Malignant hemangioendothelioma of the small intestine: report of a case

A case of malignant hemangioendothelioma (MH) of the small intestine in a 27-year-old woman is reported herein. The patient developed acute abdominal symptoms during investigations for anemia, weight loss, anorexia, and recurrent gastrointestinal bleeding. An emergency laparotomy revealed perforation of a jejunal tumor. The results of a histopathological study of the resected small bowel segment were interpreted as MH with lymph node involvement. Following this case report, a review of the relevant literature on small intestinal MH is presented.

Synergistic action of apoptosis induced by eicosapentaenoic acid and TNP-470 on human breast cancer cells

The effects of eicosapentaenoic acid (EPA) and an angiogenesis inhibitor (TNP-470) on the suppression of breast cancer cell growth were examined in five human breast cancer cell lines (MDA-MB-231, T-47D, MCF-7, KPL-1, and MKL-F). In all five cell lines, EPA and TNP-470 alone both showed tumor growth inhibition in a time- and dose-dependent manner, and in combination, a synergistic effect was seen at high concentrations. EPA plus TNP-470 treatment evoked apoptosis as confirmed by the appearance of sub G1 populations, by DNA fragmentation, and by cell morphology. With the combination, the expression of Bax and Bcl-xS, the apoptosis-enhancing proteins, was more up-regulated and that of Bcl-2 and Bcl-xL, the apoptosis-suppressing proteins, was more down-regulated compared to the use of EPA or TNP-470 alone, suggesting that their synergistic effect was due to an acceleration of apoptosis.

Restricted diversification of T-cells in chronic active Epstein-Barr virus infection: potential inclination to T-lymphoproliferative disease

To assess the abnormal T-cell expansion in chronic active Epstein-Barr virus infection (CAEBV), T-cell antigen receptor (TCR) repertoire was analyzed in four patients with the disease. All fulfilled the diagnostic criteria of CAEBV, presenting with fever, hepatosplenomegaly, cytopenia, abnormal high titers of anti EBV-antibodies, and positive EBV genome of unknown cause. Southern blotting probed with EBV-terminal repeats and TCR Cbeta gene indicated clonal expansion of the infected cells in 3 and 2 patients, respectively. The number of CD4+ HLA-DR+ cells appreciably increased in patients 1 (59%) and 2 (24%), who had a coronary aneurysm and central nervous system involvement, respectively. TCR gene expression examined by the inverse polymerase chain reaction methods revealed that Vbeta gene usages were preferential in all patients (Vbeta7 and Vbeta12: patient 1, Vbeta4: patient 2, Vbeta13: patients 3 and 4), compared with those in healthy controls. Valpha18 gene expression was remarkably high in patients 1 and 2. Moreover, Jbeta gene expression was skewing in the reigning Vbeta clones in all patients. Vbeta4-Jbeta1.5 and Vbeta13-Jbeta1.5 genes were clonally expressed in patients 2 and 4, respectively. These results suggest that CAEBV is associated with the restricted diversity of T-cells, which may stem from the sustained expansion of oligoclonal T-cells possibly driven by conventional viral antigens, but not, superantigens. Although the study is limited by the small number of patients, the unbalanced T-cell repertoire might contribute to the evolution of T-lymphoproliferative disease, otherwise, imply the innate defective immunity to EBV in CAEBV patients.

Change in telomerase activity during human colorectal carcinogenesis

Telomerase activities in endoscopically resected colorectal adenomas, surgically resected colorectal cancers and adjacent normal colonic mucosa were examined semiquantitatively by a polymerase chain reaction-based telomeric repeat amplification protocol (TRAP) assay. All normal mucosa (n = 15) presented weak telomerase activity (mean +/- SE: 0.99 +/- 0.00). When the value of 1.00 was arbitrary given to the mean activity of normal mucosa, the telomerase activity in the adenomas (n = 14) was up-regulated (2.01 +/- 0.22) relative to the normal mucosa. The telomerase activity in the high-grade atypia (severe atypia and carcinoma in situ) (2.58 +/- 0.34) was significantly higher than that in the low-grade (mild and moderate) atypia (1.59 +/- 0.18) (P < 0.05), and the adenomas 10 mm or more in diameter presented significantly higher telomerase activity (2.56 +/- 0.09) than compared to the smaller ones (1.44 +/- 0.17) (p < 0.05). Carcinomas (n = 20), showed a telomerase activity that varied from 0.97 to 16.93, which was than the greater mean telomerase activity (6.96 +/- 1.25) noted in the adenomas. The telomerase activity in the carcinomas tended to be higher in the larger (> or = 4 cm), histologically less-differentiated (moderately differentiated), late-stage (Dukes C + D), and nodal metastatic tumors, suggestive of unfavorable prognosis. These results suggests that the weak telomerase activity in normal colonic mucosa is gradually activated during the course of colorectal carcinogenesis.

