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J M Smits

Publications and source records attributed to J M Smits.

At least 19 recordsLinked to original sources
PubMed2003

[Risk factors of contamination of pig farms in the Netherlands with pig diseases and agents thereof: a review of the literature].

Part of the project 'Clean pigs' an extensive study of literature was made of the risk factors related to the introduction of pathogenic micro-organisms in pigfarms in the Netherlands. On the basis of this study of literature and in close cooperation with the experts of the steering group of the project 'Clean pigs' a number of risk factors relevant for the Dutch pig farming were estimated. The impact of these risk factors on the introduction of the most important pig diseases/-agents in Dutch pig farming was quantified for three different levels of preventive measures. It is shown that many risks can be reduced or even be neglected by the biosecurity measures already applied on pig farms. For most diseases, including list A and B diseases of the OIE list, introduction of new animals is regarded as the main risk factor, but this risk can be reduced in several ways. Besides this, aerogenic transmission and introduction by rodents and pet animals need the most attention. Through specific actions and measures several important risk factors can be diminished or even eliminated.

Animal Husbandry↗
PubMed2002

[Improved pig health with farm management systems. Project 'Beautiful stream of pigs' 21].

As part of the project 'Clean pigs', an inventory was made of the different pig farm management systems described in the literature. These systems were evaluated for their potential use in improving animal health, focusing on the pathogens important in the Netherlands. The most promising systems for the control and/or eradication of pig pathogens in the Netherlands can be divided into two groups (with decreasing effect): I. Eradication from an existing positive population. The best systems for this are Embryo Transplantation (ET), Specific-Pathogen Free pigs (SPF), Piglet Snatching and Segregated Weaning (SW). II. Strategic veterinary and breeding strategies. The best systems for this are Freeze infection, test and removal, Test and removal, Vaccination, Medical elimination, Strategic medication and Genetic resistance. Farm systems can be a big help when trying to improve animal health, but the 'biosecurity' measures on the farm are at least of equal importance.

Animal Husbandry↗
PubMed2001

Horseshoe kidney transplantation within the eurotransplant region: a case control study.

BACKGROUND: The horseshoe kidney is the most common anatomic renal variation, with an incidence of 1 in 600 to 800. It represents a fusion anomaly, usually of the lower poles. Horseshoe kidneys can be transplanted en bloc or after division of the renal isthmus. However, the great variation in origin, number, and size of renal arteries and veins leads to some reluctance to use horseshoe kidneys for transplantation. The aim of this study is to assess the results of horseshoe kidney transplantation. METHODS: All data concerning horseshoe kidney transplantations within the Eurotransplant region were collected and were divided into en bloc and split transplantations. A matched control group was defined, and the three groups were analyzed with respect to the occurrence of primary nonfunction, graft survival, patient survival, and finally posttransplant serum creatinine values. RESULTS: From 1983 to 2000, 8 horseshoe kidneys were transplanted en bloc and 26 were split and transplanted into 47 recipients. The results of these transplantations were compared with 110 transplantations in the control group. No significant differences among the three groups could be found, either in the short- or long-term posttransplant results. CONCLUSIONS: The results of horseshoe kidney transplantation, either en bloc or split, are equal to the posttransplant results of kidneys with a normal anatomy. Bearing in mind the shortage of donors, horseshoe kidneys should certainly be used for transplantation.

Adolescent↗
PubMed2001

[The importance of different pig diseases in the Netherlands].

As part of the project 'Clean pigs', IPG Institute for Pig Genetics BV made an inventory of the impact of different diseases on the Dutch pig industry. An expert panel assessed the importance of the different diseases with regard to public health, farm economy, the pig sector and export sales. The possibilities for the diagnosis of the different pathogens were listed and the goal for the next years, was set. Diseases were classified into three categories, according to their importance for the Dutch pig industry (Table 2). The diseases that can be eradicated are Salmonella (only specific strains), Pasteurella multocida DNT + PAR), Actinobacillus pleuropneumoniae, Haematopinus suis (lice) and Sarcoptes scabei (var. suis) (mange). National introduction of list A en most list B diseases of the OIE classification must be prevented.

Actinobacillus Infections↗
PubMed2001

Transplanting horseshoe kidneys: a worldwide survey.

