Editor's Choice - Nationwide Analysis of Patients Undergoing Iliac Artery Aneurysm Repair in the Netherlands

OBJECTIVE

The new 2019 guideline of the European Society for Vascular Surgery (ESVS) recommends consideration for elective iliac artery aneurysm (eIAA) repair when the iliac diameter exceeds 3.5 cm, as opposed to 3.0 cm previously. The current study assessed diameters at time of eIAA repair and ruptured IAA (rIAA) repair and compared clinical outcomes after open surgical repair (OSR) and endovascular aneurysm repair (EVAR).

METHODS

This retrospective observational study used the nationwide Dutch Surgical Aneurysm Audit (DSAA) registry that includes all patients who undergo aorto-iliac aneurysm repair in the Netherlands. All patients who underwent primary IAA repair between 1 January 2014 and 1 January 2018 were included. Diameters at time of eIAA and rIAA repair were compared in a descriptive fashion. The anatomical location of the IAA was not registered in the registry. Patient characteristics and outcomes of OSR and EVAR were compared with appropriate statistical tests.

RESULTS

The DSAA registry comprised 974 patients who underwent IAA repair. A total of 851 patients were included after exclusion of patients undergoing revision surgery and patients with missing essential variables. eIAA repair was carried out in 713 patients, rIAA repair in 102, and symptomatic IAA repair in 36. OSR was performed in 205, EVAR in 618, and hybrid repairs and conversions in 28. The median maximum IAA diameter at the time of eIAA and rIAA repair was 43 (IQR 38-50) mm and 68 (IQR 58-85) mm, respectively. Mortality was 1.3% (95% CI 0.7-2.4) after eIAA repair and 25.5% (95% CI 18.0-34.7) after rIAA repair. Mortality was not significantly different between the OSR and EVAR subgroups. Elective OSR was associated with significantly more complications than EVAR (intra-operative: 9.8% vs. 3.6%, post-operative: 34.0% vs. 13.8%, respectively).

CONCLUSION

In the Netherlands, most eIAA repairs are performed at diameters larger than recommended by the ESVS guideline. These findings appear to support the recent increase in the threshold diameter for eIAA repair.

A comparative study of the psychological problems of HIV-infected and HIV-uninfected children in a South African sample

According to research children living with HIV experience elevated levels of depression, anxiety, ADHD and disruptive behavioural disorders. Although South Africa's paediatric population that is infected with the human immunodeficiency virus (HIV) is the largest worldwide, little research has been conducted on their mental health challenges. However, attributing high levels of mental health problems solely to their HIV status can be problematic as there may be other contributory factors. This research explored the mental health problems of HIV-infected children and compared these to the mental health problems of their HIV-unaffected peers from similar backgrounds. Data was gathered from two samples of child and caregiver pairs. HIV-infected children (aged 6-12 years) and their caregivers/mothers (n = 54) were recruited from the Kalafong paediatric clinic where they received medical treatment and routine ART. A comparison group of 113 HIV-uninfected children and their uninfected mothers were recruited from primary care clinics in the same community. Caregivers completed the Child Behaviour Checklist (CBCL) to assess children's mental health. Children completed the Self-Description Questionnaire (SDQ-I) and the Revised Children's Manifest Anxiety Scale (RCMAS). The scores of the psychometric sub-scales of the two groups were compared using parametric and non-parametric statistics. HIV-infected children experienced more somatic and affective problems, physiological anxiety, less ADHD and lower self-esteem than HIV-uninfected children in the comparison group, while controlling for age differences. The high levels of mental health problems of both groups of children may be attributed to similar difficult socio-economic circumstances. The fact that most infected children were not aware of their HIV-status could have influenced the results. Mental health services should not be limited to HIV-infected children but should form part of all health care services.

Impact of atopic dermatitis and loss-of-function mutations in the filaggrin gene on the development of occupational irritant contact dermatitis

BACKGROUND

Atopic dermatitis (AD) and loss-of-function mutations in the filaggrin gene (FLG) are both associated with chronic irritant contact dermatitis (ICD). As FLG mutations also are a major risk factor for AD, it is not clear whether FLG mutations are an independent risk factor for ICD or whether the risk is mediated by AD.

