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M J Slooff

Publications and source records attributed to M J Slooff.

At least 55 records · Page 3Linked to original sources
PubMed1998

Quantitation of immunosuppression by flow cytometric measurement of the capacity of T cells for interleukin-2 production.

BACKGROUND: Methods to quantitate the effects of immunosuppressive drugs on immune reactivity might be helpful for monitoring immunosuppressive treatment. Cyclosporine (CsA) inhibits the induction of cytokine synthesis in T cells, and measurement of interleukin (IL)-2 production might constitute a parameter of this drug's effect. METHODS: We determined the percentages of CD4+ and CD8+ lymphocytes producing IL-2 upon stimulation by phorbol myristate acetate and calcium ionophore in whole blood culture, using immunostaining of intracytoplasmatic and membrane markers, followed by multiparameter flow cytometry. A total of 38 clinically stable transplant patients on various immunosuppressive protocols were studied. RESULTS: The percentage of CD4+ T cells producing IL-2 was strongly reduced in patients compared with healthy controls (23% [range, 3-68%] vs. 59.0% [range, 41-70%]; P=0.000035). The percentage of CD4+ T cells producing IL-2 was negatively correlated with the CsA level (Rc=-0.0821, P=0.00002297) but not with prednisolone or azathioprine doses. Fewer CD8+ T cells produced IL-2 in transplant patients compared with controls, but the difference failed to reach statistical significance. The percentage of CD8+ T cells capable of producing IL-2 was inversely correlated to CsA levels (Rc=-0.0375, P=0.0011). CONCLUSIONS: These data suggest that the functional effects of CsA in transplant recipients can be quantitatively determined and that the capacity of CD4+ T cells to produce IL-2 upon stimulation constitutes a functional parameter of CsA effects on the immune system. Prospective studies are required to determine whether this method is useful for clinical monitoring.

Adult↗
PubMed1998

Clinical relevance of transforming growth factor alpha, epidermal growth factor receptor, p53, and Ki67 in colorectal liver metastases and corresponding primary tumors.

To determine whether the expression of transforming growth factor alpha (TGF-alpha), its receptor (epidermal growth factor receptor [EGFr]), p53 nuclear protein, and proliferation influences prognosis of patients with liver metastases, a study was performed in 45 liver metastases and 33 corresponding primary colorectal carcinomas in patients referred for liver surgery. The expression of TGF-alpha, EGFr, p53 nuclear protein, and proliferation rate was correlated with clinicopathological characteristics and survival after partial liver resection. In liver metastases, TGF-alpha expression was low in 42%, intermediate in 35%, and high in 23%. TGF-alpha expression was higher in liver metastases derived from lymph node-positive primary carcinomas, in synchronous and in irresectable liver metastases compared with those derived from lymph node-negative primary carcinomas, metachronous, and resectable liver metastases. Nuclear p53 expression was found in 83% of primary tumors and 71% of liver metastases. p53 expression did not correlate with the various clinicopathological characteristics. Ki67 expression was not associated with clinicopathological characteristics in primary and metastatic tumors. In the 38 patients in whom a partial liver resection was performed, median survival was 25 months in patients with a higher TGF-alpha expression in the metastasis than in the primary tumor and 60 months in patients with comparable or lower TGF-alpha expression in the metastasis than in the primary tumor (P = .036). Median survival after liver resection was 21 months in patients with p53-negative liver metastases and 58 months in patients with p53-positive metastases (P = .043). By multivariate analysis, p53 and EGFr expression on liver metastases were the best predictors of disease-free survival after partial liver resection, with relative risks of 2.38 and 3.33, respectively. In patients with colorectal liver metastases, referred for liver surgery, a higher TGF-alpha expression is associated with unfavorable tumor characteristics, whereas p53 and absence of EGFr expression is associated with a better survival after partial liver resection.

Adenocarcinoma↗
PubMed1998

Routine Doppler ultrasound for the detection of clinically unsuspected vascular complications in the early postoperative phase after orthotopic liver transplantation.