Down-regulation of TGF-beta receptors in human colorectal cancer: implications for cancer development

Many colorectal cancer cells are resistant to the anti-proliferative effects of transforming growth factor-beta (TGF-beta). TGF-beta also acts as paracrine factor from cancer cells on their mesenchymal cells. The aim of this study was to examine the expression of TGF-beta and its receptors in human colorectal cancer tissue and determine any relationship with cancer growth. In situ hybridization and Northern blot hybridization detection of TGF-beta1, type I and type II receptor mRNA and immunohistochemical staining of TGF-beta1 were performed using 11 human colorectal adenomas, 22 colorectal cancers and ten normal colorectal mucosas as control. TGF-beta receptor mRNAs were expressed mainly by normal colorectal epithelial cells and adenoma. However, mRNAs for TGF-beta receptors were only faintly, if at all, expressed in eight of 22 human colorectal cancers. In addition, intense signals of TGF-beta1 mRNA and the protein were detected in all colorectal cancers. TGF-beta receptor mRNAs and TGF-beta1 protein were also distributed in fibroblasts and endothelial cells in the interstitium. Moreover, Smad 4 protein was translocated to nucleus in primarily cultured adenoma cells, but not in cancer cells after TGF-beta stimulation. The escape of human colon cancer from TGF-beta-mediated growth inhibition by down-regulation of TGF-beta receptors as well as the effects of TGF-beta on stroma formation and angiogenesis indicate a possible role for TGF-beta in the progression of colon cancer in an intact host.

Lipopolysaccharide enhances the production of vascular endothelial growth factor by human pulp cells in culture

We investigated whether vascular endothelial growth factor (VEGF) production by human pulp cells (HPC) is regulated by lipopolysaccharide (LPS) in relation to the pathogenesis of pulpitis. Although HPC incubated with medium alone only marginally expressed VEGF mRNA and produced a low level of VEGF as detected by enzyme-linked immunosorbent assay, the VEGF mRNA expression and VEGF production were markedly enhanced upon stimulation with LPS from Escherichia coli. Prevotella intermedia LPS, phorbol 12-myristate 13-acetate, and interleukin-6 also induced VEGF mRNA expression in HPC. A simian virus 40-infected HPC line also exhibited increased VEGF mRNA expression in response to E. coli LPS, but lung and skin fibroblasts did not. Fetal bovine serum (FBS) increased the sensitivity of HPC to LPS in a dose-dependent manner. HPC did not express membrane CD14 on their surfaces. However, the anti-CD14 monoclonal antibody MY4 inhibited VEGF induction upon stimulation with LPS in HPC cultures in the presence of 10% FBS but not in the absence of FBS. LPS augmented the VEGF production in HPC cultures in the presence of recombinant human soluble CD14 (sCD14). To clarify the mechanisms of VEGF induction by LPS, we examined the possible activation of the transcription factor AP-1 in HPC stimulated with LPS, by a gel mobility shift assay. AP-1 activation in HPC was clearly observed, whereas that in skin fibroblasts was not. The AP-1 inhibitor curcumin strongly inhibited LPS-induced VEGF production in HPC cultures. In addition, a protein synthesis inhibitor, cycloheximide, inhibited VEGF mRNA accumulation in response to LPS. These results suggest that the enhanced production of VEGF in HPC induced by LPS takes place via an sCD14-dependent pathway which requires new protein synthesis and is mediated in part through AP-1 activation.

Sudden death in school children: role of physical activities and meteorological conditions

BACKGROUND

This current study is aimed at investigating the effect of physical activities and meteorological conditions on the sudden deaths of children without obvious causes at school.

