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Biomedical subjects

K Riedel

Publications and source records attributed to K Riedel.

At least 55 records · Page 3Linked to original sources
PubMed1988

Formation of some extracellular enzymes during the exponential growth of Bacillus subtilis.

The formation of the exoenzymes, neutral and alkaline proteinase as well as alpha-amylase of Bacillus subtilis, is characterized by the same time course. The exoenzyme formation starts in the exponential phase of growth by an excess of C and N sources. We assume that carbon metabolism of pyruvate is responsible for the exoenzyme formation during this growth phase. The proteinase formation at the transient and/or stationary phase of growth is related to amino acid limitation.

Alanine↗
PubMed1987

Formation of extracellular neutral proteinase and the stringent response in Bacillus subtilis.

The kinetics of extracellular neutral proteinase synthesis by an isogenic stringent (IS58) and a relaxed (IS56) strain of B. subtilis were compared. The specific enzyme formation rate by the stringent strain was higher than that of the relaxed one. Norvaline addition (1 mg/mL) induced the formation of pppGpp and ppGpp, respectively, as well as the appearance of extracellular neutral proteinase activities in cultures of the stringent strain IS58 and a strain with high proteinase production (ZF-178) only. These correlations support the suggestion that (p)ppGpp are involved in the regulation processes responsible for production of extracellular neutral proteinases by B. subtilis.

Bacillus subtilis↗
PubMed1985

An electrochemical method for determination of cell respiration.

The respiration of microorganisms was determined with a sensor composed of microorganisms and an oxygen electrode. The microorganisms (suspensions of about 100 microliters) are sedimented by centrifugation in a special tube on a very thin paper layer (diameter 4 mm). This paper layer is sandwiched between a polyethylene membrane and a dialysis membrane. A linear relationship is obtained between the current and the cell mass of Bacillus subtilis (between 0.05-0.35 mg dry weight per electrode preparation). When an assimilable substrate is added to the measuring solution the respiration rate is increased. It is possible to determine very fast changes in the respiration rates (1-5 sec). The application of this electrode system for investigations of the physiological state of cells during the growth cyclus is demonstrated.

Bacillus subtilis↗
PubMed1985

Extending formant transitions may not improve aphasics' perception of stop consonant place of articulation.

Synthetic speech stimuli were used to investigate whether aphasics' ability to perceive stop consonant place of articulation was enhanced by the extension of initial formant transitions in CV syllables. Phoneme identification and discrimination tests were administered to 12 aphasic patients, 5 fluent and 7 nonfluent. There were no significant differences in performance due to the extended transitions, and no systematic pattern of performance due to aphasia type. In both groups, discrimination was generally high and significantly better than identification, demonstrating that auditory capacity was retained, while phonetic perception was impaired; this result is consistent with repeated demonstrations that auditory and phonetic processes may be dissociated in normal listeners. Moreover, significant rank order correlations between performances on the Token Test and on both perceptual tasks suggest that impairment on these tests may reflect a general cognitive rather than a language-specific deficit.

Adult↗
PubMed1984

[Knowledge about and therapy of Shepherd's fracture].

In literature the compression of the distal part of the talus is described as Sherpherd's fracture. Although many proposals of treatment have been made there is a high rate of complications. Well timed surgical reconstruction and implantation of autogenous cancellous bone is the therapy of choice. Avascular bone necrosis can be avoided in this way.

Adult↗
PubMed1983

[Nucleoside polyphosphates: occurrence, metabolism and function].

Procaryotes have regulatory systems allowing to vary the metabolism in response to nutritional variations, to reduce the growth, and to start development. Nucleoside polyphosphates are mediators of coordinated alterations of metabolism. In this review, after a brief recall of the characteristics of the stringent response, the occurrence, determinations, and the metabolism of the nucleoside polyphosphates are presented. The representation of the pleiotropic effects includes the regulation of the protein synthesis and of the protein synthesis apparatus, of the protein turnover, of the N- and carbohydrate metabolism, of the formation of cell membranes and cell walls as well as the possible function of the development.

Adenine Nucleotides↗
PubMed1983

[Oncocytoma of the ocular adnexa].

The authors report on the clinical and pathological findings in 8 oncocytic lesions of the ocular adnexa. These tumors may involve the caruncle, the conjunctiva, the lacrimal gland and the lacrimal sac. They are often clinically mistaken for haemangiomas, nevi or cysts. In the present authors series the tumor involved the caruncle in 4 cases, the lacrimal gland in 3 and the conjunctiva in one. The clinical and histopathological findings are presented. The occurrence of a malignant oncocytoma (oxyphilic adenocarcinoma) in a 58-year-old man, an oncocytoma (oxyphilic adenoma) in 18-month-old girl and a cystic oncocytoma in a 76-year-old woman are particularly remarkable findings. They are compared, on the basis of a review of the literature, with 50 previously reported oncocytic lesions of the ocular adnexa, of which only 3 involved the lacrimal gland.

Adenocarcinoma↗
PubMed1983

Bilateral and unilateral mesodermal corneal metaplasia.

We report on 2 infants, one with a bilateral and the other with a unilateral corneal metaplasia. The first case with bilateral corneal metaplasia showed shortening of both upper and lower lids with formation of symblephara. By ultrasonography the right eye presented with microphthalmos, aphakia, and persistent hyaloid, whereas the inner parts of the left eye appeared to be normal. The question remains to be answered whether this is an abortive cryptophthalmos leading to bilateral corneal metaplasia or a primary corneal metaplasia inhibiting the lid growth. No suggestions concerning the aetiology are made. The second case presented with a unilateral corneal metaplasia, normal eye lids, aphakia, and microphthalmos. This aberration was probably caused by an amniotic band, as it is associated with malformation of the nose on the same side. In case 2 the dermoid was excised and a lamellar corneal graft performed. The histology is reported.

Cornea↗