To assess the role of routine Doppler ultrasound in the detection of clinically unsuspected vascular complications in the early postoperative phase after orthotopic liver transplantation (OLT), the findings of 858 routinely performed Doppler ultrasound examinations were analyzed in 268 transplants. At various time intervals after OLT, we encountered 46 abnormal Doppler findings: hepatic artery (thrombosis), portal vein [anastomotic stenosis, (non)occlusive thrombosis or reversed flow], inferior vena cava [anastomotic stenosis with reversed flow, no flow, or (non)occlusive thrombosis], and hepatic veins (to-and-fro flow or stenosis with reversed flow) in 14, 20, 9, and 2 transplants, respectively. Most of these abnormal Doppler findings were confirmed by angiography, cavography, or surgery. The positive predictive value for hepatic artery thrombosis (HAT) was 12 out of 14, or 86%. In the first 2 weeks after OLT, routine Doppler ultrasound revealed 20 of the 46 abnormal findings (43%). Clinically unsuspected complications of the hepatic artery, portal vein, inferior vena cava, and hepatic veins were found in 9 of the 14 (64%), 6 of the 20 (30%), 3 of the 9 (33%), and 2 of the 2 (100%) transplants, respectively. The highest incidence--nine vascular complications--was found on the 1st day. On each of the remaining days (except for the 2nd and 9th days), one or two vascular complications were detected. HAT was found mainly in the 1st week. Vascular complications developed independently or concomitantly. We conclude that routine Doppler ultrasound is very important for the detection of clinically unsuspected vascular complications, particularly HAT, in the first 2 weeks after OLT. We recommend routine Doppler ultrasound of all hepatic vessels every 3 days in the early postoperative phase after OLT. Special attention should be paid to the 1st day.

Adolescent↗
PubMed1998

Donor-specific immunological non-responsiveness after liver transplantation.

Since the rate of immunological losses of liver allograft after the immediate posttransplant period is much lower than in other organs, we studied the immune responses against donor HLA antigens in 18 patients with a good long-term outcome to determine whether the development of a state of immunological non-responsiveness to donor antigens might account for this favorable outcome. The reactivity against donor spleen cells was measured before and 2 years after transplantation. The reactivity in mixed lymphocyte culture (MLC) and the frequencies of cytotoxic T cell precursors (CTLp) were determined. Responses against third-party spleen cells were determined concurrently to exclude a generalized reduction of immunocompetence due to chronic immunosuppressive treatment. Before orthotopic liver transplantation, the majority of patients had normal T cell responses against donor antigens that were comparable to those against third-party antigens. Two years after transplantation, donor-specific MLC non-reactivity had developed in 10 of the 18 (56%) patients. In addition, 15 of 18 (83%) patients had developed donor-specific cytotoxic T cell (CTL) non-responsiveness; 2 had reduced numbers of CTLp against both donor and third-party cells, while the remaining patient had maintained reactivity against donor antigens. In conclusion, donor-specific non-responsiveness is present in the majority of patients 2 years after successful liver transplantation, but occurs predominantly at the CTL level.

Humans↗
PubMed1998

Quantification of immunosuppression by flow cytometric measurement of intracellular cytokine synthesis.

The availability of a method to measure the effects of drugs on immune reactivity should be helpful in optimizing treatment after organ transplantation. Since cyclosporine A (CSA) interferes with activation of T cells and cytokine synthesis, production of IL-2 and IFN-gamma might constitute a marker of this drug's effects. We measured the capacity for mitogen-stimulated production of these cytokines in whole blood by using immunostaining of intracellular and membrane antigens, followed by flow cytometry. The percentage of CD4+ T cells producing IL-2 or IFN-gamma was strongly reduced in 20 transplant patients compared with 24 healthy controls. The capacity for IL-2 production of CD4+ and CD8+ cells correlated inversely with CSA blood levels (P values 0.0087 and 0.0396, respectively). IFN-gamma production by CD4+ T cells showed a negative correlation with the prednisolone dose (P = 0.0175) and, for the CD8+ subset, with CSA trough levels (P = 0.0023). These data show that inhibition of T cell cytokine synthesis by CSA and prednisolone can be quantified.

Flow Cytometry↗
PubMed1998

Mutual tolerance after liver and not after heart transplantation? Evaluation of patient-anti-donor and donor-anti-patient responses by mixed lymphocyte culture.