METHODS

The subjects are 76 victims of sudden death at school in the 12 years from 1983 to 1994 in Aichi Prefecture, Japan. The incidence of these sudden deaths is shown by month of the year, day of the week and hour of the day in relation to physical activities and meteorological factors. The analysis of Hayashi's quantitation type II was used for evaluation of the relationship between sudden deaths under the different physical conditions, such as sedentary (at rest or slow walking) or active (running, competitive sports or swimming) conditions, and meteorological or weather factors such as, season of the year, wind-chill factor, atmospheric pressure and relative humidity.

RESULTS

Of 76 cases, 21 died suddenly under sedentary physical conditions and 55 under active conditions. The incidence of sudden death was highest from 10.00 to 11.00 h and on Thursday. Sudden death under sedentary conditions was associated with autumn and winter or with winter with high humidity and low atmospheric pressure. Sudden deaths during running were associated with spring with low humidity and high pressure and sudden deaths during competitive sports were associated with dry and cloudy weather.

CONCLUSION

Sudden deaths in children at school may be associated with physical activities and meteorological conditions.

[Clinical findings and genetic bases of congenital complement deficiencies]

The clinical findings and genetic bases of inherited deficiencies of plasma complement components and complement control proteins are reviewed. In Japan, since the frequencies of late complement component deficiencies (LCCD) are high, clinical features of neisserial infections associated with LCCD are described in details. C 9 deficiency is one of the most frequent genetic disorders in Japan and most of them are healthy. However, C 9 deficiency is weakly but significantly associated with the development of meningococcal meningitis but not of systemic lupus erythematosus. The common Arg 95 Stop mutation was found in most individuals with C 9 deficiency. Molecular epidemiologic study revealed that homozygous and heterozygous Arg 95 Stop mutation of C 9 gene is found in approximately one of 1000 individuals and one of 15 individuals, respectively. Complement studies including C 9 antigen and DNA analyses should be performed in patients with meningococcal meningitis or recurrent bacterial infections.

Lipoteichoic acid acts as an antagonist and an agonist of lipopolysaccharide on human gingival fibroblasts and monocytes in a CD14-dependent manner

CD14 has been implicated as a receptor of lipoteichoic acid (LTA) and other bacterial components as well as lipopolysaccharide (LPS). Since the structures of LTAs from various gram-positive bacteria are heterogeneous, we analyzed the effects of LTAs on the secretion of interleukin-8 (IL-8) by high- and low-CD14-expressing (CD14(high) and CD14(low)) human gingival fibroblasts (HGF). While Bacillus subtilis LTA had an IL-8-inducing effect on CD14(high) HGF which was considerably weaker than that of LPS, Streptococcus sanguis and Streptococcus mutans LTAs had practically no effect on the cells. B. subtilis LTA had only a weak effect on CD14(low) HGF, as did LPS. S. sanguis and S. mutans LTAs at a 1,000-fold excess each completely inhibited the IL-8-inducing activities of both LPS and a synthetic lipid A on CD14(high) HGF. The effect of LPS was also inhibited by the presence of an LPS antagonist, synthetic lipid A precursor IVA (LA-14-PP), with a 100-fold higher potency than S. sanguis and S. mutans LTAs and by anti-CD14 monoclonal antibody (MAb). S. sanguis and S. mutans LTAs, LA-14-PP, and anti-CD14 MAb had no significant effect on phorbol myristate acetate-stimulated IL-8 secretion by HGF. These LTAs also inhibited the IL-8-inducing activity of B. subtilis LTA on CD14(high) HGF, as did LA-14-PP and anti-CD14 MAb. The antagonistic and agonistic functions of LTAs were also observed with human monocytes. Binding of fluorolabeled LPS to human monocytes was inhibited by S. sanguis LTA, although the inhibition was 100 times weaker than that of LPS itself, and anti-CD14 MAb inhibited fluorolabeled LPS and S. sanguis LTA binding. Binding of LTAs to CD14 was also observed with nondenaturing polyacrylamide gel electrophoresis. These results indicate that LTAs act as antagonists or agonists via a CD14-dependent mechanism, probably due to the heterogeneous structure of LTAs, and that an antagonistic LTA might be a useful agent for suppressing the periodontal disease caused by gram-negative bacteria.