PURPOSE: Horseshoe kidney is the most common anatomical renal variation. It represents a fusion anomaly, usually of the lower poles. Horseshoe kidneys can be transplanted en bloc or after division of the renal isthmus. We constructed a decision cascade for horseshoe kidney transplantation. MATERIALS AND METHODS: A worldwide survey of transplantation clinics and foundations was performed to discover cases of horseshoe kidney transplantation. In each case data were collected on horseshoe kidney anatomy and post-transplantation results. The number of renal arteries and veins was correlated with primary nonfunction due to technical failure. RESULTS: From 1975 to 2000, 23 horseshoe kidneys were transplanted en bloc, while 57 were split and transplanted into 97 recipients. Primary nonfunction was observed in 4.3% and 13.4% of en bloc and divided transplanted kidneys, respectively. Postoperatively a urinary fistula formed after renal isthmus division in 2 cases. An increased number of renal vessels was not associated with an increased risk of primary nonfunction. CONCLUSIONS: Horseshoe kidney anatomy should be closely inspected after explantation. The decision to split a horseshoe kidney should be based on urinary collecting system anatomy in the renal isthmus and on the number as well as the position of the renal vessels. Horseshoe kidneys can and should always be considered for transplantation.

Adolescent↗
PubMed2001

Listing for lung transplantation: life expectancy and transplant effect, stratified by type of end-stage lung disease, the Eurotransplant experience.

BACKGROUND: Increased referral for lung transplantation, persistent shortage of donor lungs, and moderate transplant outcome call not only for adequate listing criteria, but also for an optimal allocation scheme. We used global cohort survival after listing and survival benefit from transplantation to study the effect of a lung allocation scheme, primarily driven by waiting time, on the different types of end-stage lung disease. METHODS: We followed all adult patients consecutively listed for first, lung-only transplantation between 1990 and 1996 (n = 1,208) for at least 2 years, with an additional 2-year follow-up after transplantation (n = 744). We used the competing risk method, the Kaplan-Meier method, and a time-dependent non-proportional hazards model to analyze waiting-list outcome and global mortality after listing, post-transplant survival, and transplant effect, respectively. Each analysis was stratified for type of end-stage lung disease. RESULTS: At 2 years, 57% of the total cohort had received lung transplants, whereas 25% had died on the waiting list. The 2-year survival post-transplant was 55%. The global mortality of the cohort, since listing, amounted to 46% at 2 years. Compared with continued waiting, patients experienced benefit from transplantation by Day 100, which lasted until the end of the 2-year analysis period. We noticed the highest global mortality rates for patients with pulmonary fibrosis and pulmonary hypertension (54% and 52%); emphysema patients had the lowest (38%). Patients with pulmonary fibrosis and cystic fibrosis had much earlier benefit from transplantation, 55 and 90 days, respectively. Transplantation also benefited emphysema patients by Day 260. CONCLUSIONS: Lung transplantation conferred transplant benefit in a Western European cohort of adults, in particular for patients with pulmonary fibrosis and cystic fibrosis, but also for patients with emphysema. The global survival rate, reflecting the real life expectancy for a newly listed transplant candidate, is poor for patients with pulmonary fibrosis and pulmonary hypertension. Allocation algorithms that lessen the impact of waiting time and take into account the type of end-stage lung disease should be developed.

Adolescent↗
PubMed2001

Iso-risk curves as a tool for clinical decision-making: donor factors and medical urgency in cardiac transplantation.

UNLABELLED: BACKGROUND; No significant improvement of overall graft survival in cardiac transplantation has occurred during the past decade, notwithstanding the identification of several prognostic donor and recipient risk factors. By translating multivariate results into iso-risk curves plots, stratified for medical urgency, we attempt to present results in a more practical manner, to be used as guidelines at the time of donor heart offer and of allocation. METHODS: We analyzed all first heart-only transplants performed in adults and carried out between January 1, 1997, and June 30, 1998 (N = 1120). Before transplant, 687 patients were at home, 233 on hospital wards, and 200 on the intensive care unit. The overall Cox model yielded 5 independent factors associated with 1-year graft outcome: donor age, donor:recipient weight ratio, medical urgency, end-stage heart disease, and transplant country. We used the significant donor variables of donor age and donor:recipient weight ratio for the iso-risk curves; we calculated relative risks for all combinations of donor age and donor:recipient weight ratio. We obtained iso-risk curves by linking equal relative risks. RESULTS: All iso-risk curves showed that with older donor age, the donor:recipient weight ratio must be higher to obtain the same relative risk for all 3 medical urgency groups. The more urgent the heart transplant candidate, the higher the course of the iso-risk curve for all donor ages. CONCLUSIONS: Iso-risk curve is an elegant tool for presenting multivariate analyses in a more practical and patient-oriented manner. The more understandable prognostic factors become the more likely we are to achieve better results in cardiac transplantation and to use more optimally donor hearts. As an example, we have demonstrated the interaction between donor age, donor:recipient size ratio, and medical urgency.

