Mutation analysis of two Japanese patients with Fanconi-Bickel syndrome

Fanconi-Bickel syndrome (FBS), or glycogen storage disease type XI, is a rare autosomal recessive disorder characterized by hepatorenal glycogen accumulation, Fanconi nephropathy, and impaired utilization of glucose and galactose. Recently, this disease was elucidated to link mutations in the glucose transporter 2 (GLUT2) gene. Only three mutations in three FBS families have been reported. Therefore, it is important to elucidate mutations in the GLUT2 gene in FBS by answering the question of whether the syndrome is a single gene disease. In this report, we describe two patients in two unrelated families clinically diagnosed with FBS. No mutation in the entire protein coding region of the GLUT2 gene was detected in patient 1, which suggested that no mutation existed in the GLUT 2 gene, or that some mutations had affected the expression of the GLUT 2 gene. In patient 2, a novel homozygous nonsense mutation (W420X, Trp at codon 420 to stop codon) was detected. These results support the correlation between GLTU2 gene mutation and FBS syndrome. However, many patients must be analyzed to determine whether other genes are involved in FBS. Received: July 16, 1999 / Accepted: September 3, 1999     

Human vascular smooth muscle cells and endothelial cells lack catalase activity and are susceptible to hydrogen peroxide

⁵Cr release as lytic and cell detachment as nonlytic injury were employed to estimate neutrophil-mediated injury of cultured human vascular smooth muscle cells and endothelial cells. The reagents hydrogen peroxide or hypoxanthine-xanthine oxidase produced dose-dependent killing and nonlytic cell detachment, which were specifically inhibited by catalase but not by superoxide dismutase. The concentration of hydrogen peroxide or xanthine oxidase to induce cell detachment was less than lytic dose, suggesting that cell detachment was a much more sensitive assay of injury. Neutrophil-mediated cell lysis averaged 15% at most and was mostly dependent on hydrogen peroxide, while neutrophil-mediated cell detachment was nearly 100% and its dependency on hydrogen peroxide varied from 46% to 60%. These results suggest that vascular smooth muscle cells and endothelial cells in neutrophil-mediated events are destroyed by a hydrogen peroxide-dependent process, mainly via a nonlytic cell detachment mechanism. There was no striking difference of sensitivity to hydrogen peroxide between vascular smooth muscle cells and endothelial cells. Vascular smooth muscle ceils and endothelial cells contained fairly high concentrations of superoxide dismutase, but not catalase, activity. The sensitivity of these cells to hydrogen peroxide but not to superoxide may arise from the fact that these cells lack intracellular catalase activity. The injury of vascular cells, which constitute important components of blood vessels, may lead to vascular injury and subsequent tissue damage.     

Emergence of a unique O3:K6 clone of Vibrio parahaemolyticus in Calcutta, India, and isolation of strains from the same clonal group from Southeast Asian travelers arriving in Japan.

Active surveillance of Vibrio parahaemolyticus infection among hospitalized patients in Calcutta, India, was initiated in January 1994. The incidence of cases of V. parahaemolyticus infection suddenly increased in February 1996 and has remained high since then. One hundred thirty-four strains of V. parahaemolyticus isolated from January 1994 to August 1996 were examined for serovar, the presence of the thermostable direct hemolysin gene (tdh) and tdh-related hemolysin genes (trh1 and trh2), production of urease, and antibiogram. Strains of the O3:K6 serovar appeared for the first time in February 1996. The O3:K6 serovar strains accounted for 50 to 80% of the strains isolated during the high-incidence period (February to August 1996). All of the serovar O3:K6 strains carried the tdh gene but not the trh genes and did not produce urease. All of the isolates except two were sensitive to all of the antibiotics tested. These and the results of analysis by an arbitrarily primed PCR method indicated that the O3:K6 serovar strains belong to a unique clone. When the O3:K6 serovar strains, isolated from travelers arriving in Japan from Southeast Asian countries, were compared by the arbitrarily primed PCR method, the strains isolated between 1982 and 1993 were distinct from Calcutta O3:K6 while the strains isolated in 1995 and 1996 were indistinguishable from the Calcutta O3:K6 strains. The results suggest that this unique O3:K6 clone may have become prevalent not only in Calcutta but also in Southeast Asian countries very recently. Not only the O3:K6 strains but also the non-O3:K6, tdh-bearing strains isolated in 1996 produced thermostable direct hemolysin at high levels, and thus the level of hemolysin produced does not appear to have influenced the high incidence of serovar O3:K6 strains.     