The ultimate goal in organ transplantation is the induction of donor-specific transplantation tolerance. The fact that in some patients it is possible to withdraw immunosuppressive therapy completely, suggests that immunological adaptation or donor-specific nonresponsiveness can occur following transplantation. In earlier studies we have shown that after blood transfusion, the mixed lymphocyte reactivity of the donor against patient peripheral blood mononuclear lymphocytes taken after blood transfusion gradually decreased with time. This may reflect the induction of an immunoregulatory mechanism, which protects the recipient against an immune reaction of the donor, enhancing a state of mixed chimerism. A similar phenomenon might also play a role in the immunological mechanism leading to transplantation tolerance. Therefore, we studied responses in patients with a well-functioning liver and heart transplant using a primed lymphocyte test (PLT) and a mixed lymphocyte culture (MLC). Two years after liver transplantation the PLT and MLC responses of patient against donor were decreased significantly compared to the situation before transplantation. The response of donor against patient was also lower two years after transplantation. The decreased responses were donor-specific since responses to third-party cells generally remained unchanged. In heart transplant recipients we could not detect a donor-specific downregulation. The reversed response, of donor against patient, was not different from responses of third-party against patient cells. Therefore, we conclude that donor-specific nonresponsiveness is not induced in patients with well-functioning heart transplants. In contrast, after a successful liver transplantation the response of patient against donor is decreased, as is the reversed response. It may be valuable to test whether in liver transplant patients withdrawing or reducing of maintenance immunosuppression is permitted for patients who appear to have developed two-way donor-specific hyporeactivity.

Cells, Cultured↗
PubMed1998

Effect of cold and warm ischaemia on drug metabolism in isolated hepatocytes and slices from human and monkey liver.

1. The influence of short-term cold storage in University of Wisconsin organ preservation solution (UW) on the ability to metabolize lidocaine, testosterone and 7-ethoxycoumarin in isolated human and cynomolgus monkey (Macaca fascicularis) hepatocytes and liver slices has been investigated. 2. The human liver tissue was obtained from two different sources, i.e. healthy liver tissue from patients undergoing partial hepatectomy because of metastases of colorectal carcinoma (PH livers) and donor tissue remaining as surgical waste after reduced size or split liver transplantation (Tx livers). Tx livers were perfused in situ with ice-cold UW avoiding warm ischaemia. This in contrast with PH livers, where the operation caused warm ischaemia for 5-90 min. 3. Liver slices and hepatocytes from cynomolgus monkey liver showed comparable metabolic rates for the substrates tested, indicating that all hepatocytes in the slice are participating in the biotransformation of the substrates. These monkey liver preparations can be stored up to 18 h with only a slight loss of their metabolic capacity. 4. Liver slices and isolated hepatocytes from the Tx livers as well as isolated cells from the PH livers could also be stored up to 18 h without losing metabolic capacity. However, for liver slices prepared from PH livers cold storage is not recommended, because metabolic function was reduced by approximately 40% after 18 h.

Animals↗
PubMed1998

A rapid and simple method for cryopreservation of human liver slices.

1. Precision-cut liver slices represent a suitable and convenient in vitro preparation for studying metabolism and toxicity mechanisms of drugs and toxic chemicals. Particularly in the case of human liver slices, cryopreservation would enable more efficient utilization of this scarce and irregularly available tissue. 2. Liver slices from consecutive human livers were cryopreserved using a method previously developed for rat and monkey liver slices. This procedure involves incubation in 12% dimethyl sulphoxide for 30 min on ice and direct immersion into liquid nitrogen. 3. Functional integrity of cryopreserved human liver slices, as compared with that of fresh liver slices, was maintained at 66 +/- 8% (alanine aminotransferase activity retained in the slices), 78 +/- 7% (urea synthesis), 88 +/- 14% (testosterone hydroxylation), 84 +/- 7% (N-deethylation of lidocaine) and 88 +/- 10% (total O-deethylation of 7-ethoxycoumarin). The ratios of testosterone metabolites did not change on cryopreservation. 4. These results show that the cryopreserved human liver slices retained the measured drug metabolism activities. Therefore, this cryopreservation method is suitable for storing liver slices to be used for comparing drug metabolism patterns, at least qualitatively, between species.

Animals↗
PubMed1998

Effect of human liver source on the functionality of isolated hepatocytes and liver slices.

In vitro experiments using human liver tissue to study drug metabolism and transport are usually performed and interpreted without real consideration of the differences in procurement of the tissue, if it is obtained from different sources. Therefore, in this study the functionality of isolated hepatocytes and liver slices prepared either from healthy human liver tissue obtained from patients undergoing partial hepatectomy [livers from partial hepatectomy (PH-livers)] or from donor tissue remaining after reduced-size or split-liver transplantation [livers from transplantation (Tx-livers)] was compared. From each liver sample, both liver slices and hepatocytes were prepared and compared with respect to viability and drug disposition. The viability of hepatocytes was assessed by trypan blue exclusion, ATP content, and energy charge and that of liver slices by potassium retention. In both preparations phase I metabolism was studied using lidocaine and testosterone as substrates, whereas phase I and II metabolism was assessed with 7-ethoxycoumarin. The membrane transport capability of the hepatocytes was investigated by measuring the uptake of taurocholic acid. The hepatocytes from PH-livers and Tx-livers showed similar viabilities and functional capacities. Metabolism in cells and slices from Tx-livers was found to be quantitatively comparable. However, liver slices from PH-livers showed a significantly lower metabolic capacity, compared with cells from the same tissue. This may indicate that only some of the hepatocytes in the liver slices from PH-livers participate in the metabolism of the compounds studied and that a selection of healthy cells takes place during isolation of the hepatocytes. Our results imply that hepatocytes isolated from Tx-livers and PH-livers can be used in the same study without consideration of the procurement of the tissue. However, the procurement of the tissue may significantly influence the functions of liver slices; the liver slices prepared from PH-livers showed significantly lower metabolic function, compared with slices prepared from Tx-livers.

