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Biomedical subjects

J May

Publications and source records attributed to J May.

At least 109 records · Page 6Linked to original sources
PubMed1998

Type III and type IV endoleak: toward a complete definition of blood flow in the sac after endoluminal AAA repair.

In this document the authors continue to refine their seminal categorization of endoleak, a major complication of endovascular aneurysm repair. In addition to type I (related to the graft device itself) and type II (retrograde flow from collateral branches) endoleak, they propose two new categories: endoleak due to fabric tears, graft disconnection, or disintegration would be classified type III, and flow through the graft presumed to be associated with graft wall "porosity" would be categorized as type IV endoleak.

Aortic Aneurysm, Abdominal↗
PubMed1998

Diameter of large balloons used in endoluminal graft deployment varies with inflation pressure.

PURPOSE: To evaluate the characteristics of large-diameter balloon catheters used during endoluminal repair of aortic aneurysms. METHODS: Thirty-three large balloon dilatation catheters in the diameter range of 15 to 30 mm were measured at controlled pressures from 1 to 4 atm. The balloons were inflated with water using an inflation syringe connected to a pressure transducer. Diameters at stable pressure and pressure changes against time were recorded for each balloon. RESULTS: Dilation catheters in the range of 15 to 20 mm in diameter were significantly smaller (p < 0.005) than their nominal diameter at 1 and 2 atm; they reached nominal diameter only at the relatively high pressure of 4 atm. Most larger diameter balloons (25 and 30 mm) did not attain their nominal diameter even with pressures up to 4 atm. All sizes of balloon catheters tested became relatively compliant at pressures > 3 atm. CONCLUSIONS: The large balloon catheters tested in this study were designed for arterial angioplasty or valvuloplasty. They attained a significantly smaller size than their nominal diameter at pressures < 3 atm and became compliant at pressures exceeding 3 atm. Interventionists should be aware of these characteristics when using balloon catheters such as these during endoluminal graft deployment. Large balloons that reach predictable diameter at lower pressures should be designed specifically for use in endoluminal graft procedures.

Aortic Aneurysm↗
PubMed1998

HLA-DP control of human Schistosoma haematobium infection.

The DPA1 and DPB1 alleles of the major histocompatibility complex (MHC) class II were determined in 110 patients and 120 healthy controls of a Gabonese population from an area endemic for Schistosoma haematobium infection. The MHC-DP alleles of the variable second exons and their human leukocyte antigen (HLA) epitopes were correlated with egg excretion, interleukin-4 and interferon-gamma patterns, and bladder abnormalities, as detected by ultrasonography. A methionine at position 11 of the DP alpha molecule (Met-11) and DPA1*0301 were associated with schistosomiasis when compared with controls (phenotypic gene frequencies = 0.791 versus 0.583 and 0.555 versus 0.375, respectively). Met-11 homozygosity occurred more often in patients, whereas healthy controls were more frequently homozygous for an alanine at position 11 (Ala-11). The combination of the DPB1-epitope DEAV (positions 84-87 of the DP beta molecule) and Met-11 positive DPA1 alleles was more frequent in patients than in controls (0.573 versus 0.316). Two years after antischistosomal treatment, the rate of reinfection as examined in 55 of the 110 former patients was higher in DPA1*0301-positive individuals than in those not possessing this allele (P < 0.001). Ala-11 positive individuals showed less frequently ultrasonographic signs of bladder pathology than Ala-11 negative individuals (P < 0.05). Our results suggest a role of MHC-DP elements in the manifestation of disease in S. haematobium infection.

Adult↗
PubMed1998

Fact sheets on the Web: a case study of the on-line dissemination of information on the anti-infective properties of breast milk.

As the World Wide Web expands, it is beginning to take on a new role as a publishing medium for authoritative encyclopaedic information. This development is likely to impact the way in which many professionals work--improving their access to up-to-date information on the one hand, while enabling their clients to be much better informed on the other. This article draws on the experience gained from publishing a small, specialised Web site providing information on the anti-infective properties of human breast milk. It describes the way in which the Web site came into being, the nature and structure of the information that is provided, and the types of responses the site has received. The article concludes with a discussion of the ways in which the availability of authoritative information on the Web is likely to impact the future roles of health professionals.

