Hyperimmunoglobulin E-recurrent infection syndrome in a patient with juvenile dermatomyositis

A 13-year-old girl presented with multiple skin abscesses. She was diagnosed as having juvenile dermatomyositis (DM) at the age of 7 years. She had suffered from recurrent skin infections, atypical pruritic dermatitis and pneumonia since the age of 8 years. Bacteriologic and fungal cultures for skin abscesses and oral mucosa were positive S. aureus and C. albicans, respectively. Chemotactic defect in peripheral blood neutrophils was observed. The level of serum IgE was markedly elevated, and anti-S.aureus specific IgE was found. A diagnosis of hyperimmunoglobulin E-recurrent infection syndrome (HIE) was made and she was successfully treated with surgical drainage and antibiotics. To our knowledge, this is the first case report of HIE in a patient with juvenile dermatomyositis.

Cloning and expression of a G protein-linked acetylcholine receptor from Caenorhabditis elegans

We have isolated a cDNA clone from the nematode Caenorhabditis elegans that encodes a protein of greatest sequence similarity to muscarinic acetylcholine receptors. This gene codes for a polypeptide of 682 amino acids containing seven putative transmembrane domains. The amino acid identities, excluding a highly variable middle portion of the third intracellular loop, to the human m1-m5 receptors are 28-34%. When this cloned receptor was coexpressed with a G protein-gated inwardly rectifying K+ channel (GIRK1) in Xenopus oocyte, acetylcholine was able to elicit the GIRK current. This acetylcholine-induced current was substantially inhibited by the muscarinic antagonist atropine in a reversible manner. However, another muscarinic agonist oxotremorine and antagonists scopolamine and pirenzepine had little or negligible effects on this receptor. Taken together, these results suggest that the cloned gene encodes a G protein-linked acetylcholine receptor that is most similar to but pharmacologically distinct from muscarinic acetylcholine receptors.

Partial purification of protein farnesyl cysteine carboxyl methyltransferase from bovine brain

C-terminal farnesyl cysteine carboxyl methylation has been known to be the last step in the post-translational modification processes of several important signal transduction proteins in eukaryotes including ras related GTP binding proteins and the gamma-subunit of heterotrimeric G proteins. Protein farnesyl cysteine carboxyl methyltransferase (PFCCMT; EC, 2.1.1.100) catalyzing the reaction is well characterized as being stimulated by guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) and suppressed by N-acetyl-S-farnesyl-L-cysteine (AFC). As an initial step to understand the physiological significance of the process, we attempted to purify the enzyme, which was partially purified 130-fold (specific activity, 143 pmol of methyl group transferred/min/mg of protein) with yield of 1.8% after purification by fast protein liquid chromatography (FPLC) on a Superdex 75 column. The enzyme was further purified with non denaturing polyacrylamide gel electrophoresis (ND-PAGE) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weight of PFCCMT was determined to be about 30 kDa based on Superdex 75 FPLC as well as photoaffinity labelling with S-adenosyl-L-[methyl-3H] methionine ([methyl-3H]SAM). The partially purified enzyme (Superdex 75 eluate) was found to be characteristically affected by GTP gamma S, being activated about 40-fold in 2 mM, in contrast to ATP which did not show any effect on enzyme activity. Meanwhile, the enzyme was found to be markedly inhibited by AFC, reaching 0 activity in 2 mM. These observations strongly suggested that the partially purified enzyme was PFCCMT.

Intracellular Ca2+ mediates lipoxygenase-induced proliferation of U-373 MG human astrocytoma cells