Identification of mutations in the c-mpl gene in congenital amegakaryocytic thrombocytopenia

Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare disorder expressed in infancy and characterized by isolated thrombocytopenia and megakaryocytopenia with no physical anomalies. Our previous hematological analysis indicated similarities between human CAMT and murine c-mpl (thrombopoietin receptor) deficiency. Because the c-mpl gene was considered as one of the candidate genes for this disorder, we analyzed the genomic sequence of the c-mpl gene of a 10-year-old Japanese girl with CAMT. We detected two heterozygous point mutations: a C-to-T transition at the cDNA nucleotide position 556 (Q186X) in exon 4 and a single nucleotide deletion of thymine at position 1,499 (1,499 delT) in exon 10. Both mutations were predicted to result in a prematurely terminated c-Mpl protein, which, if translated, lacks all intracellular domains essential for signal transduction. Each of the mutations was segregated from the patient's parents. Accordingly, the patient was a compound heterozygote for two mutations of the c-mpl gene, each derived from one of the parents. The present study suggests that at least a certain type of CAMT is caused by the c-mpl mutation, which disrupts the function of thrombopoietin receptor.

Prognostic significance of Bcl-2, Bcl-xL/S, Bax and Bak expressions in colorectal carcinomas

The immunohistochemical expressions of the apoptosis-related proteins Bcl-2, Bcl-xL/S, Bax and Bak were investigated in tumor specimens selected from 58 consecutive patients undergoing surgery for advanced colorectal carcinoma. The expression patterns in 50 specimens of adjacent normal colonic mucosa were also examined. In the normal colonic mucosa, Bcl-2-positive epithelial cells tended to be located at the base of the crypts, while the Bcl-xL/S-, Bax- and Bak-positive epithelial cells tended to be located at the luminal surface. The intracellular expression patterns of Bcl-2 and Bax were diffuse cytoplasmic, whereas those of Bcl-xL/S and Bak were granular cytoplasmic. In the adenocarcinomas, the intracellular expression patterns of all antibodies were diffuse cytoplasmic, and the percentages of Bcl-2-, Bcl-xL/S-, Bax- and Bak-positive cases (>20% of cancer cells labeled) were 29%, 43%, 45% and 69%, respectively. Bax expression was significantly correlated with less lymph vessel invasion (p=0.02) and less depth of invasion (p=0.04). In relation to prognosis (5-year-survival), the patients with Bax-positive tumors had significantly better prognoses than the patients who had Bax-negative tumors (p<0.05). However, the Bcl-2, Bcl-xL/S and Bak expressions were not related to any clinicopathological factors examined. Thus, Bax expression may be an additional prognostic marker in colorectal carcinomas.

Outbreak of severe neurologic involvement associated with Enterovirus 71 infection

Enterovirus 71 has been associated with several outbreaks, as well as sporadic cases, of central nervous system infection and has a worldwide distribution. Seven children with encephalitis and five with aseptic meningitis caused by Enterovirus 71 were seen at Otsu Municipal Hospital during the summer of 1997. The infections were confirmed serologically, although detection of the viral genome in cerebrospinal fluid was unsuccessful. Seven children were diagnosed as having hand-foot-and-mouth syndrome, two were diagnosed as having herpangina, and three patients younger than 12 months old developed no eruptions. The skin or mucosal manifestations of this outbreak demonstrated considerable variation. The Enterovirus 71 strain that caused the outbreak had a strong neurovirulent tendency. Among the patients with encephalitis, symptoms originating from the impairment of diencephalon were seen in four patients, and those originating from cerebellar impairment were seen in two patients. Brain magnetic resonance imaging in one patient revealed an abnormality in the pons. The neurologic manifestations associated with Enterovirus 71 infection may be characterized by involvement of the cerebellum, brainstem, and diencephalon. Enterovirus 71 is one of the pathogenic viruses that cause hand-foot-and-mouth syndrome, as well as a variety of other clinical manifestations. The most important of these is neurologic disease, especially in infants and young children.

