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N Hosokawa

Publications and source records attributed to N Hosokawa.

At least 19 recordsLinked to original sources
PubMed2001

Upregulation of HSP47 and collagen type III in the dermal fibrotic disease, keloid.

Keloid is a dermal fibrotic disease characterized by excessive accumulation of mainly type I collagen in extracellular matrix of the dermis. We have studied the expression levels of collagen types I and III, and its molecular chaperone HSP47 in keloid lesions and surrounding unaffected skin using Northern and Western blotting and immunohistochemical analyses. Collagen types I and III mRNA levels were found to be upregulated 20-fold in keloid tissues, contradicting previous reports of nearly normal type III collagen levels in this disease. HSP47 expression in keloid lesions was also highly upregulated; eightfold at mRNA level and more than 16-fold at the protein level. Strong upregulation of these three proteins in keloid was confirmed by immunohistochemical staining. These results suggest that accumulation of both type I and type III collagen is important for the development of keloid lesions, and that HSP47 plays a role in the rapid and extensive synthesis of collagen in keloid tissues.

Adolescent↗
PubMed2001

Mnl1p, an alpha -mannosidase-like protein in yeast Saccharomyces cerevisiae, is required for endoplasmic reticulum-associated degradation of glycoproteins.

The endoplasmic reticulum (ER) has a mechanism to block the exit of misfolded or unassembled proteins from the ER for the downstream organelles in the secretory pathway. Misfolded proteins retained in the ER are subjected to proteasome-dependent degradation in the cytosol when they cannot achieve correct folding and/or assembly within an appropriate time window. Although specific mannose trimming of the protein-bound oligosaccharide is essential for the degradation of misfolded glycoproteins, the precise mechanism for this recognition remains obscure. Here we report a new alpha-mannosidase-like protein, Mnl1p (mannosidase-like protein), in the yeast ER. Mnl1p is unlikely to exhibit alpha1,2-mannosidase activity, because it lacks cysteine residues that are essential for alpha1,2-mannosidase. However deletion of the MNL1 gene causes retardation of the degradation of misfolded carboxypeptidase Y, but not of the unglycosylated mutant form of the yeast alpha-mating pheromone. Possible roles of Mnl1p in the degradation and in the ER-retention of misfolded glycoproteins are discussed.

Amino Acid Sequence↗
PubMed2001

Molecular cloning of a novel ubiquitin-like protein, UBIN, that binds to ER targeting signal sequences.

To identify proteins that interact with HSP47, an endoplasmic reticulum (ER)-resident molecular chaperone, a yeast two-hybrid screening was performed using mouse full-length HSP47 including an N-terminal signal sequence as a bait. Analysis of several positive clones led to the identification and cloning of a novel gene, ubin, encoding a ubiquitin-like protein. Unlike other ubiquitin-like proteins, UBIN was shown to interact with signal sequences of various secretory and ER-luminal proteins, including HSP47, but not interact with signal sequences of mitochondrial targeting in two-hybrid system. The possible function of UBIN will be discussed with regards to novel characteristics of binding to signal sequences for ER targeting.

3T3 Cells↗
PubMed2001

Heat shock protein (HSP) 47 and collagen are upregulated during neointimal formation in the balloon-injured rat carotid artery.

Heat shock protein (HSP) 47, a collagen-specific molecular chaperone, is thought to be essential for the proper processing and secretion of procollagen molecules. We investigated the time course and localization of HSP47 and collagen expression after balloon catheter angioplasty in the rat carotid artery, based on the premise that accumulation of extracellular matrix components is a main feature of intimal hyperplasia in humans and in laboratory animals. Low levels of HSP47 expression were evident in uninjured carotid arteries. Northern blot analysis revealed that HSP47 mRNA expression was markedly stimulated 1--3 days after the induced injury and a high level was maintained for 7 days, followed by a gradual decline for up to 21 days after the injury. These changes in HSP47 expression paralleled changes in alpha 1(I) collagen expression. Immunohistochemical staining revealed colocalization of HSP47 and collagen in smooth muscle cells (SMCs) of the media and intima. In situ hybridization analysis showed that activated SMCs, which proliferated and migrated into the intima, expressed high levels of HSP47. In cultured human aortic SMCs, similar upregulation of HSP47 and alpha1(I) collagen by TGF-beta was noted. These results show that SMCs activated after balloon injury express high levels of HSP47 and collagen during cell proliferation and migration, hence an overproduction of collagen and development of intimal thickening. Thus, HSP47 plays a role in the formation and progression of neointima after angioplasty.

Animals↗
PubMed2001

A novel ER alpha-mannosidase-like protein accelerates ER-associated degradation.