OBJECTIVES

To investigate the relative contribution and interaction of FLG mutations and AD in German patients with occupational ICD and controls (vocational school apprentices).

METHODS

A total of 634 patients and 393 controls were genotyped for R501X, 2282del4, R2447X and S3247X. Current or past flexural eczema was used as an indicator of AD.

RESULTS

FLG mutations were found in 15·9% of the patients with ICD and 8·3% of the controls, with a crude odds ratio (OR) of 2·09 [95% confidence interval (CI) 1·33-3·28] for the combined genotype. The adjusted OR for FLG mutations, corrected for AD, was 1·62 (95% CI 1·01-2·58). Subjects with AD were at approximately three times higher risk of developing ICD than controls (OR 2·89; 95% CI 2·09-3·99). There was no evidence of an interaction between these two risk factors.

CONCLUSIONS

Our results indicate that both FLG mutations and AD increase the risk of ICD. Individuals with concurrent FLG mutations and AD are at the highest risk of developing ICD.

Support group processes: Perspectives from HIV-infected women in South Africa

This study examined the experiences and perceived benefits of support group participation among HIV-infected women in South Africa. From a qualitative analysis of responses, key psychological processes through which support groups are potentially beneficial were identified. These processes included: identification; modeling; acceptance; and empowerment. The participants' consequent life changes were explored in order to associate these processes with the positive outcomes of support group participation. Through understanding the relationship between the psychological processes within a support group setting and the potential benefits, and by targeting these processes in the development and implementation of future support group interventions, a framework is provided for achieving positive outcomes associated with support group participation.

Aortic aneurysm and orchitis due to Wegener's granulomatosis

We present a patient with Wegener's granulomatosis (WG) with involvement of the abdominal aorta, testis, peripheral nerve system, and skin. A 51-year-old man presented at our outpatient clinic with lower back pain. He had a history of smoking, hypertension, and an embryonal carcinoma of the left testis, treated 13 years ago with orchidectomy and chemotherapy. One month earlier, he underwent a partial orchidectomy of the right testis due to testicular swelling. Abdominal computed tomography showed a 3.8 cm wide aneurysm of the distal part of the aorta with inflammation. One week later he was admitted to the hospital with numbness of his hands and feet. Physical examination showed signs of peripheral microemboli. Serological laboratory tests revealed elevated antineutrophil cytoplasmic antibody titers with positive reactions against proteinase-3, indicating Wegener's disease. The chest X-ray was normal. Pathological examination of the right testis showed necrotizing vasculitis of a small artery. He was treated with cyclophosphamide and prednisolone. WG with extrapulmonary involvement occurs infrequently, and reports of manifestations of WG in aorta, testis, the peripheral nerve system, and skin are even more uncommon. Small- and medium-vessel vasculitis can precede large-vessel vasculitis or occur in the absence of small-vessel involvement. Therefore, WG should be included in the work-up of large-vessel vasculitis, which can give rise to periaortic inflammation.

HIV/AIDS stigma in a South African community

HIV/AIDS-related stigma threatens to undermine interventions to prevent and treat HIV/AIDS. To address stigma in a South African community, a thorough understanding of the nature of stigma in the specific cultural context is needed. The goals of this research were to assess the level of stigmatising attitudes among members of a community, compare this to the level of stigma that is perceived to exist within the community and determine to what extent stigmatising attitudes are affected by socio-demographic characteristics, HIV-related experience and cultural beliefs. A questionnaire was completed by 1077 respondents in key areas in two communities in Tshwane, South Africa. The questionnaire included an assessment of HIV-related experience, HIV-knowledge, personal stigma and perceptions of stigma within the community. The findings indicate that the level of personal stigma was significantly lower than that perceived to be present in the community. Respondents who were more stigmatising were older, male, less educated and less knowledgeable about HIV. They were less likely to know someone with HIV and had more traditional cultural viewpoints. While socio-demographic and cultural factors are difficult to change, efforts aimed at increasing people's knowledge and experience of the epidemic occurring in their community could change the level of stigmatising attitudes within their community. Such efforts could have potential benefits in addressing the epidemic and providing greater support for those with HIV.