Peripheral hemodynamics evaluated by acceleration plethysmography in workers exposed to lead

To clarify the effect of lead exposure on peripheral hemodynamics, acceleration plethysmography (APG) was performed for 48 male subjects occupationally exposed to lead (exposure group) and 43 male subjects with no history of occupational exposure to lead (control group). In the exposure group, the blood lead concentration (Pb-B) was also measured. Each APG parameter was assessed by comparing measured data with the standard aging curves. A significant negative correlation was obtained between the parameter--b/a and Pb-B. The exposure group showed significantly lower values of parameters--b/a (p < 0.01) and d/a (p < 0.05) than the control group. The parameter--b/a in the exposure group dose-dependently decreased with increases in length of working career (duration of exposure to lead) and Pb-B. The parameter--b/a significantly (p < 0.05) decreased in subjects with working careers of 5 years or more and in subjects whose Pb-B was 40 micrograms/100 ml or more. These results suggest that lead exposure affects peripheral hemodynamics as evaluated by APG.

Central nervous system T-cell lymphoproliferative disorder in a patient with chronic active Epstein-Barr virus infection

PURPOSE

Central nervous system (CNS)-T cell lymphoproliferative disorder (T-LPD) developing during the course of chronic active Epstein-Barr virus (CAEBV) infection is reported.

PATIENTS AND METHODS

CAEBV was diagnosed in a 14-month-old boy with fever, cytopenia, hepatosplenomegaly, and abnormal high titers of anti-Epstein-Barr virus (EBV) antibodies. At 8 years of age, he had a splenectomy because of progressive disease.

RESULTS

After 27 months of clinical remission, muscle weakness and paresthesia developed. Magnetic resonance imaging of his brain showed spotty T2 prolongation in left parietal, bilateral frontal, and temporal white matter with meningeal enhancement. Brain biopsy revealed the cerebral infiltration of CD3+, CD4+, CD8-, CD45RO+, CD56-, and EBV-encoded RNA 1+ cells.

CONCLUSIONS

The CNS involvement of EBV-associated T-LPD is a rare but serious complication in CAEBV without known underlying immunodeficiency.

Acute cerebellar ataxia with human parvovirus B19 infection

A 2 year old boy developed acute cerebellar ataxia in association with erythema infectiosum. During the disease, genomic DNA and antibodies against human parvovirus B19 were detected in serum but not in cerebrospinal fluid. Parvovirus B19 associated acute cerebellar ataxia might occur due to transient vascular reaction in the cerebellum during infection.

Interstitial fibrin-fibronectin deposition with T cell infiltrates precedes fibrosis in murine viral myocarditis

This study was carried out to investigate interstitial fibrin and fibronectin deposition and subsequent myocardial connective tissue abnormalities in BALB/c-nu/+ (euthymic and normal T cell function) and BALB/c-nu/nu (athymic and T cell-deficient) mice. Both types of mice were inoculated with encephalomyocarditis virus and sacrificed periodically. Sections of the hearts were stained with haematoxylin-eosin, trichrome, lymphocyte subsets, silver impregnation, and fibrin or fibronectin. In addition, myocardial collagen concentration was measured. Interstitial fibrin and fibronectin appeared in parallel with inflammatory T lymphocytes and myocardial necrosis in the BALB/c-nu/+ mice. The changes increased until 14 days, subsequently decreasing with time. Interstitial fibrosis and abnormal reticulin fibres were absent until 7 days postinfection, and then increased with time until 60 days. In BALB/c-nu/nu mice, in contrast, although myocardial necrosis and fibrin-fibronectin deposition associated with immature T lymphocytes were evident on days 7 and 14, subsequent myocardial fibrosis and reticulin fibre abnormalities were minimal on days 30 and 60. In BALB/c-nu/+ mice, myocardial collagen concentration increased on day 30, but it did not in BALB/c-nu/nu mice. Thus, interstitial fibrin-fibronectin deposition resulting from virus-induced and T lymphocyte-mediated myocyte necrosis precedes the subsequent development of interstitial fibrosis and abnormal reticulin architectures in this model of murine myocarditis.

