Sumiyoshi Takasugi

Neural and humoral factors influence gastric receptive relaxation in dogs

To clarify the neural and humoral factors which control gastric receptive relaxation, the effects of various types of vagotomy or splanchnicotomy on receptive relaxation of the canine innervated corpus pouch were investigated. The influence of gastrin, histamine H1-receptor antagonist, and anti-histamine releasing agents on receptive relaxation were also examined. Selective proximal vagotomy or splanchnicotomy resulted in a slight disturbance in receptive relaxation. Truncal vagotomy produced a marked disturbance in receptive relaxation. Administration of tetragastrin potently inhibited receptive relaxation, however, recovery occurred by injecting a histamine H1-receptor antagonist. Increased serum gastrin induced by perfusion of the antrum with liver extract solution disturbed receptive relaxation and this response was inhibited by pretreatment with transamine, an inhibitor of histamine release from histamine secreting cells. These results indicate that receptive relaxation in the canine stomach is controlled not only by vagal and splanchnic nerves, but also by gastrin and histamine.

Isolation of an Elastase-Like Enzyme from Skin Lesions with Sweet’s Syndrome

In the present study, an elastase-like enzyme which possessed elastolytic, proteolytic and Nα-Acetyl-L-tyrosine ethyl ester hydrolytic activities was extracted from skin lesions with Sweet’s syndrome.

Studies on a kallikrein-kinin system in plasma of patients with acute pancreatitis: The preparation and characterization of a kallikrein-like enzyme in patient's plasma

In a previous paper, the authors reported that the kallikrein-like activity was eluted in alpha 2-macroglobulin fractions when patients plasma was fractionated with Sephadex G-200 gel filtration. In order to clarify the characteristics of the kallikrein-like enzyme, enzyme isolation methods were investigated. Success was attained by the addition of 1 % sodium-dodecyl-sulfate to alpha 2-macroglobulin fractions followed by G-200 chromatography. It was also confirmed that alpha 2-macroglobulin from which the enzyme was removed regained antiplasmin activity, and that some proteases other than the kallikrein-like enzyme were also bound to alpha 2-macroglobulin. The kallikrein-like enzyme isolated by sodium-dodecyl-sulfate-treatment was examined in respect of its molecular weight and its ability to be adsorbed on DEAE-cellulose and was found to possess a molecular weight approximating that of ovalbumin or human pancreatic kallikrein and a binding affinity for DEAE-cellulose. From these results, the authors speculate that during attacks of acute pancreatitis, the pancreas liberates kallikrein into the blood.

Multiple molecular forms of acid-stable plasmin inhibitor derived from human urinary trypsin inhibitor.

It was found that cyanogen bromide (BrCN) treatment of the highly purified human urinary trypsin inhibitors (H-UTI; specific activity 1,897 U/mg protein, and L-UTI; specific activity 1,850 U/mg protein) readily produced new plasmin inhibitors with almost no loss of UTI activity. Five multiple forms of chemically cleaved inhibitors (UTIB-I, UTIB-II, UTIB-III, UTIB-IV and UTIB-V) could be isolated from BrCN-treated L-UTI by isoelectric focusing and gel filtration. These inhibitors were very acid-stable and their isoelectric points (pI) were 4.5, 4.6, 4.9, 5.1 and 6.4, respectively. The molecular weights by SDS-polyacrylamide gel electrophoresis were almost the same at about 23,000 +/- 3,000. Although these inhibitors showed both anti-plasmin and anti-trypsin activities, much higher anti-plasmin/anti-trypsin activities were observed in the cleaved inhibitors than in the parent UTI. They competitively inhibited human plasmin with Ki values of 3.0-4.1 X 10(-8) mol/l (H-D-Val-Leu-Lys-pNA substrate).

Kinetic studies of three different molecular forms of urokinase for the activation of native human plasminogen.

The kinetic parameters of three different molecular forms of urokinase (UK) for the activation of native Glu-plasminogen were compared. The apparent Michaelis constant (Km. app.) of each UK was almost of the same order of magnitude (31-38 microM), but the catalytic constants (kc) were observed to be different: UKh (high molecular weight form, molecular weight 53,000), 2.4 +/- 0.2 s-1; UK+ (low molecular weight form, molecular weight 33,000), 0.83 +/- o.10 s-1, and UKl (trypsin-digested form, molecular weight 36,000), 0.91 +/- 0.18 s-1. The overall second order rate constant, kc/Km calculated for UKh was 7.7 X 10(4) M-1 s-1, higher than for UKl (2.2 X 10(4) M-1 s-1) or UKt (2.4 X 10(4) M-1 s-1), indicating the possibility of a much higher degree of enzymatic specificity and efficiency.