The role of intracellular Ca2+ in the regulation of tumor cell proliferation by products of arachidonic acid (AA) metabolism was investigated using U-373 MG human astrocytoma cells. Treatment with nordihydroguaiaretic acid (NDGA), a lipoxygenase (LOX) inhibitor, or caffeic acid (CA), a specific 5-LOX inhibitor, suppressed proliferation of the tumor cells in a dose-dependent manner. However, indomethacin (Indo), a cyclooxygenase (COX) inhibitor, did not significantly alter proliferation of the tumor cells. At anti-proliferative concentrations, NDGA and CA significantly inhibited intracellular Ca2+ release induced by carbachol, a known intracellular Ca2+ agonist in the tumor cells. Exogenous administration of leukotriene B4 (LTB4), an AA metabolite of LOX pathway, enhanced proliferation of the tumor cells in a concentration-dependent fashion. In addition, LTB4 induced intracellular Ca2+ release. Intracellular Ca2+ inhibitors, such as an intracellular Ca2+ chelator (BAPTA) and intracellular Ca(2+)-release inhibitors (dantrolene and TMB-8), significantly blocked the LTB4-induced enhancement of cell proliferation and intracellular Ca2+ release. These results suggest that LOX activity may be critical for cell proliferation of the human astrocytoma cells and that intracellular Ca2+ may play a major role in the mechanism of action of LOX.

Induction of quinone reductase by a methanol extract of Scutellaria baicalensis and its flavonoids in murine Hepa 1c1c7 cells

The effect of extracts of scutellariae radix (Scutellaria baicalensis Georgi) and its flavonoids, baicalin, baicalein and wogonin, on induction of quinone reductase (QR) in the Hepa 1c1c7 murine hepatoma cell line was examined. A significant and dose-dependent induction of QR activity was observed in the methanol extract of scutellariae radix and baicalin. HPCL analysis showed that baicalin was contained as a main component in the methanol extract of scutellariae radix, indicating that baicalin may be the major active principle of QR induction mediated by scutellariae radix extract. To elucidate the mechanism of baicalin-mediated induction of QR enzyme activity, the effect on QR mRNA levels in Hepa 1c1c7 cell cultures was investigated. Using reverse transcriptase-polymerase chain reaction techniques, time- and dose-dependent induction of QR mRNA levels by baicalin were demonstrated in Hepa 1c1c7 cells. On the basis of these results, the scutellariae radix extract or baicalin can be regarded as a readily available, promising, novel cancer chemopreventive agent.

The Gln-Arg 191 polymorphism of the human paraoxonase gene is not associated with the risk of coronary artery disease among Chinese in Taiwan

Paraoxonase (PON1) is a high density lipoprotein-associated enzyme capable of hydrolyzing lipid peroxides, and thus, might protect lipoproteins from oxidation. A common polymorphism due to an amino acid substitution (Gln-Arg) at codon 191 is considered to be a major determinant of variation in serum PON1 activity. Recent studies have suggested that the PON1-191 polymorphism is an independent risk factor for coronary atherosclerosis in patients with or without diabetes mellitus. The association of PON1-191 polymorphism genotypes and coronary artery disease (CAD) among Chinese subjects in Taiwan was examined. The genotype of 218 angiographically documented CAD patients and the same number of age- and sex-matched control subjects was determined. Genotypes AA, AB and BB were present in 25 (11%), 102 (47%) and 91 (42%) of control subjects, respectively, and in 30 (14%), 96 (44%) and 92 (42%) of CAD patients, respectively (chi2 = 0.57, P = 0.75 between groups). The frequency of the A allele was 0.36 for the control group and 0.35 for CAD patients (P = 0.94). No significant differences in the PON1-191 genotype frequencies could be found between groups when multivariate logistic regression analysis was performed, or different subgroups of age, sex or risk factors were analyzed. Among control subjects, there was also no significant difference between genotypes of the PON1-191 polymorphism and various clinical and lipid variables. In conclusion, our data suggest that there is no association between the Gln-Arg 191 polymorphism of the human PON1 gene and CAD among Chinese subjects in Taiwan.

