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Biomedical subjects

M Wirth

Publications and source records attributed to M Wirth.

At least 127 records · Page 7Linked to original sources
PubMed1988

Efficient expression system for human antithrombin III in baby hamster kidney cells.

A DNA fragment carrying the enhancer of an immediate early gene of human cytomegalovirus (hCMV) was tested as a transcriptional control element by fusion downstream of a transcription unit for human antithrombin III (AT III) driven by the Simian virus (SV40) enhancer and promoter. Measurement of transient AT III expression in baby hamster kidney cells (BHK) shows that by the presence of the hCMV enhancer the synthesis of AT III is increased considerably (three to fourfold). The AT III expression vectors carrying the hCMV enhancer were used to establish stable BHK cell-lines by a new and fast G418/methotrexate selection protocol, which express up to 12 micrograms AT III/10(6) cells/24h after 40-50 days. The given system might be generally useful for the fast expression of recombinant proteins in mammalian cells, e.g. the screening of altered AT III molecules obtained by site directed mutagenesis.

Animals↗
PubMed1988

Transrectal aspiration biopsy and punch biopsy in the diagnosis of prostate carcinoma--a comparative study and literature review.

It can be concluded from the data presented here, that perineal punch biopsy is able to supply more reliable results than fine needle aspiration biopsy in the diagnosis of prostate cancer. The advantage of aspiration biopsy, however, is its low incidence of complications. Since the application of both methods, namely transrectal aspiration biopsy and perineal punch biopsy, offers an additional factor of reliability, it appears worth-while to utilize both procedures in the diagnosis of carcinoma of the prostate.

Biopsy↗
PubMed1987

Changes of N-6 and N-3 fatty acids in liver from spontaneously hypertensive (SHR) and normotensive rats after diets supplemented with alpha-linolenic or eicosapentaenoic acids.

In spontaneously hypertensive (SHR) and normotensive rats (WKY), diets supplemented with n-3 fatty acids of different chain length (alpha-linolenic acid, LNA-C 18:3, n-3 with linseed oil and eicosapentaenoic acid, EPA-C 20:5, n-3 with cod liver oil) were fed over a period of 22 weeks. A diet with commercially available pellets served as control. After the LNA-rich diet the augmentation of LNA was most pronounced in liver triglycerides (TG) and free fatty acids (FFA), whereas the increase of EPA was most marked in phosphatidylethanolamine (PE) and phosphatidylcholine (PC) when compared with the controls. Docosahexaenoic acid (DHA) was decreased mainly in neutral lipids. Of the n-6 fatty acids linoleic acid (LA) appeared significantly depressed in TG and FFA, but increased in phospholipids. Arachidonic acid (AA), however, was lower in all lipids. In SHR and WKY fed the EPA-rich diet EPA and DHA were significantly higher as compared to the controls on a pellet diet. On the contrary, LNA was not detectable in all lipid classes. LA and AA were markedly depressed. Docosenoic acids were significantly increased. The p/s-ratio did not reflect the changes in the 20:5/20:4- and n-3/n-6-ratios. The data indicate a differential effect of dietary n-3 fatty acids of different chain length on the supply of other n-3 fatty acids. Moreover, after an LNA-rich diet divergent alterations of LA in neutral lipids and phospholipids occurred. The results are dissimilar to those obtained in adipose tissue. Blood pressure was not influenced by the diets in either SHR or WKY.

Animals↗
PubMed1987

The phycobiliprotein beta 16.2 of the allophycocyanin core from the cyanobacterium Mastigocladus laminosus. Characterization and complete amino-acid sequence.

The minor phycobiliprotein beta 16.2 was isolated from the APC-core of phycobilisomes from the cyanobacterium Mastigocladus laminosus. Its complete amino-acid sequence and some spectral characteristics are presented. beta 16.2 consists of 169 amino acids and its molecular mass is 19,390 Da. A phycocyanobilin chromophore is covalently bound to a cysteine at position 84 as in all other phycobiliproteins. The first 138 amino acids are highly homologous to the N-terminal part of beta AP (62.5%), whereas the C-terminal part has no homology. The absorption maximum is situated at 624 nm, the fluorescence emission maximum at 644 nm in phosphate buffer, pH 7.0. Both values are slightly redshifted compared with alpha AP and beta AP.

Amino Acid Sequence↗
PubMed1987

Crosslinking of phycobiliproteins from the cyanobacterium Mastigocladus laminosus with bis-imidates: localization of an intrasubunit and an intersubunit crosslink in C-phycocyanin.

The light-harvesting pigment-protein complexes allophycocyanin (AP), C-phycocyanin (PC) and phycoerythrocyanin (PEC) of the cyanobacterium Mastigocladus laminosus consist of alpha- and beta-subunits containing about 170 amino-acid residues each. These two subunits form an alpha,beta-monomer, three of which build up a disc-shaped trimer. In this study these phycobiliproteins were crosslinked with bis-imidates. Various spacer lengths of the reagent and various aggregation states of the phycobiliprotein were tested. An intersubunit crosslink could be verified in all three phycobiliproteins. PC-trimers were crosslinked with the homobifunctional reagent dimethyl pimelimidate having a maximal crosslinking distance of 10 A. Two crosslinks could be identified: an intramonomer intersubunit crosslink with a yield of 48% and an intrasubunit crosslink within alpha PC (57%). These products were chemically and enzymatically fragmented and the small crosslinked peptides were isolated and then identified by amino-acid analysis. The following amino acids were crosslinked: alpha-Val 1 with beta-Ala 1 and alpha-Lys 62 with alpha-Lys 134. Both crosslinks could be localized within the known three-dimensional structure of PC.