Influence of Different Cleaning Practices on Endotoxin Exposure at Sewage Treatment Plants

Exposure to endotoxin at sewage treatment plants is associated with an increased prevalence of work-related symptoms in sewage workers. Since cleaning activities are regarded as an important determinant of endotoxin exposure, workers' endotoxin exposure levels during different cleaning activities were compared in an experimental setting. Variables considered were water used (tap water, surface water or effluent), water pressure (low or high pressure, and a fire hose with the mouth open or obstructed), presence of mechanical ventilation and the distance between the worker and the object to be cleaned (concentration gradient). Experimental cleaning scenarios were defined, during which endotoxin exposure was measured with personal and stationary air sampling. Data were statistically analyzed with mixed effects models. The water used for cleaning appeared to have a large influence on endotoxin exposure, especially the use of effluent, which caused a factor 2.4 increase in exposure. Use of high pressure did not significantly add to the exposure. Use of a fire hose with fully opened mouth (spout opening) led to a 3-fold decrease in exposure when compared with a partially obstructed mouth. The presence of mechanical ventilation decreased endotoxin concentration in a room, provided that the capacity of the ventilation system was sufficient. The worker's distance to the object that was cleaned did not significantly influence exposure.

Side-effects of fluticasone in asthmatic children: no effects after dose reduction

To assess long-term effects and side-effects of fluticasone propionate (FP), a 2-yr study was performed, comparing a step-down dose approach (1,000 microg.day(-1), with reductions every 2 months to 500, 200 and 100 microg.day(-1) for the remainder of the study) versus a constant dose (200 microg.day(-1)). In 55 children with chronic persistent asthma, aged 6-10 yrs, airways hyperresponsiveness (AHR) and systemic side-effects (height, bone parameters and adrenal cortical function) were assessed at predetermined intervals in a double-blind prospective 2-yr study. AHR improved after 4 months treatment with 1,000 microg.day(-1) FP followed by 500 microg.day(-1), without significant differences during long-term treatment between the two approaches. Dose-dependent reduction of growth velocity, adrenal cortical function and biochemical bone turnover was found during therapy with 1,000 and 500 microg.day(-1) FP when compared with 200 microg.day(-1). In conclusion, doses of 1,000 and 500 microg.day(-1) fluticasone propionate are associated with marked reductions of growth velocity, bone turnover and adrenal cortical function. However, conventional doses (< or =200 microg.day(-1) fluticasone propionate) appear to be safe in the long-term management of childhood asthma. From a safety point of view, high doses of fluticasone propionate should only be prescribed in exceptions, e.g. in persistent severe asthma.

Influence of different dosage schedules of inhaled fluticasone propionate on peripheral blood cytokine concentrations in childhood asthma

BACKGROUND

Asthma is characterized by eosinophilic airways inflammation with elevated levels of IL-4, IL-5 and sICAM-1, and reduced levels of IL-10 and IFN-gamma. Inhaled corticosteroids powerfully reduce airways inflammation.

OBJECTIVE

To investigate if eosinophil counts, serum eosinophilic cationic protein (ECP) and sICAM-1 levels, as well as serum and production of cytokines (IL-4, IL-5, IL-10, IFN-gamma) by peripheral blood monocytes (PBMCs) are useful markers to monitor therapy with inhaled fluticasone propionate (FP) in asthmatic children.

METHODS

In a double-blind, 1-year study, 55 asthmatic children (aged 6-10 years) stopped inhaled corticosteroids for a mean period of 24 days and were randomized to receive either FP 200 microg/day (constant dose group), or a starting dose of FP 1000 microg/day with two monthly reductions to 500, 200 and 100 microg/day (stepdown group). Hyper-responsiveness, symptom scores and blood sampling were performed at 2-month intervals.

RESULTS

Symptoms and hyper-responsiveness improved significantly in both treatment groups after reintroduction of FP. Eosinophil counts decreased significantly more during the first 2 months of FP in the stepdown group than in the constant dose group (P = 0.03). We found a trend towards a dose-dependent response in changes of eosinophil counts and serum ECP levels during treatment. Serum IL-4 and IL-5 levels were undetectable in the majority of children. No significant effect of the dose of FP on the release of IL-4, IL-5, IL-10 or IFN-gamma by Con A stimulated PBMCs was found. sICAM-1 levels did not significantly differ at any time point between the two groups.

