Hepatic syndecan-1 changes associate with dyslipidemia after renal transplantation.

Syndecan-1 is a transmembrane heparan sulfate (HS) proteoglycan present on hepatocytes and involved in uptake of triglyceride-rich lipoproteins via its HS polysaccharide side chains. We hypothesized that altered hepatic syndecan-1 metabolism could be involved in dyslipidemia related to renal transplantation. In a rat renal transplantation model elevated plasma triglycerides were associated with fivefold increased expression of hepatic syndecan-1 mRNA (p < 0.01), but not protein. Expression of syndecan-1 sheddases (ADAM17, MMP9) and heparanase was significantly up-regulated after renal transplantation (all p < 0.05). Profiling of HS side chains revealed loss of hepatic HS upon renal transplantation accompanied by significant decreased functional capacity for VLDL binding (p = 0.02). In a human renal transplantation cohort (n = 510), plasma levels of shed syndecan-1 were measured. Multivariate analysis showed plasma syndecan-1 to be independently associated with triglycerides (p < 0.0001) and inversely with HDL cholesterol (p < 0.0001). Last, we show a physical association of syndecan-1 to HDL from renal transplant recipients (RTRs), but not to HDL from healthy controls. Our data suggest that after renal transplantation loss of hepatic HS together with increased syndecan-1 shedding hampers lipoprotein binding and uptake by the liver contributing to dyslipidemia. Our data open perspectives toward improvement of lipid profiles by targeted inhibition of syndecan-1 catabolism in renal transplantation.

Effect of amelogenin ECM protein on the healing of chronic leg ulcers with atrophie blanche.

OBJECTIVE: To determine the effect of topically applied amelogenin extracellular matrix protein(AEMP) in patients with non-healing venous leg ulcers combined with atrophie blanche. METHOD: This retrospective case series of patients with non-healing venous leg ulcers with atrophie blanche of the distal proportion of their lower legs, where non-healing was defined as no progress toward healing for 3 months previously, under standard therapy. Patient records were reviewed for associated diseases, wound diagnoses, distal blood pressure, previous treatments and changes in wound area. Patients were treated with AEMP once a week, for a period of 12 weeks, or until full healing. RESULTS: Eleven patient records were reviewed retrospectively. The median age of the patients was 81 years (range 40-95 years), with a mean wound size of 4.7 ± 3.Scm2 and median wound duration of 6 months (range 3-444 months).AII patients had venous or combined arterial/venous insufficiency. After 12 weeks' treatment with AEMP, complete healing, defined as I 00% re-epithelialisation, was documented in four patients (36%), marked improvement(> SO% epithelialisation) in three patients (54%, 55% and 83% wound closure, respectively), slight improvement in one patient (9.4% wound closure), no change for two patients and worsening in one.AEMP was well tolerated, and no patients reported side effects. CONCLUSION: The results of this retrospective study suggest that AEMP improves healing in chronic venous leg ulcers combined with atrophie blanche.

Virilization of the external genitalia and severe mental retardation in a girl with an unbalanced translocation 1;18.

A female infant with dysmorphic facial features, psychomotor retardation, and clitoris hypertrophy is described. Molecular cytogenetic analyses revealed a de novo unbalanced translocation, causing partial monosomy 1p36 and partial trisomy 18q22. Monosomy 1p was confirmed by FISH, and trisomy of the distal part of chromosome 18q was demonstrated by microFISH. Gene copy number changes in these chromosomal regions were determined by array-CGH. The absence of a number of facial dysmorphic signs, and the presence of clitoris hypertrophy indicate that the combination of a del(1p36->pter) with a dup(18q22->qter) may lead to a unique phenotypic constellation. The findings at birth and at age 12 years in our patient are compared with genotype-phenotype correlations discussed in the literature.

Antagonism of HSV-tk transfection and ganciclovir treatment on chemotherapeutic drug sensitivity.

