[Benefits of 0.5T MR diffusion-weighted images for super-acute-phase cerebral infarction]

Though diffusion-weighted images (DWI) have been increasingly used to detect super-acute-phase cerebral infarction in recent years, they have primarily been obtained through the use of high magnetic machines of more than 1.5T. In this study, we discussed the usefulness of DWI obtained using 0.5T MRI in comparison with CT, MRI (FLAIR and T2 weighted image) and SPECT (99mTc-HMPAO). DWI were able to detect ischemic lesions earlier than FLAIR or T2-weighted images. Scanning time was short at four seconds for eight slices, and the quality of image was sufficient for clinical usage. The most available b-value seems to be 800. There were less susceptibility artifacts in the 0.5T DWI than in the 1.5T DWI. From these data, we presume that it is possible to detect super-acute-phase cerebral ischemia on the 0.5T DWI, proving the clinical usefulness of DWI. Furthermore, DWI is considered useful in observing chronological changes in cerebral infarction, differentiation of abscess or brain tumor, diagnosis of moyamoya disease, degenerative disease and so on.

Computed-tomography-based computer preoperative planning for total hip arthroplasty

For precise preoperative planning in total hip arthroplasty (THA), we developed a technique of computed tomography (CT)-based computer preoperative planning and compared this technique with the single X-ray and template method generally used. The subjects of this study were 42 hips in 38 patients who underwent THA using a cementless total hip system. Preoperatively, a standard anteroposterior X-ray of the hip was taken, and conventional preoperative planning was done with a template of the total hip system. Transverse images were obtained using a helical CT scanner, and a CT-based computer preoperative plan was performed on true coronal slice images of the proximal femur reconstructed from CT data. Postoperatively, 29 hips (69%) showed good proximal fit of the femoral component to the medial endosteal line. Of the 20 hips with good proximal fit on preoperative X-ray planning, 12 hips had good proximal fit on postoperative X rays. Sensitivity and specificity of the proximal fit on X-ray templating were 41 and 23%, respectively. In 27 of 28 hips with good proximal fit on reconstructed CT images preoperatively, the postoperative X ray revealed good proximal fit. Sensitivity and specificity of the proximal fit on computer planning were 93 and 86%, respectively. Twelve hips with good proximal fit on preoperative templating, the reconstructed images, and the postoperative X ray had 20 degrees or less of combined femoral neck anteversion and external rotational contracture of the hip on the X-ray table. Eight hips with good proximal fit on preoperative templating and proximal poor fit on the reconstructed images had 17-65 degrees of combined version and rotational contracture. In 16 hips with poor proximal fit on preoperative templating and good proximal fit on the reconstructed images, the combined version and rotational contracture ranged from 17 to 69 degrees. When combined femoral neck anteversion and external rotational contracture of the hip is less than 15 degrees, the simple X-ray and template method might be sufficient for THA planning. Otherwise, the CT-based method of preoperative planning is recommended.

Reduction of serum thyroxine concentrations by methylsulfonyl metabolites of tetra-, penta- and hexachlorinated biphenyls in male Sprague-Dawley rats

