Early benefits of pravastatin to experimentally induced atherosclerosis

There is little information regarding the time of hypolipidemic treatment of changes in atherosclerotic plaque, tissue cholesterol content, and also for the recovery of endothelial function. To assess the early effects of lipid-lowering treatment on these parameters, six groups of New Zealand male rabbits were studied. Animals in groups I and II were fed regular chow; groups III and IV received a 12-week 0.5% cholesterol diet followed by 12 weeks of 0.05% cholesterol diet. Finally, groups V and VI were fed a 12-week 0.5% cholesterol diet and were then shifted to a regular diet for 12 weeks. During the last four weeks, the rabbits in groups I, III, and V received low-dose pravastatin (2 mg/day), added to the diet. Group IV animals had the highest cholesterol plasma levels (vs. groups I, II, III, and V, p < 0.01) and presented atherosclerotic plaques in a more advanced stage. Nonatherogenic diet was insufficient to restore endothelial function in animals previously fed cholesterol-enriched diets (groups IV and VI). Conversely, pravastatin treatment promoted significant improvement in endothelial function and reduced the progression of atherosclerosis. Marked increase in cholesterol content was seen in aorta and liver in response to the atherogenic diet. However, neither treatment with pravastatin nor nonatherogenic diet was capable of modifying the tissue cholesterol content. Our study supports the hypothesis that the early use of statins can attenuate the progression of atherosclerosis and ameliorate endothelial function. In addition, significant changes in the tissue cholesterol pool probably need a longer period of treatment.     

Recombinant antibody Fab against the hypervariable region 1 of hepatitis C virus blocks the virus adsorption to susceptible cells in vitro

Antibodies against hypervariable region 1 (HVR1) of hepatitis C virus (HCV) are putatively considered to be neutralizing. We previously found that monoclonal antibodies (mAbs) (30F1 and 30F3) against the HVR1 of HCV neutralize HCV in vitro. To develop potentially therapeutic molecules against HCV, we cloned cDNAs of antibody Fab fragments from the mouse hybridoma cells secreting these two mAbs. Fab fragments produced in Escherichia coli were purified by a single step of nickel-chelate affinity chromatography via a hexa-histidine tag. The specificity of the Fabs was confirmed by competition ELISA, BIAcore analysis, and N-terminal amino acid sequencing. The binding constant for the interaction with HVR1 was 1.39 nM for Fab 30F1 and 3.96 nM for Fab 30F3. The HCV capture assay and inhibition of HCV adsorption test demonstrated that both Fabs had neutralizing activity. The data may be useful for designing immunological therapy of HCV.     

Chronic cerebral hypoperfusion induces white matter lesions and loss of oligodendroglia with DNA fragmentation in the rat

Cerebrovascular white matter lesions represent an age-related neurodegenerative condition that appears as a hyperintense signal on magnetic resonance images. These lesions are frequently observed in aging, hypertension and cerebrovascular disease, and are responsible for cognitive decline and gait disorders in the elderly population. In humans, cerebrovascular white matter lesions are accompanied by apoptosis of oligodendroglia, and have been thought to be caused by chronic cerebral ischemia. In the present study, we tested whether chronic cerebral hypoperfusion induces white matter lesions and apoptosis of oligodendroglia in the rat. Doppler flow meter analysis revealed an immediate reduction of cerebral blood flow ranging from 30% to 40% of that before operation; this remained at 52–64% between 7 and 30 days after operation. Transferrin-immunoreactive oligodendroglia decreased in number and the myelin became degenerated in the medial corpus callosum at 7 days and thereafter. Using the TUNEL method, the number of cells showing DNA fragmentation increased three- to eightfold between 3 and 30 days post-surgery compared to sham-operated animals. Double labeling with TUNEL and immunohistochemistry for markers of either astroglia or oligodendroglia showed that DNA fragmentation occurred in both of these glia. Messenger RNA for caspase-3 increased approximately twofold versus the sham-operated rats between 1 and 30 days post-surgery. Immunohistochemistry revealed up-regulation of caspase-3 in the oligodendroglia of the white matter, and also in the astroglia and neurons of the gray matter. Molecules involved in apoptotic signaling such as TNF- and Bax were also up-regulated in glial cells. These results indicate that chronic cerebral hypoperfusion induces white matter degeneration in association with DNA fragmentation in oligodendroglia.     

