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Biomedical subjects

M Maeda

Publications and source records attributed to M Maeda.

At least 1,531 records · Page 85Linked to original sources
PubMed1978

[Effect of caerulein on pancreatic endocrine and exocrine secretion from the perfused rat pancreas (author's transl)].

Several investigations in vivo and in vitro have shown that gastro-intestinal hormones stimulate insulin secretion. However, the reports on the insulinotropic activity of pancreozymin are contradictory. The conflicting results are probably due to the fact that pure native preparation of this hormone has not been obtained in "physiologic" doses. In the present study this problem has been investigated by exposing rat pancreas to caerulein in vitro. Caerulein, an active decapeptide isolated from the skin of the Australian amphibia Hyla caerulea, resembles pancreozymin in chemical structure, including C-terminus. This active polypeptide of nonmammalian origin has been shown to possess all the biological activities of pancreozymin. The present investigation was undertaken to evaluate the significance of the interactions of exocrine and endocrine pancreas using perfused rat pancreas in vitro. Biphasic insulin release was demonstrated with caerulein at concentrations higher than 1 ng/ml. Insulin response of the first phase was proportional to the dose up to 1 microgram/ml. The second phase of insulin release was, however, almost constant, regardless of the concentrations of caerulein. Release of glucagon was stimulated by the same concentrations of caerulein which stimulated insulin release. Maximal response of the pancreatic amylase and pancretic juice output were observed with 1 ng/ml of caerulein. With higher doses, significantly less secretory responses were observed. The dissociation of the response to caerulein between endocrine and exocrine pancreas was found.

Amylases↗
PubMed1978

Clinical evaluation of the pancreatitis-like isoamylase pattern in normal persons.

Amylase isoenzyme analysis of serum and urine has been performed in 4001 normal persons and 500 patients with various disease using electrophoresis on thin layer polyacrylamide gel. Although elevation of amylase activity in amylase-1 and 2 has been reported to be the specific findings in patients with pancreatitis, 1.69% of normal persons had an elevated Amylase-2(named "Dominant Amylase-2") up to the same levels as major isoenzymes (Amylase-1 and 3), along with Amylase-1. Pedigree study confirmed an autosomal dominant mode of inheritance for Dominant Amylase-2. Knowledge of the genetic polymorphism is of importance in clinical assessment of amylase isoenzymes in patients having an elevated Amylase-2 suggestive of pancreatitis. Predominance of the pancreatic components in serum and urine has been revealed to be a specific index of pancreatic involvement. However, the existecne of an inherited trait of pancreatitis-like isoamylase pattern in healthy individuals must be borne in mind. On the basis of the present study, it may be concluded that a rise in the pancreatic type isoenzymes may not necessarily indicate underlying pancreatitis, especially in the absence of elevated amylase and lipase levels.

Acute Disease↗
PubMed1978

Early and late components of Epstein-Barr virus-associated membrane antigen in superinfected Daudi cells and their reactivity with sera from nasopharyngeal carcinoma patients.

Investigations were carried out on newly synthesized MA, VCA and EA in Daudi cells superinfected with the P3HR-1 strain of EBV and treated with trypsin to remove previously adsorbed MA-positive material from the cell surface. Synthesis of MA, VCA and EA was completely blocked by puromycin. A marked reduction in the frequency of MA-positive cells was observed in the infected cell cultures in the presence of either Ara-C or PA, but a fraction of the MA-positive cells was insensitive to the inhibitors. Differential absorption of an EBV antibody-positive human serum with Ara-C-treated or -untreated infected cells revealed two antigenically different components of MA: early (Ara-C-insensitive) and late (Ara-C-sensitive) MA. Three of five sera from patients with NPC, but none of five sera from normal adults, showed an apparent 'prozone' phenomenon in their reactivity against late but not early MA.

Agglutination↗