Mutation of the uracil DNA glycosylase gene detected in glioblastoma

Despite extensive characterization of genetic changes in gliomas, the underlying etiology of these tumors remains largely unknown. Spontaneous DNA damage due to hydrolysis, methylation, and oxidation is a frequent event in the brain. Failure of DNA repair following this damage may contribute to tumorigenesis of gliomas. Uracil DNA glycosylase (UDG), an enzyme which excises uracil from DNA, is an important component of the base excision repair pathway. The sequence of a human homologue of uracil DNA glycosylase gene (UNG) has been recently identified. We performed PCR-based SSCP mutational analysis of UNG in 11 sporadic gliomas (six glioblastomas, two anaplastic astrocytomas, and three oligodendrogliomas) and eight glioblastoma cell lines. One out of six sporadic glioblastomas had a point mutation in exon 3, which resulted in a missense mutation in codon 143. None of the eight glioblastoma cell lines or the five non-glioblastoma sporadic gliomas showed a mutation. Genetic alterations of UNG may play a role in the development of a subset of primary glioblastomas.

Differentiation of cultured human epidermal keratinocytes at high cell densities is mediated by endogenous activation of the protein kinase C signaling pathway

Normal human epidermal keratinocytes (NHEK) grown in serum-free medium on a plastic substrate spontaneously differentiate at high cell densities in vitro. Because protein kinase C (PKC) regulates murine keratinocyte differentiation triggered by a variety of stimuli, we examined the role of this signaling pathway in density-dependent activation of NHEK differentiation. Relative to subconfluent cultures, confluent NHEK expressed markedly higher levels of multiple differentiation markers assayed by immunoblotting, including keratin 1, loricrin, filaggrin, involucrin, TGK, and SPR-1. Expression of several of these markers continued to increase for several days after cells reached confluency. The total level of several PKC isoforms was not substantially altered in NHEK harvested at different cell densities, based on immunoblotting; however, subcellular fractionation revealed that PKCalpha underwent a redistribution to the particulate fraction in confluent and postconfluent NHEK cultures, suggesting that this isozyme was activated under these conditions and may be involved in triggering the terminal differentiation program. Supporting this concept, inhibition of PKC function using bryostatin 1 or GF 109203X blocked the induction of keratinocyte differentiation markers at high cell densities. These data suggest that endogenous activation of PKC is responsible for cell density-mediated stimulation of NHEK differentiation, establishing a critical role for this pathway in regulating human as well as murine keratinocyte differentiation.

Enzyme-linked immunosorbent assay for serum procollagen type III peptide in rats with hepatic fibrosis

The process of hepatic fibrosis, and the changes in contents of hepatic hyproxyproline (HYP) and serum procollagen type III peptide (PIIINP) were examined in two rat models for hepatic fibrosis, i.e. bile duct ligation/scission (BDL/s)- and dimethylnitrosamine (DMN)-induced models. In addition, an expression of type III collagen mRNA in the liver of BDL/s model was also examined. In BDL/s model, hepatic fibrosis started at 2 weeks after operation (WAO) and cirrhosis with prominent bile duct hyperplasia was detected at and after 5 WAO. Serum PIIINP content measured using a modified double armed inhibition enzyme-linked immunosorbent assay (ELISA) method proposed by us started to increase at 1 WAO and continued to increase thereafter. Hepatic HYP content measured colorimetrically started to increase at 3 WAO and it continued to increase until 7 WAO. An expression of type III collagen mRNA in the liver was enhanced at and after 2 WAO, especially at 4 and 5 WAO. In DMN model, marked hepatic fibrosis was detected at 1 week after the last DMN administration (WAA), and the degree of fibrosis was apparently reduced at 4 WAA. Serum PIIINP content prominently increased at 1 WAA and decreased at and after 3 WAA. Hepatic HYP content showed a marked increase at 1 WAA and decreased thereafter. The present results indicated that the sequences of hepatic fibrosis, hepatic HYP content and serum PIIINP content were well correlated with each other in both BDL/s and DMN models. In conclusion, ELISA system for the detection of serum PIINP content is considered to be reliable method for assessment of cirrhotic liver, and the present two rat models for liver fibrosis/cirrhosis seems to be a good tool for researching antifibrotic agents.

Ultrastructural and biochemical characterization of catecholamine release mechanisms in cultured human pheochromocytoma cells

OBJECTIVE

To characterize ultrastructurally and biochemically catecholamine release mechanisms of cultured human pheochromocytoma cells in the basal and stimulated states.

