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Biomedical subjects

R Wagner

Publications and source records attributed to R Wagner.

At least 505 records · Page 28Linked to original sources
PubMed1978

Experimental study on the free transplantation of mucosa and lyophilised dura to the oral cavity.

The covering of epithelial defects in the oral cavity presents special problems in preprosthetic surgery, since special requisites for function and quality of mucosal grafts must be satisfied. In animal experiments mucosal defects in the oral cavity of 30 rabbits were repaired with free transplants of autologous mucosa and heterologous lyophilised dura. A comparative clinical and histological assessment of the healing processes showed that there was no essential difference between both methods. Considering the necessary second intervention, the infliction of a second wound, as well as the limited source of mucosa, our results show that the use of lyophilised dura in preprosthetic surgery is preferable.

Animals↗
PubMed1978

A new RNA-RNA crosslinking reagent and its application to ribosomal 5S RNA.

The synthesis of a new RNA specific bifunctional crosslinking reagent, 1.4-phenyl-diglyoxal, is described which reacts exclusively with guanosines. The properties of the crosslinked products enabled us to develop a straightforward method for identifying the reacted nucleotides. Results obtained with ribosomal 5S RNA of Escherichia coli demonstrate the formation of an intramolecular crosslink between guanosine-2 and guanosine-112 in the stem region.

Aldehydes↗
PubMed1978

Hepatic scintigraphy in Caroli's disease.

Caroli's disease (communicating cavernous ectasia of the intrahepatic bile ducts) is manifested on the 99Tc-sulfur colloid images as multiple focal defects in the liver. Since several other conditions have a similar presentation, intravenous or transhepatic cholangiography may be of assistance in reaching the correct diagnosis.

Bile Ducts, Intrahepatic↗
PubMed1978

Fine structure of rat prolactin cells after treatment with a long acting depot contraceptive.

Adult intact female rats were injected with norethisterone oenanthate (NOe), with or without simultaneous administration of CB-154, or with oestradiol benzoate (OeB). The ultrastructure of prolactin (PRL) cells due to the various treatment regimens was investigated and compared with the situation found in controls. Both after treatment with NOe or NOe plus CB-154, the number of PRL cells increased and displayed various ultrastructure signs of stimulation. The determination of serum PRL levels coincides with these morphological findings. In all treated animals mammary gland DNA content was significantly increased. The results presented indicate that proliferative changes in the rat mammary gland depend predominantly on the presence of progestogenic activities additionally to PRL, whereas the effect of oestrogens was regarded as an indirect effect via their PRL-stimulatory action.

Animals↗
PubMed1977

Gated proton conduction via the coupling factor of photophosphorylation modified by N,-N-orthophenyldimaleimide.

The membrane bound coupling factor of photophosphorylation is studied after pretreatment of broken chloroplasts with the bifunctional N,N-orthophenyldimaleimide under energization of the thylakoid membrane by mild flashing light. The proton conduction of the membrane is monitored both via the electrochromic absorption changes and via selective pH-indicating dyes. It is found that the coupling factor, after interaction with N,N-orthophenyldimaleimide during the preillumination period, shortcircuits one of the two protons pumped inside after excitation of chloroplasts with one short flash of light. In contrast to the low proton conductivity of the unperturbed thylakoid membrane (relaxation time for a proton gradient greater than 5s), this extra proton channel leads to a partial relaxation of a proton gradient within a few ms. Although limited to only one proton per electron, this extra proton conducting pathway is not otherwise specific. It operates with protons resulting from both Photosystem I and Photosystem II activity. In addition it operates with protons already present in the internal phase before firing of the exciting light flash. These effects are prevented by the presence of ATP (but not GTP) during the preillumination period. It is suggested that the modified coupling factor is gated open by the light induced electric field across the thylakoid membrane while self closing after passage of one proton per activated coupling factor.

Chemical Phenomena↗
PubMed1977

Differentiation between Clostridium acidiurici and Clostridium cylindrosporum on the basis of specific metal requirements for formate dehydrogenase formation.

The formate dehydrogenases of Clostridium acidiurici and of C. cylindrosporum coupled the oxidation of formate with the reduction of viologen dyes. The basal activity level was about 0.85 mumoles/min X mg of protein for both species. The level of formate dehydrogenase of C. acidiurici increased 12-fold when 10(-7) M tungstate and selenite were present during growth. Molybdate exerted no effect. On the other hand, molybdate and selenite were required to increase the formate dehydrogenase of C. cylindrosporum, and tungstate exhibitedan antagonistic effect in this organism. Growth on hypoxanthine generally depended on the addition of bicarbonate. Supplementation with tungstate and selenite accellerated growth of C. acidiurici and increased again the level of formate dehydrogenase. The addition of both, molybdate and selenite was necessary to initiate growth of C. cyclindrosporum and to form an active formate dehydrogenase. The differences in the requirement for metal ion supplementation to form high levels of formate dehydrogenase and their involvement in hypoxanthine degradation can be used to differentiate between C. acidiurici and C. cylindrosporum.

