Extension of A beta2M amyloid fibrils with recombinant human beta2-microglobulin.

In order to elucidate the pathogenesis of A beta2M amyloidosis, we established an experimental system to study the mechanism of amyloid fibril formation or degradation in vitro. We compared the kinetics of A beta2M amyloid fibril (fA beta2M) extension with native beta2microglobulin (n-beta2M) purified from the urine of a patient suffering from renal insufficiency, with that with recombinant beta2M (r-beta2M) in vitro. n-Beta2M and r-beta2M were incubated with fA beta2M purified from synovial tissues excised from A beta2M amyloidosis patients. The fA beta2M extension reaction could be explained by a first-order kinetic model in both beta2Ms. The extension reaction was greatly dependent on the pH of the reaction mixture and maximum around pH 2.5-3.0 in both beta2Ms. The fA beta2M extended with both beta2Ms assumed the similar helical filament structure, although the fibrils extended with r-beta2M were slightly wider than those extended with n-beta2M and the former fibrils assumed a helical structure more clearly as compared to the latter. In order to obtain pure, unmodified fA beta2M, we next extended fA beta2M repeatedly by the algorithmic protocol with r-beta2M. As the generation of the extended fibrils proceeded, the initial rate of the extension reaction increased The ultrastructure of fibrils was completely preserved throughout the repeated extension steps. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting revealed that fA beta2M extended repeatedly with r-beta2M were composed solely of r-beta2M. The use of these r-beta2M and fA beta2M will be advantageous to assess the effects of several amyloid-associated molecules in the formation or degradation of fA beta2M in vitro.     

Potential utility of magnetic resonance cholangiography in the management of endoscopic biliary drainage tubes

An 80-yr-old woman with advanced hilar cholangiocarcinoma underwent a placement of endoscopic biliary drainage (EBD) tube from the common hepatic to common bile duct through the stricture. Magnetic resonance cholangiography clearly demonstrated the later dislocation and obstruction of the EBD tube. The present case suggests that magnetic resonance cholangiography may be a potentially useful tool in the management of EBD tubes.     

Chronic hepatitis caused by hepatitis C virus showing a discrepancy between serogroup and genotype because of intergenotypic 2b/1b recombination: A pitfall in antiviral therapy with direct‐acting antivirals

A 40‐year‐old male patient with virologic relapse after daclatasvir plus asunaprevir therapy for a serogroup 1 hepatitis C virus (HCV) infection visited our hospital for retreatment. Virologic examinations revealed that a genotype 2b HCV strain carrying both NS3‐S122N / D168A and NA5A‐R30Q / L31M / Q54H / Y93H mutations had relapsed. The patient received sofosbuvir plus ribavirin therapy, but virologic relapse occurred once again. Sequencing of the HCV genome clarified an intergenotypic recombination of 2b and 1b with an estimated crossover point between nucleotides 3114 and 3115, corresponding to the N‐terminal end of the NS3 region (DDBJ/EMBL/GenBank databases accession no. LC273304). The NS5B‐S282T mutation was not detected in the HCV strain, and resistance‐association substitutions in the NS3 and NS5A regions were similar to those at baseline. Direct sequencing of the core and NS4A regions corresponding to the targeting sites of genotyping and serogrouping, respectively, is useful to determine the combination of direct‐acting antivirals when a discrepancy is observed between the serogroup and genotype of HCV strains.     

Esophageal Erosion as a Possible Bacterial Entry Site in an Acute Lymphoblastic Leukemia Patient with Sepsis

A 69-year-old man with relapsed acute lymphoid leukemia was treated with adriamycin, vincristine, and prednisolone. During this chemotherapy, the patient developed sepsis and meningitis. Although many kinds of antimicrobial drugs, including imipenem, meropenem, amphotericin-B, and gamma-globulin were administered, the patient died of respiratory failure. A positive result for Enterococcus faecalis was obtained in both blood and cerebrospinal fluid culture. Autopsy revealed multiple small erosions in the lower esophagus. Histopathological examination showed multiple nuclear inclusion bodies of herpes simplex virus in the squamous epithelial cells at the edge of the erosions. Moreover, proliferation of micrococci was observed at the base of the erosions and in the lumina of the submucosal small vessels. These findings suggested that E faecalis entered the blood circulation from this lesion. In many patients with febrile neutropenia, the pathogenesis of infection remains unclear. Our case seems significant for clarifying the focus and pathogenesis of febrile neutropenia.     

