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R van Schilfgaarde

Publications and source records attributed to R van Schilfgaarde.

95 records · Page 6Linked to original sources
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Amount and distribution of collagen in pancreatic tissue of different species in the perspective of islet isolation procedures.

Because collagen is the major target in the enzymatic dissociation of the pancreas for islet isolation, we determined the amount of collagen and its distribution in a comparative study comprising normal pancreata of rat, dog, man, young pig, and adult pig. Collagen content was determined using a colorimetric method and its distribution was assessed in tissue sections stained with Sirius red. The collagen content is relatively low in the rat and adult pig pancreas, and the amount of collagen is relatively low in the septa of the rat and dog pancreas. Not the amount of collagen in the septa but collagen in the rest of the pancreas, mainly located between the acini, seems to determine the dissociation of the pancreatic tissue. This can be exemplified by the higher islet yields obtained from the adult vs. the young pig pancreas; the latter contains a higher total amount of collagen but a similar, relatively high, amount of collagen in the septa. A high amount of collagen surrounding the islets seems to be of secondary importance in islet isolations, because yields of the same magnitude are obtained from the canine and human pancreas containing a relatively low vs. high amount of collagen around the islets but a similar total collagen content. The rat pancreas contains both a low total amount of collagen and a high amount of collagen around the islets; therefore, the general experience that islet isolation procedures are effective in rats can be readily understood.

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Histochemical analysis of the role of class I and class II Clostridium histolyticum collagenase in the degradation of rat pancreatic extracellular matrix for islet isolation.

To understand why class II Clostridium histolyticum collagenase is much more effective than class I in the isolation of rat pancreatic islets, we analyzed the role of these collagenases in pancreatic tissue dissociation. Crude collagenase was purified and then fractionated into class I and II with different enzyme activities and protein compositions. Pancreatic tissue was incubated with either class I, class II, or class I + II, with or without added protease, under conditions that eliminated endogenous proteolytic activity. The degradation of pancreatic extracellular matrix was monitored by selective histochemical staining of tissue samples. Class I and II showed similar capacities to degrade glycoproteins and degraded about one-third of the glycoproteins during 120 min of incubation. The degradation of collagens by class I and II was relatively more effective, 80 to 95% of the collagens being removed in 120 min, and also class dependent. Both in the presence and absence of protease, class II was more effective at degrading collagens than class I, but this difference in efficacy was less apparent than with islet isolation. Class I + II degraded collagens faster and more complete than did the individual classes, indicating a synergistic effect of class I and II. Evaluation of collagen degradation at various pancreatic locations did not show a selective degradation of collagens by any of the collagenase classes. The present data offer a partial explanation for the major role of class II in islet isolation.

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Lumbar sympathectomy for severe lower limb ischaemia: results and analysis of factors influencing the outcome.

Sixty consecutive patients (66 legs) underwent surgical lumbar sympathectomy as the only therapy for severe lower limb ischaemia (pain at rest and/or frank gangrene) caused by arteriosclerosis in the period 1977 to 1982. After six months results were good, as defined by absence of pain at rest, healing of ischaemic lesions and no major amputation, in 48% of limbs and bad in all other limbs. Patients with rest pain only fared much better than those with gangrene: after six months a major amputation had to be performed in 14% and 45% respectively. The presence or absence of diabetes mellitus and palpable pulsations at knee level and the angiographic patterns were of no help in the prediction of the results of lumbar sympathectomy. Doppler ankle/arm indices did have predictive value, since in all limbs with Doppler indices lower than 0.30 a major amputation had to be performed. Lumbar sympathectomy still remains a useful procedure in the treatment of selected patients with severe lower limb ischaemia in which reconstructive surgery is not feasible. But it is only advocated in the presence of ankle/arm indices above 0.30 and in the absence of gangrenous lesions.

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