Male Sprague-Dawley rats received four consecutive intraperitoneal doses of nine methylsulfonyl (MeSO2) metabolites of tetra-, penta- and hexachlorinated biphenyls (tetra-, penta- and hexaCBs) to determine their effects on thyroid hormone levels. Nine MeSO2 metabolites, major MeSO2-PCBs detected in human milk, liver and adipose tissue, were 3-MeSO2-2,2',4',5-tetraCB (3-MeSO2-CB49), 3-MeSO2-2,3',4',5-tetraCB (3-MeSO2-CB70), 3-MeSO2-2,2',3',4',5-pentaCB (3-MeSO2-CB87), 3-MeSO2-2,2',4',5,5'-pentaCB (3-MeSO2-CB101), 4-MeSO2-2,2',4',5,5'-pentaCB (4-MeSO2-CB101), 3-MeSO2-2,2',3',4',5,6-hexaCB (3-MeSO2-CB132), 3-MeSO2-2,2',3',4',5,5'-hexaCB (3-MeSO2-CB141), 3-MeSO2-2,2',4',5,5',6-hexaCB (3-MeSO2-CB149) and 4-MeSO2-2,2',4',5,5',6-hexaCB (4-MeSO2-CB149). All nine MeSO2 metabolites (20 micromol/kg once daily for four days) reduced serum total thyroxine levels (16-44%) at a much lower dose than phenobarbital (431 micromol/kg once daily for four days) on days 2, 3, 4 and 7 after the last dosage. Total triiodothyronine level was reduced 37% by treatments with 3-MeSO2-CB49 and 3-MeSO2-CB149 at day 7, but increased 35% and 38% by 3-MeSO2-CB70 and 4-MeSO2-CB101 at days 3 and 4, respectively. The reductions in thyroxine levels led to an increase in thyroid-stimulating hormone levels by 3-MeSO2-CB49, 3-MeSO2-CB87, 3-MeSO2-CB101, 3-MeSO2-CB132, 3-MeSO2-CB141, 3-MeSO2-CB149 and 4-MeSO2-CB149. A 30% increase in thyroid weight was produced by 3-MeSO2-CB101 and 3-MeSO2-CB141 treatments. Total cytochrome P450 content and the activity of 7-pentoxyrosorufin O-dealkylase were increased by all seven 3-MeSO2-PCBs. 3-MeSO2-CB49, 3-MeSO2-CB87, 3-MeSO2-CB101 and 3-MeSO2-CB132 also increased the activity of 7-ethoxyresorufin O-dealkylase. Thus, it is likely that all nine tested MeSO2 metabolites could influence thyroid hormone metabolism. The results show that tested 3- and 4-MeSO2 metabolites of tetra-, penta- and hexaCBs reduce thyroid hormone levels in rats, suggesting that the metabolites may act as endocrine-disrupters.

MR findings of necrotic lesions and the extralesional area of osteonecrosis of the femoral head

OBJECTIVE

To investigate the MR findings of necrotic lesions and the extralesional area of osteonecrosis of the femoral head (ONFH) for each of the radiological stages.

DESIGN AND PATIENTS

Forty-nine hips in 29 patients (15 female, 14 male; mean age 38 years, range 17-59 years) were imaged using a 1.0-T superconducting magnet. T2-weighted spin echo pulse sequences (T2WI), spoiled gradient recalled echo pulse sequences (SPGR) and fat suppression SPGR (FS-SPGR), followed by Gd-DTPA enhanced fat suppression SPGR (Gd-FS-SPGR), were all obtained with the aid of a TORSO surface coil.

RESULTS AND CONCLUSIONS

While a normal fat intensity area with a low-intensity band on SPGR (band pattern) was seen in 16 of 16 stage 1 (100%), nine of 11 stage 2 (82%), four of 17 stage 3 (24%), and none of five stage 4 hips, all hips showed peripheral rim enhancement on Gd-FS-SPGR (100%). This enhancement band on Gd-FS-SPGR corresponded to histological findings of necrotic trabecular bone, repaired marrow, and fibrous reparative tissue. Bone marrow edema was also clearly demonstrated as a diffuse, high-intensity area outside this enhancement band on Gd-FS-SPGR in two stage 2 (18%), 12 stage 3 (71%), and one stage 4 hip (20%). In cases at stage 2 or more advanced stages with homogeneous or inhomogeneous low intensity on nonenhanced MRI, the reparative process both inside and outside the necrotic lesion, including bone marrow edema, was detected clearly on contrast-enhanced MRI.

