Comparison of the morphological changes of restenosis after the implantation of various types of stents in a swine model

BACKGROUND: Stent design causes the differences of restenosis rate, but the morphological differences after the various types of stent implantation have not been clarified. DESIGN: Seven types of stents were implanted in pig coronary arteries to clarify how the mechanism of restenosis differs with coil stents and tube stents. METHODS: The left anterior descending coronary arteries (LADs) of pigs were injured using coronary angioplasty balloons (diameter: 3.0 mm; length: 20 mm; balloon/artery ratio: 1 : 2). Fourteen days after the injury, four types of coil stents (Cordis, Wiktor, GR-I, and GR-II) and three types of tube stents (Palmaz-Schatz, gfx, and Multilink) were implanted, and the LADs were extracted 28 days after the implantation. RESULTS: The proliferated neointima was eccentric in the coil stents and concentric in the tube stents. Although there was no significant difference in the area of neointima, the area of the lumen was significantly larger in the tube stents than in the coil stents ( < 0.01) because of the larger area of stent. Cells positive for anti-proliferating cell nuclear antigen antibody were mainly observed around the stent struts, and most of these cells were also positive for either anti-macrophage or anti-smooth muscle actin antibodies. CONCLUSIONS: Compared to the coil stents, the tube stents induce less negative remodelling including stent recoil, resulting in a wider luminal area. In order to prevent restenosis, it is crucial to implant a stent that will cause less negative remodelling.     

Early postnatal protein malnutrition affects learning and memory in the distal but not in the proximal cue version of the Morris water maze

Learning and memory of early postnatal protein malnourished rats were investigated in the Morris water maze. During the lactation period (21 days) each litter (mother plus six male and two female pups) was provided with 16% (well-nourished) or 6% (malnourished) protein diets. After weaning, rats remained on the same diet until 49 days of age. From day 50 on all animals were fed a commercial lab chow. Experiments started on day 70. In experiment I (proximal cue version) the animals were trained to escape from water to a visible platform (3 cm above the water level) in six trials daily for four consecutive days, completing 24 trials. In experiment II (distal cue version) the animals were trained to escape from water to a submerged platform using the same procedure as in experiment II. After the 24th trial, the platform was removed and the animals were submitted to a 60-s trial (probe trial). Seven and twenty-eight days after training, the retention test was conducted in one 180-s trial. The results showed no impairment of the learning or memory of malnourished animals tested in the proximal cue version but an increased latency and distance traveled to find the submerged platform in the distal cue version of the procedure. In the distal cue version the malnourished animals also showed increased latency to find the platform 7 and 28 days after the test training. No difference due to diet was found in the probe trial test indicating that, once the task is acquired, malnourished rats can manage extra-maze cues as easily as well-nourished rats. It is suggested that the present results can be due to alterations produced by protein malnutrition in the hippocampal formation or also to reflect the higher emotionality of rats following early malnutrition, specially considering the fact that postnatally malnourished animals are more reactive to unpleasant or aversive stimuli as cold water.     

The effects of benzodiazepines on event-related potential indices of automatic and controlled processing in schizophrenia: a preliminary report

The effects of benzodiazepines on cognitive function in schizophrenic patients were investigated using event-related potential (ERP) measurement during an auditory selective attention task. In this study, the authors compared the mismatch negativity (MMN) and N2b components between two subgroups of schizophrenic patients: one is comprised of patients who received no benzodiazepines (NT group, n = 7) and the other is comprised of those administered benzodiazepines in the daytime (T group, n = 7). There were no significant differences in MMN and N2b amplitudes between the two subgroups, whereas the N2b latency was significantly prolonged in the T group relative to the NT group. This suggested that benzodiazepines induce delayed stimulus classification processing in schizophrenic patients.     

Questionnaire on the attitude of the physicians in educating the elderly patients with chronic obstructive pulmonary disease about smoking cessation

Smoking status, the extent of recognition of the relationship between smoking and COPD, and actual nature of education for smoking cessation by physicians have not yet been fully elucidated. To investigate perceptions about education for smoking cessation in the elderly by physicians who work in the clinic, questionnaires were sent to the 1,012 physicians who belong to the Yokohama City Medical Association. Of these, 311 respond and their data (31%) were included in the analysis. The questionnaire included questions on the importance of smoking cessation in the elderly, on the perception about the relationship between smoking and various diseases, and actual education for smoking cessation. The smoking status of the physicians themselves was also investigated. The distribution of current smokers, ex-smokers, and non-smokers among the physicians was 13%, 33%, and 54%, respectively. Seventy-five percent of ex-smokers answered that their experience of smoking cessation influenced their patient education for smoking cessation, and 39% of smokers answered that their smoking status did not influence it. Only 53% of the physicians replied that they actually performed education for smoking cessation to the elderly, and 8% of them replied that they hardly perform any or do not perform it. Smoking cessation is thought to be the only way to prevent the development of COPD. However, only a half of physicians recognized the importance of smoking cessation for the treatment and control of COPD in the elderly. In addition, less than one third of physicians perform nicotine replacement therapy for smoking cessation. Enlightenment for physicians should be needed to make them perform education for smoking cessation more aggressively.     