CONCLUSION

Serum ECP as well as peripheral blood eosinophils, cytokine production by PBMCs and sICAM-1 levels are insensitive markers in titrating and monitoring therapy with inhaled corticosteroids over a wide dose range in childhood asthma.

Clinical and immunologic factors associated with the presence or absence of airways hyper-responsiveness in childhood asthma

BACKGROUND

During the baseline period of a clinical trial comparing different dosage schedules of inhaled steroids, asthmatic children (aged 6-10 years) were expected to meet the inclusion criterion of airways hyper-responsiveness (PD(20) methacholine < 80 micro g) after withdrawal of inhaled corticosteroids for 2-8 weeks. However, many children failed to do so.

OBJECTIVE

It has been shown that young wheezing children may outgrow their symptoms. We investigated if differences between children with and without airways hyper-responsiveness after withdrawal of inhaled corticosteroids were compatible with differences between transient and persistent wheezers found in other studies.

METHODS

Seventy-eight children entered the study, of which 41 developed airways hyper- responsiveness after withdrawal of inhaled corticosteroids, and 37 did not. These two groups of children were compared with respect to differences in demographic, clinical, and immunological features (IL-4, IL-5, IL-10, and IFN-gamma produced by Con A stimulated peripheral mononuclear cells (PBMCs) and serum IL-4, IL-5 and soluble intercellular adhesion molecule-1 (sICAM-1)).

RESULTS

Hyper-responsive children had more atopic features (positive RAST, high IgE, eczema), lower levels of FEV1 and lower concentrations of sICAM-1 than non-hyper-responsive children. Apart from a borderline significantly higher IL-4 production in the hyper-responsive group, other immunologic parameters were comparable. Multivariate logistic regression analysis showed that high serum IgE, low FEV1, and low sICAM-1 levels were independently associated with the presence of airways hyper-responsiveness after stopping inhaled corticosteroids. Atopy was associated with higher concentrations of IL-4 in the hyper-responsive group.

CONCLUSION

After withdrawal of inhaled corticosteroids many children previously diagnosed with asthma did not develop airways hyper-responsiveness. We conclude that hyper-responsive children share features with persistent wheezers as found in previous studies, whereas the non-hyper- responsive children may represent transient wheezers.

One-year treatment with different dosing schedules of fluticasone propionate in childhood asthma. Effects on hyperresponsiveness, lung function, and height

Dose-dependent effects of inhaled corticosteroids have been described. Although it has been advised to start treatment with inhaled corticosteroids with a high dose tapering off subsequently (stepdown approach), no clinical studies have assessed this strategy. We compared two different dosage schedules of inhaled fluticasone propionate (FP) in chronic persistent childhood asthma with respect to efficacy (airways hyperresponsiveness [PD(20)], lung function, exhaled nitric oxide [eNO]) and safety (height). During this double-blind study, children with asthma (aged 6-10 yr) were randomized to receive either FP 200 microg/d (constant dose approach) or to start with 1000 microg/d with two monthly reductions to 500, 200, and 100 microg/d (stepdown approach). PD(20) improved in both approaches during treatment with FP, with a significantly better PD(20) after 2 mo of 1000 microg/d followed by 500 microg/d in the stepdown approach versus 200 microg/d in the constant dose approach. No significant differences in PD(20) or other efficacy parameters were found after 1 yr. Changes in standing height were similar in both treatment approaches. This study showed no superior clinical effect of a stepdown approach compared with a constant dose strategy of FP for 1 yr in children with chronic persistent asthma.

Nerve-preserving aortoiliac reconstruction surgery: anatomical study and surgical approach

OBJECTIVE

Dysfunctional ejaculation and, to a lesser extent, dysfunctional erection caused by disruption of efferent sympathetic pathways is a common complication after aortoiliac reconstruction surgery. The aim was to give an anatomic motivation for a nerve-preserving approach on the basis of right-sided unilateral disruption of lumbar splanchnic nerves.