METHODS

The cultured pheochromocytoma cells were prepared from human adrenal pheochromocytoma tumors. Biochemical determinations of catecholamine secretion from the cultured cells were carried out in the basal and stimulated states. Transmission electron microscopy was used to observe the modes of catecholamine release from the cells without and with stimulation by depolarization of the cells with the administration of 50 mmol/L KCl.

RESULTS

Biochemical determinations consistently showed spontaneous secretion of catecholamines from the cultured cells in the basal state without stimulation. Catecholamine release in a calcium-dependent manner could be enhanced in the cells in response to high extracellular potassium concentration. A series of electron microscopic observations of the cultured cells consistently disclosed the classical exocytotic profiles on the cell surface in the basal state. In addition to abundant increase in the number of classical single exocytosis, compound exocytosis was frequently observed in the stimulated cells. Furthermore, other modes of catecholamine release mechanism involving the formation of pseudopodial and/or tubule-like structures, which were different from classical exocytosis, were often present in the intensely stimulation cells.

CONCLUSIONS

Based on the biochemical and electron microscopic findings, we concluded: (1) classical single exocytosis is considered to be a primary mechanism responsible for spontaneous secretion of catecholamines from the cells in the basal state; (2) compound exocytosis is an essential mechanism for extruding large amounts of catecholamines in the stimulated cells; and (3) other modes of catecholamine release mechanism may operate in the cells in response to intense stimulation. These morphological data may be helpful in explanation of biochemical variability and extreme diversity of clinical manifestations in patients with pheochromocytoma tumor.

Changes in natural killer cell activity and prostaglandin E2 levels during the progression of diethylnitrosamine-induced hepatocarcinogenesis in Fischer 344 rats

The sequential changes of natural killer cell (NK) activity and prostaglandin E2 (PGE2) during hepatocarcinogenesis induced by diethylnitrosamine (DEN) in male Fischer 344 rats were investigated. DEN at a concentration of 40 ppm was administered in drinking water for 10 weeks. At weeks 5, 10, 20 and 30, rats were autopsied and the development of glutathione S-transferase placental form positive foci (GST-P+ foci) at weeks 5 and 10 and hepatocellular tumors at weeks 20 and 30 were examined. The labeling index of bromodeoxyuridine (BrdU) an indicator of DNA synthesis, was also sequentially checked. GST-P+ foci were found to increase with age. Hepatocellular nodules increased until week 20, but by week 30 when the incidence of hepatocellular carcinoma was 100%, the incidence of nodules had decreased. BrdU positive cells also increased with age, and by week 30 when the incidence of hepatocellular carcinoma was 100%, the number of BrdU-positive cells had decreased. NK cell activity increased until week 10, but at week 20, was less than in the untreated control group. The level of PGE2 increased until week 5, but at week 10, levels were not significantly different from those seen in the untreated control group. On the basis of these results, we concluded that NK activity is closely related to the progression of hepatocarcinogenesis, but PGE2 levels show no significant change.

Autofluorescence in normal and malignant human oral tissues and in DMBA-induced hamster buccal pouch carcinogenesis

Light-induced fluorescence spectroscopy was conducted on human oral malignant and normal tissues. Under 330-nm excitation wavelength, significant differences in fluorescence intensity were observed around 380- and 460-nm emission. Furthermore, 7,12-dimethylbenz[a]anthracene (DMBA)-induced carcinogenesis in hamster buccal pouch was investigated to elucidate whether similar alterations of fluorescence spectroscopy occurred during the development of squamous cell carcinoma. Similar to the spectral profiles of human oral malignant and normal tissues, the most intense fluorescence peaks in the pouches occurred at 380 nm and 460 nm emission under 330 nm excitation wavelength. At 380 nm emission, the fluorescence intensity of normal pouch mucosa was stronger than those of DMBA-treated abnormal tissues at different stages of carcinogenesis. However, at 460 nm emission, the fluorescence intensity of DMBA-treated tissues was not only stronger than that of normal pouch mucosa but also shifted to 470 nm. These results suggest that under 330 nm excitation wavelength fluorescence spectroscopy may be useful for the detection of oral malignant lesions.

