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Biomedical subjects

M Gibson

Publications and source records attributed to M Gibson.

At least 37 records · Page 2Linked to original sources
PubMed2001

Early results of retrograde transpopliteal angioplasty of iliofemoral lesions.

PURPOSE: To assess whether the retrograde transpopliteal approach is a safe, practical and effective alternative to femoral puncture for percutaneous transluminal angioplasty (PTA). METHODS: Forty PTAs in 38 patients were evaluated. Intentional subintimal recanalization was performed in 13 limbs. Ultrasound evaluation of the popliteal fossa was carried out 30 min and 24 hr postprocedurally in the first 10 patients to exclude local complications. All patients had a follow-up of at least 6 weeks. RESULTS: The indication for PTA was critical ischemia in seven limbs and disabling claudication in the remainder. Stenoses (single or multiple) were present in 24 and occlusion in 15. The superficial femoral artery (SFA) was the commonest segment affected (36) followed by common femoral artery (CFA) in four and iliac artery in four. Technical success was achieved in 38 of 39 limbs where angioplasty was carried out. In one limb no lesion was found. Immediate complications were distal embolization in two and thrombosis in one. None of these required immediate surgery. There were no puncture site hematomas or popliteal arteriovenous fistulae. Symptomatic patency at 6 weeks was 85%. Further reconstructive surgery was required in three limbs and amputation in two. CONCLUSION: The transpopliteal approach has a high technical success rate and a low complication rate with a potential to develop into an outpatient procedure. It should be considered for flush SFA occlusions or iliac disease with tandem CFA/SFA disease where the contralateral femoral approach is often technically difficult.

Aged↗
PubMed2001

Stereotaxic delivery of corticosterone to the amygdala modulates colonic sensitivity in rats.

Episodes of anxiety are often associated with the onset or exacerbation of visceral pain in patients with irritable bowel syndrome (IBS). The central amygdaloid nucleus (CeA) is a key limbic structure involved in the expression of anxiety as well as a major site for regulating autonomic and visceral responses to stress. Previous experiments have shown that glucocorticoids can act directly at the CeA to increase the level of anxiety in rats. Therefore, the goal of this study was to examine the effect of stereotaxic delivery of corticosterone into the CeA on the development of visceral hypersensitivity by measuring visceromotor response to colorectal distention in rats. Stereotaxic delivery of corticosterone to the CeA increases indices of anxiety and produces a hypersensitive colon as demonstrated by an exaggerated visceromotor response to colorectal distention in the F344 rat strain. Our findings suggest that modulation of anxiety by manipulating amygdala function with corticosterone induced colonic hypersensitivity via descending neuronal pathways from the CeA.

Acetic Acid↗
PubMed2001

Measurement of personal exposure to aerosols of Nephrops norvegicus (scampi) using a monoclonal-based assay.

BACKGROUND: The industrial processing of scampi (Nephrops norvegicus) generates bioaerosols which can cause occupational respiratory disease in exposed individuals. The objective of this study was to develop a monoclonal antibody-based immunoassay to measure scampi proteins collected using standard personal air sampling methods. METHODS: A monoclonal antibody was generated which predominantly bound to a single 97 Kd scampi protein, which we have shown to be a major allergen. This protein was shown by SDS PAGE immunoblotting to be present in various aqueous extracts from wastes produced during scampi processing. A quantitative immunoslotblot method was developed to quantify scampi from air sample filters. RESULTS: We demonstrated the utility of this method by showing a significant difference (P = 0.015) in the level of exposure of two groups of 12 workers processing scampi at a traditional open workstation (GM = 607 ng m(-3)) and at an enclosed workstation (GM = 451 ng m(-3)). CONCLUSION: We conclude that this assay can be used, in conjunction with health surveillance, to monitor exposure and the efficacy of measures to reduce exposure to airborne scampi allergen in an occupational environment.

Aerosols↗
PubMed2001

An audit of root canal treatment performed by undergraduate students.