Alzheimer's disease: beta-Amyloid protein and tau

Research on the molecular pathogenesis of Alzheimer's disease (AD) has made great strides over the last decade. This progress is the result of protein chemical analysis of two extracellular and intracellular fibrillary lesions in AD brain conducted during the 1980s, which identified beta-amyloid protein (A beta) and tau as their major components, respectively. Linkage analysis of familial AD identified four responsible genes: three causative genes (beta-amyloid precursor protein, presenilin 1, and presenilin 2) and one susceptibility gene (apolipoprotein E epsilon 4). All those genes causing and predisposing to AD exhibit a common phenotype: an increased production of A beta 42, a longer, more amyloidogenic A beta species, and/or its enhanced deposition. This observation was substantiated when presenilins were shown to be directly involved in A beta production. Whereas A beta deposition is relatively specific for AD, tau deposition is observed in various neurodegenerative diseases and is assumed to be intimately associated with neuronal loss. The genetic analysis of frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17) revealed the presence of mutations in the tau gene in affected members. Thus, tau can lead to intracellular tau deposits and neuronal loss, although the mechanism remains to be clarified. Taken together, A beta might exert neurotoxicity through tau, leading to neuronal loss in the AD brain.     

A comparative study on the expression of cyclooxygenase and 5-lipoxygenase during cerebral ischemia in humans

Prostaglandins and leukotrienes (eicosanoids), metabolites of the arachidonic acid pathway, are subjected to altered synthesis or relocation after an ischemic insult. Although cyclooxygenase (COX) expression has been reported in human cerebral ischemia, no information is available on the expression of 5-lipoxygenase (5-LO) and its topographical correlation to COX induction. The objective of this study was to elucidate the comparative distribution of eicosanoids in ischemic tissues. COX and 5- LO, key enzymes for the synthesis of prostaglandins and leukotrienes, respectively, were examined in autopsied brains. COX1 was expressed intensely in the microglia but weakly in the neurons in control brains. These COX1-immunoreactive microglia showed a more activated form following ischemic damage and hypoxemia. In contrast, COX2 was absent in the control brains, and was induced robustly in the neuronal cell bodies and dendrites during the acute stages of focal ischemic damage, and then subsided at the subacute stages. These COX2-immunoreactive neurons accumulated in the peri-infarct regions, but were absent from the distant regions. In focal ischemic damage and Binswanger's disease, COX2 was up-regulated in the microglia. Neuronal immunostaining for 5-LO was up-regulated occasionally during hypoxemia and focal ischemic damage. Glial cells immunoreactive for 5-LO appeared in the foci of the ischemic damage, with small blood vessels being infiltrated by 5-LO-immunoreactive mononuclear leukocytes. These findings indicate that the isozymes of COX are differentially regulated depending on the cellular source and the types of ischemic damage, and that vascular 5-LO may accelerate the migration of leukocytes and augment the blood-brain barrier permeability. The possibility of increased substrate availability for the other should be noticed in specific inhibition of either COX or 5-LO since these two enzymes are accumulated in parallel in ischemic tissues.     

The microvasculature of the human cerebellar meninges

The vascular architecture of the human cerebellar meninges was investigated. The surface meninges were poor in vasculature. In the sulci, the meninges were highly vascular but had few capillaries. The venous blood vessels gave long side branches at right angles to the parent vessels in a cruciform pattern, running horizontally along the cerebellar sulci. They were situated at the origin of the secondary or tertiary sulci. Anastomoses between these horizontal branches gave a crosshatched appearance. Short branches often extended to the bases of the sulci, terminating in T-shaped bifurcations with numerous tiny branches, like the roots of a tree. The arteries ran perpendicular to venous branches which were parallel to each other exclusively along the sagittal plane. These arteries bifurcated to straddle the horizontally running veins at the origin of the secondary or tertiary sulci. They gave off many small branches like teeth of a fork from each artery in the secondary or tertiary sulci after they bifurcated to straddle the venous branches and penetrated the cerebellar cortex at the bases of sulci. These fork-like ramifications in the bases of the sulci were most likely responsible for the ready development of pronounced ischemic state. They might also play an important role in the occurrence of ischemic damage at the bases of sulci in cases of severe generalized ischemia.     