Aldehyde Oxidoreductases↗
PubMed1977

[Severe toxic liver injury after overdosage of parenteral administered carbohydrates: a case report (author's transl)].

A 31-year old female patient with anorexia nervosa developed a severe toxic liver injury after parenteral hyperalimentation. Over a period of five days she received a total amount of carbohydrates of 0.47-1.07 g/kg/hr consisting of glucose, fructose and the polyalcohols sorbitol and xylitol. A steep rise in SGOT, SGPT, and GLDH were noted as well as prolongation of the prothrombin time and decrease of the clotting factors; uric acid and lactate increased, serum phosphate decreased. After termination of parenteral hyperalimentation a laparoscopy and liver biopsy were performed. The liver biopsy revealed by light- and electronmicroscopy signs of a severe toxic liver injury. After reduction of total carbohydrates and later oral feeding a complete remission occurred. The cause of the toxic liver lesions was believed to be due to an overdosage of fructose and sorbitol.

Adult↗
PubMed1977

[Pathology, clinical appearance and therapy of Ménétrier's disease (author's transl)].

Clinical pathology of Ménétrier's disease is reviewed and 3 own cases are presented. All symptoms are unspecific exception made for the enteral protein loss. Roentgenologic and endoscopic appearance contribute to the diagnostic but only histologic examination is decisive. Gastrointestinal bleeding, acute pyloric stenosis, profuse albumin loss are all clear indications for an operation, but also the possibility of malignancy should be kept in mind. Resection should include all abnormal parts of the stomach. Recurrency of the Ménétrier's disease is only known after incomplete resection.

Adult↗
PubMed1977

An RNA core in the 30S ribosomal subunit of Escherichia coli and its structural and functional significance.

1. Evidence is presented for the occurrence of a very stable RNA core (S4-RNA) in "native" 16S RNA that is also present in the 30S subunit of Escherichia coli. A model giving the approximate location of this RNA core in the 30S subunit is presented. 2. It is proposed (a) that this S4-RNA acts as a nucleus for the assembly of the 30S subunit, and (b) that a small class of "linkage" proteins, including S4, further facilitate the assembly of the proteins to the RNA, thereby explaining some of the "cooperative" effects that are observed during in vitro assembly. 3. Evidence for the importance of the RNA core in the functioning of the ribosome is discussed.

Bacteria↗
PubMed1976

Repair tracts in mismatched DNA heteroduplexes.

Heteroduplexes with mismatches at four sites were constructed from separated strands of lambda DNA and used to transfect Escherichia coli under recombinationless conditions. The output phages from 967 single cells in one experiment and 1016 in another were analyzed to determine the pattern of mismatch repair. A wide range of repair frequencies was found among the mismatches studied. Repair involving two or more close sites in the same heteroduplex occurs much more often on thesamestrandthanonopposite strands. Analysis of the pattern of repair suggeststhat repair tracts initiate at mismatches, propagate preferentially in the 5'leads to 3' direction, and extend an average distance of ca 3000 nucleotides.

Base Sequence↗
PubMed1976

Adequacy of vitamin B6 supplementation during pregnancy: a prospective study.

This prospective study assesses the effect of 2.5, 4, and 10 mg of pyridoxine supplementation during pregnancy on maternal and fetal plasma levels of pyridoxal 5'-phosphate (PLP) and on the degree of coenzyme saturation (activation factor) of aspartate aminotransferase and alanine aminotransferase (alphaEGOT and alphaEGPT) in maternal erythrocytes. More than 4 mg of pyridoxine supplementation daily was required for most pregnancies to maintain maternal plasma PLP levels within the range observed during the first trimester and in the nonpregnant state. The plasma PLP concentrations in maternal and cord blood were highly correlated and indicated a dependence of fetal vitamin B6 nutrition on maternal circulating PLP. Measurements of alphaEGOT and alphaEGPT were not as reproducible as plasma PLP assays and were less sensitive and quantitative indicators. In the majority of subjects, the changes in alphaEGOT and alphaEGPT with time correlated poorly with the changes in plasma PLP. However, when the data were analyzed without regard for their dependence on time, they demonstrated a negative, linear correlation between alphaEGOT and log plasma PLP and between alphaEGPT and log plasma PLP for the group on 2.5 mg of pyridoxine and for all the subjects combined. Finally, the dietary records showed that most of the subjects consumed less than 2 mg of vitamin B6 daily from their food. The results indicate that the current Recommended Dietary Allowance for vitamin B6 during pregnancy (2.5 mg) is too low and that supplementation of this vitamin in an amount more than 4 mg daily is recommended.

Alanine Transaminase↗