METHODS

Anatomic and microscopic analysis of preaortic and para-aortic retroperitoneal regions in human cadavers was performed. Anatomic analysis was conducted of two aortoiliac reconstruction operations performed on human cadavers; one was performed according to a single-blind procedure, the second with a modified procedure.

RESULTS

The lumbar splanchnic nerves supplying the superior hypogastric plexus from the right side were found to be less voluminous than the left-sided ones. The superior hypogastric plexus was found slightly shifted to the left of the midsagittal plane across the abdominal aorta and its bifurcation. Microscopic analysis revealed a thin fascia between the aorta and the subperitoneal tissue compartment. This fascia was used as a plain of dissection to mobilize the preaortic nerve-plexuses without damage from the aortic wall. Analysis of the specimens operated on showed a significant difference in nerve disruption. The standard procedure caused total disruption of the superior hypogastric plexus and extensive disruption of the inferior mesenteric plexus. The modified procedure only caused right-sided unilateral disruption of lumbar splanchnic nerves.

CONCLUSION

The autonomic nerves supplying the bladder neck, the vas deferens, and the prostate are closely related to the abdominal aorta and its bifurcation. Right-sided unilateral disruption of lumbar splanchnic nerves without further damage to nervous structures would ensure at least one functional sympathetic pathway remaining after aortoiliac reconstruction surgery.

The feasibility of airways hyperresponsiveness as an inclusion criterion for studies on childhood asthma

The feasibility of moderately severe airway hyperresponsiveness (AH) was examined as an inclusion criterion for clinical trials in asthmatic children. During the baseline period of a long-term clinical trial in asthmatic children, maintenance therapy with fluticasone (200 microg x day(-1)) was stopped for a maximum of 8 weeks and methacholine challenges were performed at 2-week intervals or earlier if the patients' condition deteriorated. Patients were eligible to continue the study if the provocative dose of methacholine causing a 20% fall in forced expired volume in one second (FEV1) (PD20) was <80 microg. Fifty-one per cent of the children did not develop a PD20 < 80 microg after withdrawal of fluticasone. Patients with or without a PD20 <80 microg did not differ in duration of asthma, duration of treatment, or peak flow variation. Patients with a PD20 <80 microg had higher levels of total and specific immunoglobulin-E, and lower levels of FEV1 and mean maximal expiratory flow than patients with a PD20 > or = 80 microg. Forty-four per cent of the patients with a PD20 > or = 80 microg did not have any symptoms during the wash-out period and 39% of these patients remained free from symptoms during one year follow-up. The results of this study suggest that recruiting asthmatic children for clinical trials may be difficult if airways hyperresponsiveness is used as the sole inclusion criterion.

Exhaled nitric oxide in children measured by tidal breathing method: differences between asthmatics and nonasthmatic controls

The single-breath maneuver used to measure nitric oxide (NO) in adults cannot be performed by young children. We, therefore, developed a method of measuring NO in mixed exhaled gas collected during tidal breathing. NO was measured in mixed exhaled gas during 5 min of tidal breathing in 113 children 4-14 years of age: 22 nonasthmatics, 21 asthmatic children not taking inhaled corticosteroids, and 70 asthmatic children using inhaled corticosteroids. Exhaled NO levels (median, range) were significantly lower in nonasthmatic controls (median, range: 7, 2-10 ppb) than in asthmatic children on inhaled corticosteroids (8, 3-25 ppb; 95% CI for difference in medians with those of controls, 0-4 ppb), and in those not on inhaled corticosteroids (13, 6-37, ppb; 95% CI for difference in medians, 5-17 ppb). Asthmatic children not using inhaled corticosteroids had significantly higher exhaled NO levels than asthmatic children using inhaled corticosteroids (95% CI for difference in medians, 3-10 ppb). The tidal breathing method is a useful and practical way of measuring exhaled NO levels in children regardless of their age.

Thrombus within an aortic aneurysm does not reduce pressure on the aneurysmal wall

PURPOSE

The role of thrombus within an aneurysm in relation to the risk of rupture is controversial. In literature, reports describing reduction and increase of rupture risk can be found. In the era of endovascular treatment of abdominal aortic aneurysms, a possible reduction of risk of rupture by the presence of thrombus within the aneurysmal sac can be important in relation to the location of an endoleak to the aneurysmal wall and in relation to the effect of the thrombosis of the endoleak, either spontaneously or by intervention.

