PubMed Health⌕ Search

Biomedical subjects

B de Vries

Publications and source records attributed to B de Vries.

At least 19 recordsLinked to original sources
PubMed2006

Redox-active iron released during machine perfusion predicts viability of ischemically injured deceased donor kidneys.

Redox-active iron, catalyzing the generation of reactive oxygen species, has been implicated in experimental renal ischemia-reperfusion injury. However, in clinical transplantation, it is unknown whether redox-active iron is involved in the pathophysiology of ischemic injury of non-heart-beating (NHB) donor kidneys. We measured redox-active iron concentrations in perfusate samples of 231 deceased donor kidneys that were preserved by machine pulsatile perfusion at our institution between May 1998 and November 2002 using the bleomycin detectable iron assay. During machine pulsatile perfusion, redox-active iron was released into the preservation solution. Ischemically injured NHB donor kidneys had significantly higher perfusate redox-active iron concentrations than heart-beating (HB) donor kidneys that were not subjected to warm ischemia (3.9 +/- 1.1 vs. 2.8 +/- 1.0 micromol/L, p = 0.001). Moreover, redox-active iron concentration was an independent predictor of post-transplant graft viability (odds ratio 1.68, p = 0.01) and added predictive value to currently available donor and graft characteristics. This was particularly evident in uncontrolled NHB donor kidneys for which there is the greatest uncertainty about transplant outcomes. Therefore, perfusate redox-active iron concentration shows promise as a novel viability marker of NHB donor kidneys.

Adenosine↗
PubMed2003

Comparison of E-selectin expression at mRNA and protein levels in murine models of inflammation.

BACKGROUND: Drug targeting to activated endothelial cells via E-selectin is currently being explored as a new approach to treat chronic inflammatory disorders. This approach uses E-selectin directed antibodies as carrier molecules to selectively deliver anti-inflammatory drugs into activated endothelial cells, thereby theoretically decreasing drug-associated side-effects. Therapeutic effects of developed drug targeting constructs will have to be tested in animal models of inflammation, in which E-selectin is expressed during the course of the disease. In this study several murine models of inflammation were investigated regarding expression of E-selectin. METHODS: E-selectin expression was determined both at the mRNA level using RT-PCR and at the protein level by immunohistochemistry using two monoclonal antibodies (10E9.6 and MES-1). The models studied included delayed type hypersensitivity induced skin inflammation, dextran sodium sulphate induced colitis, kidney ischemia/reperfusion injury, atherosclerosis in ApoE knockout mice, and collagen induced arthritis. RESULTS: In all animal models E-selectin mRNA expression was detected, although to a different extent. In contrast, only the delayed type hypersensitivity model and, to a minor extent, the collagen induced arthritis model showed E-selectin protein expression. CONCLUSION: These results stress the need to determine E-selectin protein expression and not only mRNA expression, when choosing an animal model for testing E-selectin directed drug targeting preparations. In addition, in the arthritis model, E-selectin protein detection was dependent on the particular anti-E-selectin antibody used. This finding may not only have implications for the development and/or choice of homing devices to be used in E-selectin directed drug targeting preparations, but also for inflammation research in general.

Animals↗
PubMed2002

Anomalies associated with oesophageal atresia in Asians and Europeans.

Oesophageal atresia (OA) is often associated with anomalies of other systems. The genetic contribution to the formation of the VACTERL association is not clear. The objective of this study was to evaluate the incidence of associated anomalies in two different racial populations. The associated anomalies in neonates with OA managed in an Asian and a European paediatric surgical centre from 1982 to 1998 were reviewed. Non-Asian and non-European patients were excluded from the respective centres. The incidence of anomalies was compared using Fisher's exact test, taking #E5/E5# below 0.05 as statistically significant. Forty-eight consecutive Asian (25 boys and 23 girls) and 34 consecutive European patients (20 boys and 14 girls) were included in the analysis. The percentage of patients with at least one associated anomaly was 50% and 74% in the Asian and European populations, respectively, which was significantly different (#E5/E5#=0. 04). There was no statistically significant difference in the incidence of associated cardiovascular (29% vs 39%), anorectal (11% vs 18%), and musculoskeletal (16% vs 22%) anomalies, duodenal atresia (4% vs 3%), or Down's syndrome (3% vs 6%) between the two populations. However, the European patients had a significantly higher incidence of urogenital (UG) anomalies (26% vs 4%, #E5/E5#=0.006), the most common being agenesis (n=4) and dysplasia (n=3) of one or both kidneys. Hereditary factors may influence the incidence of associated anomalies in children with OA, particularly of the UG system. However, environmental factors cannot be excluded.

