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  • 1
    ISSN: 1432-1440
    Keywords: Phospholipase A2 ; Pancreatic pseudocysts ; HPLC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Phospholipase A (PLA) is able to attack membrane phospholipids and thereby plays a putative role in the pathogenesis of pancreatic pseudocysts. We looked for PLA2-like activity in aspirates from human pancreatic pseudocysts. In material originating from one cyst which occurred shortly after an acute pancreatitis attack, hydrolyzing enzymatic activity measured by a sensitive bioassay system for PLA2 activity was found without prior trypsin activation (67×103 U/min/100 µl). A biochemical characterization of this hydrolyzing enzymatic activity was provided after resolution of the respective proteins contained in the cyst fluid by HPLC. High hydrolyzing activities were found in correspondence to one specific, early eluting peak. The purified enzyme had pH optima at 3.5 and 6. Addition of EDTA (5 mM) to the test system abolished the enzymatic activity which mirrored the requirement for calcium ions. The activity was optimal at calcium concentrations ranging from 1–2 mM. Higher calcium concentrations reduced the enzymatic activity. The enzyme showed high heat stability. SDS-gel analysis of the peak showed one single band with a molecular weight of about 20,000 Daltons. Our findings demonstrate the possibility of activated, PLA-like activity in human pancreatic pseudocyst fluid. We speculate that an inappropriate activation of this enzyme in peri- or intrapancreatic “fluid collections” could account for pseudocyst formation after an acute pancreatitis attack.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1433-8580
    Keywords: Camostate (FOY 305) ; Degradation ; Rat liver ; HPLC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The elimination of the low molecular weight proteinase inhibitor camostate (FOY 305) was studied in rats after oral administration and in the the situ perfused rat liver. After feeding of camostate (400 mg/kg b. w.) only the metabolites (FOY 251, GBA) were detected in blood samples withdrawn from the portal and hepatic vein. This indicated a rapid degradation of FOY 305 after absorption from the gut lumen. The hepatic extraction of the anti-proteolytic active metabolite FOY 251 during a single liver passage was 23%. It remained almost constant over the period of 120 min. In the perfused rat liver, FOY 305 was given in concentrations comparable to the in vivo studies. It was eliminated by 20%. In these experiments, the compound was metabolized to FOY 251 and in minor amounts to guanidino-benzoate (GBA), the latter being an anti-proteolytic ineffective degradation product. In conclusion, a low hepatic extraction of FOY 305 led to pharmacologically effective concentrations of the active metabolite FOY 251 in the circulation after oral ingestion of the proteinase inhibitor.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Diabetologia 8 (1972), S. 250-259 
    ISSN: 1432-0428
    Keywords: Insulinoma ; immunohistologic investigation of B-cell tumours ; peroxidase labelled antibodies ; insulin and C-peptide in B-cells ; insulin concentration of insulinomas ; difference between insulin in normal and tumour B-cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé 14 insulinomes ont été soumis à un examen immunohistologique à l'aide de la méthode de l'anticorps marqué à la peroxydase. 8 tumeurs ont été étudiées immédiatement après leur extirpation. 7 d'entre elles réagissaient avec les sérums anti-insuline et anti-porcine-C-peptide, mais non avec le sérum anti-glucagon. Un seul carcinome à cellules B avec un contenu en insuline inhabituellement bas, a été négatif. Un an après l'inclusion dans la paraffine, la réaction immunohistologique avec le sérum anti-insuline avait nettement diminué dans les tumeurs, mais non dans les îlots du pancréas adjacent. Chez 6 patients, on disposait de fragments de la tumeur et du pancréas normal inclus dans la paraffine depuis 1 à 4 ans. Dans ce groupe, 4 tumeurs avec un contenu élevé en insuline, n'avaient qu'une faible réaction immunohistologique avec un sérum antiinsuline, et deux tumeurs (l'une avec un contenu élevé en insuline, l'autre avec un contenu faible) ont eu une réaction immunohistologique négative, tandis que les îlots du pancréas adjacent réagissaient fortement dans les six cas. Donc, la réaction immunohistologique de l'insuline dans les tumeurs à cellules B, mais non dans les îlots normaux, dépend du temps écoulé entre l'inclusion dans la paraffine et le moment où elles sont examinées. Seules les tumeurs fixées dans du liquide de Bouin, mais non dans la solution de Karnovsky, ont eu une réaction immunohistologique positive, tandis que les îlots du pancréas adjacent réagissaient positivement après fixation dans la solution de Karnovsky. Ces résultats suggèrent qu'il existe des différences entre l'insuline du pancréas normal et l'insuline des tumeurs. Une comparaison entre la coloration à l'aldéhyde-thionine et l'immunohistologie indique la supériorité de l'immunohistologie dans l'identification des cellules tumorales produisant de l'insuline.
