Search PubMed⌕ Search

Biomedical subjects

C McGrath

Publications and source records attributed to C McGrath.

At least 73 records · Page 4Linked to original sources
PubMed1996

Angioscopically-assisted in situ saphenous vein bypass for infrainguinal revascularisation.

OBJECTIVES AND STUDY DESIGN: The diagnostic capability of angioscopy for endoluminal evaluation is established and its superiority over arteriography for completion studies has been confirmed. The therapeutic use of angioscopy in vein graft preparation is more controversial. The aim of this prospective study was to establish whether angioscopic vein preparation confers real benefits over existing techniques. METHODS: Forty-seven patients were randomised to either full angioscopic (ANG) vein preparation (23 patients) or conventional (CON) in situ grafting (19 patients). All patients underwent completion studies with arteriography and angioscopy and postoperatively, entered a Duplex graft surveillance programme. RESULTS: There was a significant difference in the incidence of wound morbidity: 26% in the ANG group as against 63% in the CON group (Fisher's exact test: p = 0.043), but no significant differences with respect to duration of operation, duration of vein graft preparation, length of hospital stay and both 30 day and 12 month secondary cumulative patencies (log rank test: p > 0.5). Completion angioscopy detected eight persistent valve cusps in six patients, all missed at arteriography, but failed to detect arteriovenous fistulae. CONCLUSIONS: Angioscopic preparation reduces wound morbidity and complements arteriography for detecting intraoperative defects. A large, prospective, randomised trial is now warranted to fully evaluate the potential therapeutic role of angioscopy with respect to current vascular practice.

Aged↗
PubMed1996

Angioscopy for quality control of saphenous vein during bypass grafting.

OBJECTIVES: Although autogenous vein is the conduit of choice for infrainguinal bypass grafting, some 20-30% of vein grafts fail during the first year postoperatively. Many of these failed veins are now known to have pre-existing pathological changes. Angioscopy enables intraoperative endoluminal visualisation of veins and can reveal anomalies, some previously unsuspected, despite preoperative Duplex ultrasound mapping and normal external appearances. The aim of this study was to compare angioscopic findings with contemporary histological appearances and with subsequent graft outcome and ultimately, to identify those endoluminal features which might be predictive for failure. METHODS: Angioscopic vein inspection was carried out using Olympus 1.4 and 2.2mm angioscopes in patients undergoing femoropopliteal/distal bypass. Severe disease in the veins of five patients led to preferential use of polytetrafluoroethylene (PTFE) for above-knee bypasses. The remaining 38 videotaped sequences were reviewed by two surgeons and scored using a scale of 0 to 3, based on frequency and distribution of angioscopically detected lesions. These included haemorrhagic mural plaques, flimsy intraluminal strands, webs/bands and mobile/adherent thrombus. Vein harvested at operation was assessed by a pathologist according to the level of pre-existing abnormality. RESULTS: There were significant associations between angioscopy/histology scores and graft survival (chi 2 = 22.00; df:3; p < 0.001; chi 2 = 22.43; df:3; p < 0.001 respectively). There was a significant correlation between angioscopy and histology scores (R8 = 0.725; p < 0.001). CONCLUSIONS: Angioscopy allows immediate identification of the at risk, poor quality vein graft at the time of surgery, without the delays inherent with histological preparation and assessment. Recognition of abnormalities at angioscopy may ultimately improve graft outcome by prospectively eliminating use of poor vein.

Adult↗
PubMed1996

Hyperhomocysteinaemia is a risk factor for vein graft stenosis.

