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Biomedical subjects

J May

Publications and source records attributed to J May.

At least 91 records · Page 5Linked to original sources
PubMed1999

Association of the ICAM-1Kilifi mutation with protection against severe malaria in Lambaréné, Gabon.

The intercellular adhesion molecule-1 (ICAM-1) is thought to be a receptor that mediates binding of Plasmodium falciparum-infected erythrocytes. Especially in vital organs, the binding of parasitized cells to the endothelium via ICAM-1 may lead to severe disease and death. Recently, a mutation in the coding region of ICAM-1, termed ICAM-1Kilifi, was described, causing a change from Lys to Met in the loop that interacts with rhinoviruses, lymphocytes, and parasitized red blood cells. Surprisingly, this mutation was shown to increase susceptibility of Kenyan children to severe malaria in one study. When we compared the distribution of ICAM-1Kilifi in two groups of Gabonese children enrolled in a case-control, matched-pair study who presented with either mild or severe malaria, we found that 55% of the patients with mild malaria were carriers whereas only 39% of those with severe malaria were carriers. The difference in the distribution of ICAM-1Kilifi homozygous pairs between the groups, as well as the distribution of ICAM-1Kilifi carriers, was statistically highly significant (P = 0.027 and P = 0.012, by the McNemar test). In a group of healthy school children from the same region, a distribution of 52% ICAM-1Kilifi carriers to 48% wild-type individuals was found. In a survey for the ICAM-1Kilifi in other malaria-endemic regions, this allele was also found in Nigeria and Papua New Guinea, but not in Thailand.

Animals↗
PubMed1999

Early and late conversion from endoluminal to open repair.

Conversion from endoluminal to open repair of abdominal aortic aneurysms (AAA) may be primary, at the original operation or secondary, at a subsequent operation. The indications for primary conversion include aortic rupture and migration of an endograft resulting in obstructed blood flow and irreversible twisting of an endograft. The indications for secondary conversion include persistent endoleak, sealed endoleak with continued AAA expansion, apparently successful AAA repair, with continued expansion and the presence of an infected endograft. The technique of conversion varies from standard repair through modified standard repair to supraceliac control, depending on the cause of failure leading to conversion. All conversion procedures expose the patient to an increased risk and are best avoided by careful case selection, accurate sizing, and good procedural technique.

Aneurysm, Ruptured↗
PubMed1999

Serum transferrin receptor levels are increased in asymptomatic and mild Plasmodium falciparum-infection.

BACKGROUND AND OBJECTIVE: The serum transferrin receptor (sTfR) concentration in an individual reflects the extent of erythropoietic activity and is considered a useful marker of iron deficiency independent of concurrent inflammation or infection. However, data on the impact of malaria on this parameter are ambiguous. We have examined potential associations of asymptomatic and mild Plasmodium falciparum-infections and of several erythrocyte variants with sTfR values in South West Nigeria. DESIGN AND METHODS: In a cross-sectional study among 161 non-hospitalized children, sTfR concentrations and P. falciparum parasitemia were assessed. In addition, hemoglobin (Hb) and serum ferritin values, Hb-types, glucose-6-phosphate dehydrogenase (G6PD)deficiency and a-globin genotypes were determined and the effects of these factors on sTfR levels were analyzed by univariate and multivariate statistical methods. RESULTS: P. falciparum-infection was present in 77% of the children. Mean sTfR levels were higher in infected than in non-infected children (geometric mean, 3.68, 95% confidence interval [3.5-3.9] vs. 2.99 [2.7-3.3] mg/L; p = 0.0009). There was a significant trend for higher sTfR values with increasing parasite density. sTfR values decreased continuously with age. Hb-types, G6PD-, and a-globin genotypes did not correlate with sTfR levels. In the multivariate analysis, age, Hb and log ferritin values, and parasite density of P. falciparum were independently associated with log sTfR values. INTERPRETATION AND CONCLUSIONS: sTfR concentrations are increased in asymptomatic and mild P. falciparum-infections suggesting adequate bone marrow response in this condition. The diagnostic value of sTfR levels for iron deficiency may be impaired in areas where stable malaria occurs.

Age Factors↗
PubMed1999

Novel Aortic Reconstruction Strategies: Endovascular Aneurysm Repair.