The persistence of high uptake of serum albumin in the olfactory bulbs of mice throughout their adult lives

Brain to plasma concentration ratios of i.v. administered human serum albumin (HSA) in the olfactory bulb, frontal cortex and cerebellum were evaluated in DDD mice of different ages. We measured the brain uptake of serum albumin excluding intravascular content by using a double isotope technique and examined the time course of the brain uptake to evaluate the brain uptake at different time intervals. In young adult mice, the value was significantly higher in the olfactory bulb than in other brain regions 3-24 h after (125)I-HSA injection. It was about 2.3 times higher in the olfactory bulb than in the cerebellum (P < 0.01). The high concentration ratios in the olfactory bulb were observed in all 4-22-month-old mice. Moreover, the ratio in the olfactory bulb 24 h after (125)I-HSA injection was higher in 22-month-old mice than in younger animals. The high uptake of serum albumin in the olfactory bulb suggests that intravascular macromolecules can be transported into the olfactory bulb more easily than in other brain regions with tight endothelium, and the persistence of high uptake during adult life may be associated with age-related morphological changes in the olfactory bulb.     

Evidence for a new species of Leishmania associated with a focal disease outbreak in Ghana

A previously unknown Leishmania spp., inferred by DNA sequence analysis of the small subunit ribosomal RNA gene and the internal transcribed spacer region (ITS1), was detected in tissue biopsies from patients living in the Eastern Ghanaian community of Taviefe. Restriction fragment length polymorphism analysis of the ITS1 amplicon supports the possibility of an uncharacterized Leishmania spp.     

Blood-borne factors inhibit Alzheimer's beta-amyloid fibril formation in vitro

Soluble amyloid beta-protein (Abeta) does not aggregate to beta-amyloid fibrils (fAbeta) in the brain of normal humans. We recently found that the cerebrospinal fluid (CSF) from non-Alzheimer's disease (AD) subjects inhibited the formation of fAbeta(1-40) and fAbeta(1-42) more strongly than that from AD subjects, although the CSF obtained from both groups inhibited the fAbetas formation in vitro. Here, we examined the influence of plasma obtained from AD, non-AD and healthy control (CTL) subjects on the formation of fAbeta(1-40) and fAbeta(1-42) in vitro. Although the plasma obtained from all groups inhibited the formation of fAbeta(1-40) and fAbeta(1-42), the plasma from non-AD and CTL subjects inhibited the formation of fAbetas more strongly than that from AD subjects. These results indicate that the plasma as well as CSF in AD would provide a molecular environment favorable for fAbeta formation, suggesting a decrease of specific inhibitory factors and/or increase of specific accelerating factors.     

Living-donor liver transplantation for carbamoyl phosphate synthetase 1 deficiency

CPS1 is a mitochondrial matrix enzyme that catalyzes the first committed step of the urea cycle, the primary system for removing nitrogen produced by protein metabolism using N-acetylglutamate. Patients with CPS1 deficiency have severe hyperammonemia that results in serious neurologic sequelae and sometimes death. LT has been indicated for neonatal-onset CPS1 deficiency. This study retrospectively reviewed five children with a diagnosis of CPS1 deficiency who underwent LDLT from heterozygous donors. Between November 2005 and May 2010, 124 children underwent LDLT with an overall patient and graft survival of 91.0%. Five patients were indicated for LDLT because of CPS1 deficiency. All recipients achieved resolution of their metabolic derangement, without donor complication, with a normal feeding regimen without medication for their original metabolic liver disease. LDLT, even from heterozygous donors, appears to be a feasible option, associated with a better quality of life for treating patients with CPS1 deficiency. Long-term observation may therefore be necessary to collect sufficient data to confirm the efficacy of this treatment modality.