Adult↗
PubMed1998

Two-year follow-up study to evaluate the reduction of left ventricular mass and diastolic function in mild to moderate diastolic hypertensive patients.

OBJECTIVE: To compare the effects of two antihypertensive agents, amlodipine and lisinopril, on left ventricular mass and diastolic filling in patients from primary care centers with mild to moderate diastolic hypertension. STUDY DESIGN: A second-year, open follow-up of a prospective, double-blind, randomized, parallel group, comparative study. METHODS: Male and female patients between 25 and 75 years-of-age with elevated diastolic blood pressure (four measurements > or = 95 mmHg from multiple measurements taken on three occasions and average diastolic blood pressure < 115 mmHg) were recruited from a population survey. After 4 weeks' placebo run-in, 71 patients were included of whom 60 finished the first study year and 51 finished the second study year. Patients were randomly assigned to receive doses of 5-10 mg amlodipine or 10-20 mg lisinopril, which were titrated on the basis of the effects on blood pressure. Primary endpoints were left ventricular mass index (LVMI) and early to atrial peak filling velocity. Office and ambulatory blood pressure were considered secondary endpoints. RESULTS: The decrease in blood pressure was equal for both treatment regimens in the first year. A statistically significant (P< 0.001) decrease in LVMI in both treatment groups was observed in the first year [-11.0 g/m2 (95% Cl -6.0 to -16.1) in the amlodipine group and -12.6 g/m2 (95% Cl -8.2 to -17.0) in the lisinopril group]. Early to atrial peak filling velocity did not change significantly within the treatment groups in the first year [+0.07 (95% CI -0.01 to +0.15) in the amlodipine group and +0.01 (95%9 Cl -0.06 to +0.08) in the lisinopril group. Blood pressure, LVMI and early to atrial peak filling velocity did not change in the second year of treatment. No significant differences in primary and secondary endpoints between treatment groups were found in the first or second year. CONCLUSION: The effects of amlodipine and lisinopril on left ventricular mass and early to atrial filling peak velocity after 2 years of treatment were similar and these effects were already observed after 1 year of treatment. Additional studies of longer duration (> or = 4 years) and with a larger sample size are recommended.

Adult↗
PubMed1997

Hepatitis G virus RNA and hepatitis G virus antibodies in renal transplant recipients: prevalence and risk factors.

BACKGROUND: Hepatitis G virus (HGV/GBV-C) RNA indicating current infection has been frequently isolated from the sera of transplant recipients and other multitransfused individuals. Lifetime exposure to the virus, however, is unknown. We carried out a study to determine the prevalence and risk factors of HGV antibodies and of HGV RNA among renal transplant recipients, and to investigate possible associations between HGV RNA and immunosuppressive treatment. METHODS: HGV RNA was detected by reverse transcriptase-polymerase chain reaction, and HGV antibodies (anti-E2) by a newly developed immunoassay. To assess risk factors for HGV exposure, univariate and multivariate analysis was performed. RESULTS: Of the 221 patients, 14% were HGV RNA positive and 40% had HGV antibodies. Both HGV RNA and anti-HGV were present in only two individuals. Thus, the overall HGV exposure prevalence was 53%. It increased significantly with the number of blood transfusions. In logistic regression, the adjusted HGV exposure prevalence odds ratio was 5.7 (95% confidence interval [CI]: 2.2-15) among patients with > or =10 transfusions (baseline: no transfusions). Other independent risk factors were a longer duration of hemodialysis and a longer time interval since transplantation. HGV viremia was not associated with the type of immunosuppressive treatment. Alanine aminotransferase levels were not significantly increased among HGV RNA-positive patients. CONCLUSIONS: Much higher proportions of renal transplant recipients were exposed to HGV than is suggested by HGV RNA detection alone. The majority of infected individuals apparently eliminate the virus over time. Contaminated blood transfusions have to be regarded as a main risk factor for HGV infection.