Minimum effective dose of casein phosphopeptides (CPP) for enhancement of calcium absorption in growing rats

We examined the effect of ingested casein phosphopeptides (CPP) on intestinal calcium (Ca) absorption and determined the minimum effective dose for enhancement of Ca absorption under conditions of marginal dietary Ca levels. Male Sprague-Dawley rats, divided upon weaning into five groups, were fed a control diet (isolated soyprotein, ISP; 20%) or a CPP diet (ISP + CPP; 20%, CPP/Ca: 0.1, 0.2, 0.35 and 1.0) for 4 weeks. All diets contained the same amounts of Ca (0.35%) and phosphorus (0.70%). The apparent Ca absorption, the retention of Ca, and the luminal soluble Ca content in the small intestine as determined at 4 weeks in the rats fed CPP diet with a weight ratio of CPP/Ca of more than 0.2 were significantly (p < 0.05) higher than those in the rats fed control diet. The wet weight, length and Ca content of the femur were not significantly different among the groups. These results indicate that the minimum effective dose of CPP for enhancement of Ca absorption is 0.7 g/kg or a weight ratio of CPP/Ca of 0.2 in the ISP diet and that CPP supplementation has the effect of significantly increasing Ca absorption at least under conditions of marginal dietary Ca levels.

Maternal or paternal exposure to radiation increases susceptibility to the induction of glutathione S-transferase-positive hepatic foci in offspring rats

Experiments were conducted to determine whether gamma-ray-induced genetic damage in parental rats can lead to the development of cancer in their offspring rats using glutathione S-transferase-positive (GST-P+) hepatic foci with or without the addition of diethylnitrosamine (DEN), a carcinogen. A single 1 Gy whole-body exposure of gamma-rays was given to pregnant rats at day 14 and during postnatal week 3, DEN was intraperitoneally injected twice in 1 week. Female pups from irradiated maternal and paternal rats were also used. Twelve weeks after birth, the rats were sacrificed. GST-P+ foci in animals subjected only to radiation were not different to those of normal control pups, but the incidence of GST-P+ foci was 2.4 times higher in pups treated with DEN alone at 3 weeks after birth than in those irradiated after the onset of pregnancy. In DEN-combined groups, irradiation of post-pregnant or maternal and paternal rats with gamma-rays before mating significantly increased both the incidence and area of GST-P+ foci when compared to those of rats treated with DEN alone. The proliferating cell nuclear antigen (PCNA) labeling index was significantly higher in the offspring of rats subjected to radiation alone or radiation combined with DEN than in normal control pups. Using a rat-liver model, the results of this study indicate that although the dose did not induce phenotypic malformation, exposure to radiation during the embryonic or pre-embryonic stage increases susceptibility to carcinogens.

Immunological properties of recombinant hepatitis B surface antigen expressed in mammalian cell (C127)

We examined the immunological properties of the recombinant hepatitis B surface antigen (r-HBsAg) which was expressed in mammalian cell (C127). The cross-immunity of r-HBsAg and plasma-derived hepatitis B surface antigen (p-HBsAg) were tested using Western blotting and ELISA with guinea pig polyclonal antibody and naturally infected human-derived antibody and the both antigens show the same results in their response pattern and intensity, which indicate they have a good cross-immunity. From the measurement of ED50 after formalin- or heat-inactivation, both r-HBsAg and p-HBsAg showed ED50 of 0.2-0.3 in formalin-inactivation, while r-HBsAg was 0.05-0.09 and p-HBsAg was 0.03-0.07 in heat-inactivation, which means heat-inactivation method is 3-4 times superior in immunogenicity. In the immunopersistency test performed in guinea pig for the period of 3 months with two different adjuvants, antibody titer was 34.2 with muramyl dipeptide adjuvant, which was 1.8 times greater than the antibody titer of 18.9 with AlPO4 adjuvant. The mutagenicity of r-HBsAg, examined by Ames test and micronucleus test, were all negative. In conclusion, r-HBsAg has the same cross-immunity with p-HBsAg, and heat-inactivation method and muramyl dipeptide adjuvant allow development of r-HBsAg vaccine with excellent immunogenicity.

