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Biomedical subjects

D Melville

Publications and source records attributed to D Melville.

At least 19 recordsLinked to original sources
PubMed2004

Diverticular disease of the colon: ethnic differences in frequency.

BACKGROUND: Colonic diverticular disease is more common in Western populations than in developing countries. AIM: To determine whether the frequency of colonic diverticular disease is different in British patients of Indian-subcontinent Asian origin compared with other ethnic groups. METHODS: All colonoscopies performed over a 3-year period in a London hospital were studied. Patients of Indian-subcontinent Asian origin were identified by name. RESULTS: Five of 134 Indian-subcontinent Asian males (4%) had colonic diverticular disease, compared with 278 of 1268 patients of other ethnic groups (22%; P < 0.001). Five of 91 Indian-subcontinent Asian females (6%) had colonic diverticular disease, compared with 333 of 1486 patients of other ethnic groups (23%; P < 0.001). Although patients of Indian-subcontinent Asian origin (54.8 +/- 15.8 years) were younger than those of other ethnic groups (60.3 +/- 17.8 years; P < 0.0001), the ethnic difference in the frequency of diverticular disease persisted even when age was taken into account. CONCLUSION: There is a lower frequency of colonic diverticular disease in Indian-subcontinent Asians presenting for colonoscopy, compared with other ethnic groups. This cannot be explained by sex or age differences. Our findings require confirmation, but may provide opportunities for research into the aetiology of colonic diverticular disease.

Adult↗
PubMed2003

Diverticular disease of the colon--on the rise: a study of hospital admissions in England between 1989/1990 and 1999/2000.

BACKGROUND: Diverticular disease emerged as a common problem in Western countries over the course of the 20th century. AIMS: To determine the time trends in diverticular disease for hospital admissions in England between 1989/1990 and 1999/2000 and population mortality rates from 1979 to 1999. METHODS: Hospital Episode Statistics were obtained from the Department of Health and mortality data from the Office for National Statistics. RESULTS: Between 1989/1990 and 1999/2000, annual age-standardized hospital admission rates for diverticular disease increased by 16% for males (from 20.1 to 23.2 per 100,000) and 12% for females (from 28.6 to 31.9 per 100,000). Female rates were significantly higher than male rates throughout the study period. The proportions of admissions with an operation increased by 16% for males (from 22.9% to 24.1%) and 14% for females (from 19.7% to 22.3%). Older patients were less likely to undergo operation than younger patients. In-patient case fatality rates and population mortality rates remained unchanged. CONCLUSIONS: Admission rates for diverticular disease increased over the study period. The proportion of patients who underwent operation increased, but in-patient and population mortality rates remained unchanged. With an ageing population, diverticular disease will become an increasingly important clinical problem in England.

Adult↗
PubMed2002

Diaphragm disease of the small bowel--a case report and literature review.

A 75-year-old man who had an emergency laparotomy for small bowel obstruction was found at operation to have multiple mid-ileal strictures. Histology of the resected specimen confirmed diaphragm disease of the bowel. The pathogenesis of this disease remains unclear but it is associated with long-term use of NSAID. Diagnosis is often difficult as many clinicians are unaware of this condition. The relevant literature has been reviewed.

Abdomen, Acute↗
PubMed1999

Fibro-osseous lesions involving the brain: MRI.

We present the MRI findings in two patients with "fibro-osseous lesions" involving the central nervous system. A left temporal lobe mass was present in one patient and an extra-axial mass at the skull base in the other. In both cases, calcification was present, with low signal intensity on T1- and T2-weighted images.

Adult↗
PubMed1999

Randomised controlled trial shows that glyceryl trinitrate heals anal fissures, higher doses are not more effective, and there is a high recurrence rate.

BACKGROUND: Topical application of glyceryl trinitrate (GTN) ointment heals chronic anal fissures, providing an alternative to the traditional first line treatment of surgical sphincterotomy. AIMS: To determine the most effective dose of topical GTN for treatment of chronic anal fissures and to assess long term results. METHODS: Seventy consecutive patients with chronic anal fissure, were randomly allocated to eight weeks treatment with placebo, 0.2% GTN three times daily, or GTN starting at 0.2% with weekly 0.1% increments to a maximum of 0.6%, in a double blind study. RESULTS: After eight weeks fissure had healed in 67% of patients treated with GTN compared with 32% with placebo (p=0.008). No significant difference was seen between the two active treatments. Headaches were reported by 72% of patients on GTN compared with 27% on placebo (p<0.001). Maximum anal sphincter pressure reduced significantly from baseline by GTN treatment (p=0.02), but not placebo (p=0.8). Mean pain scores were lower after treatment with GTN compared with placebo (NS). Of fissures healed with placebo 43% recurred, compared with 33% of those healed with 0.2% GTN and 25% healed with escalating dose GTN (p=0.7). CONCLUSIONS: GTN is a good first line treatment for two thirds of patients with anal fissure. An escalating dose of GTN does not result in earlier healing. Significant recurrence of symptomatic fissures and a high incidence of headaches are limitations of the treatment.

Adult↗
PubMed1999

Evaluation of a training and diagnostic ultrasound service for general practitioners using narrowband ISDN.

