Hydrogen sulfide donor micelles protect cardiomyocytes from ischemic cell death

Hydrogen sulfide, an important gaseous signaling molecule in the human body, is known to protect cardiomyocytes from ischemia, a condition characterized by insufficient oxygen supply to the cells. Here we show that a nanosized H₂S donor micelle releases H₂S intracellularly and prevents cardiomyocyte apoptosis in an in vitro ischemia model.

Receptor clustering and activation by multivalent interaction through recognition peptides presented on exosomes

We demonstrate a novel system for inducing clustering of cell surface receptors via recognition peptide segments displayed on exosomes, leading to receptor activation. With this system, targeting of receptor-expressing cells and facilitation of the endocytic uptake of exosomes, which contained the anti-cancer protein saporin, were successfully achieved, leading to cell death.

Arginine-rich peptides and their internalization mechanisms

As the versatility and use of CPPs (cell-penetrating peptides) as intracellular delivery vectors have been widely accepted, the cellular uptake mechanisms that enable their efficient internalization have become the subject of much interest. Arginine-rich peptides, including HIV-1 Tatp (transactivator of transcription peptide), are regarded as a representative class of CPPs. Evidence suggests that macropinocytosis plays a crucial role in the cellular uptake of these peptides. We have recently shown that treatment of cells with arginine-rich peptides induces activation of Rac protein leading to F-actin (filamentous actin) organization and macropinocytosis. We have also shown that depletion of membrane-associated proteoglycans results in the failure of this signalling pathway, suggesting that membrane-associated proteoglycans may act as a potential receptor for the induction of macropinocytic uptake of arginine-rich peptides. However, when the macropinocytic pathway is inhibited at a low temperature or by cholesterol depletion, these peptides can be internalized by alternative mechanisms, one of which appears to be direct translocation of the peptides through the plasma membrane. This review summarizes the current theories on both endocytic and non-endocytic aspects of internalization of arginine-rich peptides.

A ‘cassette’ RNase

RNase S is a unique protein comprising the non-covalent association of two components, the S-peptide and the S-protein. An RNA-recognition segment derived from the human immunodeficiency virus (HIV)-1 Rev protein was conjugated with the S-peptide to form a complex with the S-protein. The resulting RNase S bearing the RNA-recognition segment preferentially hydrolyzed a single position of the RNA stem-loop derived from the specific binding site for the Rev protein.

Simultaneous extensive resection of the liver and the pancreas in dogs

Mortality, morbidity, liver function and regeneration were evaluated in dogs that had undergone simultaneous major resection of the liver and the pancreas. The 10-week survival rate was only 25% in the dogs that underwent 70% hepatectomy with more than 92% pancreatectomy, and many of them died of liver failure. Long-term survival was observed in more than 60% of the dogs after 70% hepatectomy with less than 92% pancreatectomy or after 40% hepatectomy with more than 92% pancreatectomy. The liver regeneration rate was reduced with the extent of the pancreatectomy, and the reduction was remarkable especially when more than 92% of the pancreas was resected. The frequency of diabetes was reduced when the pancreatectomy was combined with hepatectomy. Hyperlipemia and fatty liver were noted in all the dogs of the group that underwent more than 92% pancreatectomy alone. They were observed also in the postoperative diabetic groups but not in non-diabetic groups. The postoperative recovery of hepatic function and liver regeneration were delayed after simultaneous hepatectomy-pancreatectomy. Also, postoperative carbohydrate and lipid metabolism was better maintained in the hepatectomy-pancreatectomy groups than in the pancreatectomy-alone groups.

Coexistence of pancreas divisum and intestinal malrotation in a patient with cholecystolithiasis--a case report

An unusual case of a coexistence of pancreas divisum and intestinal malrotation in a patient with cholecystolithiasis is described herein. The diagnosis of pancreas divisum was established by endoscopic retrograde pancreatography, and the intestinal malrotation was diagnosed by duodenography and barium enema. An operation was performed for the cholecystolithiasis. The pancreas was soft, and its shape was almost normal. Cholecystectomy and prophylactic appendectomy were performed, however nothing was done to the pancreas.