Cost performance and efficacy of off-pump coronary artery bypass grafting

Off-pump coronary artery bypass grafting (Off-Pump CABG) may provide an alternative form of surgical revascularization by avoiding the unwanted complications of cardiopulmonary bypass, particularly in high-risk patients. To clarify the efficacy and cost performance of Off-Pump CABG, we studied the postoperative course of Off-Pump CABG and compared it to On-pump coronary artery bypass grafting (On-Pump CABG). From Aug. 1998 to Feb. 2002, twenty-eight patients who had preoperative complications such as cerebral vascular disease (11), chronic renal failure (4), atheromatous aorta (4), one lung (1), severely impaired left ventricular function (6), re-do CABG (1), and cancer (1) underwent Off-Pump CABG. Another thirty-six patients who underwent On-Pump CABG served as a control. The Off-Pump CABG patients were almost the same age as the On-Pump CABG patients (68 +/- 8 vs 64 +/- 8 years, ns). The Number of grafts was similar in both groups (2.6 +/- 1.0 vs 2.9 +/- 1.0, ns). Peak CK, peak CKMB, peak LDH, and peak GOT release were significantly lower in the Off-Pump CABG group compared with the On-Pump CABG group. Graft patency rates were similar in both groups (98% in Off-Pump CABG vs 98% in On-Pump CABG). The total cost for surgery and patient care was significantly lower (p < 0.0001) in the Off-Pump CABG group (dollar 21000 +/- 7000) compared with the On-Pump CABG group (dollar 33000 +/- 4200). Off-Pump CABG is less invasive to the myocardium, is less expensive, and has a similar efficacy in comparison with On-Pump CABG.     

Case Report: Adjuvant Therapy with a High Dose of Mitotane for Adrenocortical Carcinoma in a 4-year-old Boy

This report concerns control of adrenocortical carcinoma in a 4-yr-old boy by adjuvant mitotane therapy. He presented precocious puberty and was diagnosed with adrenocortical carcinoma. He underwent surgical resection, and adjuvant mitotane therapy was initiated, leading to a final dose of 5.0 g/day. Despite monitoring of the plasma mitotane level, encephalopathy developed 5 mo after initiation. Although he recovered from the encephalopathy, careful follow-up of his growth and development is necessary. On the other hand, he has been free of recurrence and metastases for 3 yr since discontinuation of mitotane. A high dose of mitotane is potentially effective as an adjuvant chemotherapy for adrenocortical carcinoma, although optimal and safe usage needs to be established for children.     

A severe outbreak of haemorrhagic colitis and haemolytic uraemic syndrome associated withEscherichia coli 0157: H7 in Japan

In 1990, an outbreak ofEscherichia coli 0157: H7 infection occurred in 174 children in a nursery school in Saitama, Japan. The organism was isolated from tap water supplied from the well in the school. Clinical manifestations varied from asymptomatic infection to non-bloody diarrhoea, haemorrhagic colitis, haemolytic uraemic syndrome (HUS) and death. Among culture-confirmed 42 cases ofE. coli 0157: H7, 7 children were asymptomatic, 21 children had only diarrhoea, and 14 children developed HUS. Bloody diarrhoea with abdominal pain following initial frequent diarrhoea appeared to be associated with subsequent HUS. In patients with HUS, both leucocyte count and lactate dehydrogenase activity continued to increase in the early phase of the disease, and on day 3 of illness attained markedly higher levels than in patients without HUS. These two parameters seemed to be important as predictors of the development of HUS.Committee for epidemiological and clinical study of epidemic diarrhoea due to pathogenicE. coli in a nursery school, Saitama, Japan