Physicochemical properties of recombinant hepatitis B surface antigen expressed in mammalian cell (C127)

The physicochemical properties of recombinant hepatitis B surface antigen (r-HBsAg), which was expressed in C127 mammalian cell were studied. Using roller bottle culture in DMEM supplemented with fetal bovine serum, 10-15 mg/L of r-HBsAg was produced with about 31% of purification yield. The purity of r-HBsAg by HPLC was 99.8% and electron microscopic examination showed homogeneous spherical particle with 22 nm in diameter, a morphological characteristic of HBsAg. The density of r-HBsAg by CsCl density gradient method was 1.19 g/ml and the isoelectric point by Mono P HR 5/20 column was 4.6. The analysis of subunit protein pattern using SDS-PAGE followed by scanning densitometry gave 81.3% of S protein and 18.7% of pre-S protein. Fluorophore-assisted-carbohydrate-electrophoresis analysis showed the relative amount of carbohydrate to protein was 1.7% and its major component was N-acetyl glucosamine, which was about 39% of total carbohydrate. The relative amount of lipid to protein determined by vanillin phosphoric acid method was 32.5% and its major component was phospholipid, which was about 70% of total lipid. The physicochemical properties of C127 mammalian cell-derived r-HBsAg are similar to those of p-HBsAg, suggesting that the r-HBsAg can be used in developing a new preventive vaccine against hepatitis B.

Cytotoxic effects of quinoxaline derivatives on human cancer cell lines

The cytotoxicities of 6,7-modified-5,8-quinoxalinedione derivatives and heterocyclic quinoxaline derivatives containing nitrogen, sulfur, and oxygen on human lung adenocarcinoma cell (PC 14), human gastric adenocarcinoma cell (MKN 45), and human colon adenocarcinoma cell (colon 205) were examined in vitro using MTT assay. Pyrido[1,2-a]imidazo[4,5-g]quinoxaline-6,11-dione (10) was markedly cytotoxic against MKN 45 compared with adriamycin and cis-platin used as anticancer drugs. The IC50 value of compound 10 was 0.073 microM while those of adriamycin and cis-platin were 0.12 microM and 2.67 microM, respectively.

Molecular modeling studies of the binding modes of aldose reductase inhibitors at the active site of human aldose reductase

Molecular modeling studies using the CHARMM method have been conducted to study the binding modes of aldose reductase inhibitors at the active site of aldose reductase. The energy minimized structures of aldose reductase with six structurally diverse inhibitors (spirofluorene-9,5'-imidazolidine-2',4'-dione (1), 9-fluoreneacetic acid (2), AL1576 (3), 2,7-difluoro-9-fluoreneacetic acid (4), FK366 (5), and Epalrestat (9)) indicate that the side chains of Tyr48, His110, and Trp111 can form numerous hydrogen bonds with either the carboxylate or the hydantoin group of the inhibitors while the side chains of Trp20, Trp111, and Phe122 are positioned to form aromatic-aromatic interactions. Of the three residues (Tyr 48, His 110, and Trp 111) that can form hydrogen bonds with the ionized portion of aldose reductase inhibitors, protonated His110 appears to play an important role in directing charged inhibitors to bind at the active site through charge interaction. Based on the binding mode of the inhibitors and their observed inhibitory activities, pharmacophore requirements for aldose reductase inhibitors are discussed.

Pathogenetic mechanism of senile calcific aortic stenosis: the role of apoptosis

OBJECTIVE

To investigate the pathogenetic mechanisms leading to the development of calcific degeneration of the aortic valve in the elderly patients with particular reference to the relationship between apoptosis and calcification in the aortic valve tissue.

METHODS

High resolution scanning and transmission electron microscopic observations of the calcified aortic valves obtained during aortic valve replacement were carried out in 10 patients with senile calcific aortic stenosis.

