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W Hilbe

Publications and source records attributed to W Hilbe.

45 records · Page 3Linked to original sources
PubMed1994

[Functional detection of P-glycoprotein expressing cells with flow cytometry].

Classical multidrug resistance (MDR) is associated with the overexpression of a membrane glycoprotein termed P-glycoprotein (P-gp) that transports a variety of apparently unrelated anti-cancer drugs out of cells. Based on the fluorescent properties of the dye rhodamine 123 (Rh 123) we aimed to develop a functional flow cytometric assay for the detection of MDR-expressing cells. Using drug sensitive cell lines (KB-3-1) and MDR mutants (KB-8-5, KB-C1) experimental conditions were established enabling demonstration of significant differences in Rh 123 accumulation/efflux. Using two-colour flow cytometry we subsequently analysed 42 consecutive patients suffering from B-cell chronic lymphocytic leukemia (B-CLL). 34/42 (81%) cases showed a marked Rh 123 efflux which was completely abolished in the presence of the MDR inhibitor verapamil. The percentage of Rh 123 effluxing cells ranged from 10 to 70% with a median of 32%. In 26 cases extracted RNA was analysed by quantitative polymerase chain reaction to evaluate the expression of MDR 1 mRNA. In 25 of 26 (96%) cases MDR 1 mRNA was detectable. The levels of MDR 1 mRNA expression correlated well with the results of the Rh 123 efflux assay (r = 0.72; p < 0.0001). In addition, 37 cases of acute myeloid leukemia were analysed and demonstrated Rh 123 efflux in 18/37 (49%) cases. In this entity the percentage of Rh 123 effluxing cells ranged from 12 to 80% (median 45%). Additionally, we evaluated the Rh 123 efflux/retention in peripheral blood cells of healthy volunteers.(ABSTRACT TRUNCATED AT 250 WORDS)

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Activity of P-glycoprotein in B-cell chronic lymphocytic leukemia determined by a flow cytometric assay.

BACKGROUND: Chemoresistance in some hematologic malignancies has been associated with overexpression of P-glycoprotein, which is encoded by the MDR1 gene (also known as PGY1). However, inconsistencies in data on frequency and clinical relevance of multidrug resistance in B-cell chronic lymphocytic leukemia (B-CLL) may reflect a need for improved techniques to detect this overexpression. PURPOSE: Our purpose was to measure P-glycoprotein activity in peripheral blood cells of B-CLL patients and to analyze possible clinical correlations (disease duration, prior treatment, Rai disease stage, lymphocyte counts, and disease progression). METHODS: P-glycoprotein activity was assayed in peripheral blood cells of 42 consecutive B-CLL patients (22 treated and 20 untreated). We used dual fluorescence in a flow cytometric assay that detects efflux of the fluorescent dye rhodamine 123, which is transported from the cell by the P-glyprotein pump. Leukemia cells were costained with monoclonal antibody Leu12/CD19, and rhodamine 123 efflux was measured. Expression of MDR1 and MDR3 (also known as PGY3) messenger RNA (mRNA) was quantitatively evaluated by polymerase chain reaction (PCR) in 26 cases. RESULTS: Marked rhodamine 123 efflux was observed in 34 (81%) of the 42 cases and was abolished in the presence of multidrug resistance inhibitors. Rhodamine 123 efflux was not associated with Rai stage, lymphocyte counts, duration of disease, or disease progression. Although rhodamine 123-negative cases were about equally distributed among untreated and previously treated patients, the percentage of cells with rhodamine 123 efflux was significantly lower for untreated patients than for those treated with chemotherapy regimens including at least one multidrug resistance-associated drug. MDR1 mRNA was detected in 25 of 26 cases and MDR3 mRNA in all 26. MDR1 mRNA expression was significantly correlated with rhodamine 123 efflux, whereas MDR3 mRNA expression was not significantly correlated; MDR1 and MDR3 mRNA expression was not significantly associated with Rai stage, prior treatment, or disease progresssion. CONCLUSIONS: These findings suggest that P-glycoprotein overexpression in B-CLL is intrinsic rather than acquired and that P-glycoprotein activity is enhanced after exposure to multidrug resistance-associated drugs. This enhanced activity does not seem to be associated with more aggressive disease. Our results also indicate that an assay of P-glycoprotein function combined with PCR is suitable for clinical multidrug resistance screening. IMPLICATIONS: Additional studies are needed to determine whether functional activity of P-glycoprotein, measured by rhodamine 123 efflux, is directly related to clinical drug resistance.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1986

Prostaglandin excretion in pseudohypoaldosteronism type I.