AIM: The objective of this study was to audit the quality of root canal treatment performed by undergraduate students on adult patients. METHODOLOGY: All root canal treatment completed by first and second clinical year undergraduates over a 12-month period were included in the study. The availability and readability of pretreatment, diagnostic length, try-in point and postoperative radiographs were noted for each case. All readable postoperative radiographs of primary treatments were examined for quality of the root filling, categorized as complete, incomplete apical, incomplete apical and lateral or not assessable. The distance from the radiographic apex of the root to the apical extent of each root filling was measured to 0.1 mm precision. RESULTS: Undergraduates performed primary treatment on 157 teeth. A postoperative radiograph was available in 97% of cases. A try-in point radiograph was unavailable in one-fifth of cases. Twenty-seven teeth (13%) were categorized as satisfactory in terms of both radiographic quality and distance of the root filling from the radiographic apex. CONCLUSIONS: Overall, the technical quality of root canal treatment completed by undergraduate students was poor.

Adult↗
PubMed2001

Stenting for localised arterial stenoses in the aorto-iliac segment.

OBJECTIVE: to determine complications and patency following angioplasty (PTA) and stenting of aorto-iliac stenoses. SETTING: District General Hospital in U.K. DESIGN: prospective observational study. PATIENTS AND METHODS: between December 1994 and June 2000, 50 patients (38 men), median age 64 (41-89) years underwent aorto-iliac stenting. A total of 61 stents were placed. Indications were intermittent claudication in 38 and rest pain, ulceration or gangrene in 12. Sites stented were aorta 11, common iliac artery 32, external iliac artery 14, common and external iliac arteries two. Bilateral iliac procedures were carried out in nine. Two stents were used to correct residual stenoses after aortic stenting. Some 11 recurrent stenoses were treated. The other reasons for stenting were residual stenoses greater than 30% after PTA, tight calcified stenoses or when a stenosed iliac artery was being used as a donor prior to crossover or femoropopliteal bypass. RESULTS: two immediate technical failures occurred due to malposition. Residual stenoses were corrected by PTA. Two further patients sustained minor complications. None of the aortic stents occluded through two required secondary procedures. Primary-assisted patency was thus 100% at three years. Primary patency following iliac stenting for claudication and critical ischaemia were 97% and 86% at three years respectively. CONCLUSION: PTA and stenting of aorto-iliac stenoses can be safely achieved with durable results.

Adult↗
PubMed2001

Randomized comparison of a novel anticoagulant, vasoflux, and heparin as adjunctive therapy to streptokinase for acute myocardial infarction: results of the VITAL study (Vasoflux International Trial for Acute Myocardial Infarction Lysis).

BACKGROUND: Vasoflux is a low-molecular-weight heparin derivative that inhibits factor IXa activation of factor X and catalyzes fibrin-bound thrombin inactivation by heparin cofactor II. We studied whether vasoflux improves the results of thrombolysis with streptokinase for acute myocardial infarction. METHODS AND RESULTS: We randomized 277 patients with acute myocardial infarction to standard intravenous unfractionated heparin (UFH) or intravenous vasoflux 1, 4, 8, or 16 mg/kg as a bolus followed by 1, 4, 8, or 16 mg/kg per hour infusion, on top of streptokinase and aspirin, until angiography at 90 minutes. Patency and corrected Thrombolysis in Myocardial Infarction (TIMI) frame count were studied at 60 and 90 minutes. Rates of TIMI grade 3 flow with vasoflux at any dose (35% to 42%) were not different from UFH (41%) at either time point, nor was the corrected TIMI frame count. However, there was an excess of bleeding in the patients randomized to vasoflux 8 or 16 mg/kg: 78% and 71%, compared with 53% for UFH (P =.004 and.043, respectively). Major bleeding was observed in 13% and 28% at these vasoflux doses compared with 8% with UFH (P =.558 and.01, respectively). CONCLUSION: At doses that increase the risk of bleeding, the addition of vasoflux to streptokinase and aspirin did not lead to improved patency rates compared with UFH. Targeting factor IXa and heparin cofactor II may not be a useful adjunct to thrombolysis.

Adult↗
PubMed2001

A relational schema for both array-based and SAGE gene expression experiments.