RESULTS

Various degrees of endothelial alterations from focal disruption of individual endothelial cells to extensive denudation of entire endothelium were observed particularly on the aortic side of the valve tissues. The apoptotic changes occurring in the nuclei of endothelial cells and fibroblasts were common findings in the calcified valve tissues. It was noteworthy that the severity of endothelial damage was closely related to apoptotic changes of the fibroblasts. Calcific deposits were frequently observed in association with the cellular fragments mainly derived from the apoptotic fibroblasts.

CONCLUSIONS

Our results strongly indicate that apoptosis may play an important role in the alterations of endothelial integrity leading to the increased filtration of calcium into the deeper layer of the valve tissues. Then, the cellular degradation products and organelles extruded from the dead cells, mainly resulted from apoptosis provided the substrates for calcium binding with progressive development of calcification in the valve tissue. Although the role of apoptosis in contribution to the pathogenesis of senile calcific aortic stenosis is evident, further studies using modern molecular biotechnology are mandatory in order to clarify the mechanism for the initiation of apoptotic process in the endothelial cells and fibroblasts.

Nonossifying fibroma: characteristics at MR imaging with pathologic correlation

PURPOSE

To correlate the findings of nonossifying fibroma at magnetic resonance (MR) imaging with those at pathologic examination.

MATERIALS AND METHODS

In 19 patients (age range, 8-25 years; mean age, 14 years) with pathologically proved nonossifying fibroma, MR images were analyzed for signal intensity and patterns of contrast enhancement. Findings at MR imaging and biopsy were correlated.

RESULTS

On T1-weighted images, all nonossifying fibromas had low signal intensity compared with that of skeletal muscle. On T2-weighted images, 15 lesions (79%) were hypointense and four (21%) were hyperintense. On gadolinium-enhanced images, intense contrast enhancement was seen throughout 15 lesions (heterogeneous pattern in 12 and homogeneous in three) and in the margins and septa in four. Extensive hypercellular fibrous tissue and hemosiderin seen at pathologic examination were depicted with low signal intensity on T2-weighted MR images.

CONCLUSION

The distinguishing features of nonossifying fibroma included hypointensity and septation on T2-weighted images. Signal intensity on T1- and T2-weighted MR images and the patterns of contrast enhancement were dependent on the amounts of hypercellular fibrous tissue, hemosiderin, hemorrhage, collagen, foamy histiocytes, and bone trabeculae.

Electron microscopic studies of microvasculature and sympathetic nerve fibers in dilated cardiomyopathy

OBJECTIVE

To investigate the ultrastructural pathological alterations of the microvasculature and nerve fibers in the endomyocardial biopsied specimens of the left ventricular myocardium obtained from patients with idiopathic dilated cardiomyopathy and chronic heart failure.

METHODS

Transmission electron microscopic observations of endomyocardial biopsied specimens of the left ventricular myocardium were carried out in 10 patients with idiopathic dilated cardiomyopathy and chronic heart failure.

RESULTS

Various degrees of ultrastructural pathological alterations in the microvessels and sympathetic nerves in the diseased myocardium were consistently demonstrated in idiopathic dilated cardiomyopathy. In addition, abnormal accumulation of collagen tissue and edematous fluid were often seen in the interspace between myocardial cells and nerve endings and capillaries.

CONCLUSIONS

Based on the ultrastructural pathological findings in this study, we consider that all the structures forming the muscle cells and the tissues around them, namely the microvessels and nerves may participate in the pathological process in the course of dilated cardiomyopathy. The damage of microvasculature and sympathetic nerves resulting from the underlying disease processes are considered to be an important pathogenetic mechanism responsible for progressive development of myocardial degeneration and dysfunction throughout the course of the disease. It is hoped that our data may provide some insights into the understanding of the role of microcirculation and sympathetic nerves in the etiopathogenesis of dilated cardiomyopathy.