New technology has given vascular surgeons novel treatment options for aortic diseases. Endovascular aortic aneurysm repair is a minimally invasive technique that uses a graft to reconstruct an aneurysmal segment without laparotomy, aortic incision, or cross-clamping. The procedure results in less pain and suffering for patients and requires fewer health care resources. Although still experimental in the United States, this operation has become routine in several centers in Australia and Europe. Collective experience with endovascular repair has yielded complication and mortality results that compare favorably with those from leading studies of conventional repair, despite significant medical comorbidity among its cohorts. The durability of contemporary endovascular repair approaches, but does not yet equal, that of conventional surgery. However, in conditions such as complicated aortic dissection, the new technique may be superior. In this review we describe endovascular devices and their selection and discuss results of the largest contemporary studies.

Journal Article↗
PubMed1998

Total or subtotal gastrectomy for gastric carcinoma? A study of quality of life.

The aim of this study was to compare quality of life after total gastrectomy (TG) with that after subtotal gastrectomy (STG) for gastric carcinoma. The value of the routine use of TG de principe in the treatment of gastric carcinoma, wherever the tumor may be sited in the stomach, remains controversial. The advocates of TG contend that when it can be performed safely, with relatively low operative mortality and morbidity, it yields better long-term survival than STG. Most surgeons, however, believe that the routine use of TG increases both operative mortality and morbidity and the risk of nutritional deficiency in the long term, without improving survival. TG may also be associated with poorer outcome in terms of quality of life (QOL), but the evidence for this is tenuous. Forty-seven consecutive patients who had undergone potentially curative (R0) gastric resection for carcinoma were studied: 26 had undergone TG and 21 STG. A radical D2 lymph node dissection had been performed in each, and all patients were free from recurrence at the time of the study. QOL was measured before operation and 1, 3, 6, and 12 months after operation by means of five questionnaires to measure functional outcome: the Rotterdam symptom checklist (RSCL), the Troidl index, the hospital anxiety and depression (HAD) scale, activities of daily living score, and Visick grades. Before operation there was no significant difference in QOL between the two groups of patients. At 1 year after operation, however, patients who had undergone STG had a significantly better QOL than patients who had undergone TG: Their median RSCL score was lower (10 versus 19 respectively, p < 0.05), and their Troidl index was higher (11 versus 9 respectively, p < 0.05). The QOL of patients who underwent STG was also significantly better after operation than it had been before operation, whereas the QOL of the TG group was not significantly better after operation than before operation. The QOL of patients was found to be significantly better after STG than after TG for gastric carcinoma. Because operative mortality is greater and long-term survival is no better after TG than after STG, the latter is recommended as the treatment of choice for tumors of the distal stomach.

Activities of Daily Living↗
PubMed1998

Concurrent comparison of endoluminal versus open repair in the treatment of abdominal aortic aneurysms: analysis of 303 patients by life table method.

PURPOSE: The aim of this study was to compare the outcome of consecutive patients with abdominal aortic aneurysm (AAA) treated concurrently by open operation and endoluminal intervention by the same surgeons during a defined interval. METHODS: Between May 1992 and May 1996, 362 consecutive patients with AAA underwent repair. Fifty-three patients who underwent open operations for ruptured AAA plus two patients who underwent endoluminal repair of false AAA and four patients who underwent secondary endoluminal repair of AAA were excluded, leaving 303 patients who underwent elective repair of true AAA in the study. The elective operations were conventional open repair (OR) in 195 patients (151 men, 44 women; mean age, 69 years) and endoluminal repair (ER) in 108 patients (100 men, 8 women; mean age, 70 years). The decision to perform ERwas based on comorbidities that precluded open repair (n = 48) and patient choice (n = 60). Graft configuration in the open repair group was tubular (n = 180) and bifurcated (n = 15), and in the ER group tubular (n = 48), aortoiliac/femoral (n = 25), and bifurcated (n = 35). All procedures were performed in the operating department, and radiographic guidance was used in the ER group. Follow-up was by interview, examination, and telephone. In addition, contrast-enhanced computed tomography was performed within the first 10 days after operation, 6 months and 12 months after operation, and then annually thereafter in the ER group. Outcome measures were successful exclusion of the aneurysm sac from the general circulation and survival. Data were analyzed by the life table method. Other outcome measures were length of hospital stay, length of intensive care unit stay, and operative blood loss. RESULTS: No significant difference was found between the perioperative mortality rate for OR (11 deaths [5.6%] in 195 patients) and ER (six deaths [5.6%] in 108 patients). Three of the six deaths in the latter group occurred in patients with successful ER, and three occurred in 18 patients with failed ER who were converted to OR. Similarly, no significant difference was seen in the survival rate between the endoluminal and open repair groups when analyzed by the log-rank test (p = 0.14). The rate of graft failure, however, was significantly higher in the ER group than in the OR group (Fisher's exact test, p < 0.001). Success in the ER group was defined as continuing graft function without endoleak or conversion to open repair. Kaplan-Meier curve for graft failure times for the endoluminal group revealed a 3-year graft success probability of 70%. CONCLUSIONS: This study suggests that ER is safe, sharing the same perioperative mortality risk as OR despite 44% of the ER group being rejected as unfit for OR. Conventional open repair is the most reliable method of successfully managing AAA. The endoluminal method, however, results in shorter length of hospital stay, shorter length of intensive care unit stay, and less blood loss than the open method. Patients who opt for the endoluminal method of repair should be made aware that the minimally invasive technique carries the disadvantage of a higher failure rate.