The induction of hepatic microsomal UDP-glucuronosyltransferase by the methylsulfonyl metabolites of polychlorinated biphenyl congeners in rats

The effects of nine methylsulfonyl (MeSO(2)) metabolites of tetra-, penta- and hexachlorinated biphenyls (tetra-, penta- and hexaCBs; 20 micromol/kg once daily for 4 days) on the hepatic microsomal UDP-glucuronosyltransferase (UDP-GT) were investigated in male Sprague-Dawley rats. Each of the seven 3-MeSO(2)-PCBs, 3-MeSO(2)-2, 2',4',5-tetraCB (3-MeSO(2)-CB49), 3-MeSO(2)-2,3',4',5-tetraCB (3-MeSO(2)-CB70), 3-MeSO(2)-2,2',3',4',5-pentaCB (3-MeSO(2)-CB87), 3-MeSO(2)-2,2',4',5,5'-pentaCB (3-MeSO(2)-CB101), 3-MeSO(2)-2,2',3', 4',5,6-hexaCB (3-MeSO(2)-CB132), 3-MeSO(2)-2,2',3',4',5,5'-hexaCB (3-MeSO(2)-CB141), 3-MeSO(2)-2,2',4',5,5',6-hexaCB (3-MeSO(2)-CB149) and 4-MeSO(2)-2,2',4',5,5'-pentaCB (4-MeSO(2)-CB101) increased the activities of UDP-GT toward chloramphenicol, 4-nitrophenol and 4-methylumbelliferone. 4-MeSO(2)-2,2',4',5,5',6-hexaCB (4-MeSO(2)-CB149) increased the activity of UDP-GT toward chloramphenicol (UGT2B1) but not toward 4-nitrophenol (UGT1A6) and 4-methylumbelliferone (UGT1A6). The activity of UDP-GT toward thyroxine (T(4)) significantly increased after the administration of each of the seven 3-MeSO(2)-PCBs and 4-MeSO(2)-CB101. Significant correlation was found between the activity of UDP-GT toward T(4) and serum total T(4) concentration after the administration of each of the MeSO(2) derivatives except 4-MeSO(2)-CB149. In conclusion, seven 3-MeSO(2)-PCBs and 4-MeSO(2)-CB101 induce both UGT2B1 and UGT1A6, and 4-MeSO(2)-CB149 induces UGT 2B1. The results from the present study indicate that increase in the hepatic T(4) glucuronidation after the administration of the seven 3-MeSO(2)-PCBs and 4-MeSO(2)-CB101 possibly because of the induction of both UGT1A1 and UGT1A6 caused the reduction of serum T(4) levels.

Cloning of inulin fructotransferase (DFA III-Producing) gene from Arthrobacter globiformis C11-1

A gene encoding an inulin fructotransferase (DFA III-producing) [EC 2.4.1.93] from Arthrobacter globiformis C11-1 was cloned and the nucleotide sequence was determined. The cloned fragment contained a 1353 bp open reading frame. The initiation codon was estimated to be an unusual codon, GTG. The gene encoded a signal peptide (40 amino acid residues) for secretion. The molecular mass of the native enzyme was calculated as 43,400 Da from the sequencing data. The deduced amino acid sequence of the enzyme had 74.0 % homology with that of inulin fructotransferase (DFA III-producing) from Arthrobacter sp. H65-7. It also had 45.1% homology with that of inulin fructotransferase (DFA I-producing) [EC 2.4.1.200] from Arthrobacter globiformis S14-3. The enzyme produced in the culture supernatant of an Escherichia coli clone was purified to the electrophoretically homogeneous stage. The N-terminal amino acid sequence of the cloned enzyme secreted in the broth was the same as that of the native enzyme from A. globiformis C11-1. Therefore, on this enzyme, it is estimated that the cleavage sites by the signal peptidase for secretion of A. globiformis C11-1 and E. coli JM109 are the same.

The role of 3-methylsulfonyl-2,2',4',5,5'-pentachlorobiphenyl, a metabolite of 2,2',4,5,5'-pentachlorobiphenyl, in the induction of hepatic microsomal drug-metabolizing enzymes by 2,2',4,5,5'-pentachlorobiphenyl in rats