Amino Acid Sequence↗
PubMed1987

Isolation and localization of N4-methylasparagine in phycobiliproteins from the cyanobacterium Mastigocladus laminosus.

The occurrence of post-translationally methylated asparagine residues in beta AP from Anabaena variabilis, Synechococcus PCC 6301 and Porphyridium cruentum has recently been reported (Klotz, A.V., Leary, J.A. & Glazer, A.N. (1986) J. Biol. Chem. 261, 15891-15894). We reinvestigated the amino-acid compositions of all phycobiliproteins from Mastigocladus laminosus. During total hydrolysis of beta AP, beta 16.2 and beta PC one mol methylamine per mol protein was released. These proteins were chemically and enzymatically fragmented and the sequences of the fragments containing the modified asparagine residue were determined by automated Edman degradation. Residues beta AP72, beta 16.2 72 and beta PC 72 were identified as N4-methylasparagine. This derivative of asparagine was also found at a homologous position in beta PE of Calothrix. In the x-ray structure model of C-phycocyanin (PC) the residue beta PC 72 points towards the chromophore beta 84, presumably having an effect on the spectroscopic characteristics of this light harvesting pigment protein complex.

Amino Acid Sequence↗
PubMed1986

[Changes in blood pressure and serum lipids with fish diets in patients with mild essential hypertension].

14 male patients with moderate essential hypertension were treated in the cross-comparison with a mackerel and herring diet, respectively, for two weeks. The mackerel diet contained double as much eicosapentaenic (EPA) and docosahexaenic acid (DHA) as the herring diet which served as control. In the serum triglycerides particularly DHS, in the cholesterol esters above all EPA were enriched. In the phospholipids the increase of the two fatty acids was approximately the same. At the end of the mackerel period the serum triglycerides, the total and LDL-cholesterol, the activity of the lecithin-cholesterol-acyl-transferase (CALT) and the serum sodium were significantly decreased. On the other hand, the HDL-cholesterol and the uric acid in the serum significantly increased. Under influence of the herring diet the parameters mentioned appeared only slightly changed. After the mackerel diet also a significantly lower systolic blood pressure was found. The systolic and diastolic blood pressure during a standardized psychophysiological stress test was more diminished at the end of the mackerel period than after the herring diet. The plasma renin activity (PRA) was increased after the mackerel diet. Its increase under the stress test could no more be proved at the end of the mackerel diet. In similar way the stress-conditioned increase of thromboxane B2 could no more be observe both after mackerel and after herring diet. When the results should confirm themselves in long-term studies, a mackerel diet in practicable dosage can be recommended as non-medicamentous treatment of moderate hypertension.

Blood Pressure↗
PubMed1986

Serum triglycerides and HDL cholesterol from SHR after evening primrose oil and other polyunsaturated fats.

Spontaneously hypertensive rats (SHR) were fed diets enriched with evening primrose (EPO), sunflower (SO) and linseed oils (LO) as well as palm kernel fat (PKF), the latter being deficient in polyunsarated fatty acids (PUFA). In SHR fed EPO serum triglycerides were lowest and HDL1 cholesterol was highest as compared to the other groups of animals. Total cholesterol was not different. The data suggest that - as with blood pressure - serum lipids and lipoproteins might be influenced most effectively by EPO in comparison to other polyunsaturated fats.

Administration, Oral↗
PubMed1986

Slow desaturation and elongation of linoleic and alpha-linolenic acids as a rationale of eicosapentaenoic acid-rich diet to lower blood pressure and serum lipids in normal, hypertensive and hyperlipemic subjects.

In normal, hypertensive and hyperlipemic subjects, diets supplemented with linoleic acid (LA) or alpha-linolenic acid (LNA) resulted in an increase of the corresponding fatty acids in serum lipids. However, their C20-derivatives, the prostaglandin precursors arachidonic acid (AA) and eicosapentaenoic acid (EPA), respectively, were not or only slightly augmented. On the other hand, an EPA-rich diet produced a marked increase of this fatty acid, especially in cholesterol esters. After this diet the decreases of blood pressure and serum lipids were more pronounced when compared with LA- and LNA-rich diets containing a 20-fold higher dose of the polyunsaturated fatty acids. The slow formation of AA and EPA from LA and LNA seems to be a characteristic finding in humans, being different from preferred laboratory animals, for instance, rats. This observation was independent of the presence of risk factors, like arterial hypertension or hyperlipoproteinemia (HLP).

Adult↗
PubMed1986

Synthesis, tissue distribution and cytostatic properties of two new daunorubicin derivatives of 2-thiouracil containing a guanidine bridge.

In further attempts to utilize the affinity of 2-thiouracil for melanin-producing tissues in the design of drugs active against malignant melanomas, guanidine-bridged adducts of the anthraquinone drug daunorubicin (1a) with 2-thiouracil were prepared (Scheme 3). The expected adduct (4), and a by-product in its preparation (5) (Scheme 3), were inactive against murine melanoma, in vivo, and did not show affinity for melanin-producing tissues. They were efficient DNA intercalating agents, but were much less cytostatic than daunorubicin against Cloudman melanoma, and were inactive, in vitro, against human cervical carcinoma MS 751. The coupling chemistry employed may have application in current attempts to effect binding of drugs to high molecular weight targeting antigens.

Animals↗