OBJECTIVES: Many infrainguinal vein graft failures are due to progressive vein graft stenosis (VGS) from intimal hyperplasia. Systemic factors have been implicated in the aetiology of intimal hyperplasia. Hyperhomocysteinaemia (HHCA) is established as an independent risk factor for coronary and peripheral arterial disease. The objective of this study was to examine the influence of HHCA and other serological factors upon the development of VGS. STUDY DESIGN: Thirty-eight patients who had undergone infrainguinal vein bypass were recruited to a case/control study from a graft surveillance program. Nineteen patients with documented VGS were matched against controls without stenosis for age, sex, length of time from surgery, diabetes, smoking history and preoperative symptom score. All patients were recalled for Duplex ultrasound scans, venesection and carbon monoxide estimation which were performed in a blinded fashion. RESULTS: Statistical analysis of all parameters revealed that plasma homocysteine was significantly elevated in patients with VGS (p < 0.3, Wilcoxon rank sum). CONCLUSIONS: These results suggest that HHCA is a previously unidentified risk factor for VGS. Patients with HHCA are susceptible to VGS and preoperative investigation would allow identification of patients at risk.

Adult↗
PubMed1995

Late reoperation in vascular surgery.

OBJECTIVES: Assessment of late reoperation (after 30 days) following vascular surgery. DESIGN: Analysis of a prospectively collected database of consecutive patients undergoing vascular surgery. SETTING: A single teaching unit's experience between 1986-1993. MATERIALS: Patients undergoing 2501 primary arterial reconstructions. CHIEF OUTCOME MEASURES: Reoperation after 30 days. MAIN RESULTS: One hundred and fifty eight patients (6%) underwent further operations, at more than 1 month after the primary procedure. Primary procedures at highest risk for reoperations were axillobifemoral bypasses and femorodistal bypasses with respective late reoperation rates of 20% and 16%. The majority of patients required late reoperation because of graft occlusion or stenosis. Overall, of the 158 late reoperations performed, 114 were related to the same arterial segment with the same presenting symptoms as the primary operation, and 44 for a different indication. A second or subsequent reoperation was required in 54 patients and the overall operative mortality was 11%. CONCLUSION: Patients undergoing certain vascular procedures, should be informed of the high risk of a subsequent procedure when consent is obtained.

Aged↗
PubMed1995

The value of pre-discharge Duplex scanning in infrainguinal graft surveillance.

OBJECTIVES: Protocols and criteria for Duplex-based graft surveillance programmes (GS) vary widely as to the optimum regimens for maximising detection of "at risk" grafts. Few centres recommend starting GS before discharge. The aim of this study was to audit our experience with respect to early scanning. SETTING: Vascular Studies Unit, Bristol Royal Infirmary. METHOD: The records of 123 patients entering GS from January 1992 were reviewed. Patients were scanned at 1 week, 6 weeks and 3, 6, 9 and 12 months post-bypass. Haemodynamic criteria used were a peak mean velocity (PMV) less than 45 cm/s and a focal velocity disturbance with a V2/V1 ratio of 1.5 or more. RESULTS: Forty-six abnormalities (37% detection rate) were identified on scans within one week. In all cases, on-table completion studies with either arteriography and/or flow measurements had failed to identify the anomalies subsequently detected by Duplex. At 1 week, six grafts had occluded, 27 had a focal PMV increase (mean V2/V1 ratio: 2.6; range 1.5-4.3), four had low flow velocities, four had arteriovenous fistulae, one contained mobile thrombus, two had retained cusps and two had hamstring entrapment. Of 40 patent, but compromised grafts, 18 warranted immediate investigation. Of the 27 patients with velocity disturbances on Duplex, 25 were simply observed but, eight have since required intervention for definitive stenoses at these sites which, in retrospect, were evident within the first postoperative week. CONCLUSIONS: Pre-discharge scanning is a useful modality for detecting technical problems. Intrinsic graft abnormalities, possibly the sites of future definitive stenoses, have been visualised even at 1 week and once identified, can be more closely scrutinised thereafter. Pre-discharge colour Duplex is recommended as standard practice for quality control after infrainguinal bypass.

Arterial Occlusive Diseases↗
PubMed1993

An uncommon presentation for a common problem.

One of the axioms of general practice is that 'common things present commonly', both in the community incidence of disease and in the symptoms with which illnesses usually present. This was somewhat enigmatically put by a renowned neurologist at the Mayo Clinic: "When you hear hoof-beats, why think of zebras?". A most difficult, yet important feat for the GP is to keep on the alert for the uncommon symptom of a common cause, and the common symptom with an uncommon cause.