MOTIVATION AND RESULTS: A relational schema is described for capturing highly parallel gene expression experiments using different technologies. This schema grew out of efforts to build a database for collaborators working on different biological systems and using different types of platforms in their gene expression experiments as well as different types of image quantification software. The tables are conceptually organized into three categories of information: Platform, Experiment (which includes image scanning and quantification), and Data. The strengths of the schema are: (i) integrating information on array elements using a gene index; (ii) describing samples using ontologies; (iii) reducing an experiment to a single RNA source for precise descriptions yet not losing the relationships between experiments done at the same time or for the same project; and (iv) maintaining both raw and processed (e.g. cleansed and normalized) data and recording how the data is processed. The result is a novel schema, which can hold both array and non-array data, is extensible for detailed experimental descriptions that are precise and consistent, and allows for meaningful comparisons of genes between experiments.

Databases, Factual↗
PubMed2001

Multicystic dysplastic kidney and Kallmann's syndrome: a new association?

BACKGROUND: Kallmann's syndrome is characterized by anosmia and hypogonadotrophic hypogonadism. Radiographic studies of teenagers and older subjects with the X-linked form of the syndrome have shown that up to 40% have an absent kidney unilaterally. Although this has been attributed to renal "agenesis", a condition in which the kidney fails to form, little is known about the appearance of the developing urinary tract either pre- or post-natally in individuals with Kallmann's syndrome. METHODS: We describe two brothers who had features of Kallmann's syndrome, most probably of the X-linked variety, who both had a major urinary-tract malformation detected before birth. RESULTS: The brothers were found to have unilateral multicystic dysplastic kidneys on routine antenatal ultrasound scanning and both underwent surgical nephrectomy of these organs post-natally. Immunohistochemical studies on the younger sibling revealed hyperproliferative dysplastic kidney tubules which overexpressed PAX2, a potentially oncogenic transcription factor, and BCL2, a cell-survival factor, surrounded by metaplastic, alpha smooth-muscle actin-positive stroma: similar patterns have been observed in patients with non-syndromic multicystic dysplastic kidneys. CONCLUSIONS: Our results describe a new type of urinary-tract malformation associated with Kallmann's syndrome. However, since multicystic kidneys tend to involute, only when more Kallmann's syndrome patients are screened in utero or in early childhood using structural renal scans, will it be possible to establish whether multicystic kidney disease is a bona-fide part of the syndrome.

Child, Preschool↗
PubMed2001

The association football medical research programme: an audit of injuries in professional football.

OBJECTIVES: To undertake a prospective epidemiological study of the injuries sustained in English professional football over two competitive seasons. METHODS: Player injuries were annotated by club medical staff at 91 professional football clubs. A specific injury audit questionnaire was used together with a weekly form that documented each club's current injury status. RESULTS: A total of 6,030 injuries were reported over the two seasons with an average of 1.3 injuries per player per season. The mean (SD) number of days absent for each injury was 24.2 (40.2), with 78% of the injuries leading to a minimum of one competitive match being missed. The injury incidence varied throughout the season, with training injuries peaking during July (p<0.05) and match injuries peaking during August (p<0.05). Competition injuries represented 63% of those reported, significantly (p<0.01) more of these injuries occurring towards the end of both halves. Strains (37%) and sprains (19%) were the major injury types, the lower extremity being the site of 87% of the injuries reported. Most injury mechanisms were classified as being non-contact (58%). Re-injuries accounted for 7% of all injuries, 66% of these being classified as either a strain or a sprain. The severity of re-injuries was greater than the initial injury (p<0.01). CONCLUSIONS: Professional football players are exposed to a high risk of injury and there is a need to investigate ways of reducing this risk. Areas that warrant attention include the training programmes implemented by clubs during various stages of the season, the factors contributing to the pattern of injuries during matches with respect to time, and the rehabilitation protocols employed by clubs.

Adult↗
PubMed2001

Open versus percutaneous dilatational tracheostomy: efficacy and cost analysis.