Adolescent↗
PubMed1997

Endoluminal repair of internal carotid artery aneurysm: a feasible but hazardous procedure.

PURPOSE: The aim of this study was to report the repair of an aneurysm of the internal carotid artery using the endoluminal method. METHODS: A 70-year-old male patient noted a swelling in the right side of his neck 22 years after endarterectomy of the right internal carotid artery. Duplex ultrasound confirmed the clinical diagnosis of aneurysm of the internal carotid artery. Further investigation included contrast-enhanced computed tomographic (CT) scanning and carotid angiography performed via a retrograde femoral approach. The aneurysm contained thrombus and was 3 cm in diameter and in length. It extended superiorly from a point 0.5 cm above the carotid bifurcation to a point estimated to be 2 cm from the base of the skull. Repair of the aneurysm was undertaken using the endoluminal method. A self-expanding endograft 8 mm in diameter and 4 cm in length was introduced through a 12F sheath in the common carotid artery. An on-table completion angiogram of the right-sided extracranial carotid arteries and the intracranial internal carotid artery and branches was obtained. RESULTS: The completion angiogram and postoperative CT scan confirmed exclusion of the aneurysm sac from the circulation. The patient awoke from anesthesia with complete paralysis of the left arm. Recovery of movement commenced 1 hour later. A brain CT scan demonstrated the event to be an embolic stroke. Strength had returned by 7 days. Function of the arm was good 1 month after operation, but coordination for fine movements was lacking. At the 6-month follow-up, good arm function was maintained. A duplex ultrasound scan demonstrated not only continued exclusion of the aneurysm sac but occlusion of the endograft, also. CONCLUSIONS: Endoluminal repair of aneurysms of the internal carotid artery is feasible but carries the risk of major morbidity as a result of peripheral embolization and early occlusion of the endograft.

Aged↗
PubMed1997

Concurrent comparison of endoluminal repair vs. no treatment for small abdominal aortic aneurysms.

UNLABELLED: Endoluminal repair of abdominal aortic aneurysms (AAA) requires the aneurysm to have a proximal neck of at least 1.5 cm between the renal arteries and the aneurysm. Therefore, there may be advantages in performing endoluminal repair in the early stages of aneurysm development. However, the results of endoluminal repair performed in patients with small aneurysms with favourable morphology are not known. The aim of this study was to determine whether a randomised trial of endoluminal repair vs. no treatment for small aneurysms would be justified by using a concurrent comparison of endoluminal repair vs. no treatment for AAA 5 cm or less in diameter in patients presenting to the same centre during a 4-year period. METHODS: Data on 117 patients presenting with AAA 5 cm or less in diameter were entered into a registry. The decision to perform endoluminal repair vs. no treatment was based on the patient's preference following surgical consultation and investigation by computed tomography. This study reports the mortality, morbidity and survival of patients presenting between June 1992 and August 1996. During this time 43 patients had endoluminal repair and 67 patients had no treatment for small AAA. Seven patients were unfit for any intervention. Despite patient selection for different management in each group, close analysis revealed that the groups were similar with regard to co-morbidities and risk factors, as well as age, sex, and size of aneurysm. Follow-up was by progress CT scanning and ranged from 1 to 51 months (mean 18 months (NT) and 22 months (ER)). RESULTS: Endoluminal repair failed in six of 43 patients (14%) and resulted in 11 (25%) local vascular complications. There were two perioperative deaths and one late death in this group. Twenty-one of 67 AAA (31%) patients in the no treatment group enlarged beyond 5 cm in diameter during the study period. There was one death from aneurysm rupture and one death from myocardial infarction in this group. CONCLUSIONS: The patients in the endoluminal repair group have gained an asset in having their aneurysms repaired at a cost of early morbidity following operation. These results suggest that a randomised trial of endoluminal repair vs. no treatment will become justified in the subset of patients with small AAA 5 cm or less, if the incidence of complications can be reduced by further improvements in endoluminal technology.