A case of ruptured hepatoma followed by elastase-induced disseminated intravascular coagulation.

In the present study, the first case of ruptured hepatoma followed by disseminated intravascular coagulation is reported. An elastase-like enzyme which possessed elastolytic and caseinolytic activities was confirmed from patient plasma. On the other hand, no elastase activity was detected in the plasma of patients with hepatitis, liver cirrhosis or hepatoma without disseminated intravascular coagulation. The patient plasma did not possess H-D-Val-Leu-Lys-p-nitroanilide hydrochloride, succinyl-L-alanyl-L-alanyl-p-nitroanilide, and pyro-Glu-Pro-Val-p-nitroanilide amidolytic activities. However, when chromatographed on Sephadex G-200, the presence of low-molecular weight plasminogen was confirmed. Its molecular weight was approximately 52,000. A slight decrease of alpha 2-plasmin inhibitor was noted, but no decrease of alpha 2-macroglobulin was detected.

EFFECT OF PLANT SH‐PROTEASE ON HUMAN POLYMORPHONUCLEAR LEUKOCYTE GRANULE ELASTASE

In the present study, attempts were made to examine the effects of plant SH‐protease on human polymorphonuclear leukocyte granule elastase. S‐2484 amidolytic activity in extracted solution using 0.1% Triton X‐100 was remarkably higher than in the solution without Triton X‐100. The authors confirmed the possibility that the presence of solvents such as Triton X‐100 might be required for extraction of elastase from the granule membrane. It was also confirmed that ficin and papain inhibited extraction of elastase from the granule membrane by Triton X‐100, and that SH‐protease can inhibit S‐2484 amidolytic and Congo red‐elastinolytic activities of the released elastase. However, it is not clear whether SH‐protease inhibits the release of proelastase from the granule membrane or inhibits activation of released proelastase to elastase. The authors assume that there may be competitive inhibition between SH‐protease and elastase against the substrate.

Studies on the role of polymorphonuclear leukocyte granule elastase in arthus reaction

SummaryIn the present study, attempts were made to clarify the role of an elastase-like enzyme in Arthus reaction by using rabbit-peritoneal polymorphonuclear leukocytes (PMNs). It was first confirmed that the injection of large amounts of PMNs with antibody can increase tissue damage in reversed Arthus reaction. The five various fractions, which were intact PMNs, whole homogenate, granule fraction, nuclei and cell debris, and membrane extract, were prepared from rabbit-peritoneal exudate. Each fraction was intracutaneously injected into the abdominal wall of rabbit. It was of particular interest that the tissue damage induced by membrane extract occurred earlier and was more severe than that caused by the others. Furthermore, membrane extract possessed remarkably higher caseinolytic and elastinolytic activities than the others. The membrane extract was partially purified by Sephadex G-100 column chromatography. The protein concentration of the elastase-like enzyme solution was 3.64 mg/ml, and its specific activity was 195 caseinolytic units and 0.45 elastinolytic units per milligram of protein. The cutaneous reaction by membrane extract was dependent on the concentration of this elastase-like enzyme and could be strongly inhibited by Elastatinal. From these results, the authors suggest that an elastase-like enzyme which originates in PMN granules is the key enzyme that promotes the severity of tissue damage in Arthus reaction.

INFLUENCE OF CIMETIDINE ON NEURO-HUMORAL EXCITATORY RESPONSES OF GASTRIC SECRETION AND MOTILITY IN DOG

The influence of intravenous administration of cimetidine on excitatory response of gastric secretion and motility of innervated or denervated pouches caused by electrical stimulation of vagal and splanchnic nerves and administration of tetragastrin or histamine respectively were investigated. Dogs were anesthetized with nembutal, and also immobilized with gallamine tricthiodide. The following results were obtained. (1) Administration of cimetidine inhibited the augmentation of gastric juice and acid output from the innervated corpus pouch by vagal and splanchnic nerve stimulation and vestibulo-gastric excitatory reflexes of gastric secretory functions via the vagal or splanchnic nerve. (2) Augmentation of gastric acid output from the denervated corpus pouch caused by electrical stimulation of vagal and splanchnic nerves was inhibited by administration of cimetidine. (3) Administration of cimetidine inhibited the augmentation of acid output from denervated corpus pouch caused by injection of tetragastrin or histamine. (4) The excitatory responses of gastric motility caused by nerve stimulation and administration of tetragastrin or histamine could not be effected by cimetidine. (5) No changes were observed in the gastric venous blood flow by continuous intravenous injection of cimetidine, but by rapid injection both the flow was augmented and the systemic blood pressure decreased transiently. These results indicate that histamine stimulates gastric secretory cells directly.