We carried out a four-month pilot study of telemedicine for the delivery of training and diagnostic ultrasound services for general practitioners (GPs). Two health centres and a district general hospital were linked using ISDN (128 kbit/s) and PC-based videoconferencing units. Sixteen videoconferencing sessions were conducted, with 64 patients scanned over the ISDN link for a range of clinical conditions. Nine cases of pathology were demonstrated and confirmed by a consultant radiologist. A total of 229 images were transmitted using the store-and-forward facility, of which 194 (85%) images were of diagnostic quality and 35 (15%) were regarded as non-diagnostic. Allowing for sampling error, we would expect 79-89% of stored images to provide diagnostic information at a 95% confidence level. A total of 115 store-and-forward images (SAFI) were randomly selected and compared with hard-copy images (HCI) for technical quality. There was a significant difference in the quality of images. The results show that SAFI are far superior to HCI, traditionally used by clinicians for making primary diagnosis and that the superior quality of the SAFI improved diagnostic accuracy. This pilot study showed a high degree of confidence in videoconferencing for training GPs to carry out ultrasound clinics, enhancing their ability to make accurate diagnoses, and providing them with immediate access the second and higher opinion.

Education, Medical, Continuing↗
PubMed1998

Nontraumatic rupture of the thoracic aorta: chest radiographic features of an often unrecognized condition.

OBJECTIVE: The purpose of our study was to evaluate chest radiographic features of nontraumatic mediastinal hemorrhage occurring after extrapericardial thoracic aorta rupture. MATERIALS AND METHODS: Twenty-seven consecutive chest radiographs obtained at admission of patients with hemorrhage from ruptured thoracic aorta aneurysms, aortic dissections, or penetrating aortic ulcers were randomized with radiographs of 23 subjects with nonruptured thoracic aorta aneurysms, 20 subjects with nonruptured dissections, and 20 control subjects. Diagnoses were established by interpreting CT scans, MR images, and findings at surgery or autopsy or both. A retrospective review was performed by three independent radiologists who were unaware of patients' diagnoses. Observers assessed 20 parameters on each of these 90 radiographs and summarized their findings with final diagnoses. The 20 parameters were analyzed with logistic regression and rank correlation to determine the best predictors of hemorrhage. RESULTS: Logistic regression analysis showed a combination of obscuration or convexity of the aorticopulmonary window and a displaced left paraspinal interface to be the most useful predictor of hemorrhage (p < .05). Rank correlation analysis indicated obscuration or convexity of the aorticopulmonary window; a displaced left paraspinal interface; enlarged aortic knob width; enlarged thoracic aorta size; an enlarged, obscured, or irregular aortic margin; and left pleural or extrapleural space fluid were potential individual predictors of hemorrhage (p < .05). Observer sensitivities for recognizing hemorrhage were 30-59% and specificities were 83-91%. Sensitivities for distinguishing an abnormal (n = 70) from a normal (n = 20) mediastinum were 79-90% and specificities were 65-90%. CONCLUSION: Obscuration or convexity of the aorticopulmonary window and a displaced left paraspinal interface on radiographs may indicate mediastinal hemorrhage. Further imaging is required to establish a definitive diagnosis.

Adult↗
PubMed1985

Exchange rates and numbers of annular lipids for the calcium and magnesium ion dependent adenosinetriphosphatase.

A spin-labeled phospholipid is used to study lipid-protein interactions in the (Ca2+,Mg2+)-ATPase of sarcoplasmic reticulum from muscle. A novel null method is used to decompose composite electron spin resonance spectra into two components, characteristic of immobilized and mobile environments. Calculations based on a random mixing model suggest that protein-protein interactions will be relatively rare in these systems and that the immobilized lipid does not represent lipid trapped between proteins but rather represents annular phospholipid at the lipid-protein interface of the adenosinetriphosphatase. The apparent decrease in the amount of immobilized lipid with increasing temperature is shown to be consistent with lipid exchange between bulk and annulus, characterized by an exchange time of 10(-7) s at 37 degrees C. A minimum number of annular phospholipid sites of 32 and 22 are calculated at 0 and 37 degrees C, respectively.

Animals↗
PubMed1985

The morphology and viability of blood components processed by high-gradient magnetic separation.

The effect of high-gradient magnetic separation on blood components has been investigated. For erythrocytes there is no significant change in the morphology, size distribution and in the in-vivo survival times at the confidence level P = 0.05. For neutrophils stimulated nitro-blue tetrazolium reduction is maintained after HGMS. No change in chemotaxis and yeast cell phagocytosis was observed. Platelet distribution curves show no detectable changes before and after filtration. It is concluded that blood separated by HGMS is suitable for diagnostic analysis and may be considered for return to the patient.

Animals↗
PubMed1984

The superdiamagnetic effect of magnetic fields on one and two component multilamellar liposomes.