Effect of P-glycoprotein on intestinal absorption and brain penetration of antiallergic agent bepotastine besilate.

The antiallergic agent bepotastine besilate is a nonsedating, second-generation H1-antagonist with high oral absorption and negligible distribution into brain. To clarify the role of P-glycoprotein (P-gp) in the pharmacokinetics of bepotastine, intestinal absorption and brain penetration studies were performed. [(14)C]Bepotastine transport in P-gp-overexpressed LLC-PK1 cells indicated that bepotastine was a substrate of P-gp. The affinity of bepotastine to P-gp estimated by ATPase activity assay was low, with a K(m) value of 1.25 mM. After i.v. administration, the brain/plasma free concentration ratio in mdr1-knockout mice was 3 times higher than that in wild-type mice. The in situ intestinal absorption studies of [(14)C]bepotastine in rats showed a clear regional difference, showing highest permeability at the upper part of small intestine with a decreasing permeability in the descending part of small intestine. The apparent absorption rate constant (ka) of [(14)C]bepotastine in the small intestine was greatly increased by cyclosporin A and verapamil, especially in the distal portion, and the site-specific absorption of [(14)C]bepotastine disappeared. The concentration dependence of ka of [(14)C]bepotastine was observed with a higher ka at higher concentration (20 mM) compared with that at lower concentration (1 microM). In conclusion, bepotastine is a substrate for P-gp, and P-gp clearly limited the brain distribution of bepotastine, whereas the effect of P-gp on intestinal absorption of bepotastine was minimal, presumably because of high membrane permeability at the upper region of small intestine where P-gp is less expressed. Such intestinal absorption property of bepotastine is distinctly different from the low membrane-permeable P-gp substrate fexofenadine.     

New staining methodology: Eastern blotting for glycosides in the field of Kampo medicines

Ginsenosides separated by silica gel TLC blotted to a polyvinylidene difluoride (PVDF) membrane treated with a NaIO₄ solution followed by bovine serum albumin (BSA) resulted in a ginsenoside–BSA conjugate on a PVDF membrane. The blotted spot were stained by antiginsenoside Rb1 (GRb1) and Rg1 (GRg1) monoclonal antibodies (MAbs). The newly established immunostaining method, Eastern blotting, was applied for the determination of ginsenosides possessing protopanaxadiol and/or protopanaxatriol in the Kampo medicines. In this method, we developed a new way to separate the ginsenoside molecule into two functional parts using a simple and well-known chemical reaction. The sugar parts were oxidized by sodium periodate to give dialdehydes, which reacted with amino groups of the protein and covalently bound to the adsorbent PVDF membrane. The MAb bound to the aglycone part of the ginsenoside molecule for immunostaining. Double staining of Eastern blotting for ginsenosides using anti-GRb1 and GRg1 MAbs promoted complete identification of ginsenosides in Panax species. This method was validated for immunocytolocalization of ginsenosides in fresh ginseng root. In addition, Eastern blotting for the detection of glycyrrhizin (GC) was also investigated. GC can be clearly determined by Eastern blotting in the Glycyrrhiza species. It is also possible for GC in rat serum to be surveyed by Eastern blotting by simple pretreatment as a further application.     

Balloon-occluded retrograde transvenous obliteration (B-RTO) for portal hypertension

We reviewed the current techniques and published results of balloon-occluded retrograde transvenous obliteration (B-RTO) for gastric varices (GV) and hepatic encephalopathy. The portal hemodynamics of gastric varices were classified into three types according to their feeding vessels, and the development of collateral veins under balloon occlusion of gastro-renal shunt was classified into five grades. The main draining veins of gastric varices were gastro-renal and gastro-inferior phrenic shunts. Preprocedural diagnosis of portal hemodynamics is important in selecting the technique for B-RTO. The rate of disappearance or marked reduction of GV was 98%, and the rate of recurrence of GV was 2%. Hepatic encephalopathy due to gastro-renal shunt improved markedly. In contrast, esophageal varices were aggravated at rates of 10% to 62.5% by the post-procedural elevation of portal pressure. Common adverse effects were hemoglobinuria, abdominal pain, and low-grade fever, but ascites and pleural effusion were also reported. Severe complications such as cardiogenic shock, atrial fibrillation, and pulmonary embolism were reported. We await technical improvements and further indications for this procedure.