Abnormalities, Multiple↗
PubMed2001

Effect of fenoterol-induced constitutive beta(2)-adrenoceptor activity on contractile receptor function in airway smooth muscle.

In the present study, we investigated the effect of fenoterol-induced constitutive beta(2)-adrenoceptor activity on muscarinic receptor agonist- and histamine-induced bovine tracheal smooth muscle contractions. Bovine tracheal smooth muscle strips were incubated with 10 microM fenoterol or vehicle for various periods of time (5, 30 min, 18 h) at 37 degrees C. After extensive washout (3 h, 37 degrees C), isometric contractions were measured to the full muscarinic receptor agonist methacholine, the partial muscarinic receptor agonist 4-(m-chlorophenyl-carbamoyloxy)-2-butynyltrimethylammonium (McN-A-343) and histamine. Fenoterol treatment significantly reduced the sensitivity (pEC(50)) to methacholine in a time-dependent manner, without affecting maximal contraction (E(max)). Fenoterol treatment similarly reduced the pEC(50) of McN-A-343 and histamine; however, E(max) values were also reduced, to approximately 70% of control after 18-h treatment. The inverse agonist timolol, having no effect on control preparations, consistently restored the reduced pEC(50) and E(max) values of the contractile agonists. Remarkably, in the presence of timolol the pEC(50) values of McN-A-343 and histamine in fenoterol-treated airways were significantly enhanced compared to controls. In conclusion, fenoterol-induced constitutive beta(2)-adrenoceptor activity reduces muscarinic receptor agonist- and histamine-induced contractions of bovine tracheal smooth muscle, which can be reversed by the inverse agonist timolol. Moreover, after beta(2)-adrenoceptor agonist treatment, inverse agonism by beta-adrenoceptor antagonists may cause enhanced airway reactivity to contractile mediators.

Adrenergic beta-2 Receptor Agonists↗
PubMed2001

Apoptosis and chemokine induction after renal ischemia-reperfusion.

BACKGROUND: One of the earliest prerequisites for the development of inflammation after ischemia-reperfusion (I/R) is local chemokine expression. We recently demonstrated that apoptosis, characterized by intracellular caspase-activation, contributes to the development of inflammation after I/R. METHODS: The contribution of apoptosis was investigated using the pan-caspase inhibitor Z-Val-Ala-Asp(OMe)-CH2F in a murine model of renal I/R. Renal expression of the chemokines macrophage inflammatory protein-2 (MIP-2) and KC was studied using RT-PCR and immunohistology. Measuring myeloperoxidase activity and serum ureum and creatinine levels assessed neutrophil influx and kidney dysfunction. RESULTS: We demonstrate renal up-regulation of KC and MIP-2 after 1 to 16 hr of reperfusion. Treatment with the caspase inhibitor Z-Val-Ala-Asp(OMe)-CH2F effectively prevented I/R-induced renal apoptosis, KC, and MIP-2 up-regulation after 2 hr of reperfusion as well as neutrophil influx and functional impairment after 24 hr of reperfusion. CONCLUSIONS: These data for the first time show that chemokine induction following I/R is dependent on caspase activation.

Amino Acid Chloromethyl Ketones↗
PubMed2000

Beta-agonist-induced constitutive beta(2)-adrenergic receptor activity in bovine tracheal smooth muscle.