METHODS

In nine patients who underwent operation for an infrarenal aortic aneurysm by open procedure at the level of the thickest thrombus lining, the pressure within the aneurysmal thrombus (just inside the aneurysmal wall) was measured and compared with the systemic pressure.

RESULTS

Pressure within systemic circulation and aneurysmal thrombus correlated well for the mean pressure (r = 0.90; P <.001) and for pulse pressure (r = 0.74; P <.01) Also, there was agreement between the levels of the mean pressure. Conduction of mean and pulse pressure to the aneurysmal wall was not related to the thickness of the thrombus at the level of the pressure measurement (r = 0.18 and r = 0.08, respectively).

CONCLUSION

We conclude that thrombus within the aneurysm does not reduce both the mean and the pulse pressure near the aneurysmal wall and thus will not reduce the risk of rupture of the aneurysm.

Short-term growth in asthmatic children using fluticasone propionate

BACKGROUND

Inhaled corticosteroids may reduce short-term growth velocity in asthmatic children and knemometry is the most sensitive tool to detect this short-term growth suppression.

STUDY OBJECTIVE

To compare lower leg growth velocity, as measured by knemometry, in asthmatic children during and after treatment with inhaled fluticasone propionate (FP), 100 microg twice daily.

DESIGN

Nonrandomized open trial.

SETTING

University hospital, outpatient clinic for pediatric pulmonology.

PATIENTS

Twenty-one asthmatic children (13 boys), aged 6 to 10 years.

INTERVENTIONS

Inhalation of FP from a dry powder inhaler, 100 microg, twice daily for 6 weeks, followed by 2 weeks during which only an inhaled beta2-agonist was used on demand (washout). During treatment and washout periods, patients were seen every 2 weeks at the same time of day.

MEASUREMENTS AND RESULTS

Lower leg growth velocity measured by knemometry during FP treatment was not significantly different from that during washout (p=0.33, one-way analysis of variance).

CONCLUSIONS

No significant suppression of lower leg growth velocity was found in prepubertal asthmatic children using FP, 100 microg, by dry powder inhaler twice daily for 6 weeks.

Evaluation of various methods to quantify endothelial cells attached to vascular prostheses: comparison with a new "gold standard" FACS method

For in vitro evaluation of functional properties of endothelial cells seeded on synthetic vascular prostheses accurate and reproducible quantification of cells is mandatory. Comparison of these properties with those resulting from other studies requires correlation of the functional parameters to reliably counted cell numbers. The accuracy of methods of quantification currently being used is unknown due to the lack of a "gold standard" method to which these methods can be compared. To determine the accuracy and reproducibility of four widely used methods, we have developed a "gold standard" model, using a flow cytometer (FACS). Endothelial cells, attached to collagen-coated Dacron vascular prostheses, were counted by four conventional methods and a new method of quantification after the attached number of cells had been determined with 99% accuracy by FACS. Subsequently, ratios were computed by dividing the cell numbers determined by the methods under investigation by those determined by FACS (x100%). The four conventional methods investigated were (1) removal and subsequent counting of cells from substrata by trypsin (T), (2) digestion of cells by citric acid and counting of crystal violet-stained cell nuclei (CV), (3) light microscopy after hematoxylin staining (LM), and (4) scanning electron microscopy (SEM). The new method consists of the measurement of cell fluorescence after labeling with fluorescein-diacetate (FDA). T and CV had average accuracy ratios of 127 +/- 58% and 96 +/- 48%, respectively (+/- standard deviation). The ratios for LM and SEM were 116 +/- 101% and 44 +/- 10% (respectively). FDA had a ratio of 99 +/- 7%. Reproducibility of cell quantification by T and CV was significantly less than that of quantification by LM, SEM, and FDA, as expressed by data on inter- and intraobserver agreement. Our results indicate that the investigated conventional methods of quantification failed to meet criteria of both high accuracy and reproducibility. Light microscopy and scanning microscopy methods were inaccurate but yielded reproducible countings. We conclude that the FACS method can serve as a "gold standard" to compare the accuracy and reproducibility of cell quantification methods. Moreover, the FDA method results in both accurate and reproducible quantification of endothelial cells attached to vascular prosthetic material.