The economic advantages of percutaneous dilatational tracheostomies versus open tracheostomies in the operating room have been thoroughly evaluated. We are now reporting our comparison of the costs and charges of percutaneous dilatational tracheostomies with those of open bedside tracheostomies at our institution. The current literature comparing the two open techniques and the percutaneous method of placing tracheostomies was reviewed and the charges and costs for these procedures at our institution were compared. Patients were placed into one of three groups for analysis: open tracheostomies in the operating room (Group I), open tracheostomies in the intensive care unit (Group II), and percutaneous dilatational tracheostomies in the intensive care unit (Group III). Based on our own experience and a literature review it is evident that all three approaches to tracheostomies are safe. Economic analysis showed a savings of $180 in cost per procedure and a $658 savings in charges per procedure for the open method at the bedside when compared with the percutaneous method at the bedside. The professional fee for bronchoscopy was not included in this calculation; including this would lead to greater savings with the open method over the percutaneous method. Open tracheostomy in the operating room increased costs over the bedside procedure by $2194 and increased charges by $2871. For the 150 to 180 tracheostomies done each year at our institution utilization of the open technique at the bedside results in a cost savings of approximately $31,500 and a charge savings of $109,000 compared with the percutaneous dilatational tracheostomy. Both the open bedside and percutaneous dilatational methods are reasonable and safe options. However, the open bedside tracheostomy is a better utilization of resources and is more cost effective, and it is the procedure of choice at our institution.

Cost Savings↗
PubMed2000

A conserved role for H15-related T-box transcription factors in zebrafish and Drosophila heart formation.

T-box transcription factors are critical regulators of early embryonic development. We have characterized a novel zebrafish T-box transcription factor, hrT (H15-related T box) that is a close relative of Drosophila H15 and a recently identified human gene. We show that Drosophila H15 and zebrafish hrT are both expressed early during heart formation, in strong support of previous work postulating that vertebrate and arthropod hearts are homologous structures with conserved regulatory mechanisms. The timing and regulation of zebrafish hrT expression in anterior lateral plate mesoderm suggest a very early role for hrT in the differentiation of the cardiac precursors. hrT is coexpressed with gata4 and nkx2.5 not only in anterior lateral plate mesoderm but also in noncardiac mesoderm adjacent to the tail bud, suggesting that a conserved regulatory pathway links expression of these three genes in cardiac and noncardiac tissues. Finally, we analyzed hrT expression in pandora mutant embryos, since these have defects in many of the tissues that express hrT, including the heart. hrT expression is much reduced in the early heart fields of pandora mutants, whereas it is ectopically expressed subsequently. Using hrT expression as a marker, we describe a midline patterning defect in pandora affecting the anterior hindbrain and associated midline mesendodermal derivatives. We discuss the possibility that the cardiac ventricular defect previously described in pandora and the midline defects described here are related.

Amino Acid Sequence↗
PubMed2000

Directional coronary atherectomy in intermediate sized vessels: final results of the intermediate vessel atherectomy trial (IVAT).

Revascularization options for intermediate sized vessels (2.5-2.9 mm) have historically been limited. IVAT is a pilot study to assess the efficacy and safety of debulking intermediate sized vessels using directional coronary atherectomy (DCA). Between March 1996 and June 1997, 50 patients were enrolled at seven hospitals in the United States. Of those patients, 70% presented with unstable angina and 52% had single vessel disease. Of the lesions treated, 96% were de novo. Adjunctive PTCA after DCA was performed in 90% of cases at the discretion of the investigator to maximize luminal diameter. The GTO DCA device was used in 90% of cases. Procedural success (residual stenosis <50% without major complications) was 94%. Stents were placed in 12% of patients. The only complications were three non-Q wave MIs. Mean reference vessel diameter increased from 2.49 mm pre-procedure to 2.57 mm after DCA and 2.61 post-procedure; mean MLD increased from 0.76 mm to 2.03 mm to 2.31 mm; and mean stenosis decreased from 70% to 21% post DCA and to 11% post procedure. At six months follow-up, 18.0% of target lesions required revascularization. Total revascularization, including non-target vessels, was 32%. These results suggest that DCA has a high procedural success rate and a low target lesion revascularization rate in intermediate sized vessels.

Adult↗
PubMed2000

Maintenance of patency following remote superficial femoral artery endarterectomy.