Adenosine Triphosphate↗
PubMed1998

Liver cell proliferation after partial hepatectomy in rats with liver metastases.

OBJECTIVE: To validate proliferating cell nuclear antigen (PCNA) expression and flow cytometry as proliferation markers in regenerating rat liver containing metastases. STUDY DESIGN: Rats containing colorectal liver metastases were killed at various days after 70% partial hepatectomy or a sham operation. [3H]thymidine and 5-bromo-2'deoxyuridine (BrdU) incorporation, PCNA expression and flow cytometry were used to evaluate liver cell proliferation. RESULTS: The assessment of proliferating liver cells by PCNA expression and BrdU incorporation was more reliable than autoradiography. PCNA expression correlated well with BrdU incorporation (r = .68, P = .003) and autoradiography (r = .57, P = .02) in regenerating liver. BrdU incorporation and PCNA expression were higher in hepatectomized rats as compared to sham-operation rats at days 1-4 after hepatectomy. Flow cytometry of propidium-stained nuclei from livers of hepatectomized rats showed a higher proportion of S-phase nuclei as compared to S-phase nuclei in control rats. The correlation coefficients of the number of S-phase nuclei, BrdU-positive nuclei and PCNA-positive nuclei were .39 (P < .02) and .56 (P < .0005), respectively. CONCLUSION: Flow cytometry and PCNA expression are simple and reliable methods of studying proliferation in metastases containing rat liver after partial hepatectomy.

Animals↗
PubMed1998

Characterization of the uptake of rocuronium and digoxin in human hepatocytes: carrier specificity and comparison with in vivo data.

Mechanisms of drug transport in the liver have been investigated predominantly in rodents. Most of the in vitro drug research in the liver is performed in liver preparations of animals. The results of such experiments frequently are discussed in relation to anticipated metabolic profiles in man, but these extrapolations are often inappropriate because of large interspecies differences in drug metabolism. In the present study, the mechanisms and specificity of the uptake of the organic cation rocuronium and the cardiac glycoside digoxin were investigated in human hepatocytes and were compared with results obtained in rat hepatocytes. The extraction ratio for the intact liver was calculated from the measured uptake rates of the compounds in the human cells in vitro and compared with published in vivo data. The initial hepatic extraction ratio, calculated from the in vitro uptake data for digoxin and rocuronium, very well reflected the initial extraction ratio for distribution in the liver in vivo in man. Uptake of 100 microM rocuronium was inhibited by 40 microM K-strophantoside (80% inhibition), and although not significantly, by 160 microM procainamide ethobromide, whereas no inhibitory effect was found in the presence of 160 microM taurocholic acid. In a previous study in rat hepatocytes, marked inhibition of digoxin uptake by quinine and only minimal inhibition by the diastereomer quinidine was demonstrated, showing clear stereoselectivity in transport inhibition. Unexpectedly, the uptake of digoxin in human hepatocytes was not inhibited significantly by quinidine or quinine, which indicates clear species differences. This is the first study to investigate the uptake mechanisms of organic cations and cardiac glycosides in human hepatocytes in some detail. The results show that uptake characteristics of drugs found in rats can not be extrapolated directly to humans.

Androstanols↗
PubMed1997

Value of the in vitro or in vivo monoethylglycinexylidide test for predicting liver graft function.