Arthritis↗
PubMed1991

The effect of race on waiting time in two urban emergency departments.

This study examines the relation between patient race and waiting time in two urban Emergency Departments, located in the northeastern United States. Consecutive patients presenting with lacerations make up the subjects in the study. In order to control for the effect of disease severity, we restricted the sample to patients presenting with small, single lacerations requiring sutures. Patients who were intoxicated, had experienced syncope, had been involved in motor vehicle accidents, or who required tests or consultation were excluded. Taking socio-demographic (age, sex, insurance status) and clinical variables (location of laceration, time of day, day of week) into account, we found no substantial difference in total time spent in the Emergency Departments between whites and non-whites.

Attitude of Health Personnel↗
PubMed1991

Safety and efficacy of a broad-spectrum sunscreen in patients with discoid or subacute cutaneous lupus erythematosus.

An eight-week, open-label study was conducted to test the efficacy, safety, and cosmetic acceptability of a broad-spectrum sunscreen in patients with discoid lupus erythematosus or subacute cutaneous lupus erythematosus. The sunscreen combined the ultraviolet A absorber avobenzone (Parsol 1789, Givaudan Corp) and the ultraviolet B absorber padimate O and had a sun protection factor greater than fifteen. The overall clinical disease severity decreased from 2.7 (four point scale) at baseline to 1.7 after eight weeks (p = 0.005). Cutaneous signs and symptoms, including hyperpigmentation, papules, scaling, and erythema, were significantly less severe at the end of the study. The level of protection provided by the sunscreen was good to excellent in 54 percent of patients, and was judged to be superior or far superior to previously used sun protection factor-fifteen sunscreens in 77 percent of patients. Most patients found the sunscreen highly acceptable with respect to its cosmetic properties.

4-Aminobenzoic Acid↗
PubMed1991

Recurrent vaginitis.

Recurrent vulvo-vaginitis is indeed a difficult problem with both a physical and psycho-sexual impact on the patient. A thorough and caring approach is important to help patients through a demanding time. Future hopes lie in the refinement of better tolerated oral imidazoles and the research into the immunology of candidiasis.

Female↗
PubMed1985

An analysis of 12 months admissions to a regional infection unit with an open door admission policy.

All admissions to the Aberdeen Infection Unit over a period of 12 months have been analysed. Forty per cent of the patients proved to have non-infectious conditions although most were referred as having an infectious disease. Those patients with infectious diseases were younger and had a shorter stay in hospital. Also there was seasonal variation in the time of their admission as well as a low mortality rate when compared with older patients with non-infectious disease admitted over the same period. Cross infection did not arise in spite of patients sharing accommodation.

Cross Infection↗
PubMed1985

Assessment of the optical contributions to the age-related deterioration in vision.

Contrast sensitivities were measured in human observers of different ages in response to sinusoidal grating patterns generated by laser interferometer and cathode ray tube (c.r.t.). The former method bypasses the effects of the optical media to assess directly the contrast sensitivity of the retina/visual system, while the over-all assessment including optical media is made to the c.r.t. display. The ratio of the two sets of values gives the contrast ratio of the optical media. The latter assessment does not include the effects of wide-angle light scattering which were measured by comparing the responses of eyes with a Perspex lens implant or without any lens at all (i.e. without the major source of scattering) with natural eyes. With increasing age, c.r.t. contrast sensitivities remained steady until the sixth decade when they declined while laser interference fringe contrast sensitivities declined continuously, apart from some abnormally low results for teenage observers. In contrast, the optical contrast did not vary systematically with age nor did its rate of change with spatial frequency vary. The latter was always less than the rate for laser interference fringe contrast sensitivities indicating that the retina/visual system always sets the limit to visual resolution. Wide-angle light scattering was not found to contribute significantly to the changes in ageing nor did reduced retinal illumination, as reproduced by reduced pupil diameter or viewing through a neutral density filter. We therefore conclude that the age-related deterioration is primarily caused by changes within the central nervous system rather than the optical media, the transmission quality of which remains unaffected.

Adult↗
PubMed1981

The effects of age on spatial frequency perception in human subjects.

