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Biomedical subjects

H Ziegler

Publications and source records attributed to H Ziegler.

At least 109 records · Page 6Linked to original sources
PubMed1980

Protoplasts as a means of studying chloroplast development in vitro.

Protoplasts obtained enzymically from etiolated primary leaves of oat were illuminated in vitro, and the process of etioplast chloroplast transformation followed. Chloroplast development proceeded up to 6 hours of incubation in the light (20 C). During this period, complete photosynthetic light and dark reactions were constituted, in addition to prolamellar body-degrading protease activity.In parallel, electron microscopic investigations showed a pronounced decrease in prolamellar body area from 89.5 square micrometers at 0 hours to 40.6 square micrometers at 6 hours, whereas the length of the thylakoid membranes (prothylakoids, thylakoids) increased from 21 micrometers at 0 hour to about 293 micrometers at 6 hours. This was accompanied by the formation of grana (bi- and polythylakoids).A comparison of plastid structure and function, developed within isolated protoplasts and those of organelles greened in intact leaves up to 6 hours, showed that there was only a slight lag in development of plastids illuminated in vitro to those illuminated in vivo. However, times of in vitro illumination longer than 6 hours resulted in signs of deterioration and the lack of further development, except for photosystem I activities.

Journal Article↗
PubMed1979

[Hepato-biliary sequential scintigraphy for diagnosis of bile-passage after bilio-digestive anastomosis (author's transl)].

37 patients with bilio-digestive anastomosis--18 choledocho- and 19 hepatico-jejunostomies Roux-en-Y--had been followed up for 6--62 months. Hepato-biliary sequential scintigraphy showed in 26 patients both unimpeded bile passage and normal function of the jejunal loop. 6 patients had stenosis in the common bile duct or the anastomotic region with cholangitis and cholostasis. In 5 patients we observed an impaired function of the jejunal loop. Though all of these patients had clinical symptoms only one patient developed cholostasis.

Bile Duct Diseases↗
PubMed1977

The tubular loop fermentor: oxygen transfer, growth kinetics, and design.

Oxygen transfer measurements using a dynamic method and evaluated with an appropriate mathematical model have been made on a tubular loop bioreactor, Correlations of the type used in tank systmes are used to describe the influence of power and aeration rate on the mass transfer coefficient. Yeast cultures grown on hydrocarbon and glucose substrates show growth characteristics similar to conventional tank results. Model considerations for large-scale tubular fermentors allow for the prediction of the steady-state oxygen profiles and maximum reactor length. Combination with two-phases flow and oxygen transfer correlations yields a design procedure for commercial scale tubular loop fermentors.

Absorption↗
PubMed1977

Envelope Permeability to Possible Precursors of Carotenoid Biosynthesis during Chloroplast-Chromoplast Transformation.

During the transformation of chloroplasts to chromoplasts in Capsicum annuum L., the permeability of the envelope membranes to possible precursors of carotenoid biosynthesis (acetate, mevalonate, citrate) was tested. The plastids were isolated by gel filtration, and the uptake of labeled compounds was measured by a filtering centrifugation technique, using silicone oil. The different ripening stages were characterized by the ratio of chlorophyll to carotenoid content. The chloroplast membranes were shown to be impermeable to all of the metabolites tested. During the transformation there was a sharp increase of membrane permeability. In the mature chromoplast, the permeability to mevalonate and acetate again decreased to about 20% of the maximum value and reached zero for citrate. The results give evidence that during the transformation of chloroplasts to chromoplasts, precursors for carotenoid biosynthesis are translocated from extraplastidic sites into the plastids, there being possibly incorporated into carotenoids.

Journal Article↗
PubMed1976

[Polyposis coli. Comparison between the familial and non-familial form].

Since 1970 16 patients with polyposis coli have been treated at the Department of Surgery, Medical School, Hannover. Of these, 9 patients showed the classic type of familial polyposis, while 7 patients denied a positive family history. Comparing both groups, the nonfamilial type of polyposis coli can be separated as well from the familial polyposis as from multiple adenomas of the large bowel. Operative treatment in both groups of polyposis coli and management of nonfamilial polyposis coli are discussed.

Adult↗