Biomedical subjects

Haruko Maeda

Publications and source records attributed to Haruko Maeda.

7 recordsLinked to original sources

PubMed2006

Analysis of a processing system for proteases using yeast cell surface engineering: conversion of precursor of proteinase A to active proteinase A.

The display of a protease, carboxypeptidase Y (CPY) or procarboxypeptidase Y (proCPY), which is the vacuolar protease, on the yeast-cell surface was successfully performed using yeast-cell-surface engineering for the first time. Through that we could confirm the processing of vacuolar proteases containing proteinase A (PrA) and proteinase B (PrB) which are related to the maturation of proCPY, using a novel cell-surface engineering technique. Various protease-knockout strains of Saccharomyces cerevisiae with the CPY-displaying system were constructed to evaluate the operation of the activation process of CPY. The display of CPY (CPY-agg, which is a fusion protein of CPY with C-terminal half of alpha-agglutinin) on the cell surface was confirmed by immunofluorescence staining. The activity of the CPY-agg was determined after the conversion of proCPY to active CPY by treatment of whole cells with proteinase K. In the proCPY-displaying CPY-knockout strain and PrB-knockout strain, CPY was displayed as an active (mature) form, but in the proCPY-displaying PrA-knockout strain, CPY was present as an inactive form (proCPY). These facts indicate that PrA had been already activated before its transport to the vacuole and that active mature PrA might convert proCPY to CPY before the transport of proCPY to the vacuole. From these results, it was suggested that by using the yeast-cell-surface engineering at the location of the initial step, the autocatalytic activation from proPrA to PrA might occur before the vacuolar branch separates from the main secretory pathway.

Antigens, Surface↗

PubMed2005

Construction of a selective cleavage system for a protein displayed on the cell surface of yeast.

We constructed a novel protein-purification system in which Saccharomyces cerevisiae with a protein displayed on the cell surface is harvested and the displayed protein is then cleaved from the cell surface. GFPuv was used as a model protein in this cell surface engineering experiment. In this system, the C-terminal 320 amino acids of alpha-agglutinin were bound to the C-terminal of GFPuv for display on the cell surface. In this novel system, the insertion of the recognition sequence-encoding gene of protease factor Xa between GFPuv and alpha-agglutinin was successfully carried out. The GFPuv, displayed by the insertion, was successfully cleaved from yeast cell surface by treatment with factor Xa, and could be easily recovered. By removing such a protease with well-known properties, the displayed protein could be isolated and purified with relative ease.

Base Sequence↗

PubMed2005

Thrombocytosis at an early stage of respiratory tract viral infection.

AIM: To determine whether thrombocytosis, a platelet count of more than 500 x 10(9)/l, occurs at an early stage of respiratory tract viral infection. METHODS: The medical records of 345 patients with respiratory syncytial virus (RSV), influenza, measles, adenovirus or human herpes virus 6 infections were retrospectively reviewed. RESULTS: The mean platelet count was significantly higher in RSV patients than in patients with other respiratory infections. Among the 29 patients with thrombocytosis, 24 (82.8%) had RSV infection. CONCLUSION: When thrombocytosis is positive at an early stage of respiratory tract infection, RSV should be taken into account as a causative agent.

Humans↗

PubMed2004

Indiscriminate glycosylation of procarboxypeptidase Y expressed in Pichia pastoris.

To obtain large amounts of deglycosylated procarboxypeptidase Y (proCPY), in which all of the N-glycosylation sites were replaced by alanine residue by the point mutation method, an expression system was constructed using Pichia pastoris. The secreted enzyme was characterized by SDS-PAGE, native PAGE, MALDI-TOF mass spectrometry, and dynamic light scattering, and the results indicated heterogeneity. The recombinant proCPY contained 29 mol of glucose per mole of protein in average, according to the carbohydrate analysis by the phenol-sulfuric acid method. A large part of the recombinant enzyme absorbed on a Con A column: even the break-through fraction of the column contained 3 mol of glucose per mole of protein. These carbohydrates were removed by the mild alkaline treatment. Since the entire N-glycosylation site had been destructed in the present expression system, the carbohydrates contained in the recombinant proCPY are concluded to be O-linked ones, which bound indiscriminately to serine and/or threonine residues.

Alanine↗

PubMed2003

Leigh syndrome associated with West syndrome.

Leigh syndrome (LS) (sub-acute necrotizing encephalomyelopathy) is characterized by symmetric brain lesions occurring mainly in the basal ganglia and associated with variable clinical manifestations such as hypotonia, psychomotor retardation, and feeding difficulties. Patients with LS may develop seizures. Only three patients with LS have been identified in the literature as having West syndrome (WS). We have seen 12 children with LS in the past 20 years, and noticed that as many as five of them developed WS. This report discusses five LS children with WS, comparing them with seven LS children without WS. In all five patients, infantile spasms developed after LS had become evident, in addition to other type(s) of seizures. The onset of LS in all the patients with WS was before 10 months of age. Although not statistically proven, early onset of LS, spasticity, nystagmus, apnea, poor feeding, and cardiac problems seemed to be associated with the development of WS. We were not able to conclude that certain types of symptoms or examination results of patients with LS indicated the development of WS. The association of LS with WS did not markedly influence the prognoses of the children. WS may not be a rare complication of LS, especially in infants under 12 months of age. This report is the first review of LS associated with WS.

Female↗

PubMed2002

Cerebral hemorrhage associated with vitamin K deficiency in congenital tuberculosis treated with isoniazid and rifampin.

We report a male infant with congenital tuberculosis who developed cerebral hemorrhage associated with vitamin K deficiency during treatment with isoniazid and rifampin. Despite an absence of risk factors for vitamin K deficiency, the severe hemorrhagic disorder occurred at 4 months of age. We speculate that vitamin K deficiency in the present case may have resulted from a synergic effect of antituberculosis agents and immaturity of vitamin K metabolism and/or its absorption.

Cerebral Hemorrhage↗

PubMed2002

[Streptococcus salivarius meningitis after oral trauma by a skewer: a case report].

Although Streptococcus salivarius is one of the normal flora in the oral cavity and gastrointestinal tract, the agent may cause bacteremia, meningitis, endocarditis and sinusitis under certain circumstances. We report a 3-year-old female with meningitis after oral trauma by a skewer due to penicillin resistant S. salivarius. The girl injured her throat accidentally with a skewer. Four hours later, she became febrile and came to our emergency room. Plain CT scan was normal, and cefalexin was prescribed. The next day, she had fever, lethargy, meningeal signs, and her cerebrospinal fluid (CSF) showed neutrophilic pleocytosis. The blood culture was negative, but the CSF culture was positive for S. salivarius. The minimal inhibitory concentrations (MIC) for panipenem, penicillin G, ampicillin, cefotaxime, ceftriaxone, vancomycin were 0.125 microgram/ml, 2 micrograms/ml, 2 micrograms/ml, 0.5 microgram/ml, 0.5 microgram/ml, 0.5 microgram/ml, respectively. Intravenous administration of panipenem betamiprom (PAPM/BP) 2 g/day for 7 days and 8 courses of dexamethasone 0.15 mg/kg/dose were effective, and she has had no apparent sequelae except for a slight abnormality in her electroencephalogram. Traumatic meningitis is often caused by S. pneumoniae, but may be also caused by the normal flora pathogens including S. salivarius. In addition, our case suggests that not only S. pneumoniae but also S. salivarius can be penicillin resistant. Taking the drug resistance into consideration, we have to be careful in choosing antibiotics for treating such patients.

Child, Preschool↗