin saturation (SaO2). We studied 132 patients undergoing diagnostic or procedural endoscopic retrograde cholangiopancreatography (ERCP) under sedation, and 51 undergoing esophagogastroduodenoscopy (EGD) without sedation. In the ERCP group, SaO2 fell from 95.7 +/- 2.4% (mean +/- standard deviation) to 88.9 +/- 6.4% (p less than 0.001) with a corresponding rise in pulse from 95 +/- 19 to 116 +/- 18/min (p less than 0.001) followed by recovery. The largest falls followed positioning of the endoscope (rather than following administration of the sedative or the procedure), particularly during introduction of the endoscope within 1 minute of administering diazemuls (diazepam). The EGD group also had a fall in SaO2 (97.3 +/- 1.9% to 93.9 +/- 3.3%, p less than 0.001), although the patients were younger and undergoing shorter examinations. Again, the largest falls occurred 1 minute after introduction of the endoscope. In subgroups of patients undergoing ERCP, analysis of respiratory patterns using spectral techniques and electrocardiogram during endoscopy (n = 25), or peripheral perfusion using transcutaneous oximetry and laser Doppler velocimetry (n = 12) was undertaken. No correlations were found in relation to changes in SaO2. The cause of the fall in SaO2 during endoscopy is multifactorial.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMedDate not supplied

A controlled study comparing the conventional treatment of idiopathic anorectal abcess with that of incision, curettage and primary suture under systemic antibiotic cover.

The treatment of anorectal abscess by deroofing and packing on an initial inpatient basis has been compared in a controlled trial with that of incision, curettage and primary suture under systemic antibiotic cover in the Accident and Emergency Department. Over a three-year period 219 patients with anorectal abscess were randomly allocated to one or other treatment and subsequently followed up in a rectal clinic. In terms of the time taken for complete healing and the periods lost from work postoperatively, the method of incision, curettage and primary suture under systemic antibiotic cover was found to be significantly superior, without any increased risk of recurrence of the abscess or of subsequent fistula formation.

Abscess↗
PubMedDate not supplied

Proteinases, their inhibitors, and cytokine profiles in acute wound fluid.

Wound healing is a complex process involving the interactions of many different cell types, matrix components and biological factors, including proteinases and cytokines. This study compared the levels of proteinases (matrix metalloproteinases and plasminogen activators), proteinase inhibitors (tissue inhibitors of metalloproteinases and plasminogen activator inhibitors), inflammatory cytokines and growth factors in acute wound fluid samples collected from the surgical drains of elective breast (n = 24) and colorectal (n = 26) patients on the first postoperative day. Gelatin zymography was used to determine matrix metalloproteinase-2 and -9 levels, quenched fluorescence substrate hydrolysis was applied for total MMP activity and enzyme-linked immunoassays were used to quantitate other factors. Colorectal wound fluid samples showed significantly (p < 0.05) greater levels of the matrix metalloproteinases (MMP-1, 2, 3, and 9), tissue inhibitor of metalloproteinases-1, urokinase plasminogen activator receptor and the inflammatory cytokines (interleukin-1beta, -6, and tumor necrosis factor-alpha); e.g., matrix metalloproteinase-3 colon; median 275 (range 11-2.530) ng/ml; breast; 530-400. However, tissue plasminogen activator and growth factor levels (epidermal growth factor, platelet-derived growth factor, basic fibroblast growth factor, transforming growth factor-beta1) were significantly greater in breast samples; e.g., epidermal growth factor breast 468 (103-1, 444) pg/ml; colon 57(1-573). There was no difference in the levels of urokinase type plasminogen activator, plasminogen activator inhibitor-1 and -2, tissue inhibitor of metalloproteinases -2 or vascular endothelial growth factor. Acute wound fluid from different surgical wounds showed different profiles of proteinases, proteinase inhibitors, and cytokines. This may lead to differences in the rate of tissue remodeling and therefore healing in these two wounds in vivo.

Acute Disease↗
PubMedDate not supplied

Laser-Doppler velocimetry and photoplethysmography in the diagnosis of abnormal venous reflux.

Laser-Doppler Velocimetry (LDV) is useful in measurement of relative tissue blood flow. We have found a change in both the variability of the LDV waveform and its absolute level when measured in the supine and dependent limb, in patients with venous reflux. These changes correlated with simultaneous photo-plethysmographic (PPG) assessment of venous reflux and were more pronounced in patients with leg ulcers. These changes were also reduced by compression bandaging.

Humans↗