Our study focused on the influence of herpes simplex virus thymidine kinase (HSV-tk) expression and ganciclovir (GCV) treatment on the sensitivity of C6 glioma cells to frequently used chemotherapeutic drugs, i.e. adriamycin (ADR), cisplatin (CDDP), 5-fluorouracil (5-FU), and methotrexate (MTX). Transfection with HSV-tk revealed an increased sensitivity to GCV and CDDP and a decreased sensitivity to ADR and MTX. No significant differences were found in sensitivity to 5-FU. Combined treatment in a HSV-tk negative cell line revealed an additive effect when GCV was combined with ADR, whereas an antagonistic effect was found when GCV was combined with CDDP, 5-FU, or MTX. Comparable results were obtained in an HSV-tk positive cell line, apart from CDDP, which showed an additive effect. In conclusion, both HSV-tk transfection and subsequent GCV treatment can influence the sensitivity of tumor cells to various chemotherapeutic drugs in an antagonistic manner. Therefore, combining HSV-tk/GCV gene therapy with chemotherapy might not always be beneficial.

Supernumerary ring chromosome 7 mosaicism: case report, investigation of the gene content, and delineation of the phenotype.

We report a girl with severe retardation of expressive speech development carrying a small, supernumerary ring chromosome derived from the proximal region of the long arm of chromosome 7. The r(7) chromosome is present in 50% of lymphocytes. We also review the six additional cases with a supernumerary r(7) chromosome reported in the literature. Among these patients, a severe retardation of productive language capabilities is seen as a shared clinical feature, irrespective of the degree of mosaicism as detected in blood. The dysmorphisms in these patients are minor and no shared congenital abnormalities seen. We, therefore, recommend chromosomal investigations in children with unexplained, disproportionately retarded expressive speech performance. Because speech and language acquisition are subject to genetic influences, we investigated whether there are genes on the r(7) chromosome that may affect brain development or function in a dosage-dependent manner. We found that both in our patient and in four patients described by others, the supernumerary r(7) chromosome contains the region from the centromere up to marker D7S613 located at 7q11.23. We speculate that the effects on speech acquisition are mediated by the supernumerary copies of the STX1A and LIMK1 genes, which are both located in this region and known to suppress neurite growth when overexpressed in vitro.

Prenatal detection of complex chromosomal aberrations using advanced molecular cytogenetic techniques.

OBJECTIVE: This study aimed to identify a marker chromosome and characterize the short arm of a derivative chromosome 5 in a foetus with the following karyotype: mos 47,XX,del(5)(p?),+i(5)(p10)[50]/48,XX,del(5)(p?),+i(5)(p10),+mar[25]. METHOD: Amniocentesis was performed in the 26th week of pregnancy because of ultrasound abnormalities (polyhydramnion and decreased amount of gastric filling). All classic banding techniques were performed. FISH and microdissection combined with reverse painting were used to reveal the exact origin of the marker and any extra material on the deleted chromosome 5p. The parents decided to continue the pregnancy and we compared the clinical features of the child born in week 34 with data from the literature on trisomy 5p. The possible contribution of trisomy of the centromeric region of chromosome 8 and trisomy 8p23.3-->8pter to this clinical picture was evaluated. RESULTS: GTG banding showed one normal and two aberrant chromosomes 5 [del(5)(p?) and i(5)(p10)] in all the cells examined. Furthermore, a supernumerary marker chromosome was present in approximately 30% of the cells. The marker was CBG positive and positive with the pancentromere probe, but dystamicinA/DAPI negative. It did not contain NOR-positive satellites. FISH proved this marker to be derived from the centromeric region of chromosome 8. MicroFISH disclosed the aberrant chromosome 5 as der(5)t(5;8)(p10;p23.3). The parent's karyotypes were normal. The baby showed the characteristic features of trisomy 5p syndrome. She died at the age of 15 days after cardiorespiratory arrest. CONCLUSION: The karyotype was interpreted as mos 47,XX,add(5)(p10).rev ish der(5)t(5;8)(p10;p23.3),+i(5)(p10) (WCP5+,D5S23+)[50]/48,XX,add(5)(p10).rev ish der(5)t(5;8)(p10;p23.3),+i(5)(p10)(WCP5+,D5S23+),+mar.ish 8(p10q10)(D8Z2+,WCP8-)[25]. Therefore, the baby had complete trisomy 5p, with trisomy of the distal part of 8p and of the centromeric region of chromosome 8. The clinical significance of de novo marker chromosomes is a major problem in prenatal counselling. Molecular cytogenetic tools such as FISH and microFISH are indispensable for characterizing markers and determining the breakpoints more precisely in deleted chromosomes.

Characterization of partial trisomy 9p due to insertional translocation by chromosomal (micro)FISH.