Adolescent↗
PubMed2001

Renal retransplantation of children: is a policy 'first cadaver donor, then live donor' an acceptable option?

Retransplantation is often a necessity for children with end-stage renal disease (ESRD), as kidney graft survival is still not infinite. If a suitable live donor is present, the current policy is to use the live donor first, in order to obtain excellent long-term outcome and to prevent human leucocyte antigen (HLA) sensitization. Data from the Eurotransplant International Foundation were analyzed to determine whether the sequence, first a cadaveric donor then a live donor, is acceptable. Between January 1 1983 and December 31 1995, 1305 children received a first renal transplant; 269 of them had a second transplant during the same period. Follow-up of at least 1 yr was available. Categories were made according to the sequence of renal donor source: 217 patients were classified as first cadaver and second cadaver (1cad-2cad) transplant, 26 as first cadaver and second live (1cad-2liv) donor transplant, 23 as first live donor and second cadaver (1liv-2cad) transplant and three patients had two subsequent live donor transplants (1liv-2liv). When a live donor transplant was carried out, either first or second, the donor age was always higher, and the chance of a pre-emptive transplantation or short stay on dialysis was higher, compared with a cadaver transplant. The re-graft survival rate of the '1cad-2liv' was better than the '1cad-2cad' and '1liv-2cad' transplants. At 5 yr, the survival was 76%, 49%, and 61%, respectively. These data suggest that, when a suitable live donor is not available for a first transplantation owing to medical and/or familial reservations, a policy of 'first a cadaver donor then a live donor' transplantation is a viable option and should even be promoted. The pre-emptive stage of the second transplant, probably with a live donor, is additionally advantageous.

Adolescent↗
PubMed2001

Heart transplantation indicated only in the most severely ill patient: perspectives from the German heart transplant experience.

The COCPIT study, performed in a complete national cohort of adult patients consecutively listed for cardiac transplantation in Germany in 1997, found a beneficial effect only in the group that was at high risk of dying from heart failure without transplantation. If these results can be reproduced in other countries, the discussion on the respective roles of pharmacological and organ-saving surgical therapies for advanced heart failure, medical urgency and waiting time as heart transplantation allocation criteria, and the feasibility of a randomized clinical trial testing the survival benefit of transplantation must be reopened.

Adult↗
PubMed2000

Effect of receiving a heart transplant: analysis of a national cohort entered on to a waiting list, stratified by heart failure severity. Comparative Outcome and Clinical Profiles in Transplantation (COCPIT) Study Group.

OBJECTIVE: To determine whether there is a survival benefit associated with cardiac transplantation in Germany. DESIGN: Prospective observational cohort study. SETTING: All 889 adult patients listed for a first heart transplant in Germany in 1997. MAIN OUTCOME MEASURE: Mortality, stratified by heart failure severity. RESULTS: Within 1 year after listing, patients with a predicted high risk had the highest global death rate (51% v 32% and 29% for medium and low risk patients respectively; P<0.0001), had the highest risk of dying on the waiting list (32% v 20% and 20%; P=0.0003), and were more likely to receive a transplant (48% v 45% and 41%; P=0.01). Differences between the risk groups in outcome after transplantation did not reach significance (P=0.2). Transplantation was not associated with a reduction in mortality risk for the total cohort, but it did provide a survival benefit for the high risk group. CONCLUSION: Cardiac transplantation in Germany is currently associated with a survival benefit only in patients with a predicted high risk of dying on the waiting list. Patients with a predicted low or medium risk have no reduction in mortality risk associated with transplantation; they should be managed with organ saving approaches rather than transplantation.

Acute Disease↗
PubMed2000

Permanent detrimental effect of nonimmunological factors on long-term renal graft survival: a parsimonious model of time-dependency.

PURPOSE: We attempted to model and test the pattern of effects of prognostic factors on renal graft survival during the posttransplantation time course. PATIENTS AND METHODS: Patients who received a cadaveric kidney-only transplant between January 1990 and December 1995 in Eurotransplant, who received cyclosporine as induction therapy, and who had a complete follow-up at the time of analysis were included in the study (n= 10614). An index summarizing all covariate information was calculated and used for modeling the time-dependent effects with relation to graft failure. RESULTS: The immunological factors (HLA mismatch and % panel-reactive antibody) were seen to have a slowly decreasing negative effect on renal graft survival. The cold ischemic trauma (>24 hr) exerted a permanent detrimental effect on the grafts. The use of organs obtained from old donors was associated with a constant higher risk of graft loss. CONCLUSIONS: An analysis of determinants of human allograft dysfunction should also study the interaction between the effects and time. Nonimmunological factors had a constant detrimental effect on graft failure, whereas the impact of the immunological factors--although remaining important for late graft loss--very slowly decreased. In the context of marginal transplants, clustering of unfavorable factors should be avoided to prevent late graft losses.