The response of normal human osteoblasts to anionic polysaccharide polyelectrolyte complexes

Polyelectrolyte complexes (PEC) were prepared from chitosan as the polycation and several synthesized functional anion polysaccharides, and their effects on cell attachment, morphology, proliferation and differentiation were estimated using normal human osteoblasts (NHOst). After a 1-week incubation, PEC made from polysaccharides having carboxyl groups as polyanions showed low viability of NHOst on it although the NHOst on it showed an enhancement in their differentiation level. On the other hand, NHOst on PEC made from sulfated or phosphated polysaccharides showed similar attachment and morphology to those on the collagen-coated dish. When the number of NHOst was estimated after 1 week, the number on the PEC was ranged from 70% to 130% of those on the collagen-coated dish, indicating few effects of these PEC on cell proliferation. In addition, NHOst on PEC films made from sulfated polysaccharides differentiated to a level very similar to that observed on the collagen-coated dish, indicating that these PEC films maintain the normal potential of NHOst to both proliferate and differentiate. Measurement of gap junctional intercellular communication of NHOst on PEC revealed that PEC did not inhibit communication, suggesting that PEC films have few effects on cell homeostasis. Thus, PEC made from the sulfated polysaccharide may be a useful material as a new scaffold for bone regeneration.     

Light and electron microscopic analyses of immediate and late tissue damage caused by radiofrequency ablation in porcine liver

Radiofrequency ablation (RFA) is an effective procedure for localized hepatocellular carcinoma. Contrast-enhanced CT depicts the ablated area as a hypoattenuated area without hepatic blood flow; however, light microscopy does not show obvious necrosis in the ablated area. We evaluated liver tissue changes after RFA by light microscopy and electron microscopy. The normal livers of three anesthetized pigs were coagulated using RFA after laparotomy. The liver was examined immediately, and 1 week after operation by light and electron microscopy. After RFA, the liver parenchyma surrounding the needle electrode was brown in color and surrounded by a red marginal zone separate from the normal liver parenchyma. Hematoxylin-eosin staining of the central area did not show cell necrosis, and the structures of liver sinusoids, liver cell cord and the nuclei of hepatocytes were preserved. However, electron microscopic examination of tissue immediately after RFA showed destruction of mitochondria of hepatocytes and fixation of sinusoidal cells. One week later, there was a large quantity of debris in the enlarged sinusoids, in addition to irreversible destruction of hepatocyte organelles. RFA of the porcine liver causes hepatocyte damage. This damage was not evident by light microscopy but clearly identified by electron microscopy.     

Role of macrophage migration inhibitory factor in otitis media with effusion in adults

Otitis media with effusion (OME) is one of the most common ear diseases. Bacterial endotoxins and several inflammatory cytokines appear to be involved in the pathogenesis of OME in children; however, little is known of the immunological aspects of the onset of OME in adults. We sought to determine the presence of macrophage migration inhibitory factor (MIF) as well as interleukin 1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), RANTES (regulated upon activation, normal T-cell expressed and presumably secreted), and endotoxin in middle ear effusions (MEEs) from adult patients with OME. In addition, the levels of MIF in MEEs from adults and children were compared. MEE was obtained from 95 adults and 11 children. The levels of MIF, IL-1beta, TNF-alpha, and RANTES were determined by enzyme-linked immunosorbent assay, and the concentrations of endotoxin and total protein were determined by the Endospec assay and bicinchoninic acid assay, respectively. MIF was detected in 97.9% of the MEEs from adults, while endotoxin, IL-1beta, TNF-alpha, and RANTES were detected in 96.8, 12.6, 5.3, and 43.9%, respectively. In addition, the level of MIF was significantly higher than those of endotoxin, IL-1beta, and TNF-alpha. A positive correlation between the levels of MIF and endotoxin was observed. MIF and endotoxin were detected in 81.8 and 72.7%, respectively, of the MEEs from the children. The level of MIF was significantly higher in the children, and conversely that of endotoxin was significantly higher in the adults. These results suggest that the interaction between MIF and endotoxin may promote fluid collection in the middle ear, particularly in adults.     

