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Biomedical subjects

O Klein

Publications and source records attributed to O Klein.

At least 109 records · Page 6Linked to original sources
PubMed1985

Biliary adenocarcinoma. Characterisation of three new human tumor cell lines.

Three human cell lines from adenocarcinomas of the extrahepatic biliary tract were established in permanent tissue culture. Mz-ChA-1 and Mz-ChA-2 were cultured from mechanically dissociated gallbladder adenocarcinoma metastases and SK-ChA-1 was grown from malignant ascites of a patient with primary adenocarcinoma of the extrahepatic biliary tree. Cell doubling times in tissue culture are 3-4 days for Mz-ChA-1 and approximately 2 days for Mz-ChA-2 and SK-ChA-1. All three tumour cell lines were successfully transplanted to nude mice, inducing progressive tumour growth. Histologically, nude mouse tumours resembled the original adenocarcinomas. In vitro formation of gland-like structures were regularly seen in Mz-ChA-1 and Mz-ChA-2 but only occasionally in SK-ChA-1. All three cell lines formed contacts through interdigitating processes with desmosomes and junctional complexes. On scanning electron microscopy, an abundance of microvilli was seen at the cell surfaces. Chromosome analyses of all three tumour cell lines showed a wide range of numerical abnormalities and presence of marker chromosomes. Mz-ChA-1 appears to be highly differentiated with cells producing mucus. Mz-ChA-2 synthesizes components of complement C2, C3 and C5, while Mz-ChA-1 and SK-ChA-1 produce only C3 in detectable quantities. In addition, Mz-ChA-2 supernatants are positive for ferritin and alpha 1-fetoprotein, but not CEA; while Mz-ChA-1 and SK-ChA-1 produce only CEA. Supernatants of all three cell lines are positive for N-acetyl neuraminic acid (NANA), phosphohexoisomerase (PHI) and LDH, and negative for alpha 2-macroglobulin, alpha 1-anti-trypsin, gamma-GT, AP, coeruloplasmin, haptoglobin and albumin. A high cloning efficiency renders these new tumour cell lines suitable for continued studies on clonal heterogeneity in malignant tumours. The establishment of these cell lines in tissue culture facilitates further studies on the biology of upper gastrointestinal tract cancer in man.

Adenocarcinoma↗
PubMed1982

Sex dimorphism of the adrenal cortex in rats after treatment with dexamethasone.

Sex dimorphism of adrenal cortex of the rat was studied by light and electron microscopy as well as the karyometric, gravimetric, and histometric methods after treatment with dexamethasone (2.0 mg/kg over a period of 4 days). Sex dimorphism cannot be shown in dexamethasone-induced atrophy of adrenal glands. Male fasciculata cells have more and finer distributed liposomes resembling in this way female fasciculata cells. Normally present differences in adrenal weight and nuclear size of fasciculata cells between both sexes disappear; nevertheless, female fasciculata cells remain relatively bigger compared to the corresponding male cells. Annulment of sex dimorphism is thought to be the result of altered functional activity of the zona fasciculata due to failing pituitary stimulation. Higher secretion activity of female fasciculata cells probably ceases after dexamethasone treatment.

Adrenal Cortex↗
PubMed1982

The participation of the Shemin and C5 pathways in 5-aminolaevulinate and chlorophyll formation in higher plants and facultative photosynthetic bacteria.

Chlorophyll and bacteriochlorophyll formation from 14C-labelled precursors was studied during the illumination of etiolated maize leaves excised from dark-grown seedlings and in cell suspensions of respiring, dark-, aerobically-grown Rhodopseudomonas spheroides adapting to the photosynthetic state in the light under anaerobic conditions. It was found that 1-14C-labelled glutamate and 2-oxoglutarate were incorporated into the tetrapyrrole moieties of chlorophyll and bacteriochlorophyll. This suggests that the C5 pathway of tetrapyrrole biosynthesis operates in both Zea mays and R. spheroides since in the alternative Shemin pathway the label would have been lost as 14CO2 during the formation of succinyl-CoA prior to the condensation with glycine to form 5-aminolaevulinate. It was also found that 5(-14)C-labelled glutamate and 2-oxoglutarate were incorporated into these chlorophylls which is consistent with the operation of both the C5 and Shemin pathways. That the Shemin pathway is also involved was confirmed by the incorporation of [2(-14)C]glycine into both chlorophylls. None of these substrates were incorporated into the phytol moieties of either plant or bacterial chlorophyll or into the carotenoids. However, when [1(-14)C]acetate was added to greening maize leaves not only the tetrapyrrole and phytol moieties were labelled but also the carotenoids: the labelling of these lipids is consistent with their formation from acetate via the isopentenyl pyrophosphate pathway. By comparing the incorporation of [1(-14)C]2-oxoglutarate with that of [5(-14)C]2-oxoglutarate the approximate relative contribution of each pathway to chlorophyll biosynthesis was determined. In maize leaves both pathways contributed almost equally but in R. spheroides the contribution by the Shemin and C5 pathways was 90 and 10%, respectively.

Amino Acids↗
PubMed1982

Acute and chronic vitamin C deficiency in guinea-pigs: its effect on ceruloplasmin and cytochrome P 450 and b5 levels.

Serum and liver ceruloplasmin levels rose markedly in guinea pigs with acute scurvy and with chronic latent scurvy. Their increase in the former condition can be attributed to the general stress reaction, but the increase in ceruloplasmin levels in concentration may have a stimulant effect on the ceruloplasmin, when the oxidation of Fe2+ to Fe3+ is potentiated, may obstruct the binding of iron to protoporphyrin and prevent formation of the haeme of cytochrome P 450 and b5.

Animals↗
PubMed1978

Two Biosynthetic Pathways to delta-Aminolevulinic Acid in a Pigment Mutant of the Green Alga, Scenedesmus obliquus.

Pigment mutant C-2A' of the unicellular green alga Scenedesmus obliquus develops only traces of chlorophyll and has no detectable amount of delta-aminolevulinic acid (ALA) when grown in the dark. In light it develops ALA and in the presence of levulinic acid (LA), a competitive inhibitor of ALA dehydratase, it accumulates 0.18 mmoles of ALA per 10 microliters of packed cell volume per 12 hours. This amount could be increased up to 15 times by feeding precursors and cofactors.Incubation with [U-(14)C]glutamate, [1-(14)C]glutamate, and [2-(14)C]glycine yielded significantly labeled ALA, whereas [1-(14)C]glycine did not label the ALA specifically. Thus, two pathways using either glycine/succinyl-coenzyme A or incorporating the whole C-5-skeleton of glutamate into ALA are present in this alga. The efficiency of the glycine/succinyl-coenzyme A pathway seems to be three times higher than that of the glutamate pathway. Incubation with [5-(14)C]2-ketoglutarate, which can serve both pathways as a precursor, resulted in radioactivity of ALA as high as the sum of both labeling with [1-(14)C]glutamate and [2-(14)C]glycine.Since the newly synthesized chlorophyll was radioactive regardless of labeled substrate employed, both pathways culminate in chlorophyll formation.

Journal Article↗