According to the two state receptor model, the beta(2)-adrenergic receptor (beta(2)-AR) isomerizes between an inactive state and a constitutively active state, which couples to the stimulatory G-protein in the absence of agonist. In bovine tracheal smooth muscle (BTSM), we investigated the effect of short and long term beta(2)-AR activation by fenoterol on constitutive receptor activity. Preincubation of the BTSM strips for 5 min, 30 min and 18 h with 10 microM fenoterol, followed by extensive washout (3 h, 37 degrees C), caused a rapid and time-dependent inhibition of KCl-induced contraction, reaching 68+/-10, 51+/-6 and 46+/-4% of control, respectively, at 40 mM KCl (P:<0.05 all). At all time points, the EC(50) values to KCl were significantly reduced as well. Preincubation of BTSM with 0.1, 1.0 and 10 microM fenoterol during 18 h caused a concentration-dependent decrease of the 40 mM KCl response to 70+/-5, 47+/-12 and 43+/-9% of control, respectively (P:<0.05 all). The reduced KCl contractions were reversed in the presence of 1 microM timolol. Moreover, the sensitivity to KCl in the presence of timolol was enhanced after fenoterol incubation. Inverse agonism was also found for other beta-blockers, with a rank order of efficacy of pindolol >/=timolol=propranolol>alprenolol>/=sotalol>labetalol. At 25 mM KCl-induced tone, the contraction induced by cumulative timolol administration was competitively antagonized by the less efficacious inverse agonist labetalol, indicating that the fenoterol-induced effects cannot be explained by residual beta-agonist binding. In conclusion, fenoterol treatment of BTSM causes a time- and concentration-dependent development of constitutive beta(2)-AR activity, which can be reversed by various inverse agonists. The beta-agonist-induced changes could represent a novel regulation mechanism of beta(2)-AR activity.

Adrenergic beta-Agonists↗
PubMed2000

Friendship in childhood and adulthood: lessons across the life span.

Friendship occupies an important place in the growing body of literature in child development and gerontological research. As such, it may be useful for researchers from both fields to consider what can be learned from work carried out in each tradition. Therefore, we present a selected review of topics in friendship research across the life span. Through discussion of the value of friendship, the development of friendship, challenges to friendship, the gendered nature of friendship, and the connection between friends and family, points of commonality and contrast are identified. We conclude by presenting possible avenues for future investigation for researchers interested in friendship at any point in the life span.

Adult↗
PubMed1998

Bilateral temporal lobe necrosis after radiotherapy: confounding SPECT results.

A patient with seizures and a contrast-enhancing temporal lesion after radiation therapy for a chondrosarcoma of the nasal septum is described. To differentiate between radiation necrosis and recurrent tumor, thallium-201 (201Tl) SPECT was used. 201Tl SPECT revealed high local accumulation suggesting tumor growth; however, pathologic examination demonstrated focal necrosis with reactive changes but without tumor. The 201Tl SPECT findings in this patient demonstrate a possible diagnostic pitfall in differentiating recurrent tumor from radiation necrosis.

Bone Neoplasms↗
PubMed1997

Renal oncocytoma with t(5;12;11), der(1)1;8) and add(19): "true" oncocytoma or chromophobe adenoma?

Renal oncocytomas reveal a considerable (cyto)genetic heterogeneity. At least 2 genetic subsets are currently recognized, characterized by (1) translocations involving breakpoint 11q13 and (2) the combined loss of chromosomes 1 and X/Y. We present a case of oncocytoma revealing a 3-way translocation involving breakpoint 11q13, a der(1)t(1;8) and an add(19). The der(1) resulted in loss of chromosome 1 sequences. Using fluorescence in situ hybridization, the 11q13 breakpoint of the present case proved to be slightly different from the one observed previously in 3 cases of renal oncocytoma. Whether the 11q13 breakpoint observed in our case resides in or near another gene remains to be elucidated.

Adenoma, Oxyphilic↗
PubMed1997

Effect of machine perfusion preservation on delayed graft function in non-heart-beating donor kidneys--early results.