BACKGROUND: An adequate function test for donor livers is still lacking. The monoethylglycinexylidide (MEGX) test, performed in vivo in the donor to measure the metabolic rate of lidocaine conversion to MEGX, has been proposed as a function test for donor livers to predict postoperative organ function. METHODS: In the present study, we investigated whether the MEGX formation rate measured in needle biopsy specimens in vitro correlates with the rate of MEGX formation in vivo. The in vivo MEGX test was performed in the donors and in the recipients on days 1 and 2. The in vivo and in vitro MEGX tests were compared with posttransplant liver function in the recipients in order to investigate their possible relevance as predictors of graft function. RESULTS: The MEGX formation rate in needle biopsy specimens in vitro showed a significant correlation with the MEGX serum concentration found in the donor. A low rate of MEGX formation in the biopsy specimens tended to predict initial poor function of the grafts. In the donor, the MEGX test did not correlate with general liver function after transplantation. Only the MEGX serum concentration in the recipients on day 2 gave an indication of graft function. CONCLUSIONS: MEGX formation in liver biopsy specimens in vitro properly reflects metabolic function of the particular liver. Therefore, liver biopsies may be a valuable tool to help predict liver function in vivo. However, the MEGX test alone is not sufficient to provide the gold standard to determine liver function in donor and transplantation livers.

Adenosine↗
PubMed1997

Type IIIb glycogen storage disease associated with end-stage cirrhosis and hepatocellular carcinoma. The Liver Transplant Group.

Type III glycogen storage disease (GSD) is a disorder of carbohydrate metabolism caused by a deficiency of debranching enzyme. Different subtypes with different clinical pictures have been recognized. During childhood and early adulthood, the symptoms generally regress, and normal adulthood appears possible in most patients without symptoms or signs of cirrhosis. We report on an adult patient with GSD who developed endstage cirrhosis and a small hepatocellular carcinoma. She had GSD subtype IIIb, i.e., there were no signs of cardiomyopathy, myopathy, or neuropathy. She underwent a successful transplantation, representing the first case treated this way for this indication to our knowledge, and she is doing well after 1 year. Debranching enzyme activity was absent both in the liver and in the leukocytes before transplantation. The debranching enzyme activity remained absent in the leukocytes after transplantation. We conclude that patients with GSD type III may develop end-stage cirrhosis and hepatocellular carcinoma and therefore need hepatological follow-up during adulthood.

Adult↗
PubMed1997

Gastric mucosal pH is associated with initial graft function but is not a predictor of major morbidity after liver transplantation.

Gastric mucosal pH reflects splanchnic perfusion. Monitoring gastric mucosal pH might be useful in predicting outcome after liver transplantation. Forty patients were included in the study. Gastric mucosal pH and gastric mucosal pH corrected for systemic pH were compared with regard to initial liver function and morbidity. Eighty percent of the patients had at least one episode with a gastric mucosal pH of <7.32, and 84% of these had a concomitant arterial pH of <7.32. No differences in morbidity were found between patients with a gastric mucosal pH of <7.32 and those with a gastric mucosal pH of >7.32. If gastric mucosal pH was corrected for arterial pH, only 49% of the patients had an episode during transplantation with a corrected gastric mucosal pH of <7.32. Comparing these patients with the group that did not have such an episode, we found that flow in the venovenous bypass system was significantly lower (2.9 v 3.4 L/min; P < .02) in the first group. Also alanine aminotransferase and aspartate aminotransferase levels were higher, antithrombin III levels and lidocaine clearance rates were lower, and prothrombin times were longer in the group with corrected gastric mucosal pH of <7.32. No differences with regard to major morbidity and mortality were noted. Gastric mucosal pH during liver transplantation should be corrected for arterial pH. Patients with a corrected gastric mucosal pH of <7.32 are more likely to develop initial liver function tests disturbances, but morbidity is not different from patients with gastric mucosal pH of >7.32.

Adult↗
PubMed1997

Selective treatment of early acute rejection after liver transplantation: effects on liver, infection rate, and outcome.

To evaluate the results of selective treatment of biopsy-proven mild acute rejection episodes, we retrospectively studied 1-week liver biopsies of 103 patients with a primary liver graft in relation to liver function tests. The overall incidence of rejection was 35%. In four patients the biopsy showed histological features consistent with rejection; in 27 patients it showed mild acute rejection (grade 1), and in 5 patients it showed moderate acute rejection (grade 2). Study group 1 consisted of 19 untreated patients with grade 1 rejection and group 2 of 8 treated patients with grade 1 rejection. At 30 and 90 days, no differences in liver function tests were found. The infection rate, histology after 1 year, and survival in the two groups did not differ. It may, therefore, be concluded that withholding treatment in histologically proven mild acute rejection is possible in selected patients based on histological, biochemical, and clinical criteria. This may reflect the functional diversity of morphologically similar lymphocytic infiltrates observed in graft biopsies showing features of mild acute rejection.

Adult↗