In an infant with pseudohypoaldosteronism type I increased urinary excretion of PGE2 (1.32 ng/mg creatinine; normal mean +/- SE: 0.50 +/- 0.10) and PGF2 alpha (6.15 ng/mg creatinine; normal mean +/- SE: 2.93 +/- 0.91) was found. Prostaglandin excretion as well as the typical hyperkalemia, hyperreninemia and hyperaldosteronism normalized with adequate dietary salt supplementation. An abnormally high excretion of the renal prostaglandins was again present at age 4.4 years when the child was thriving although additional salt was withheld. These abnormalities are considered to be secondary to this condition's basic defect which remains to be elucidated.

Aldosterone↗
PubMed1981

[Hyperammonemia in the newborn through ornithine transcarbamylase deficiency (author's transl)].

This is a report of a family with hyperammonemia in the newborn, very probably due to ornithine transcarbamylase deficiency. Typically the male infant died in the newborn period within 74 hours. In the female newborn it was possible to provide a normal development with protein restricted diet. In mother's line there are unexplained death's of infants. The examination of amino acids and organic acids excluded other disturbances. The determination of orotic acid in the urines and oral loading with protein indicated to OTC-deficiency. The RDS-symptomatic and pulmonary bleeding in the newborns with hyperammonemia is emphasized.

Ammonia↗
PubMed1979

[Preliminary findings with oral whooping cough vaccination in young infants (author's transl)].

A preliminary report is presented on oral vaccination against whooping cough. 23 babies younger than, and 2 older than nine weeks and 12 newborn infants were vaccinated orally. No side effects were observed. Serum antibody titres did not increase markedly, but no child was seronegative after vaccination. An evident antibody titre rise to a higher level than in serum was found in the saliva. These results point toward an adequate local immunity. At present a definite statement about the efficacy of this oral vaccination is difficult to make. Further investigations are necessary.

Administration, Oral↗
PubMedDate not supplied

Dose escalation of ara-c may improve response rates in a subgroup of chronic myeloid leukemia patients with poor response to interferon-alpha and low-dose ara-C.

The present analysis was performed to evaluate the impact of cytosine arabinoside (ara-C) dose escalation on hematological and cytogenetic responses in patients with chronic myelogenous leukemia (CML) who failed to respond to low-dose ara-C (LD ara-C) at a dose of 10 mg/m2/d over 10 days per month and interferon-alpha (IFNalpha, 3.5 MU/d). Following the same administration schedule, dose escalation of ara-C to 15 and 20 mg/m2/d 1-10 was performed in 36 of 119 patients (30%) due to inadequate hematological response and/or disease progression. As a result, improvement of hematological and cytogenetic responses was achieved in 22 (61%) and nine (25%) patients, respectively. Escalated ara-C dose levels were usually well tolerated, although some patients experienced deterioration of preexisting side effects. Our results support the critical role of ara-C dose towards a better disease control in CML.

Adolescent↗
PubMedDate not supplied

Oxidative burst of neutrophils in patients with rheumatoid arthritis: influence of various cytokines and medication.

OBJECTIVE: Toxic oxygen products are believed to be implicated in tissue damage in some complex-mediated diseases such as rheumatoid arthritis. In the present study we compared the superoxide (O2) production of polymorphonuclear leukocytes (PMNs) in 21 patients with rheumatoid arthritis (RA) with that of 9 healthy controls, examining the effect of different stimulants and cytokines on the oxidative burst (OB). Since many drugs used in the treatment of RA may alter O2 metabolism, the effects of antirheumatic medication were also studied. METHODS: Generation of superoxide anions was analysed by a flow cytometric method, using the fluorochrome dihydro-rhodamine. As stimulants for OB, we used N-formyl-methionyl-leucyl-phenylalanine (fMLP), which acts via a membrane receptor, and phorbol-myristate acetate (PMA), which acts in a membrane receptor-independent manner. As preactivating substances, TNF-alpha, G-CSF and GM-CSF were applied. RESULTS: In RA patients under treatment with antirheumatic medication, fMLP-induced OB (+/- cytokines) was significantly reduced, while O2 production after stimulation with PMA was similar compared to controls. GM-CSF showed the highest level of preactivation in controls, whereas in RA patients TNF-alpha proved to be most potent. In both controls and RA patients, a combination of GM-CSF or G-CSF with TNF-alpha further enhanced OB. No correlation between OB and clinical data or treatment could be established in RA patients. CONCLUSIONS: There is a reduced cytokine priming capacity for OB in RA patients under antirheumatic medication in spite of the presence of an intact enzyme system of OB. Antirheumatic medication combining multiple drugs capable of decreasing OB might effectively modulate oxidative metabolism.

Adult↗