Adolescent↗
PubMed2000

2-rhodaoxetanes: their formation of oxidation of [RhI(ethene)]+ and their reactivity upon protonation.

New cationic, pentacoordinate complexes [(TPA)Rh1(ethene)]+, [1a]+, and [(MeTPA)Rh1(ethene)]+, [1b]+, have been prepared (TPA = N,N,N-tri(2-pyridylmethyl)amine, MeTPA = N-[(6-methyl-2-pyridyl)-methyl]-N,N-di(2-pyridylmethyl)amine). Complex [1a]+ is selectively converted by aqueous HCl to [(TPA)RhIII-(ethyl)Cl]+, [2a]+. The same reaction with [1b]+ results in the [(MeTPA)RhIII-(ethyl)Cl]+ isomers [2b]+ and [2c]+. Treatment of [1a]+ and [1b]+ with aqueous H2O2 results in a selective oxygenation to the unsubstituted 2-rho-da(III)oxetanes (1-oxa-2-rhoda(III)cyclo-butanes) [(TPA)RhIII(kappa2-C,O-2-oxyethyl)]+, [3a]+, and [(MeTPA)RhIII(kappa2-C,O-2-oxyethyl)]+, [3b]+. The reactivity of 2-rhodaoxetanes [3a]+ and [3b]+ is dominated by the nucleophilic character of their 2-oxyethyl oxygen. Reaction of [3a]+ and [3b]+ with the non-coordinating acid HBAr(f)4 results in the dicationic protonated 2-rhodaoxetanes [(TPA)RhIII(kappa2-2-hydroxyethyl)]2+, [4a]2+, and [(MeTPA)RhIII(kappa2-2-hydroxyethyl)]2+, [4b]2+. These eliminate acetaldehyde at room temperature, probably via a coordinatively unsaturated kappa1-2-hydroxyethyl complex. In acetonitrile, complex [4a]2+ is stabilised as [(TPA)-RhIII(kappa1-2-hydroxyethyl)(MeCN)]2+, [5a]2+, whereas the MeTPA analogue [4b]2+ continues to eliminate acetaldehyde. Reaction of [3a]+ with NH4Cl and Mel results in the coordinatively saturated complexes [(TPA)RhIII(kappa1-2-hydroxyethyl)(Cl)]+, [6a]+, and [(TPA)-RhIII(kappa1-2-methoxyethyl)(I)+, [7a]+, respectively. Reaction of [3a]+ with NH4+ in MeCN results in formation of the dicationic metallacyclic amide [(TPA)-RhIII [kappa2-O,C-2-(acetylamino)ethyl]]2+, [9]2+, via the intermediates [4a]2+, [5a]2+ and the metallacyclic iminoester [(TPA)RhIII[kappa2-N,C-2-(acetimidoyloxy)ethyl]]2+, [8]2+. The observed overall conversion of the [Rh(I)(ethene)] complex [1a]+ to the metallacyclic amide [9]2+ via 2-rhodaoxetane [3a]+, provides a new route for the amidation of a [RhI(ethene)] fragment.

Journal Article↗
PubMed1999

Eurotransplant randomized multicenter kidney graft preservation study comparing HTK with UW and Euro-Collins.

The aim was to evaluate the effect of HTK compared to UW and Euro-Collins (EC) on the initial graft function and long term graft survival in two prospective randomized studies. Only kidneys from heart-beating, kidney-only or kidney + heart donors were eligible for entry. Initial non-function (INF) was defined as the absence of life-sustaining renal function, requiring dialysis treatment on two or more occasions, during the first week after transplantation. To evaluate the contribution of the preservation solutions on INF in relation to other factors, a multivariate, 2-step logistic regression model was used. Randomization was performed between July 1990 and September 1992. The UW-HTK study comprised 342 donors and 611 transplants (UW: 168 donors and 297 transplants, HTK: 174 donors and 314 transplants). In the EC-HTK study 317 donors and 569 transplants were included (EC: 155 donors and 277 transplants, HTK: 162 donors and 292 transplants). INF occurred in 33% of either HTK-(n = 105) or UW-(n = 99) preserved kidneys (P = NS), and in 29% of the HTK-(n = 85) and in 43% of the EC-(n = 119) preserved kidneys (P = 0.001). Multivariate analysis showed no significant influence of the preservation solution on the incidence of INF in the UW-HTK study, but factors contributing to INF were donor age, cause of death, retransplantation, and cold ischemic period. The EC-HTK study showed a significantly higher risk of INF, using EC as preservation, in addition to cold ischemic period and donor quality. The 3-year graft survival of HTK-preserved kidneys was 73%, compared to 68% for UW-preserved kidneys in the UW-HTK study (P = NS); while the 3-year graft survival of HTK preserved kidneys was 70% compared to 67% for EC-preserved kidneys in the EC-HTK study (P = NS). We can conclude that HTK is comparable to UW in its preservative abilities, using kidneys from heart-beating kidney-only donors, whereas EC as renal preservation solution should be avoided.