The relationship between R amplitude in lead V5 (RV5) and left ventricular mass in the groups of adolescent subjects classified by body composition

How the amplitude of the R wave in lead V5 (RV5) of the ECG represents the left ventricular (LV) mass was investigated in 894 students aged 15 (boys: 545, girls: 349). The influence of body composition [ie, percentage of body fat (%fat)] was taken into consideration. A significant correlation was found between RV5 amplitude and LV mass for both genders. However, the relationship was stronger for boys than for girls. The students were then divided into 3 groups; that is, those at either the top or bottom 10th percentile (low or high-fat range) and the rest of the students (middle-fat range), depending on the % fat calculated by the bioelectrical impedance method. The significant correlation between RV5 and LV mass was found only for the 2 groups of boys whose percentage fat was in the low or middle-fat range. The correlation coefficients were 0.40 and 0.34, respectively. Moreover, in the boys' low-fat range, the RV5 of students whose LV mass was large (> or =90th percentile), was significantly higher (p<0.01) than in the other ranges. Setting a particular cutoff point of RV5 in the low-fat range of boys improved sensitivity as well as specificity (20-30% better among all boys) for detecting large LV mass. These observations suggest that classification of subjects by body composition could be improve the reliability of ECG assessment for left ventricular hypertrophy, although the gender and number of subjects in whom improvement is expected are limited.

Inflammatory cytokine production and specific antibody responses against possible causative bacteria in patients with multilesional periapical periodontitis

We examined the induction of inflammatory cytokines (including interleukin-1, interleukin-6, interleukin-8, and tumor necrosis factor-alpha) by several species of possible causative bacteria in periapical periodontitis. Assays were done on human whole blood cultures from patients with differing numbers of periapical lesions; those having radiographically clear periapical lesions in 10 or more teeth (high lesion group), in one or two teeth (low lesion group), and healthy volunteers having no periapical lesions (no lesion group). Prevotella melaninogenica ATCC 25845 induced interleukin-6 more strongly in subjects from the high lesion group than in the other groups. To ascertain the degree of sensitization by test bacteria, we examined the reactivities of antibodies in serum and saliva from the six subjects to different bacterial species. Porphylomonas gingivalis cells reacted strongly with sera from the high lesion group. Thus, Prevotella melaninogenica and Porphylomonas gingivalis may be involved in multilesional periapical periodontitis by inducing specific cytokines and/or humoral immune responses.

A lipoteichoic acid fraction of Enterococcus hirae activates cultured human monocytic cells via a CD14-independent pathway to promote cytokine production, and the activity is inhibited by serum components

To elucidate the cellular activation mechanisms of lipoteichoic acid (LTA) compared with those of lipopolysaccharide (LPS), a quantitatively major LTA fraction, QM-1M, was prepared from hot phenol-water extracts of Enterococcus hirae (ATCC 9790) by hydrophobic octyl-Sepharose chromatography and by ion-exchange membrane (QMA-Mem Sep 1010) chromatography as a 60% 1-propanol- and 1 M NaCl-eluted fraction. Unlike the reference Escherichia coli LPS, QM-1M did not demonstrate any ability to induce cytokines in a human whole blood culture system in this study, whereas QM-1M induced a few cytokines such as interleukin (IL)-8 and tumor necrosis factor-alpha in human monocytic THP-1 cell and human peripheral mononuclear cell (PBMC) cultures in the absence of serum. Fetal calf and human sera decreased the above cytokine induction by QM-1M in THP-1 and PBMC cultures, whereas sera increased activities of the reference LPS. IL-8 induction in the absence of serum in response to QM-1M was demonstrated to proceed through a CD14-independent pathway unlike the reference LPS.

Wax D of Mycobacterium tuberculosis induced osteomyelitis accompanied by reactive bone formation in Buffalo rats

A suspension of heat-killed Mycobacterium tuberculosis in liquid paraffin has been reported to induce foot swelling accompanied by new bone formation in Buffalo (BUF) rats, which are low responders to the induction of adjuvant arthritis. In the present study, we found that wax D, a mycobacterial cell wall peptidoglycan fragment-arabinogalactan-mycolic acid complex, was an effective component of this bacterium for the induction of osteomyelitis accompanied by reactive bone formation in BUF rats. Chronic inflammation was produced in BUF rats by a single subcutaneous injection of wax D suspended in liquid paraffin. Other Mycobacterium species and Gordona bronchialis were also capable of inducing this reaction. Other bacterial cells including the acid-fast bacteria Nocardia and Rhodococcus, purified cell walls and peptidoglycans from Lactobacillus plantarum, wax C, cord factor, arabinogalactan and mycolic acid prepared from M. tuberculosis were inactive in this respect. In addition, when wax D was administered as a water-in-oil emulsion (Freund's type adjuvant), bone formation scarcely occurred in BUF rats. In Fisher (F344) and Wistar rats, both of which are responder strains to adjuvant arthritis, wax D in liquid paraffin did not induce bone formation.