Aged↗
PubMed1998

Human leukocyte antigens in tuberculosis and leprosy.

Human mycobacterial infections are characterized by a spectrum of clinical and immunological manifestations. Specific human leukocyte antigen (HLA) factors are associated with the subtypes of leprosy that develop and the course of tuberculosis after infection. The identification of protective mycobacterial antigens presented by a broad variety of HLA molecules will have important implications for the design of vaccines.

Animals↗
PubMed1998

Endovascular grafting for abdominal aortic aneurysms: changing incidence and indication for conversion to open operation.

The incidence and indications for conversion from endoluminal to open repair of abdominal aortic aneurysms are changing. This paper is based on a 5-year experience in which endoluminal repair of abdominal aortic aneurysms was undertaken in 156 patients. Primary conversion at the original operation was required in 14 patients and secondary conversion at a subsequent operation was required in 9 patients. The reasons for primary conversion were access problems (n = 2), balloon related problems (n = 2), endograft migration (n = 4), endograft thrombosis (n = 1) and failed deployment of a bifurcated endograft (n = 5). Twelve of 14 primary conversions occurred in the first half of the study period, in which 59 endoluminal abdominal aortic aneurysms repairs were undertaken. Improvements in technology and interventional techniques for overcoming obstacles, as well as increasing experience, has resulted in primary conversion being limited to two patients in the most recent 2.5-year period in which 97 endoluminal repairs were undertaken. The reasons for secondary conversion were renal arteries covered by the endograft (n = 2), increasing abdominal aortic aneurysm diameter in the absence of endoleak (n = 1) and persistent endoleak (n = 6). The latter group comprised three patients with intact aneurysms and three with known endoleaks who presented with ruptured aneurysms. The current indications for primary conversion include: (i) rupture of the aorta; (ii) complete migration of the endograft resulting in obstruction of the iliac arteries; and (iii) irreversible twisting of a non-modular bifurcated endograft. The current indications for secondary conversion include: (i) persistent endoleak; (ii) sealed endoleak with continued abdominal aortic aneurysms expansion; (iii) apparently successful endoluminal repair without evidence of endoleak but continued abdominal aortic aneurysms expansion; and (iv) infected endograft.

Aortic Aneurysm, Abdominal↗
PubMed1998

Evaluation of the risks of using an oversized balloon catheter in the human infrarenal abdominal aorta.

OBJECTIVES: To evaluate the effects on the aortic wall of balloon dilatation as utilised in deployment of stent-graft devices during endoluminal repair of infrarenal abdominal aortic aneurysm. METHODS: Large dilatation balloons were expanded within the aorta of 41 cadavers. Testing was done to evaluate the effect of differing degrees of balloon oversizing, at pressures in the range of 0.15-2.5 atm. The aorta was then open for macroscopic inspection. RESULTS: In group 1 (mild atherosclerosis) no macroscopic abnormalities were detected with up to 6 mm oversized balloon. In group 2 (moderate atherosclerosis) fracture of atherosclerotic plaque occurred in seven of 14 aortas (50%) with 2.5 mm-4mm oversized balloon. In group 3 (severe atherosclerosis) fracture of atherosclerotic plaque occurred in six of seven (85%) with 2.5 mm to 4 mm oversized balloon and rupture of the aorta occurred at 6 mm oversizing. CONCLUSIONS: This study suggests that balloon overdilatation of the aorta by 2 mm, at pressures less than 2 atmospheres, allows safe deployment even in the presence of severe atheroma. Larger amounts of overdilatation are relatively safe in mildly atherosclerotic aorta. Aortic rupture is unlikely with overdilatation up to 6 mm, especially in less calcified vessels.

Adolescent↗
PubMed1998

Importance of graft configuration in outcome of endoluminal aortic aneurysm repair: a 5-year analysis by the life table method.