The functioning of non-heart-beating (NHB) donor kidneys upon transplantation is often delayed. To evaluate the effect of preservation by machine perfusion (MP) on early post-transplant function, 37 NHB donor kidneys were compared to 74 matched heart-beating (HB) donor kidneys preserved by cold storage (CS). The NHB donor kidneys were subject to 49 +/- 34 min of warm ischemia. Delayed function (DF) and primary nonfunction (PNF) rates were significantly higher for NHB than for HB donor kidneys (49% and 19% vs 34% and 7%, respectively). Consequently, renal function was impaired but recovered within 6 months. MP could not eliminate the differences in DF rate between NHB and HB donor kidneys. However, NHB donor kidneys preserved by MP showed less DF than that reported in kidneys preserved by CS. This suggests that MP has a beneficial effect on ischemically damaged kidneys. The similar results observed with category 2 and category 3 NHB donors also suggest this effect. The high PNF rate emphasizes the need for viability tests that prevent the transplantation of nonviable organs. We conclude that MP alone is not sufficient to reduce DF and PNF rates in NHB donor kidneys.

Adult↗
PubMed1997

Rapid antibody test for diagnosing fragile X syndrome: a validation of the technique.

To date, the identification of patients and carriers of the fragile X syndrome has been carried out by DNA analysis by means of the polymerase chain reaction and Southern blot analysis. This direct DNA analysis allows both the size of the CGG repeat and methylation status of the FMR1 gene to be determined. We have recently presented a rapid antibody test on blood smears based on the presence of FMRP, the protein product of the FMR1 gene, in lymphocytes from normal individuals and the absence of FMRP in lymphocytes from patients. Here, we have tested the diagnostic value of this new technique by studying FMRP expression in 173 blood smears from normal individuals and fragile X patients. The diagnostic power of the antibody test is "perfect" for males, whereas the results are less specific for females.

Antibodies, Monoclonal↗
PubMed1996

FreeCall, a system for emergency-call-handling support.

This article describes a system for the optimization of the prehospital assessment of emergency, in cases involving thoraco-abdominal complaints and consciousness problems. This assessment is performed by nurses on the basis of a telephone interview at ambulance dispatch centers. The system has a body of biomedical and policy knowledge available to guide the interview and to provide advice.

Algorithms↗
PubMed1995

Inversion duplication of the short arm of chromosome 8: clinical data on seven patients and review of the literature.

We report on clinical and cytogenetic data on 5 children and 2 adults with a de novo inverted duplication of the short arm of chromosome 8, and we give a review of 26 patients from the literature. The clinical picture in young children is characterized by minor facial anomalies, hypotonia, and severe developmental delay. In older patients the facial traits are less characteristic, spastic paraplegia develops, and severe orthopedic problems are frequent. Psychomotor retardation is always severe-to-profound. Duplication of 8p21-p22 results in a clinically recognizable multiple congenital anomalies/mental retardation (MCA/MR) syndrome. It is shown that in all patients examined, the duplication was accompanied by a deletion of the most terminal part of 8p.

Abnormalities, Multiple↗
PubMed1995

Rapid antibody test for fragile X syndrome.

Fragile X syndrome is the most common known cause of inherited mental retardation. Identification of patients and carriers of fragile X syndrome is usually done with a DNA test system but we have developed a rapid antibody to identify fragile X patients. This non-invasive test requires only 1 or 2 drops of blood and can be used for screening large groups of mentally retarded people and neonates for fragile X syndrome.

Antibodies, Monoclonal↗
PubMed1995

Prenatal diagnosis in two cases of de novo complex balanced chromosomal rearrangements. Three-year follow-up in one case.

We report two cases of apparently balanced complex de novo chromosomal rearrangements (BCCR) detected prenatally at 17 weeks and 10 weeks of gestation, respectively. Chromosomes were studied using GTG-banding and fluorescent in situ hybridization (FISH). In one case four chromosomes and in the other case three chromosomes were involved in the rearrangements. One of the pregnancies was terminated and no external or internal showed no abnormalities. The child is now 3 years old and has neither congenital anomalies nor evidence of delayed psychomotor development.

Adult↗