For multilamella vesicles of DMPC, DPPC, DSPC, binary mixtures of DMPC-DPPC, DMPC-DSPC, DMPC-DPPE, DOPC and egg lecithin, the optical turbidity decreases significantly on the application of a magnetic field in excess of about 0.2 T, provided that the temperature is above the pretransition value. The turbidity reaches a limiting value for magnetic fields of about 2 T. The effect is attributed to augmentation of the diamagnetic anisotropy of the lipid molecules by clustering within the bilayer, with consequent orientation of either the individual 'superdiamagnetic' clusters or the whole liposome. It is suggested that, since most animal cell membranes are largely in the liquid crystalline phase, it is possible that homogeneous magnetic fields as low as 0.2 T may cause biologically significant changes within the membrane.

Liposomes↗
PubMed1983

Dye permeability at phase transitions in single and binary component phospholipid bilayers.

By encapsulating a pH-sensitive dye, phenol red, in multilamellar liposomes of DMPC, DPPC and DMPC/DPPC mixtures, the permeability of these phospholipid bilayers to dye as a function of temperature has been studied. For both DMPC and DPPC liposomes, dye release begins well below the main gel-to-liquid-crystalline phase transition (24 degrees C and 42 degrees C, respectively) at temperatures corresponding to the onset of the pretransition (about 14 degrees C and 36 degrees C, respectively) with DPPC liposomes exhibiting a permeability anomaly at the main phase transition (42 degrees C). The perturbation occurring in the bilayer structure that allows the release of encapsulated phenol red (approx. 5 A diameter) is not sufficient to permit the release of encapsulated haemoglobin (approx. 20 A diameter, negatively charged). In liposomes composed of a range of DMPC/DPPC mixtures, dye release commences at the onset of the pretransition range (determined by optical absorbance measurements) and increases with increasing temperature until the first appearance of liquid crystalline phase after which no further dye release occurs. Interestingly, the dye retaining properties of DMPC and DPPC liposomes well below their respective pretransition temperature regions are very different: DMPC liposomes release much encapsulated dye at incubation temperatures of 5 degrees C whilst DPPC liposomes do not.

Animals↗
PubMed1982

Essential hypertension and psychological functioning: a study of factory workers.

This study was designed to examine the links between psychological characteristics and mild essential hypertension. Hypertensives were identified through mass screening of industrial populations. Sixteen men under the age of 56 whose blood pressure remained above 145/90 (145/95 for the 45-55 age group) on three separate occasions were compared with 13 age-matched normotensives from the same population. Participants completed a series of personality questionnaires, and carried out concurrent mood ratings and blood pressure self-monitoring four times daily for 14 days. Subjects remained unaware of their diagnostic status until the procedure was completed. No differences between groups were found on measures of trait anxiety, total hostility or direction of hostility. State anxiety and Type A (coronary-prone) scores were significantly higher in normotensives than in hypertensives. Analysis of mood and self-monitored blood pressure revealed consistent correlations between negative mood and higher pressure in both groups. Comparison of correlations between blood pressure, tension and anger with the correlations of pressure with a control mood scale permitted spurious associations based on expectancies or reporting biases to be distinguished from genuine effects. Only the correlation between tension and systolic pressure in the hypertensive group exceeded the correlation with the control mood scale. Self-monitored pressure also correlated with pressure levels recorded in the laboratory. These results suggest that examination of blood pressure variations and psychological factors on a longitudinal basis may be valuable, particularly in the development of self-management procedures for essential hypertensives.

Adaptation, Psychological↗
PubMed1978

Differential blood cell separation using a high gradient magnetic field.

A technique for the separation of erythrocytes from whole blood is described which exploits the magnetic property of haemoglobin in the reduced state. The technique is characterized by the use of a filter consisting of a cylinder, containing stainless steel wire mesh, placed between the jaws of an electro magnet. When activated, the electromagnet induces a magnetic field gradient in the vicinity of each of the constituent wires, sufficient to attract and trap erythrocytes in suspension. The number of erythrocytes captured varies with the applied field (0-1.4 Tesla in these experiments) and flow rate (1.9-12.9 x 10(-4) m s-1). The capture process does not cause haemolysis or observable surface damage to the erythrocytes and neither leucocytes nor platelets are retained by the filter.

Cell Separation↗
PubMed1976

Indications for beta-adrenoceptor blocking drugs in hypertension.

The past 10 years have firmly established the role of beta-adrenoceptor blocking agents in the treatment of hypertension. They have been shown to lower systolic and diastolic blood pressure in the lying and standing position in mild, moderate and severe hypertension. Precise indications for beta-blockade have not yet been completely defined. Some authorities regard them as the drug of first choice in the management of most grades of idiopathic hypertension. There are in addition certain situations where beta-blockade seems especially suitable. These include the presence of associated coronary heart disease manifest either as angina pectoris or dysrhythmia. These agents can be introduced when side effects from other drugs are severe or intolerable and are valuable in the management of hypertensive young males since beta-blocking drugs do not interfere with sexual function. Compared with normotensive subjects 'stress' has been shown to produce excessive rise of blood pressure in those with labile or sustained idiopathic hypertension. After therapy with beta-blocking agents the rise in blood pressure after 'stress' is reduced. If labile and/or mild hypertension are the precursors of subsequently more severe sustained hypertension, then long term beta-blockade may help to control this response.

Adrenergic beta-Antagonists↗