    Abstract: Zusammenfassung 14 insulinproduzierende Tumoren wurden mittels Peroxydase-markierter Antikörper immunhistologisch untersucht. 8 Tumoren gelangten unmittelbar postoperativ zur Untersuchung. Hiervon ließen sich 7 mit einem Antiserum gegen Insulin und Schweine-C-Peptid, nicht aber mit einem Antiserum gegen Glucagon anfärben. Dagegen reagierte ein B-Zellcarcinom mit einer sehr niedrigen Insulinkonzentration mit keinem dieser Seren. Bereits ein Jahr nach der Einbettung in Paraffin ließ die Anfärbbarkeit dieser Tumoren mit einem Antiinsulinserum deutlich nach, während die Inseln des umgebenden normalen Pankreas mit dem gleichen Serum unverändert stark reagierten. — Von 6 weiteren Inseladenomen standen außerdem 1– 4 Jahre altes paraffineingebettetes Tumor- und Pankreasgewebe zur Verfügung. 4 dieser Tumoren hatten eine erhöhte Insulinkonzentration, reagierten immunhistologisch jedoch mit einem Antiinsulinserum nur schwach. Die beiden restlichen Tumoren — einer mit einer hohen, der andere mit einer niedrigen Insulinkonzentration — verhielten sich immunhistologisch negativ. Im Gegensatz zu den Tumoren ließen sich die Inseln des umgebenden Pankreas sämtlicher 6 Fälle mit einem Insulinantiserum gut anfärben. Somit scheint der erfolgreiche immunhistologische Nachweis von Insulin in insulinproduzierenden Tumoren von der Dauer der Einbettung des Tumormaterials in Paraffin abzuhängen. Das Insulin in den Pankreasinseln unterliegt dagegen diesem „Alterungseffekt“ nicht. — TumorInsulin läßt sich nur in Bouin-fixiertem, nicht aber in Karnovsky-fixiertem Gewebe immunhistologisch nachweisen, während das Insulin des normalen Pankreas auch nach Karnovsky-Fixation immunhistologisch nachweisbar ist. Die Befunde sprechen für Unterschiede zwischen normalem pankreatischen und Tumor-Insulin. — Die Färbung der B-Zellen von Tumoren mit Aldehyd-Thionin gelingt seltener als der immunhistologische Nachweis von Insulin in diesen Zellen. Die immunhistologische Untersuchung ist daher zur Identifizierung von B-Zelltumoren den üblichen spezifischen Färbungen überlegen.
    Notes: Summary 14 insulinomas were examined immunohistologically using the peroxidase labelled antibody method. 8 tumours were investigated immediately after extirpation. 7 of these reacted with insulin and porcine-C-peptide antisera but not with glucagon antiserum. Only a B-cell carcinoma with an unusually low insulin concentration was negative. One year after embedding in paraffin the immunohistologic reaction with insulin antiserum had markedly decreased in the tumours; however, not in the islet of the adjacent pancreas. From 6 patients 1 to 4 years old paraffin-embedded material of the tumour and the normal pancreas was available. In this group 4 tumours with an elevated insulin concentration reacted immunohistologically only weakly with an insulin antiserum and two tumours (one with high and one with low insulin concentration were immunohistologically negative, while the islets of the adjacent panceas of all six cases showed a strong reaction. Thus the immunohistilogic reaction of insulin in B-cell tumours but not in normal islets depends on the time elapsed between the paraffin embedding and the examination. Only tumours fixed in Bouin's fluid but not in Karnovsky's solution gave a positive immunohistologie reaction, while the islets of the adjacent pancreas reacted positively also after fixation in Karnovsky's solution. These findings suggest differences between the normal and the tumour insulin. A correlation between aldehyde-thionin stain and immunohistology indicates the superiority of immunohistology in identifying insulin producing tumour cells.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0428
    Keywords: Insulinoma ; IRI content of insulinoma ; ultrastructural categorization of insulinomas ; proinsulin content of insulinomas ; functional defect in insulinomas reduced storage capacity of insulinoma cells ; non-granular insulin release ; proinsulin content of human pancreas ; diazoxide response of insulinomas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Thirty human insulinomas have been investigated histologically and their immunoreactive insulin (IRI) content estimated. In most cases immunohistological and ultrastructural studies were also performed and the percentage of proinsulin-like components (PLC) in the tumour determined. Except for 1 case the IRI concentration in the tumours was lower (0.01–89.0 U/g) than in the islet tissue. Histologically, immunohistologically and ultrastructurally a variable number of tumour cells contained few and often no beta-granules, indicating a decreased storage capacity for insulin. This defective storage capacity seems to be the major functional abnormality of insulinoma cells. Ultrastructurally four types of insulinoma can be distinguished. The ultra-structural diagnosis of an insulinoma can only be made in type I (typical beta-granules, 13 cases) and type II (typical and atypical granules, 7 cases) but not in type III (atypical granules only, 4 cases) and type IV (virtually agranular, 4 cases). The type IV tumours had the lowest IRI concentration and did not respond to diazoxide treatment. The IRI concentration of the uninvolved pancreas of 19 patients was 2.0±0.2 U/g and in the range of non-diabetic adults. — The percentage PLC in 19 insulinomas was higher (5.3–22%) than in the pancreas of human adults with and without insulinoma (1.7–4.8%). The percentage of PLC in the serum of patients with insulinoma was always higher than in their tumours (33–61%). It is suggested that the higher PLC levels found in the tumour and serum of insulinoma patients are the consequence of the reduced storage capacity of the tumour cells resulting in a rapid passage through the granular route or even a non-granular release of newly synthesized insulin.
    Type of Medium: Electronic Resource
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