After the administration of 2,2',4,5,5'-pentachlorobiphenyl (2,2',4,5,5'-pentaCB) to intact rats, the concentration of 2,2',4,5,5'-pentaCB in liver gradually decreased, whereas 3-methylsulfonyl (3-MeSO(2))-2,2',4',5,5'-pentaCB appeared in liver and remained detectable in liver for 6 weeks. A single injection of 2,2',4,5,5'-pentaCB (342 μmol/kg) or 3-MeSO(2)-2,2',4',5,5'-pentaCB (0.5 μmol/kg) caused a significant increase both in the contents of cytochromes P450 and b(5) and in the activities of aminopyrine N-demethylase and benzo[a]pyrene hydroxylase, and the increased enzyme contents and activities continued for 6 weeks after the administration. The extent of both the hepatic accumulation of 3-MeSO(2)-2,2',4',5,5'-pentaCB and the induction of the enzymes for 6 weeks after the administration of 2,2',4,5,5'-pentaCB was similar to that after the administration of 3-MeSO(2)-2,2',4',5,5'-pentaCB. 3-MeSO(2)-2,2',4',5,5'-pentaCB was considered to play a principal role in the induction of microsomal drug-metabolizing enzymes by 2,2',4,5,5'-pentaCB. When 2,2',4,5,5'-pentaCB was injected i.p. into bile duct-cannulated rats, 3- and 4-MeSO(2)-2,2',4',5,5'-pentaCBs were not detected in liver. In antibiotic-treated rats dosed with 2,2',4,5,5'-pentaCB, the concentrations of 3- and 4-MeSO(2)-2,2',4',5,5'-pentaCBs in liver were markedly reduced. These findings suggest that the process in which 3- and 4-MeSO(2) metabolites of 2,2',4,5,5'-pentaCB are formed involves the biliary secretion of some precursors which will be subjected to metabolism by intestinal microflora. The increasing effects of 2,2',4,5,5'-pentaCB both on the content of cytochrome P450 and on the activity of aminopyrine metabolizing enzyme in hepatic microsomes were not observed in the bile duct-cannulated rats, in which the phenobarbital treatment enabled the drug-metabolizing enzymes to be induced. In antibiotic-treated rats, the increases both in the cytochrome P450 content and in the aminopyrine N-demethylase activity after the administration of 2,2',4,5,5'-pentaCB were smaller than those observed in the intact rats. These findings provide the evidence that the induction of some drug-metabolizing enzymes by 2,2',4,5,5'-pentaCB is due not to the action of 2,2',4,5,5'-pentaCB itself but to its 3-methylsulfonyl metabolite, 3-MeSO(2)-2,2',4',5,5'-pentaCB.

Exophthalmos, pretibial myxedema, osteoarthropathy syndrome associated with papillary fibroelastoma in the left ventricle

EMO syndrome, a rare complication of Graves' disease, exhibits exophthalmos, pretibial myxedema, and osteoarthropathy. The presence of functional thyrotropin receptors (TSHR) in adipocytes and osteoblasts, both of which we have recently observed, may be related to these extrathyroidal manifestations of Graves' disease. In addition, the expression of TSHR in the heart has recently been reported. We describe here a patient with Graves' disease exhibiting EMO syndrome with a papillary fibroelastoma in the left ventricle. Pathological examinations showed that the fibroelastoma contained Alcian blue-stained mucinous materials that were also observed in the subcutaneous tissue of pretibial myxedema.

Differential diagnosis between organic and inorganic mercury poisoning in human cases--the pathologic point of view

Differences in pathology were found between acute and chronic exposure to methylmercury, mercury vapor, and inorganic mercury. Characteristic pathologic changes produced by organic mercury in the brain have previously been described in patients with Minamata disease. The brains of patients who presented with acute onset of symptoms and died within 2-mo showed loss of neurons with reactive proliferation of glial cells, microcavitation, vascular congestion, petechial hemorrhage, and edema in the cerebral cortices, predominantly in the calcarine, pre- and postcentral, and transverse temporal cortices and in the cerebellar cortex. The neuropathologic changes in the patients with acute onset of symptoms who survived for a long period (>10 yr) were also included neuronal loss with reactive proliferation of glial cells in similar anatomic locations. The neuropathologic changes in patients with inorganic mercury poisoning are quite different. Autopsies performed on 3 individuals with fatal cases of acute inorganic mercury poisoning who were exposed to mercury vapor for about 2 wk revealed diffuse organized pneumonia, renal cortical necrosis, disseminated intravascular coagulopathy, and infarctions in the brain and kidneys. In 2 other patients who worked in mercury mines for about 10 yr and who suffered from chronic inorganic poisoning, no specific lesions were demonstrated in the brain. However, the assay and the histochemistry of mercury revealed that inorganic mercury was present in the brain in all 3 groups irrespective of the brain lesions and the duration of clinical signs.

