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Biomedical subjects

M Wirth

Publications and source records attributed to M Wirth.

At least 37 records · Page 2Linked to original sources
PubMed1990

Blood pressure and serum lipids from SHR after diets supplemented with evening primrose, sunflowerseed or fish oil.

Spontaneously hypertensive rats (SHR) at 4 weeks of age were fed a diet supplemented with sunflowerseed oil (SO), evening primrose oil (EPO), fish oil (FO) or EPO + FO for 22 weeks. A diet with commercially available pellets served as control. Systolic blood pressure was significantly lower during and after FO, EPO and EPO + FO, whereas the lower level after SO was not significant when compared with the controls. Serum triglycerides and total cholesterol were lowest after EPO followed FO. The combination of both EPO and FO resulted in unexpected high values of triglycerides and cholesterol. HDL-cholesterol was likewise highest after EPO + FO. The results indicate a quantitatively different depression of blood pressure and serum lipids from SHR by individual polyunsaturated fatty acids (PUFA).

Animals↗
PubMed1990

Diagnostic value of transrectal ultrasound in tumor staging and in the detection of incidental prostatic cancer.

To evaluate the accuracy of transrectal ultrasonography in staging and detection of prostatic cancer, a prospective study was initiated. In 466 patients transrectal ultrasonography was performed before transurethral resection, suprapubic adenomectomy, or radical prostatectomy. The findings were compared with the histopathologic results. In 160 of the 466 patients a carcinoma of the prostate was proven by histology. In 21 patients the cancer was an incidental finding after transurethral resection. In 133 of the 160 patients (83.1%) the tumor was detected by ultrasound prior to surgery. The analysis of the results revealed, however, great differences in the accuracy in the different tumor stages. In those patients where the tumor was confined to the prostate, the carcinoma was identified only in 37.5% of the cases. Especially prostatic cancer stage pT1a-b (incidental) was detected only in 3 out of 21 patients. Thus, it can be concluded that transrectal ultrasonography is not more sensitive than the rectal palpation for detection of prostatic cancer stage T1a-b.

Carcinoma↗
PubMed1990

Effects of dietary oleic, linoleic and alpha-linolenic acids on blood pressure, serum lipids, lipoproteins and the formation of eicosanoid precursors in patients with mild essential hypertension.

Forty-four male in-patients with mild essential hypertension were randomly allocated to three groups and put on diets supplemented with 60 ml/day of olive (n = 15), sunflowerseed (n = 15) or linseed oils (n = 14), respectively, for two weeks within a blind study. In the group receiving sunflowerseed oil an increase of linoleic acid in serum lipids could be observed, whereas arachidonic and eicosapentaenoic acids appeared unchanged in serum triglycerides and even significantly lower in cholesterol esters. The subjects ingesting the linseed oil-rich diet showed an increase of alpha-linolenic acid in serum lipids, whereas arachidonic and eicosapentaenoic acids remained unchanged in serum triglycerides. In cholesterol esters, however, arachidonic acid was significantly decreased and eicosapentaenoic acid appeared increased only to a low level of significance. In the group put on the olive oil-rich regimen only a significant fall of linoleic acid was obvious in serum triglycerides. The results might indicate a defective desaturation and elongation of linoleic and alpha-linolenic acids and, consequently, a slow formation of arachidonic and eicosapentaenoic acids in patients with mild essential hypertension, which should be considered in dietary studies. After the sunflowerseed oil-rich diet a significant decrease of total cholesterol, low density lipoprotein (LDL) cholesterol and the LDL/high density lipoprotein (HDL) cholesterol ratio was found. Systolic blood pressure during a psychophysiological stress test and urinary sodium excretion appeared significantly lower after the linoleic acid-rich diet. After the linseed oil-rich diet, in addition to total cholesterol, LDL cholesterol and the LDL/HDL cholesterol ratio, serum triglycerides and lecithin cholesterol acyl transferase (LCAT) activity were significantly depressed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Tumor diagnosis by immunoscintigraphy with anti-CEA antibodies (Tc-99m MAK BW 431/26)].

We evaluated the clinical application of the monoclonal antibody MAb, BW 431/26, which is easy to label with Tc-99m for tumor localization. This is an anti-CEA antibody and a murine immunoglobulin (Ig G1, Isotype). We investigated patients with colorectal carcinoma (n = 14), with colorectal carcinoma recurrences (n = 24), breast carcinoma (n = 2), stomach carcinoma (n = 1), carcinoma of the urinary bladder (n = 3), lung carcinoma (n = 2) and patients with an elevated CEA level. In primary colorectal tumors (n = 14) all carcinomas were correctly localized by IS and ECT technique. In these patients the diagnosis was already known. The planar pictures showed a false negative result in 3 patients. In patients with colorectal recurrences the investigations were performed twice in 2 patients and three times in 1 patient. In these 31 ECT investigations we found 17 true positive results, 12 true negative results, 1 false positive result and 1 false negative result. The lesions were already visualized within 4 to 6 hours, but 24-hour pictures are desirable. SPECT pictures are absolutely necessary because sensitivity is considerably improved thereby. Elevated CEA levels increase the probability of a positive IS low CEA levels do not exclude positive tumor visualization. HAMA was found in only 1 patient, but follow-up investigations are indicated.

Adult↗
PubMed1988

Isolation of overproducing recombinant mammalian cell lines by a fast and simple selection procedure.

The expression of genes transfected into mammalian cells is critically dependent on both the copy number and the site of integration. This conclusion was derived from the transfection of a plasmid containing three linked genes, which guarantees the same dose of each gene in the recipient cell clones. The selection pressure imposed by the usual concentrations of the neomycin analogue G418 or puromycin alone is low and yields cell clones with widely differing transcription rates. Time-consuming screening procedures, which are generally applied to obtain high-yield cell lines, can be obviated by the simultaneous transfer of two drug-resistance genes (neo plus dhfr, or neo plus pac). By a combined selection procedure only cells with high-level expression for the first marker will survive upon exposure to increasing concentrations of the second antibiotic. Generally, these cells also exhibit high expression levels for the non-selected gene. Many of the selected clones exhibit increased copy numbers of the respective gene but some of them owe their high productivity to a favorable position of only one or a few copies of the gene. Screening for high-yield clones using the combined selection protocol introduced here provides rapid and simple access to authentic and mutant gene products.

Animals↗
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↗