Age Factors↗
PubMed1997

The efficacy of transfemoral endovascular aneurysm management: a study on size changes of the abdominal aorta during mid-term follow-up.

OBJECTIVES: The aim of this study was to assess efficacy of transfemoral endovascular aneurysm management (TEAM) during mid-term follow-up. DESIGN: Prospective multicentre study. MATERIALS AND METHODS: In 26 patients treated by a Tube Endograft, the pre- and postoperative contrast enhanced computed tomography (CT) images were reviewed in a blinded fashion. Aortic diameters were measured at the coeliac trunk, the inferior and superior aneurysm neck and the level of the maximal aneurysm size. The changes in diameter were related to the presence or absence of an endoleak. RESULTS: The median follow-up was 12 months. In 10 patients an endoleak was found. Three endoleaks sealed spontaneously within 30 days after operation. All aneurysms with persistent endoleaks expanded, at a median rate of 0.30 mm per month. Four patients were converted between 9 and 14 months after TEAM. Aneurysms excluded by the endoprosthesis showed a median shrinkage of 0.41 mm per month. The inferior aneurysm neck demonstrated significant growth during follow-up, unrelated to endoleaks. CONCLUSIONS: This study demonstrated the efficacy of TEAM in discontinuing the process of aneurysm expansion. Complete seal of the aneurysm sac after TEAM leads to shrinkage or arrest of growth of the aneurysm, while persistent endoleak is associated with progressive expansion.

Aged↗
PubMed1997

Conversion from endoluminal to open repair of abdominal aortic aneurysms: a hazardous procedure.

AIM: The purpose of this study was to analyse the technical problems associated with conversion from endoluminal repair of abdominal aortic aneurysms (AAA) to open repair and document the outcome in patients with this clinical course. METHODS: Between May 1992 and May 1996 endoluminal repair of AAA was undertaken in 113 patients. Forty-eight of these had medical co-morbidities which led to them being rejected for open repair at other medical centres. Conversion from endoluminal to open repair was required in 18 patients. Thirteen of these occurred at the original operation (primary conversion) and five occurred at a later operation (secondary conversion). Seven of the 18 patients undergoing conversion had serious medical co-morbidities. Three different methods of open repair were used. The technique selected was determined by the cause of failure leading to conversion. Standard open AAA repair was used in patients requiring conversion for access problems (n = 2) and balloon malfunction, where the device ended up entirely within the aneurysmal sac (n = 1). Modifications to the standard technique were required in patients in which the endograft was correctly positioned immediately below the renal arteries and/or where part of the endograft was within one or both common iliac arteries (n = 11). Supra-coeliac control was required for patients with aortic rupture (n = 1), renal arteries covered by the endograft (n = 2) and situations where the delivery catheter was trapped within the aorta above a twisted bifurcated graft (n = 1). The mean volume of contrast used was 225 ml and the mean operative time was 5.25 h in patients undergoing primary conversion. RESULTS: Conversion to open repair was achieved in all 18 patients. Renal impairment requiring dialysis occurred in three patients. There were three perioperative deaths, all of which were procedure-related (17%), and one late death. All four deaths occurred from among the group of seven patients with preoperative co-morbidities. CONCLUSIONS: Converting an endoluminal to an open AAA repair may require modifications to the standard open technique and result in a much higher than generally accepted morbidity and mortality rate. Patients rejected for open repair because of co-morbidities ran the same chance of requiring conversion as those without co-morbidities (15-17%). If conversion was required, however, they stood a 3 in 7 or 43% chance of dying.

Aged↗
PubMed1997

HLA DRB1-DQA1-DQB1 haplotype diversity in two African populations.

HLA class II DRB1-DQA1-DQB1 haplotypic polymorphism was determined in 120 Liberian and 230 Gabonese individuals. In our study groups, the number of allelic variants observed for each locus was similar to that found in non-African populations. However, 39 novel haplotypes and several yet unrecognized DRB1-DQA1 and DQA1-DQB1 combinations were identified. The extent of HLA-haplotypic variability in Africans appears to result from the high degree of allele combinations rather than from allelic polymorphism.

Africa↗