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Biomedical subjects

W Bock

Publications and source records attributed to W Bock.

34 records · Page 2Linked to original sources
PubMed1978

[Mode of action and inhibition of polygalacturonase covalently bound to polysaccharide and glass carriers].

Endo-polygalacturonase (EC 3.2.1.15.) from Aspergillus spec. is much changed as far as its mode of action and the interaction with vegetable inhibitors of pectinase (from green beans and cucumbers) are concerned when it is covalently bound to insoluble carriers (Sepharose, cellulose powder, macroporous glass and nonporous ballotinis). Whereas a 2% degradation of substrate by the soluble enzyme caused a 50% decrease of viscosity of citrus pectic acid, the comparable degradation of substrate was increased to a level of about 10% with the investigated polygalacturonase carrier complexes apparently independent of the properties of the carriers and the kind of binding of the enzyme. In contrast to this the higher degradation of substrate of 15 and 20% respectively which was further stated at a 50% decrease of viscosity is unambiguously connected with the carriers and is in direct correlation with the specific activity of the polygalacturonase carrier complexes. Contrary to the soluble enzyme the covalently bound enzyme produces more lower oligomerous galacturonic acids by an exo-mechanism or by multiple attack already at the beginning of the hydrolysis of pectic acid. During the final stage there is an enrichment of trigalacturonic acid besides mono- and digalacturonic acids independent of the state of solution of the enzyme. It could further be stated that the strong inhibition of the soluble endo-polygalacturonase by selected pectinase inhibitors which was described earlier is reduced by degrees with the enzyme covalently bound to the insoluble carriers.

Enzymes, Immobilized↗
PubMed1978

[Synthesis and properties of immobilized enzymes. X. Covalent binding of polygalacturonase to insoluble carriers].

The pectinolytic enzymes are of practical interest for the clarification of fruit juice. In the present paper the covalent coupling of polygalacturonase (PG; E. C. 3.2.1.15) is reported. A commercially available enzyme (Rohament P; 5 U/mg) and purified Endo-PG (200 U/mg) are immobilized to the following carriers: BrCN-activated Sepharose, carbodiimide-activated CH-Sepharose, dialdehyde Sepharose, dialdehyde Sephadex, dialdehyde cellulose, CMC-azide, carbodiimide-activated CMC, macroporous glass (isothiocyanate and carbodiimide coupling) and glass beads. The implications of pore diameter (Sephadex- and Sepharose derivatives), of purity of the PG, of protein content of the PG-carrier-complexes as well as the presence of substrate during the coupling reaction, are discused in relation to the relative and specific activity of the bound protein and to the efficiency of the coupling reaction. From the carriers under study derivatives of Sepharose yield the best result (relative activity max. 88%, specific activity max. 5400 U/mg). The immobilization to isothiocyanate glass yields good results, too (relative activity 20%, specific activity 500 U/g). The mechanical instability of the PG-dialdehye Sephadex-complexes and the low relative activity of the bound enzyme are unsatisfactory. Due to their low affinity to PG, the derivatives of cellulose are also inappropriate for covalent coupling of this enzyme. All PG-carrier-complexes are largely stable both during storage at 4 degrees C and repeated activity assays.

Enzymes, Immobilized↗
PubMed1977

[Computer tomography in intracranial hemorrhage (author's transl)].

For the detection of acute intracranial and intracerebral hemorrhage computer tomography C.T.- examination is of greatest importance. The diagnostic value exceeds angiographic findings. Especially in cases of urgency C.T. should be used as routine examination.

Acute Disease↗
PubMed1976

[Retention of apple starch in production of pectin by the aluminum pectinate procedure].

Apple pectin produced by means of the aluminum pectinate procedure contains less starch than apple pectin obtained by precipitation with ethanol. The degradatin of the starch which occurs during production depends to a great extent upon the conditions of pomace digestion. The absorption maxima of the amylose-iodine complexes range in general from 550 to 570 nm. Model experiments with highly esterified pectin and partially degraded (by mechanolysis) apple starches were performed to establish favourable conditions for fractionating the pectin and starch components which are obtained when the pectin is precipitated as aluminum pectinate and when the granular coagulate is washed with water.

Aluminum↗
PubMedDate not supplied

[Infection-induced pathologic change in respiratory parameters in the young infant].

While many aspects related to the etiology and pathogenesis of sudden infant death remain unclear, the ultimate trigger event appears to be an acute regulatory disturbance of the cardiorespiratory neurons of the reticular formation of the brain stem. Retrospective studies have demonstrated that SIDS often occurs after infection of the upper respiratory tract. We present the case history of a 10-week old infant, where the respiratory pattern demonstrated highly pathological alterations induced by a mild infection of the upper airways, as confirmed by oxycardiorespirography. Oxycardiorespirography provides continuous recording of the respiration (transthoracic impedance) extending over several hours during sleep and during the critical phase just before going to sleep and waking up in relation to heart rate, partial oxygen pressure (measured transcutaneously) and nasal flow. The presented infant is a premature infant delivered in the 34th week of gestation according to Dubowitz (artificial respiration for 7 days due to hyalin membrane syndrome stage II). During infection periodic breathing was found to be 19.3% with partly severe hypoxemia. The longest single episode of apnea was 30 seconds. On the average, 5 episodes of bradycardia occurred (less than 100/min/measuring hour). An OCRG investigation performed at the age of 5 weeks and after disappearance of the infection at the age of 12 weeks yielded normal findings. This permits the conclusion that in out patient an infection of the upper airways may have induced a pathologic respiratory pattern, which could be a major trigger mechanism for sudden infant death.

Carbon Dioxide↗