Adenosine↗
PubMed1999

In vitro reactivity of allospecific cytotoxic T lymphocytes does not explain the taboo phenomenon.

Matching for human leucocyte antigens (HLA) is important for graft survival in kidney transplantation. Nevertheless, most patients receive a kidney graft with multiple HLA mismatches. Some of these mismatches seem to be more harmful than others. By studying the effect of single HLA mismatches in the context of the patients' own HLA, we have previously identified donor/recipient combinations with a significantly higher incidence of early graft failure, the so-called taboo combinations. In the present study we investigated whether a higher cytotoxic T lymphocyte (CTL) response towards taboo mismatches may be involved in this phenomenon. CTL reactivity was determined both in taboo and control combinations by in vitro CTL precursor assays, using peripheral blood mononuclear cells and proximal tubular epithelial cells as target cells. Inhibition studies with CD8-antibody as well as Cyclosporin A were performed to identify high avidity and primed CTLs. Furthermore, in committed CTLp assays indirect recognition of the taboo mismatch was tested using synthetic peptides. The CTL precursor frequencies in taboo combinations were always lower than the CTL precursor frequencies in control combinations. No difference in avidity and activation status of the CTLs could be detected when taboo combinations were compared with the controls. In the committed CTLp assays no reactivity towards any of the synthetic peptides was observed. The significantly poorer graft survival of taboo combinations cannot be explained by a higher number of donor-specific CTLs. Furthermore, the avidity or activation status of these CTLs does not provide a clue to the taboo phenomenon.

Cytotoxicity Tests, Immunologic↗
PubMed1999

Lung transplant waiting list: differential outcome of type of end-stage lung disease, one year after registration.

BACKGROUND: Donor lung scarcity, distinct natural courses of the different types of end-stage lung diseases, and lung allocation schemes demand appropriate candidate acceptance for a lung transplant and time of listing. This study was undertaken to investigate the association between type of end-stage lung disease and outcome, 1 year after a lung transplant candidate was put on the waiting list. METHODS: From 1990 to 1995, 1376 adult patients were registered for a first lung (n = 1006) or heart-lung (n = 370) transplantation in Eurotransplant. All patients were followed for at least 1 year. For each type of end-stage lung disease (cystic fibrosis, pulmonary fibrosis, emphysema, pulmonary hypertension, congenital heart disease, and other), chances of transplantation, of death on the waiting list, and of removal for other reasons, 1 year after listing, were calculated with the competing risks method. A multivariate Cox regression model was used to assess the influence of the type of end-stage lung disease on the waiting list outflow among other prognostic variables. RESULTS: Lung transplant candidates with emphysema and with pulmonary fibrosis had the highest chance of a transplant; however, patients with pulmonary fibrosis had also the highest probability of dying while waiting, while the emphysema patients and those with the type "other" had the lowest probability. In the multivariate analysis, the type of end-stage lung disease appeared as an independent prognostic factor for both outcomes. Compared to the patients with cystic fibrosis (reference group), only patients with pulmonary fibrosis had a significantly higher chance of a transplant (RR = 1.50); the lowest chance of death for the emphysema and the "other" patients was confirmed (RR = 0.53 and RR = 0.51, respectively). Recipient size, ABO blood group, country and epoch of listing also had a significant impact on the transplant chance, while country of listing and recipient age were the other factors independently influencing the chance of dying on the waiting list. On the heart-lung waiting list, the type of end-stage lung disease solely affected the chance of death prior to transplant. Compared with cystic fibrosis, pulmonary fibrosis had a significantly higher risk (RR = 2.93), closely followed by pulmonary hypertension (RR = 2.57). Factors crucial for the chance of a heart-lung transplant were recipient size, ABO blood group and country of listing. CONCLUSIONS: The type of end-stage lung disease is a distinctive factor for predicting survival on the lung and heart-lung transplant waiting list, and should be taken into account whenever assessing waiting list outcomes. When developing lung allocation schemes, it is medically justified to incorporate the type of end-stage lung disease.

Adolescent↗