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Biomedical subjects

I Pahl

Publications and source records attributed to I Pahl.

6 recordsLinked to original sources
PubMed2001

Crossflow filtration for CHO cell separation by microfiltration using crossflow systems.

Chinese Hamster Ovary (CHO) cells are used for fermentation of high value proteins in the pharmaceutical- and biotechnology industry. During the fermentation process the cells are grown under specific conditions in a defined media. The CHO cells produce extra cellular proteins. Separation and purification of these proteins result in the final product of high value. The production steps utilized in any bio-pharmaceutical process must deliver the target protein with high purity and yield. The first step in the production process is the separation of cells from the rest of the fermentation broth. Currently, stacked depth filters are used in this separation. The disadvantages with this method are:- 1) low product yield (high hold-up/wetting volume) and 2) the messy "clean-up" that is inherent with stacked filters. One of the main process requirements is that the CHO cell removal be accomplished with low cell mortality. This eases the subsequent process steps to purify the target protein with high yields free of DNA and other intracellular proteins. Additionally, the CHO cells can be reused.

Animals↗
PubMed1992

Heterogeneous expression of c-myb protein in human leukemia detected by simultaneous two color flow cytometric analysis.

The expression of c-myb mRNA and protein was analyzed in fresh leukemic cells by Northern-blot analyses and by immunofluorescent staining using monoclonal c-myb specific antibodies. Staining of the cells was evaluated by flow cytometry. The results demonstrate c-myb mRNA expression predominantly in acute lymphocytic leukemia (ALL, 4/4 cases), acute myeloic leukemia (AML, 17/17) and chronic myeloic leukemia (CML, 12/12) but rarely in chronic lymphocytic leukemia (CLL, 1/17). Immunofluorescent analyses revealed expression of c-myb protein in the nucleus of ALL (5/7) and AML (9/9) with a good correlation of c-myb-positive cells and with the number of proliferating (Ki67-positive) blast cells.

Antigens, Surface↗
PubMed1990

Chromosomal rearrangements caused by the aberrant transposition of double Ds elements are formed by Ds and adjacent non-Ds sequences.

The Ds-induced unstable sh-m6258 allele is caused by the insertion of at least 45 kb of non-sh DNA. Genomic clones spanning the two junctions of sh sequences with insert sequences were isolated and analysed. The long insert in the sh-m6258 allele is bordered by Ds sequences on either side. A 3 kb double Ds structure which consists of one complete Ds element of approximately 2 kb and one half Ds element of approximately 1 kb was found in the sh-m6258 allele at the junction between the 3' region of the sh locus and the insert. At the junction between the 5' region of the sh locus and the insert a half Ds element is present. This truncated Ds element was probably left behind after the excision of a 2 kb Ds element from a 3 kb double Ds structure similar to that found at the 3' junction. Sequence analysis of the insert sequences beyond the Ds elements demonstrated that the long inserts in both the sh-m6258 and the sh-m5933 alleles originated from the same contiguous chromosomal segment in their common progenitor strain. One revertant derivative of the sh-m6258 allele was investigated. In the revertant strain, which displays a normal non-shrunken phenotype, a 2 kb Ds element is present at the site of the 45 kb insert in the mutant allele. This 2 kb insertion, which is located in the last but one intervening sequence of the Sh gene, does not inhibit expression of the gene.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMedDate not supplied

Determination of "extractables" on polymer materials by means of HPLC-MS.

In biopharmaceutical processes, in the area of food and medical technology a variety of devices is used. These devices consist of various polymers. The detection and identification of potential extractables from these polymers during application are requested by the regulatory bodies. For risk and toxicity assessment, both identification and quantification of extractables are necessary. This article describes the development of a LS-MS methodology transfered from an established HPLC-UV-VIS method for full extractables analysis of sterile-grade filtration cartridges.

Biopharmaceutics↗