We describe a family with an insertion 12;9 translocation occurring in a balanced form in a mother and two sons, but in an unbalanced form in the proband, resulting in trisomy of chromosome region 9p22-->9p24. The proband manifests typical features of trisomy 9p; the clinical signs were mental and growth retardation, microcephaly, epicanthus, low-set ears, micrognathia, clinodactyly and hypoplastic phalanges of the fifth fingers, hypoplasia or absence of toenails, and extremely small genitals. The GTG-banded findings were confirmed using (micro)FISH. Intriguingly, the mother and the two carrier sons exhibited major learning difficulties that were not present in the non-carrier sister of the mother: this may be due to a gene disruption or induction of abnormal expression. Dysmorphic features were not present in the three carriers. We compare our clinical and cytogenetic findings with other cases of partial trisomy 9p reported in the literature.

Prothrombin time ratio is reduced by magnesium contamination in evacuated blood collection tubes.

Magnesium ions were detected in sodium citrate solutions in several lots of evacuated blood collection tubes. The mean concentrations ranged between 1.3 and 1.6 mmol/L. Magnesium was also present in the rubber stoppers of the blood collection tubes and could be leached into the citrate solution. It was shown that magnesium added to citrated plasma shortened the prothrombin time of both coumarin and normal plasma. The effect of magnesium was relatively greater on coumarin than on normal plasma resulting in reduced prothrombin time ratio. Shortening of the prothrombin time was also observed when magnesium chloride was added to dialysed plasma, i.e., in the absence of citrate. These results indicate that magnesium contamination can interfere with accurate INR determination in the control of oral anticoagulant therapy.

Role of metallothionein in cisplatin sensitivity of germ-cell tumours.

Cisplatin (CDDP) is an extremely active drug in the treatment of germ-cell tumours. Earlier, we found an unexpected inverse correlation between the total amount of sulfhydryl groups and CDDP sensitivity in a panel of 3 human germ-cell-tumour and 3 colon-carcinoma cell lines. Major components of the sulfhydryl groups are glutathione and metallothionein (MT). We further investigated a possible role of MT in the CDDP sensitivity of germ-cell tumours. MT levels and functionality of the germ-cell-tumour and colon-carcinoma cell lines were found to be inversely correlated with CDDP sensitivity. No difference in sub-cellular localization of MT could be observed among the types of cell lines. In agreement with the in vitro data, immunohistochemical detection of MT was high in 11/14 primary human germ-cell tumours and low in 7/7 human colon carcinomas. MT-protein expression in primary germ-cell tumours did not discriminate between responding and non-responding patients. As compared with the primary tumours, MT-protein expression decreased in 5/7 post-chemotherapy residual vital tumours or remained undetectable (2/7). MT-protein expression in the germ-cell tumours was not related to total p53-protein expression. In summary, over-expression of MT was found in germ-cell tumours, both in cell lines and in human tumours. Although MT-protein over-expression seems to be associated with the CDDP sensitivity of germ-cell tumours, MT-protein expression in primary germ-cell tumours did not differ between responding and non-responding patients and therefore cannot be used to predict response to chemotherapy.

Mechanism of hyperthermic potentiation of cisplatin action in cisplatin-sensitive and -resistant tumour cells.

In this study, the mechanism(s) by which heat increases cis-diamminedichloroplatinum (cisplatin, cDDP) sensitivity in cDDP-sensitive and -resistant cell lines of murine as well as human origin were investigated. Heating cells at 43 degrees C during cDDP exposure was found to increase drug accumulation significantly in the cDDP-resistant cell lines but had little effect on drug accumulation in the cDDP-sensitive cell lines. DNA adduct formation, however, was significantly increased in all cell lines studied. Furthermore, ongoing formation of platinum (Pt)-DNA adducts after the end of cDDP treatment was enhanced and/or adduct removal was decreased in heated cells, resulting in relatively more DNA damage remaining at 24 h after the end of cDDP exposure. Correlation plots with survival revealed weak correlations with cellular Pt accumulation (r2 = 0.59) and initial Pt-DNA adduct formation (r2 = 0.64). Strong correlations, however, were found with Pt-DNA adducts at 6 h (r2 = 0.97) and 24 h (r2 = 0.89) after the incubation with the drug. In conclusion, the mechanism by which heat sensitizes cells for cDDP action seems to be the sum of multiple factors, which comprise heat effects on accumulation, adduct formation and adduct processing. This mechanism did not seem to differ between cDDP-sensitive and -resistant cells, emphasizing the potential of hyperthermia to reduce cDDP resistance.