A new, automated and accurate in vitro method to quantify endothelial cells attached to vascular prostheses

Over a decade ago the idea of endothelial cell seeding was introduced in an attempt to improve the function of small caliber vascular prostheses. Although endothelial cell seeding is currently being applied clinically, several questions regarding the functional properties of the seeded endothelial cells remain. Evaluation of functional properties of endothelial cells on various types of vascular prostheses can be performed partly in vitro, but it is hampered by the fact that commonly used methods to quantify endothelial cells do not adequately apply to these cells on prosthetic materials. An accurate quantification method is described that is rapidly and easily applicable to endothelial cells attached to vascular prostheses. The method can also be used to quantify endothelial cells attached to culture dishes or microcarriers. Colorless, non-fluorescing, fluorescein-diacetate was used, which was taken up by the attached endothelial cells, and which was then intracellularly converted to yellow fluorescein, emitting green fluorescence. Subsequently, triton-X-100 was applicated to release fluorescein and levels of fluorescence were measured with the automated aperture-defined microvolume (ADM) method, using an inverted fluorescence microscope to which a photometer was connected. The measured level of fluorescence is linearly related to endothelial cell numbers attached to prostheses. The accuracy and the reproducibility of cell countings are high.

Monoclonal antibodies that react with live Listeria spp

Seven monoclonal antibodies (MAbs) against Listeria spp. that were reactive with live Listeria spp. were developed. Two of these MAbs (55-8 and 55-37) were members of the immunoglobulin M class, and all other MAbs were members of the immunoglobulin G class. MAb 55-23 reacted with 148 of 157 strains tested. MAb 34-51 reacted with serotype 1/2a, 1/2b, and 1/2c strains and exhibited a scattered reaction pattern with strains belonging to other serotypes. MAb 55-44 reacted with all of the strains belonging to serotype 4b tested. MAb 55-4 reacted with all of the serotype 1/2a isolates tested, although reactivity with other isolates also was observed. The other MAbs exhibited scattered reaction patterns. No correlation of reactivity pattern with serotype was found. Marked differences were observed between the reactivities of MAbs as determined by a magnetic immunoluminescence assay and a whole-cell enzyme-linked immunosorbent assay. Only MAb 55-23 exhibited minor reactivity with three Streptococcus spp. isolates, while no reactivity was observed with six Bacillus spp. strains, one Escherichia coli strain, and one Citrobacter sp. strain. In Western blots (immunoblots) MAbs 55-23, 55-44, and 34-9 exhibited reactivity; all other MAbs were negative in this assay.

Detection of Listeria monocytogenes in cheese with the magnetic immuno-polymerase chain reaction assay

A new detection system, the magnetic immuno-polymerase chain reaction (PCR) assay (MIPA) has been developed to detect Listeria monocytogenes in food. This method separates Listeria cells from PCR-inhibitory factors present in enrichment broths containing food samples by using magnetic beads coated with specific monoclonal antibodies (MAbs). The separated bacteria were lysed, and the supernatant containing the bacterial DNA was subjected to the PCR. Detection of L. monocytogenes in three naturally contaminated cheese samples with two different MAbs and PCR primers specific for the gene encoding the delayed-hypersensitivity factor showed that with MAb 55 all three samples were positive whereas with MAb A two samples were positive. A further improvement of the method was obtained by using a PCR step based on the listeriolysin O gene. A MIPA employing MAb 55 and the listeriolysin O gene primer set detected L. monocytogenes after 24 h of culture in Listeria Enrichment Broth samples from Port Salut artificially contaminated with 40 CFU/25 g. We could detect 1 CFU of L. monocytogenes per g of cheese after a second enrichment for 24 h in Fraser broth. The analysis time including both enrichments is approximately 55 h.