AIM: The aim of this study was to determine the influence of graft configuration on the outcome of endoluminal repair of abdominal aortic aneurysm (AAA). METHODS: The 5-year study period extended from May 1992 to May 1997 and included analysis of patients undergoing endoluminal AAA repair in the first 4.5-year period with a minimum follow-up period of 6 months. Between May 1992 and November 1996 136 patients underwent endoluminal AAA repair. Two patients who had endoluminal repair of anastomotic AAA and six patients who had secondary endoluminal repair of AAA were excluded, leaving 128 patients in the study group. There were 117 males and 11 females with a mean age for the group of 71 years. The configuration of the grafts was tubular aortic (T) (n = 50), tapered aortoiliac/femoral (AI) (n = 24) and bifurcated (B) (n = 54). Patient characteristics and co-morbidities were similar in the three groups. The procedures were performed in the operating room under radiographic control. Follow-up was complete and consisted of regular physical examination and contrast enhanced computed tomography. Outcome measures were perioperative mortality rate, need for conversion to open repair, presence of early and late endoleaks, successful exclusion of AAA from the circulation, and survival. Data were analysed by the life table method. RESULTS: There was no significant difference in perioperative mortality for T (4%), AI (4%) and B (5.5%) configuration of endograft. Outcome for T, AI, and B configurations was respectively: primary conversion (%) 8, 12, 13; early endoleaks (n =) 5, 0, 1; late endoleaks (n =) 7, 0, 1. The overall incidence of failed procedures throughout the study period was higher in tube grafts compared with non-tube (aortoiliac and bifurcated) grafts (p < 0.05). Kaplan-Meier curves demonstrated a success probability at 40 months of 50% for tube grafts and 80% for non-tube grafts. However, a comparison of the time to procedure failure between tube versus non-tube after adjusting for competing risks (death without prior graft failure) was non-significant (p = 0.14). CONCLUSIONS: The poor mid-term outcome for tube prostheses requires a reassessment of the criteria for selecting this configuration. It would be unwise to abandon the use of tube prostheses entirely in endoluminal repair. With increasing information on mid and long-term outcome of endoluminal AAA repair it is likely that there will be an increasing acceptance of treating smaller AAA while they are still suitable for treatment by the endoluminal method and most likely with tube grafts. A tightening of the criteria for using tube prostheses would seem sensible. In particular, the minimum length of distal neck required for endoluminal tube graft repair should be increased to the 2-2.5 cm range.

Aged↗
PubMed1998

Endoluminal abdominal aortic aneurysm surgery.

BACKGROUND: The development of devices designed for the endoluminal repair of abdominal aortic aneurysm has led to the emergence of new endovascular techniques. METHODS: Articles and case reports obtained from a Medline search of the English language literature from 1989 to 1997 are reviewed. This search was carried out using the MeSH heading 'aortic aneurysm, abdominal' and the keywords 'endovascular' and 'endoluminal'. RESULTS: Reported mortality and complication rates for endoluminal aneurysm repair are similar to those following conventional repair, with the exception of continued perfusion of the aneurysm sac which remains a major problem following endoluminal repair. CONCLUSION: Successful endoluminal aneurysm exclusion is associated with reduced aneurysm diameter. However, longer term results of endoluminal repair, in particular of sealed endoleaks, are required before randomized controlled trials of endoluminal versus conventional repair can be undertaken.

Angioplasty↗
PubMed1998

Glycopeptide tolerance in Staphylococcus aureus.

Treatment failures with vancomycin prompted us to investigate the phenomenon of tolerance to glycopeptides in recent clinical isolates of Staphylococcus aureus. We used both MBC/MIC determinations and time-kill measurements to study tolerance to vancomycin and teicoplanin in 35 blood or heart valve isolates of S. aureus from patients with endocarditis or bacteraemia. There was generally good agreement between vancomycin tolerance indicated by an MBC:MIC ratio of > or =32 and by < or =90% kill after 6 h incubation in the presence of 20 mg/L vancomycin. However, two isolates were tolerant according to their MBC:MIC ratios but non-tolerant as judged by time-kill measurements. Seven of 15 methicillin-resistant S. aureus (MRSA) isolates but only two of 20 methicillin-susceptible ones were tolerant as judged by time-kill experiments (chi2 = 4.27 with Yates' correction, P = 0.04). Seven of the 16 isolates from patients with endocarditis were tolerant, compared with only two of the 19 isolates from patients with other conditions (chi2 = 3.43 with Yates' correction, P = 0.06). Within the endocarditis and non-endocarditis subgroups, tolerance was associated more frequently with methicillin resistance than with susceptibility, but the numbers were too small for the differences to be statistically significant. Most of the vancomycin-tolerant isolates were also tolerant to teicoplanin. We conclude that glycopeptide tolerance is a real phenomenon in S. aureus, particularly amongst MRSA isolates, and can be reliably determined by our method of time-kill analysis. Tolerance may compromise glycopeptide therapy of serious S. aureus infection and should be taken into account when deciding treatment.