20beta-hydroxysteroid dehydrogenase catalyzes ketone-reduction of acetohexamide, an oral antidiabetic drug, in liver microsomes of adult male rats

We examined the catalytic properties and physiological function of an enzyme responsible for the ketone-reduction of acetohexamide, an oral antidiabetic drug, in liver microsomes of adult male rats. Progesterone, 17alpha-hydroxyprogesterone, cortisone and cortisol, which have a ketone group at 20-position of C21-steroids, were potent inhibitors for ketone-reduction of acetohexamide in liver microsomes of adult male rats. Progesterone was also found to inhibit competitively the ketone-reduction of acetohexamide, suggesting that the ketone-reduction of acetohexamide and progesterone is catalyzed by the same enzyme. When progesterone was used as a substrate, 20beta-hydroxysteroid dehydrogenase present in liver microsomes of adult rats, such as acetohexamide reductase, exhibited a male-specific and androgen-dependent activity. Furthermore, a significant correlation was observed between the activities of 20beta-hydroxysteroid dehydrogenase and acetohexamide reductase in liver microsomes of individual male rats at various ages. Based on all results, we conclude that 20beta-hydroxysteroid dehydrogenase catalyzes the ketone-reduction of acetohexamide in liver microsomes of adult male rats.

Growth-dependent change of the 26S proteasome in budding yeast

The 26S proteasome is assembled from the 20S proteasome and the regulatory subunit complex in an ATP-dependent manner. In the present study, we found that the ATP-dependent activity and the protein amount of the 26S proteasome change during growth of the budding yeast Saccharomyces cerevisiae. Both levels in the stationary phase are higher than those in the exponentially growing phase. On the other hand, the levels of the 20S proteasome appear to remain unchanged during growth. These results suggest that the 26S proteasome undergoes a growth-dependent change and that the 26S proteasome plays a role in the survival of yeast cells under starvation conditions.

Effects of fatty acids on liver metastasis of ACL-15 rat colon cancer cells

The effects of eicosapentaenoic acid [EPA; n-3 polyunsaturated fatty acid (PUFA)], linoleic acid (LA; n-6 PUFA), and palmitic acid (PA; saturated fatty acid) on 1,2-dimethylhydrazine-induced F344 rat colon carcinoma cells (ACL-15) were investigated in vivo and in vitro. The number and size of liver metastatic foci via a superior mesenteric vein injection of ACL-15 cells in F344 rats were significantly inhibited in the EPA-treated group compared with the LA-treated group (p < 0.01); the PA-treated animals and those fed commercial rodent chow (standard diet) demonstrated intermediate values. In a dot immunoblotting assay, vascular cell adhesion molecule 1 expression on ACL-15 cells was downregulated by EPA-ethyl ester treatment and upregulated by LA-ethyl ester treatment compared with the untreated control cells, whereas the expression of matrix metalloproteinase 1 and 2 was not influenced by the fatty acid ethyl esters. In a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, EPA-ethyl ester suppressed ACL-15 cell growth in a schedule-dependent manner, and LA-ethyl ester showed schedule-dependent stimulation. In contrast, PA demonstrated no regulatory effect on cell growth at lower concentrations (< or = 5 mg/ml) but concentration-dependent inhibition at higher concentrations. According to our in vivo cell kinetic study, the difference in tumor growth at the metastatic site was due to different tumor cell proliferation rates; the cell loss rate was not altered. Therefore, the inhibitory effect of liver metastasis on ACL-15 cells by EPA can be explained by a decreased ability of tumor cell adhesion to the capillary bed (low expression of vascular cell adhesion molecule 1) and a lower potential of tumor cell proliferation (low mitotic rate) at the secondary site.