The quality control mechanism in the endoplasmic reticulum (ER) discriminates correctly folded proteins from misfolded polypeptides and determines their fate. Terminally misfolded proteins are retrotranslocated from the ER and degraded by cytoplasmic proteasomes, a mechanism known as ER-associated degradation (ERAD). We report the cDNA cloning of Edem, a mouse gene encoding a putative type II ER transmembrane protein. Expression of Edem mRNA was induced by various types of ER stress. Although the luminal region of ER degradation enhancing alpha-mannosidase-like protein (EDEM) is similar to class I alpha1,2-mannosidases involved in N-glycan processing, EDEM did not have enzymatic activity. Overexpression of EDEM in human embryonic kidney 293 cells accelerated the degradation of misfolded alpha1-antitrypsin, and EDEM bound to this misfolded glycoprotein. The results suggest that EDEM is directly involved in ERAD, and targets misfolded glycoproteins for degradation in an N-glycan dependent manner.

Alkaloids↗
PubMed2001

[The relationship of serum mitochondrial creatine kinase and rotavirus gastroenteritis in pediatric patients].

The objective of this study was to investigate the relationship between serum mitochondrial creatine kinase(mCK) and rotavirus gastroenteritis in pediatric patients. Stool and serum specimens were simultaneously collected from 45 patients(25 males and 20 females) with suspected rotavirus gastroenteritis from January to December 1998. Stool specimens were tested by rotavirus latex agglutination assay. Fourteen patients(10 males, 4 females) were proved as positive, and peak season was in winter and early spring(7 positive cases in March). Six of the 14 were younger than one and 7 were between one and two. Total serum CK activity was measured by The Japan Society of Clinical Chemistry (JSCC) recommended method, and mCK activity was calculated from mCK fraction % obtained by CK isoenzyme electrophoresis. Patients' mCK activities were as follows, rotavirus antigen positive patients(n = 14): 60.0 +/- 20.6 U/l and rotavirus antigen negative patients(n = 31): 7.2 +/- 5.5 U/l. Significant difference was observed between rotavirus antigen positive group and rotavirus antigen negative group(p < 0.01), and control children group(n = 105): 7.1 +/- 2.9 U/l, (p < 0.01). The clinical implications and mechanisms of increased serum mCK activity are unclear. It is known that histological study of the small intestine from rotavirus gastroenteritis patients reveal shortened villi and mononuclear cell infiltration of the lamia propria; electron microscopy shows mitochondrial swelling and sparse irregular microvilli. Elevated serum mCK level of rotavirus gastroenteritis patient may therefore reflect diffused intestinal epithelial cell damage.

Child, Preschool↗
PubMed2001

Survey of veterinary professionals for antibodies to Bartonella henselae in Japan.

The seroprevalence of Bartonella henselae among veterinary professionals in Japan was investigated by means of an immunoperoxidase (IP) test that used protein A-horseradish peroxidase conjugate. Sera were obtained from 233 veterinary professionals in the Tokyo and Chiba areas. As negative control group, sera from 155 healthy individuals (all medical students) were used. As positive control group, sera from 5 patients highly suspected of cat scratch disease (CSD) by clinical symptoms were tested. Serum antibody titers of > or = 200 to B. henselae were presumed seropositive, because the titer at which about 95.5% of all healthy individuals (148 of the 155) were negative, and 2 of the 5 suspected CSD patients' serum antibody titers were > or = 200. Of the individuals in the veterinary professionals group tested, 35 of the 233 (15.0%) were seropositive for B. henselae. Females were nearly twice as likely as males to have antibodies to B. henselae in the veterinary professionals group. Our data suggest that Japanese veterinary professionals, and in particular younger females who are veterinary assistants and animal beauticians are more often infected by B. henselae.

Adolescent↗
PubMed2001

[A study of serum mitochondrial enzymes(mCK, mAST, mMDH) in rotavirus and adenovirus gastroenteritis in pediatric patients].

Rotavirus and adenovirus antigens in feces from 77 cases of gastroenteritis in pediatric patients were examined. Mitochondrial enzymes, mitochondrial creatine kinase(mCK), mitochondrial aspartate amino-transferase(mAST) and mitochondrial malate dehydrogenase(mMDH) activities in their sera were also measured and compared with the results of rotavirus and adenovirus antigens in the feces. Thirty-one cases were rotavirus antigen-negative(rota-negative)/adenovirus antigen-negative(adeno-negative), 5 were rota-negative/adenovirus antigen-positive(adeno-positive), 40 were rotavirus antigen-positive(rota-positive)/adeno-negative, and only one case showed positive for both antigens. The mean activities of these three enzymes were compared among 3 groups except one both positive case mentioned above and control group(n = 105) by Mann-Whitney U-test. The serum mCK activity was significantly higher in rota-positive/adeno-negative patients than in other groups(p < 0.01). On the other hand, no significant differences were observed for mAST and mMDH activities among any groups. It is suggested that these phenomena are caused by the differences of localization of these enzymes in mitochondria, that mCK is located the outer surface of inner membrane of mitochondria, and mAST and mMDH are located on the inner surface. The difference of serum mCK activity between rotavirus infection and adenovirus infection suggests that intestinal epithelial cell injury by rotavirus is stronger than that by adenovirus.