Contrast-enhanced magnetic resonance imaging in a nontraumatic rabbit osteonecrosis model

We investigated early osteonecrosis using in vivo magnetic resonance imaging in a nontraumatic rabbit model of serum-sickness osteonecrosis in which osteonecrosis was induced after two intravenous injections of horse serum with a 3-week interval. One week (group A, 17 rabbits) and 3 weeks (group B, 13 rabbits) after the second serum injection, coronal magnetic resonance images of the femur were obtained and it was removed for histological study. Some of the necrotic lesions in the diaphysis were detected on T1-weighted, T2-weighted, or fat-suppression T1-weighted images (six of 24 necrotic lesions in group A and 16 of 18 in group B), and all of the necrotic lesions in the epiphysis, metaphysis, and diaphysis were detected on T1-weighted or fat-suppression T1-weighted images enhanced with gadolinium-diethylene triamine pentaacetic acid. All focal homogeneous enhanced areas on T1-weighted or fat suppression T1-weighted images corresponded to necrotic lesions (22 of 24 necrotic lesions in group A and 18 of 18 in group B); the contours of the enhanced areas were displayed more clearly on the fat-suppression T1-weighted than on the T1-weighted images. The fat-suppression T1-weighted image enhanced with gadolinium-diethylene triamine pentaacetic acid was thus the most sensitive and specific of five kinds of magnetic resonance images for the detection of early necrotic lesions. The results suggest that this image may be useful for early diagnosis of clinical osteonecrosis and for obtaining information about the pathomechanism of osteonecrosis.

Tumor necrosis factor-alpha and interferon-gamma suppress both gene expression and deoxyribonucleic acid-binding of TTF-2 in FRTL-5 cells

Tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) are cytokines that can individually or additively suppress thyroid cell function and the expression of thyroid-specific genes, such as thyroglobulin (TG) and thyroperoxidase (TPO). Thyroid transcription factor-2 (TTF-2) is a DNA-binding protein that modulates the expression of TG and TPO genes. In the present study, we examine the effects of TNF-alpha and IFN-gamma on TTF-2 gene expression, as well as the DNA-binding activity of TTF-2. FRTL-5 cells were maintained in 5H medium containing 0.2% calf serum for 7 days, then incubated with TNF-alpha, IFN-gamma, or TNF-alpha plus IFN-gamma. Total RNA was isolated and Northern blotted. TNF-alpha (50 ng/ml) only slightly suppressed (61+/-2% compared with control), whereas IFN-gamma (100 U/ml) modestly decreased TTF-2 messenger RNA (mRNA) levels (34+/-4%). TNF-alpha and IFN-gamma simultaneously caused a marked decrease in TTF-2 mRNA levels (13+/-2%). The suppressive effects of TNF-alpha and IFN-gamma on TTF-2 mRNA levels were concentration dependent and maximal at 50 ng/ml TNF-alpha with 100 U/ml IFN-gamma. The suppressive effect was also time dependent, reaching a maximum 12 h after exposure. Moreover, the suppressive effects of TNF-alpha and IFN-gamma upon rat TG and TTF-2 mRNA levels were similar. To test whether TNF-alpha and IFN-gamma alter TTF-2-binding to DNA, we performed electrophoretic mobility shift assays using a TTF-2-binding element in the rat TG gene as a probe. Formation of the TTF-2/DNA complex was decreased by TNF-alpha and/or IFN-gamma. Our results demonstrate that TNF-alpha and IFN-gamma additively reduce the gene expression and DNA-binding of TTF-2. These data suggest that TTF-2 is involved in the TNF-alpha and IFN-gamma-induced suppression of thyroid-specific gene expression.