Monoclonal antibodies that detect live salmonellae

Nine immunoglobulin G and nine immunoglobulin M murine monoclonal antibody-producing hybridomas reactive with live Salmonella bacteria were obtained from several fusions of immune spleen cells and Sp2/0 myeloma cells. The antibodies were selected by the magnetic immunoluminescence assay. The monoclonal antibodies were reactive with serogroups A, B, C1, C2, D, E, and K and Salmonella choleraesuis subsp. diarizonae. Each monoclonal antibody proved to be reactive with a distinct serotype. Clinical isolates belonging to these Salmonella serogroups could be detected. Reactivity with non-Salmonella bacteria proved to be minor.

Monoclonal antibodies specific for the phase-variant O-acetylated K1 capsule of Escherichia coli

Two monoclonal antibodies, one each of the immunoglobulin M and G2b types, were produced from mouse spleen cells. These monoclonal antibodies only reacted with approximately 50% of the Escherichia coli K1 strains and not against group B meningococci. No reaction was observed after the strains were boiled. E. coli K1 strains that reacted with the monoclonal antibodies could become nonreactive after subculture. Based on these findings, we conclude that the monoclonal antibodies react with the O-acetylated K1 capsule.

Cells derived from omental fat tissue and used for seeding vascular prostheses are not endothelial in origin. A study on the origin of epitheloid cells derived from omentum

The use of microvascular endothelial cells derived from omental tissue has been advocated to seed vascular grafts with autologous endothelial cells in high density. The purpose of our study was to evaluate the precise origin of these cells. Therefore we have compared cellular characteristics of these cells with those of endothelial cells isolated by collagenase treatment of human umbilical veins. The omental cells were isolated from from omental tissue from four different patients by incubation in a collagenase-dispase solution. Part of the material was processed by Percoll density gradient centrifugation in an attempt to purify the isolates. Cellular characteristics of both types of cells were determined by studying the morphologic features of the cells and by determining the presence of von Willebrand factor, antigens EN-4 and PAL-E specific for endothelial cells, cytokeratins 8 and 18, vimentin and desmin, and uptake of diI-acetylated low-density lipoprotein. Epitheloid cells from omental tissue, isolated after collagenase treatment and either purified or nonpurified by Percoll density gradient centrifugation, differed from human umbilical vein endothelial cells with respect to the presence of surface microvilli, the expression of von Willebrand factor, EN-4 and PAL-E, and the presence of cytokeratins 8 and 18 and desmin. von Willebrand factor (in a granular staining pattern) and the presence of EN-4 and PAL-E were only detected in human umbilical vein endothelial cells. Vimentin was present in both cell types, whereas cytokeratins 8 and 18 and desmin were only present in cells derived from omentum. From these data we conclude that the so called microvascular endothelial cells from omentum are not endothelial but mesothelial in nature.

CAPD peritonitis: a prospective randomized trial of oral versus intraperitoneal treatment with cephradine

In a prospective randomized clinical trial 84 peritonitis episodes were treated with cephradine, either orally or intraperitoneally. No difference in treatment outcome between both groups could be demonstrated. In episodes caused by susceptible micro-organisms a good response was seen in 82% in the oral and 82% in the intraperitoneal groups. These clinical findings were supported by the demonstration of adequate cephradine concentrations in serum and dialysate after oral as well as after intraperitoneal administration. Altogether cephradine was given orally or intraperitoneally in 88 episodes of peritonitis as drug of first choice. In 52 a complete cure was obtained, in 36 another antibiotic was subsequently needed as soon as bacterial susceptibility was known. No patient deteriorated appreciably during the delay between the start of cephradine and the switch to another antibiotic. Of the 36 episodes 14, caused by methicillin-resistant Staphylococcus epidermidis, responded well initially to cephradine but relapsed later. Change to another antibiotic effected a complete recovery in all 14 cases. Of the remaining 22 episodes, 14 were cured by the other antibiotic, in eight the catheter had to be removed. Aminoglycosides could be avoided except for ten of the episodes. During peritonitis CAPD was continued, in 71% of the cases on an outpatient basis. Mortality due to peritonitis was absent. We conclude that oral cephradine can be used as drug of first choice in the initial treatment of CAPD peritonitis, because a good initial response was obtained in 66 (52 + 14) i.e. 75% of 88 episodes. However, complete cure by cephradine alone was achieved in only 60%.(ABSTRACT TRUNCATED AT 250 WORDS)