Adenoviridae Infections↗
PubMed2000

Embryonic lethality of molecular chaperone hsp47 knockout mice is associated with defects in collagen biosynthesis.

Triple helix formation of procollagen after the assembly of three alpha-chains at the C-propeptide is a prerequisite for refined structures such as fibers and meshworks. Hsp47 is an ER-resident stress inducible glycoprotein that specifically and transiently binds to newly synthesized procollagens. However, the real function of Hsp47 in collagen biosynthesis has not been elucidated in vitro or in vivo. Here, we describe the establishment of Hsp47 knockout mice that are severely deficient in the mature, propeptide-processed form of alpha1(I) collagen and fibril structures in mesenchymal tissues. The molecular form of type IV collagen was also affected, and basement membranes were discontinuously disrupted in the homozygotes. The homozygous mice did not survive beyond 11.5 days postcoitus (dpc), and displayed abnormally orientated epithelial tissues and ruptured blood vessels. When triple helix formation of type I collagen secreted from cultured cells was monitored by protease digestion, the collagens of Hsp47+/+ and Hsp47+/- cells were resistant, but those of Hsp47-/- cells were sensitive. These results indicate for the first time that type I collagen is unable to form a rigid triple-helical structure without the assistance of molecular chaperone Hsp47, and that mice require Hsp47 for normal development.

Animals↗
PubMed2000

Procollagen binds to both prolyl 4-hydroxylase/protein disulfide isomerase and HSP47 within the endoplasmic reticulum in the absence of ascorbate.

In cells, only properly folded procollagen trimers are secreted from the endoplasmic reticulum (ER), while improperly folded abnormal procollagens are retained within the ER. Ascorbic acid is a co-factor in procollagen hydroxylation, which in turn is required for trimer formation. We examined chaperone proteins which bound to procollagen in the absence of ascorbic acid, a model which mimics the human disease scurvy at the cellular level. We found that both prolyl 4-hydroxylase (P4-H)/protein disulfide isomerase (PDI) and HSP47 bound to procollagen in the absence of ascorbic acid. However, the binding of PDI to procollagen decreased when HSP47 was co-transfected, suggesting that HSP47 and PDI compete for binding to procollagen. These data indicate that P4-H/PDI and HSP47 have cooperative but distinct chaperone functions during procollagen biosynthesis.

Animals↗
PubMed2000

Phylogenetic evidence, by multiple clone analysis of hypervariable region 1, for the transmission of hepatitis C virus to chronic haemodialysis patients.

We analysed hepatitis C virus (HCV) sequences to determine whether nosocomial transmission of HCV occurred in a haemodialysis unit. Twenty patients positive for serum HCV RNA were investigated. All were undergoing haemodialysis therapy in the same room. The hypervariable region 1 (HVR1) sequence of HCV was amplified and multiple clones sequenced. Phylogenetic analysis of these sequences revealed five genetic clusters consisting of HCV isolates from 11 of the 20 patients. In addition to two genetic clusters of HCV isolates from the four currently seroconverting patients and another patient who had been persistently infected, we identified three other phylogenetic relationships in HCV isolates from six patients. The patients grouped into the same cluster received haemodialysis individually on the same shift and/or side-by-side. Phylogenetic analysis of HCV HVR1 sequences corroborated the patient-to-patient HCV transmission suggested by an epidemiological study and that unrecognized transmission of HCV occurs in the dialysis room. Our multiple clone analysis of HCV isolates provides detailed information on nosocomial transmission of HCV. Transmission occurs more frequently when treatment is performed at the same time than in consoles located close to each other.

Adult↗
PubMed2000

Occasional infection of hepatitis C virus occurring in haemodialysis units identified by serial monitoring of the virus infection.

To examine whether hepatitis C virus (HCV) infection still occurs in haemodialysis units even after a decrease in the number of blood transfusions and in those contaminated with HCV, we tested anti-HCV antibodies and HCV RNA in 142 patients from Japanese haemodialysis units, and examined the serial prevalence of anti-HCV antibodies in 86 patients from 1992 to 1997. A high prevalence of HCV infection was observed: 34 (23.9%) and 38 (26.8%) of the 142 patients were positive for serum anti-HCV antibodies and HCV RNA, respectively. These positive rates were related to the duration of haemodialysis. We found that five patients treated in the same unit seroconverted from 1993 to 1995. Four of the five patients had been treated at the same shift and were affected at the same time. Phylogenetic analysis of the hypervariable region 1 (HVR1) sequence of HCV from serum of these patients showed that three of the four patients' sequences were phylogenetically clustered and that two of the three were closely related. Thus, an occasional transmission of HCV occurred in the haemodialysis unit. The universal precautions by staff such as carefully changing gloves may be important in inhibiting spread of HCV because no instances of infection have been seen since the instigation of educational measures for unit staff.