Tissue distribution of methylsulfonyl metabolites derived from 2,2',4,5,5'-penta- and 2,2',3,4',5',6-hexachlorobiphenyls in rats

The time courses of fecal excretion and tissue distribution of metabolites derived from 2,2',4,5,5'-pentachlorobiphenyl (CB101) and 2,2',3,4',5',6-hexachlorobiphenyl (CB149) were investigated in male Wistar rats. The metabolism of both congeners involved primarily hydroxylation at the 3-position, and methylthiolation at the 4-position. Metabolites distributed in tissue were dominated by different ratios of 3- and 4-methylsulfonyl (MeSO2) metabolites. The 3-/4-MeSO2 metabolite ratios in liver and adipose tissue for both congeners were 0.41-0.61 at day 4, and then increased to 0.85-1.00 for up to day 42. In contrast, the ratios in lung were 0.03-0.04, and then decreased to 0.01. Compared to the unchanged PCBs at day 42, the distribution ratios of 3-MeSO2 metabolites were greater in the order of liver (0.46 for CB101 and 0.21 for CB149) > kidney > blood > lung > adipose tissue, whereas those of 4-MeSO2 metabolites were in the order of lung (9.50 for CB101 and 4.00 for CB149) > kidney > blood > liver > adipose tissue, indicating the different binding affinity of 3-MeSO2 metabolites in liver from that of 4-MeSO2 metabolites in lungs of rats. Furthermore, the structure-tissue affinity relationship for 3-MeSO2 metabolites was investigated, following the administration of 11 3-MeSO2-PCB congeners to rats. The results indicated that the retention potential of 3-MeSO2 metabolites in the liver largely depends on the ortho-chlorine substitution in the biphenyl ring rather than the degree of chlorination.

Effects of thyrotropin on the proliferation and differentiation of cultured rat preadipocytes

Thyrotropin receptor (TSHR) is expressed during the differentiation of rat preadipocytes and is highly abundant in mature fat adipocytes, but its physiological role is unknown. In this article, long-term effects of thyrotropin (TSH) on the proliferation and the differentiation were investigated using cultured rat preadipocytes. When TSH was added at the beginning of differentiation, TSH increased the number of preadipocytes and 3H-thymidine uptake. Apoptosis of the cells was not influenced by TSH. Preadipocytes incubated in the presence of TSH had fewer fat droplets, decreased level of mRNA for lipoprotein lipase (LPL), a marker of adipocyte differentiation. Histochemical study showed that the cells that increased their number and expressed lower level of LPL in response to TSH were preadipocytes, and not contaminating fibroblasts. In conclusion, TSH causes the proliferation and inhibits the differentiation of rat preadipocytes. Results suggest that TSH may be a potent regulator of preadipocyte proliferation and differentiation in vivo.

[Metabolism of 3,3',4,4',5-penta- and 2,2',3,3',4,4'-hexachlorobiphenyls in rats]

Following the i.p. administration of 3,3',4,4',5-pentachlorobiphenyl (CB126) and 2,2',3,3',4,4'-hexachlorobiphenyl (CB128) to rats, blood, liver, lung, kidney, adipose tissue and feces were analyzed for the metabolites. CB126 was biotransformed to three hydroxylated metabolites identified as 4-OH-3,3',4',5'-tetraCB, 4-OH-3,3',4',5,5'-pentaCB and 5-OH-3,3',4,4',5'-pentaCB at about 1:7:2 ratio, whereas to two methylthio metabolites as 5-MeS- and 6-MeS-3,3',4,4',5'-pentaCBs at 1:2 ratio. Among the metabolites, only 4-OH-3,3',4',5,5'-pentaCB was detected in all tissues and blood. The ratio of metabolite/unchanged CB126 was 1:1.3 in blood and 1:162 in liver, indicating the high blood affinity of this metabolite. Trace amounts of 5-methylsulfonyl-3,3',4,4',5'-pentaCB was also detected in the liver. CB128 was biotransformed to 5-OH-, 5-MeS- and 6-MeS-2,2',3,3',4,4' hexaCBs which were excreted to feces in about 5:5:1 ratio. No metabolites were detected in blood and any tissues except for liver where trace amounts of 5-hydroxylated metabolite was present, indicating the low tissue affinity of hydroxylated metabolites from CB128.