BACKGROUND: Remote superficial femoral artery endarterectomy (RSFE) is a minimally invasive means of superficial femoral artery revascularisation. It comprises a single groin incision and securing of the distal cut end of atheroma with an intraluminal stent. AIM: To determine medium-term results of RSFE, with particular reference to costs of maintaining patency. METHODS: Stenosis development, and patency of 25 RSFE were compared with 25 randomly selected in situ vein bypasses with similar follow-up (18-33 months). RESULTS: Following RSFE 17 stenoses were identified by duplex surveillance. Half of those arteries patent at 1 yr had stenoses. Angioplasty (PTA) was carried out for 11 stenoses. Four stenoses developed more than 12 months following RSFE. One patient died and nine arteries occluded during follow-up. Primary and primary- assisted patency at 18 months were 31 and 63% respectively. By contrast six stenoses were identified in 25 in situ grafts, all within one year. Four PTAs were carried out. Three grafts occluded. Excluding cost of three monthly duplex surveillance the cost of maintaining RSFE patency was approximately five times that of maintaining in situ bypass patency. CONCLUSION: The initial cost advantage of RSFE is offset by the increased costs of maintaining patency. Duplex surveillance probably needs to be continued indefinitely.

Aged↗
PubMed2000

Remote superficial femoral artery endarterectomy: medium-term results.

BACKGROUND: the aim of this study is to determine the medium-term results following successful remote superficial-femoral endarterectomy (RSFE). SETTING: district general hospital in United Kingdom. METHODS: RSFE comprises a single incision over the origin of the superficial femoral artery. The endarterectomy is carried out in a closed fashion from above. The cut end of distal atheroma is secured with a stent. Twenty-five limbs were followed up with three monthly duplex scans and angiography if any abnormality was suggested. All patients presented with intermittent claudication; in addition three had rest pain and three ulceration or gangrene. The length of atheromatous core removed was 10-30 cm. RESULTS: all patients had a follow-up of at least one year (range 12-27 months). Eleven arteries developed 14 stenoses. Nine became apparent within nine months of RSFE. The cumulative risk of stenoses developing in patent arteries was 24% at 6 and 63% at 12 months. Eleven angioplasties (PTA) of these stenoses were undertaken. Nine of these remain patent at a median of 12 months after PTA. At one year primary patency was 10 of 25 (40%), primary-assisted patency 18 of 25 (72%) and secondary patency 19 of 25 (76%) and at two years 29%, 57% and 57% respectively. CONCLUSIONS: RSFE is worth considering for superficial femoral artery occlusive disease, particularly in high-risk patients without suitable vein and with limited life expectancy. Careful duplex surveillance is important. Until stenoses can be prevented, the widespread use of RSFE cannot be recommended.

Aged↗
PubMed2000

Iliac occlusions: stenting or crossover grafting? An examination of patency and cost.

OBJECTIVES: Percutaneous transluminal angioplasty with stenting is perceived to be a less invasive and cheaper option for the treatment of iliac artery occlusion than surgical reconstruction. We have carried out a prospective observational study of all patients undergoing an iliac stent or femorofemoral crossover graft for iliac artery occlusion to assess the cost effectiveness of the two approaches in a district general hospital. METHODS: Fifty-one patients underwent primary angioplasty with stenting and 87 patients crossover grafting. Patients were all assessed 2 months after their procedure and then at intervals over the following years. RESULTS: In 13 cases, it was impossible to place the stent successfully. In a further 10 patients, major complications occurred which were mainly thromboembolic. Fifteen patients underwent crossover grafting after failure to insert a stent, or after stent occlusion. No major complications occurred following crossover grafting. The median length of stay following successful stenting was 1 day; the following crossover grafting was 4 days. The mean stay was higher in each group (2.5 and 5.8 days) and is a more accurate parameter for estimation of cost, which for iliac stenting is estimated at pound1912 versus pound3072 for crossover grafting. The mean additional cost of those patients sustaining complications after stenting was pound2481. On an <<< >>> basis, patency following stent insertion at 6 months was 52%; patency after bypass was 100% (p <0.0001). If any complication occurs after stenting, the cost advantage of the procedure is lost. In those patients without complication, the initial cost benefit of iliac stenting is lost within 6 months, as patients require further intervention, usually as a crossover graft, when the stent occludes. Crossover grafting is a durable low-risk procedure. CONCLUSIONS: We suggest that stenting of occluded iliac arteries should be reserved for those patients with limited life expectancy. Patients who are younger and fitter should be offered femorofemoral crossover grafting as a primary procedure until research enables identification of those patients who are most likely to maintain long-term patency after stenting.

Aged↗