Role of Ca2+ influx in the tert-butyl hydroperoxide-induced apoptosis of HepG2 human hepatoblastoma cells

Oxidative stress appears to be implicated in the pathogenesis of various diseases including alcoholic liver injury. In this study we investigated the mechanism of apoptosis induced by tert-butyl hydroperoxide (TBHP) in HepG2 human hepatoblastoma cells. Treatment with TBHP significantly reduced glutathione content and glutathione reductase activity, and increased glutathione peroxidase activity, indicating that TBHP induced oxidative stress in the HepG2 cells. TBHP also induced reduction of cell viability and DNA fragmentation, a hallmark of apoptosis, in a dose-dependent manner. In addition, TBHP induced a sustained increase in intracellular Ca2+ concentration, which was completely prevented by the extracellular Ca2+ chelation with EGTA. TBHP also induced Mn2+ influx. These results indicate that the intracellular Ca2+ increase by TBHP is exclusively due to Ca2+ influx from the extracellular site. Treatment with either an extracellular (EGTA) or an intracellular Ca2+ chelator (BAPTA/AM) significantly suppressed the TBHP-induced apoptosis. Taken together, these results suggest that TBHP induced the apoptotic cell death in the HepG2 cells and that Ca2+ influx may play an important role in the apoptosis induced by TBHP.

Treatment of chronic hepatitis B with lamivudine in renal transplant recipients

BACKGROUND

Lamivudine is a potent inhibitor of hepatitis B virus replication. Little has been reported about the efficacy and safety of lamivudine in the treatment of chronic hepatitis B in the setting of renal transplantation.

METHODS

Two patients were treated for chronic hepatitis B with lamivudine and subsequently underwent renal transplantation. Four other patients were treated with lamivudine for reactivation of hepatitis B after renal transplantation. Chronic hepatitis B was proven histologically in all the patients. The doses of lamivudine ranged from 100 to 150 mg/day. Hepatic enzyme and viral markers were monitored.

RESULTS

Lamivudine was well tolerated for a median duration of 8 months (range, 4-14 months) without significant side effects. Viral replication was suppressed, as evidenced by negative conversion of serum hepatitis B virus DNA in all the patients. Hepatic enzyme was also normalized. Modification of doses of immunosuppressant regimen was not required in using lamivudine in all patients. One patient experienced acute rejection and responded to solumedrol pulse therapy with normalization of graft function. Normal graft function was maintained in other patients while they were treated with lamivudine.

CONCLUSION

Lamivudine was a safe and effective therapy for activated hepatitis B in renal transplant recipients in the short term.

Superiority of hepatic arterial infusion in preventing catabolism of 5-FU compared with portal vein infusion revealed by an in vivo 19F NMR study

PURPOSE

The aim of this study was to identify the route of administration of 5-FU with the greatest pharmacological advantage in a rat model using non-invasive in vivo 19F nuclear magnetic resonance (NMR) spectroscopy.

METHODS

5-FU (50 mg/kg) was administered to anesthetized Wistar rats cannulated into the hepatic artery, portal vein or tail vein and 11 NMR spectra were acquired from the liver region to 60.5 min every 5.5 min.

RESULTS

With systemic i.v. (tail vein) infusion, the 19F-NMR signal for 5-FU from the liver region peaked in the first spectrum (0-5.5 min), and then gradually decreased. The signal for the 5-FU catabolite alpha-fluoro-beta-alanine (FBAL) gradually increased to the sixth spectrum (0-33.0 min) and then plateaued. Following portal vein infusion the intensity of the first 5-FU spectrum was twice as high as that following i.v. infusion, but the intensity decreased and the FBAL signal increased gradually in the sixth spectrum as systemic i.v. infusion. In contrast, the intensity of the 5-FU signal following hepatic artery infusion was the same as that following portal vein infusion in the first spectrum, and maintained a strong intensity to the final spectrum (60.5 min). The FBAL signal was detected from the second spectrum following hepatic artery infusion, but its intensity was significantly weaker than that following i.v. or portal vein infusion.

CONCLUSIONS

Hepatic arterial infusion resulted in the active form of 5-FU being present for a longer time and its degradation in the liver being suppressed compared with the results following portal vein infusion. This catabolic advantage of hepatic arterial infusion could lead to a more potent anti-tumor activity against liver metastases, but could also lead to significant host toxicity including biliary toxicity. We recommend that the dose/schedule of 5-FU administered via the hepatic artery should be adjusted carefully.