Induction of sister chromatid exchanges in cultured human lymphocytes with methylsulphonyl PCB congeners

Methylsulphonyl polychlorinated biphenyls (MSF-PCBs) have already contaminated at relatively high concentration in the lungs and blood of Yusho patients and healthy Japanese people. Therefore, we should give due attention to their biological and toxicological effects to man. In this study, in order to evaluate S-dependent genotoxicity of five MSF-PCB congeners, namely, 3-MSF-4,5,3',4'-tetrachlorobiphenyl (TCB), 3-MSF-4,5,2',3'-TCB, 3-MSF-2,5,2',4',5'-pentachlorobiphenyl (PenCB), 4-MSF-2,5,2',3',4'-PenCB and 4-MSF-2,5,2',3',5',6'-hexachlorobiphenyl (HCB), we have examined their effects on the induction of sister chromatid exchanges (SCEs), which has been frequently used to estimate the dose of S-dependent clastogens, in cultured human lymphocytes in the absence or presence of 2,3,4,7,8-pentachlorodibenzofuran (PenCDF), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or 3,4,5,3',4'-pentachlorobiphenyl (Co-PenCB) and the following results were obtained. 1) 4 x 10(-5)M, 7,8-benzoflavone (ANF) and two of the five MSF-PCB congeners, namely, 3-MSF-2,5,2',4',5'- and 4-MSF-2,5,2',3',4'-PenCB at respective doses of 5.2 and 5.8 ppm, which were about 35,000 times higher than the concentrations in the lungs and adipose tissue of healthy Japanese people, significantly enhanced the frequency of SCEs. 2) In the simultaneous treatment of one of the five MSF-PCB congeners and PenCDF (3.9 ppb), TCDD (1.5 ppb) or Co-PenCB (8.8 ppb), the combination of 3-MSF-4,5,3',4'-TCB (6.8 ppb) or 4-MSF-2,5,2',3',5',6'-HCB and one of the three highly toxic chemicals significantly promoted the formation of SCEs. We have already studied whether these MSF-PCBs are non-S-dependent genotoxic compounds or not and have obtained the results that they seemed not to be or very weak ones. Therefore, based on the results of this and our former studies, the five MSF-PCB congeners examined are considered rather potent S-dependent genotoxic chemicals than non-S-dependent ones.

[Analysis of 209 PCB congeners by high separation gas chromatography/low resolution mass spectrometer]

All PCB congeners were analyzed by high separation gas chromatography/low resolution mass spectrometer, using 209 PCB congeners as standards. They were separated into 169 peaks, including 28 peaks containing 2 PCBs and 8 peaks containing 3 PCBs. The rice oil samples of Fukuoka and Taiwan Poisonings were analyzed for PCB congeners. They showed 115 separated peaks of PCB congeners. Total PCB concentrations were 879 and 769 ppm in 2 samples of Fukuoka rice oil and 57 and 83 ppm in 2 samples of Taiwan rice oil.

[Analysis of all PCB congeners in breast milk and blood of Yusho patients]

Breast milk and blood of Yusho patients were analyzed for polychlorinated biphenyl (PCB) congeners by High separation gas chromatography/Low resolution mass spectrometer. Seventy-one and forty-nine PCB congeners were identified and quantified in the breast milk and blood, respectively. Total PCB concentrations (Whole base) in breast milk of 2 Yusho patients were 69.9 and 15.1 ppb, respectively, being 11.6 and 2.5 times higher than those of 4 control breast milk. Average total PCB concentration of 5.0 ppb in whole blood of 13 Yusho patients was 3.6 times higher than those of control persons. Fourteen PCB congeners, such as 99, 117, 130, 137, 138, 156, 157, 164, 170, 171, 172, 189, 191 and 195, were particularly higher concentration in breast milk and blood of Yusho patients than in those of control persons. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and coplanar PCBs were also analyzed in the breast milk of Yusho patients and control persons. Large portions, 83 and 74%, of Dioxin toxic equivalency (TEQ) in the 2 Yusho breast milk were consisted of TEQ of 2,3,4,7,8-pentaCDF only, while total TEQ in the breast milk of control persons was consisted of PCDFs 48%. PCDDs 29% and coplanar PCBs 23%.