Visual performance was measured in sixty-six subjects aged from 5 to 94 years. The curve of contrast sensitivity against spatial frequency was obtained for each subject. This curve had a peak contrast sensitivity in the 2-6 c/deg (cycles/degree) range with the fall-offs to either side of the peak described, on a double logarithmic plot, by straight lines. With advancing age, the position of the peak sensitivity remained unchanged but there was an overall decrease in contrast sensitivity. The highest spatial frequency which could be perceived remained constant up to 50 years, thereafter it fell with increasing age. The slope of the low frequency straight line remained unchanged while that of the high frequency straight line fell with increasing age, i.e. the loss of contrast sensitivity was greater for middle range spatial frequencies than for higher spatial frequencies. The possible site of these changes, i.e. the optics of the eye, the retina/brain or higher decision making centres, is discussed.

Adolescent↗
PubMed1981

Malignant hyperthermia (MH): porcine erythrocyte damage from oxidation and glutathione peroxidase deficiency.

Malignant hyperthermia (MH) is a severe familial disease in both the pig and the human, with 70% fatality when fully expressed in humans. MH produces rapid elevation of temperature in response to stresses, of which there are two general kinds: Societal or emotional stress, and chemical stressors. The most commonly encountered stressor is halothane, a general anesthetic in wide use. Besides large temperature increases, there occur some twenty symptoms. Much work in other laboratories has been concentrated on elevated CPK i the plasma. However, all the symptoms are consistent with a single disorder, namely oxidative damage, especially in membranes. A deficiency in the glutathione peroxidase (GPX) system is a prime factor, likely the molecular basis allowing abnormal oxidative damage in the MH pig. Catalase activities are normal in MH pigs, but they have only 20-50% normal GPX activities. The deficiency does not cause oxidative damage. It allows failure or protective mechanisms against it. The nonstressed MH animal exhibits less acute symptoms, e.g. enhanced red cell Heinz bodies, but such animals generally mature. Under stress, their inadequate protective mechanisms dependent on GPX are overwhelmed, resulting in gross symptoms and crisis. It is important to concentrate on the GPX system(s) and their adjacent pentose shunt metabolism. We propose that a deficiency in any of these two systems is the molecular basis of the disease. Many tissues are involve in MH, but the red cell obviously provides a convenient means for assay and for screening. This paper mainly pertains to porcine MH. However, preliminary work with humans indicates that human MH has a similar molecular basis.

Animals↗
PubMed1980

Atrial septal defect (sinus venosus type) in a dog.

A 2-year-old Old English Sheepdog had right-side congestive heart failure characterized by pericardial effusion, pleural effusion, ascites, and increased pulmonary wedge pressure. A diagnosis of atrial septal defect was made by means of cardiac catheterization and angiography. Surgical correction initially was deferred because of pulmonary hypertension. However, when congestive heart failure could not be managed adequately, surgical correction was attempted. Postsurgically, thrombocytopenia developed and that led to bleeding, oliguira, and pulmonary edema. The bleeding was controlled by whole blood transfusion, but the oliguria and pulmonary edema were not resolved, even with intensive diuretic therapy. The dog died 24 hours after surgery.

Angiography↗
PubMed1976

Reexpression of the original tumor pattern by a human breast carcinoma cell line (MCF-7) in sponge culture.

A stable cell line (MCF-7), derived from a pleural effusion of a patient with metastatic breast carcinoma, was maintained in these laboratories for more than 3 years in conventional monolayer culture. To further characterize the tumor origin of the MCF-7 line, cells were grown on collagen-coated cellulos sponges. On the three-dimensional sponge matrix, the cells formed clusters, ductlike structures, and lumina similar to the patterns observed in the antecedent primary tumor and in the pleural metastasis. The similarity between the original tumor and the cells grown in sponge suggested that the MCF-7 cells did in fact retain the potential to express the histologic patterns of tumor, even in the absence of stroma support. This study confirmed the utility of sponge culture for the investigation of the retention of tumor characteristics by cultured cells of neoplastic origin.

Adenocarcinoma, Scirrhous↗