Anti-Bacterial Agents↗
PubMed1998

Comparative activity of quinupristin/dalfopristin and RPR 106972 and the effect of medium on in-vitro test results.

Quinupristin/dalfopristin and RPR 106972 were active in vitro against a wide range of aerobic Gram-positive organisms including Enterococcus faecium. However, most isolates of Enterococcus faecalis were resistant or of intermediate sensitivity. Against Staphylococcus aureus quinupristin/dalfopristin was more active but for all other species the range of activity of the two drugs was the same or RPR 106972 was more active. RPR 106972 was also more active against the respiratory pathogens Haemophilus influenzae and Moraxella catarrhalis. Quinupristin/dalfopristin MICs for isolates of H. influenzae (1-8 mg/L) clustered around the breakpoint. There were differences in the quality of growth, but little difference in MICs or zone diameters was obtained on three different media: Mueller-Hinton (MHA), Iso-Sensitest (ISA), and Diagnostic Sensitivity Test (DST) agars. The addition of blood to the medium increased MICs 2- to 4-fold, with MHA showing the greatest increase, and reduced zone diameters around quinupristin/dalfopristin discs by 3-4 mm, with the greatest effect on ISA.

Anti-Bacterial Agents↗
PubMed1998

HLA DPA1/DPB1 genotype and haplotype frequencies, and linkage disequilibria in Nigeria, Liberia, and Gabon.

The frequencies of DPA1 and DPB1 alleles and their occurrence in haplotypic linkage were assessed and compared in Nigerian, Liberian, and Gabonese individuals. Differences were seen in the distribution patterns; these differences were more pronounced between the Gabonese and the other two populations than between Liberians and Nigerians. Several haplotypic DPA1-DPB1 combinations could be verified by homozygosity. Linkage disequilibria of DPA1-DPB1 combinations, indicating further probable haplotypes, were estimated. Although different allele and haplotype frequencies were recognized in the three subgroups, the linkage disequilibria were mostly either positive or negative in all populations.

Ethnicity↗
PubMed1998

Endoluminal repair: a better option for the treatment of complex false aneurysms.

BACKGROUND: The aim of the present paper is to present the utility of endoluminal repair in the management of complex false aneurysms at various sites throughout the body. METHODS: Between May 1992 and May 1997 the endoluminal method was used to repair 183 aneurysms at various sites throughout the body. In six patients the pathology was that of false aneurysm and these are the basis of the present report. In two of the patients the false aneurysm was situated between the renal arteries and the proximal end of a previous aortic graft. The other false aneurysms were situated in the right subclavian, the popliteal and internal carotid arteries, in addition to one situated at the junction of two longstanding bypass grafts in the groin. The technique involved delivery of an endograft into the artery from which the false aneurysm had arisen via a sheath inserted through an artery of access which was superficial and remote from the site of the aneurysm. A laparotomy was avoided in the first two cases and thoracotomy avoided in the third case. Opening of the popliteal fossa, which had been the site of a recent knee replacement in the fourth patient, was also avoided. RESULTS: Post-procedure angiography confirmed exclusion of the false aneurysm from the general circulation in all six patients. There were no deaths and the mean length of hospital stay was 6 days. CONCLUSIONS: Endoluminal repair of false aneurysms is feasible and avoids the difficulty and morbidity associated with laparotomy, thoracotomy and operations at sites with scarring from previous interventions.

Aged↗
PubMed1998

A novel leucocyte-depleting filter for use in continuous venovenous haemofiltration: preliminary in vitro studies.

Multiple organ failure (MOF) secondary to circulatory shock, sepsis, or trauma was first described over 20 years ago. Despite much research effort and clinical trials of biological response modifiers, MOF continues to be the leading cause of death in both medical and surgical intensive care units (ICU). MOF is associated with widespread cellular and humoral systemic inflammatory responses which, in turn, are linked with inadequate tissue perfusion to vital organs and the inappropriate accumulation of activated neutrophils, resulting in microcirculatory injury. Much evidence suggests that such activated neutrophils cause vascular damage by adhering to the endothelium and releasing a variety of highly reactive and toxic moieties; these may subsequently produce endothelial injury and compromised organ function. We reasoned that a clinical device designed to remove such cells in a controlled fashion from the circulation of patients with MOF by means of using a continuous venovenous circuit might be beneficial. We report the leucocyte depletion performance of a novel filter medium as a first step towards the production of a clinical device, and show specific depletion of phagocytes relative to other formed elements in the blood.

Hemofiltration↗