Adult↗
PubMed2000

Interstitial expression of heat shock protein 47 and alpha-smooth muscle actin in renal allograft failure.

BACKGROUND: Tubulointerstitial inflammation and fibrosis are the main pathological features of chronic renal allograft rejection, which is characterized by accumulation of extracellular matrix protein. Heat shock protein 47 (HSP47), known as a collagen-specific stress protein, is thought to be a molecular chaperone during the processing and/or secretion of procollagen. HSP47 is thought to be involved in the progression of fibrosis, but its expression in chronic renal allograft rejection is still unknown. METHODS: We examined the expression of HSP47 together with that of alpha-smooth muscle actin (alpha-SMA), a marker of myofibroblasts, and CD68, a marker of macrophages, by immunohistochemistry in allograft kidney tissues. Uninvolved portions of surgically removed kidneys with tumours served as control tissue. RESULTS: Expression of HSP47 was detected in the interstitium of fibrotic regions of allograft kidneys. Cells positive for HSP47 were also stained for alpha-SMA and type I collagen, and the expression of HSP47 correlated with the degree of interstitial fibrosis. Furthermore, the expression of HSP47 correlated with the number of infiltrating macrophages. In contrast, HSP47 and alpha-SMA were not expressed in the control tissues, sections of 1 h post-transplantation biopsy specimens and acute allograft rejection without fibrosis. CONCLUSION: Our results suggest that HSP47 may contribute to the progression of interstitial fibrosis in allograft renal tissues.

Actins↗
PubMed2000

Melleolides K, L and M, new melleolides from Armillariella mellea.

Three new sesquiterpenoid aromatic esters designated melleolides K (1), L (2) and M (3) were isolated from the cultured mycelia of Armillariella mellea (Vahl. ex Fr.) Karst. Structures of these compounds were determined on the basis of various NMR spectral data, chemical transformations and X-ray analysis. Compounds 1, 2 and 3 showed antimicrobial activities.

Agaricales↗
PubMed2000

New triene-ansamycins, thiazinotrienomycins F and G and a diene-ansamycin, benzoxazomycin.

New triene-ansamycins designated thiazinotrienomycins F (TT-F) and G (TT-G) and a new diene-ansamycin, benzoxazomycin, were isolated from a culture broth of Streptomyces sp. MJ672-m3 and their structures were elucidated by spectroscopic analyses. The Mean Graphs of TT-G suggests that the tumor growth inhibitory activities are almost as strong as TT-B, in respect of GI50 and TGI against several human cancer cell lines.

Alanine↗
PubMed2000

A study on task-analysis of clinical pathologists as medical consultants in Nihon University Hospital--a Japanese perspective by comparison with current status in the USA.

To identify our role and the customers' satisfaction, the on-call consultation service records of the Department of Clinical Pathology, Nihon University School of Medicine, Itabashi Hospital (NUIH), were analyzed. Between 1995 and 1998, 1,789 consultation services were recorded, and approximately 40% were from physicians, and 50% were from medical technologists. During office hours, many physicians made contact with us at the office of clinical pathology, the clinical laboratory and other places in the hospital by various means. They asked us to interpret multidisciplinary laboratory data, and to provide the specific information that might affect clinical management. Medical technologists asked for clinical information of patients with extreme measured values and requested that we contact with physicians. In contrast, on weekends/holidays or after routine working hours, physicians sometimes requested non-automated laboratory tests such as peripheral blood smears/bone marrow smears or Gram stains. The major contents of our responses to medical technologists were concerned with blood banking and handling of instruments not to be operated in routine work. These results reconfirm that we are still required to have clinical competence for common laboratory procedures and to have the capability of interpretation of multidisciplinary laboratory data in the university hospital. Traditionally, most Japanese clinical pathologists have been focused their attention on bench work in research laboratories. However, the present study shows that the clinical pathologists need to bridge the real gap between laboratory technology and patient care. Our on-call service system can enhance the education of clinical pathologists, and improve not only laboratory quality assurance but also patient care. In addition, in response to a need for customer access to this service with a shortage of clinical pathologists, a more effective method would be to set up a proactive systemic approach in a more rigorous academic environment adopting advances in medical informatics.

Consultants↗