Distribution and frequencies of PDS (SLC26A4) mutations in Pendred syndrome and nonsyndromic hearing loss associated with enlarged vestibular aqueduct: a unique spectrum of mutations in Japanese

Molecular diagnosis makes a substantial contribution to precise diagnosis, subclassification, prognosis, and selection of therapy. Mutations in the PDS (SLC26A4) gene are known to be responsible for both Pendred syndrome and nonsyndromic hearing loss associated with enlarged vestibular aqueduct, and the molecular confirmation of the PDS gene has become important in the diagnosis of these conditions. In the present study, PDS mutation analysis confirmed that PDS mutations were present and significantly responsible in 90% of Pendred families, and in 78.1% of families with nonsyndromic hearing loss associated with enlarged vestibular aqueduct. Furthermore, variable phenotypic expression by the same combination of mutations indicated that these two conditions are part of a continuous category of disease. Interestingly, the PDS mutation spectrum in Japanese, including the seven novel mutations revealed by this study, is very different from that found in Caucasians. Of the novel mutations detected, 53% were the H723R mutation, suggesting a possible founder effect. Ethnic background is therefore presumably important and should be noted when genetic testing is being performed. The PDS gene mutation spectrum in Japanese may be representative of those in Eastern Asian populations and its elucidation is expected to facilitate the molecular diagnosis of a variety of diseases.     

Rat strain differences in the early stage of porcine-serum-induced hepatic fibrosis.

Rat strain differences in the early development of porcine serum (PS)-induced hepatic fibrosis were histologically and immunohistochemically examined using Brown Norway (BN), Sprague Dawley (SD) and Wistar rats. They were injected i.p. with 0.5 ml sterile PS twice a week for 4 and 8 weeks. In addition, rats treated with physiological saline in the same way served as controls. At 4 weeks, hepatic fibrosis accompanying fibrous septa mainly composed of type III collagens developed in BN and SD rats but not in Wistar rats. In addition, the numbers of eosinophils, CD3-positive cells and ED-1-positive cells significantly increased in BN and SD rats, that of CD45RA-positive cells in BN rats, and that of alpha-smooth muscle actin (SMA)-positive cells in SD rats, respectively. Such differences in the number of inflammatory cells may be related with the absence of hepatic fibrosis in Wistar rats at 4 weeks. At 8 weeks, hepatic fibrosis with formation of many small-sized pseudolobules was observed in all strains at almost similar degree, and the numbers of infiltrating cells increased in all strains of rats with some exception. In addition, the main location of inflammatory cells was different, suggesting a different role of each inflammatory cell in the process of hepatic fibrosis.     

Estrogen receptor-associated expression of keratinocyte growth factor and its possible role in the inhibition of apoptosis in human breast cancer

Although estrogen is known to play a crucial role in the pathogenesis of breast cancer, the molecular mechanisms underlying the action of estrogen remain elusive. In the present study, we focused on keratinocyte growth factor (KGF) and its receptor (KGFR) in the pathogenesis of breast cancer, as a growth factor mediating estrogen action, since significant roles of KGF were demonstrated in various steroid hormone-dependent tissues. First, using paraffin-embedded specimens from 42 breast cancer patients, we examined expression patterns of KGF and KGFR by both immunohistochemistry using newly generated antibodies and nonradioactive in situ hybridization with T-T dimerized synthetic oligonucleotide probes. We next compared the results with the expression of estrogen receptor (ER) alpha and beta, proliferative activity and apoptotic frequency (TUNEL staining). Also, the similar approaches were taken to analyze the expression and role of KGF in ER-positive (MCF7, ZR-75-1) and ER-negative (SK-BR-3, MDA-MB-231) human breast cancer cell lines in vitro. In the surgical specimens, KGF was expressed in cancer cells as well as stromal cells in 19/42 cases (45%), while KGFR was found in cancer cells in 24/42 cases (57%). The distribution of protein and mRNA in the analysis of both KGF and KGFR expression generally coincided. Moreover, KGF expression was closely associated with the expression of ER alpha, and the coexpression of KGF and KGFR significantly correlated with lower TUNEL index, but not with proliferative activity. In accordance with the in vivo findings, KGF expression was detected only in ER alpha-positive MCF7 and ZR-75-1 cells in vitro. And more importantly, we found the inhibitory effect of KGF upon the induction of apoptosis by anticancer drugs in MCF7 cells. Collectively, our results indicate that ER alpha may be involved in KGF expression, and that KGF may play antiapoptotic roles, rather than mitogenic, in human breast cancer.