A novel adenovirus E1B19K-binding protein B5 inhibits apoptosis induced by Nip3 by forming a heterodimer through the C-terminal hydrophobic region

The adenovirus E1B19K protein inhibits apoptosis induced by E1A and other divergent signals. The cellular proteins that interact with E1B19K have been analyzed by isolating cDNA clones by the yeast two hybrid system. One of these clones encodes B5 which consists of 219 amino acid residues and contains the putative BH3 and transmembrane regions. B5 binds strongly to Nip3 and itself, weakly to E1B19K, but not to Bcl-2 and localizes in nuclear envelope, endoplasmic reticulum and mitochondria. B5 has sequence homology with Nip3 in the middle and C-terminal regions, but not in the N-terminal region. Unlike other E1B19K binding BH3 proteins so far characterized, B5 does not induce apoptosis, but inhibits apoptosis induced by Nip3. However the deletion mutant B5Delta1-31 lacking the N-terminus does induce apoptosis, although weaker than does Nip3, suggesting that the N-terminal region is masking the apoptosis-inducing capacity of B5.

Reduction of thyroid hormone levels by methylsulfonyl metabolites of tetra- and pentachlorinated biphenyls in male Sprague-Dawley rats

Male Sprague-Dawley rats received four consecutive intraperitoneal (i.p.) doses of five kinds of methylsulfonyl (MeSO2) metabolites of tetra- and pentachlorinated biphenyls (tetra- and pentaCBs) to determine their effects on thyroid hormone levels. The five MeSO2 metabolites, which were the major MeSO2-PCBs detected in human milk, liver and adipose tissue were 3-MeSO2-2,2',4',5-tetraCB (3-MeSO2-CB49),3-MeSO2-2,3',4',5-tetraCB (3-MeSO2-CB70), 3-MeSO2-2,2',3',4',5-pentaCB (3-MeSO2-CB87), 3-MeSO2-2,2',4',5,5'-pentaCB (3-MeSO2-CB101), and 4-MeSO2-2,2',4',5,5'-pentaCB (4-MeSO2-CB101). All five tested MeSO2 metabolites (20 mumol/kg once daily for 4 days) reduced serum total thyroxine levels 16-40% on days 2, 3, 4, and 7 (after the last dosage). The total triiodothyronine level was reduced 37% by treatment with 3-MeSO2-CB49 at day 7, but was increased 35% and 38% by 3-MeSO2-CB70 and 4-MeSO2-CB101 at days 3 and 4, respectively. The reductions in thyroid hormone levels led to an increase in thyroid stimulating hormone (TSH) levels by 3-MeSO2-CB49, 3-MeSO2-CB87 and 3-MeSO2-CB101. A 30% increase in thyroid weight was produced by 3-MeSO2-CB101 treatment. Thus, it is likely that all five tested MeSO2 metabolites could influence thyroid hormone metabolism. The results show that the tested 3- and 4-MeSO2 metabolites of tetra- and pentaCBs reduce thyroid hormone levels in rats, suggesting that the metabolites may act as endocrine-disrupters.

Hydroxylation and methylthiolation of mono-ortho-substituted polychlorinated biphenyls in rats: identification of metabolites with tissue affinity

The metabolism of three mono-ortho-substituted congeners, 2,3,3',4, 4'-pentachlorobiphenyl (CB105), 2,3',4,4',5-pentachlorobiphenyl (CB118), and 2,3,3',4,4',5-hexachlorobiphenyl (CB156), was investigated with regard to the identification of hydroxy- and sulfur-containing metabolites and their tissue retention in rats. Hydroxylation proceeded primarily at the meta or para position either via an arene oxide, involving NIH shift and dechlorination, or by direct insertion of a hydroxyl group. CB105 was hydroxylated preferably in the 2,3,4-trichlorinated ring to yield 4-OH-2,3,3',4', 5-pentaCB, whereas CB118 was hydroxylated in the 2,4, 5-trichlorinated ring to yield the same hydroxy metabolite to a similar extent. The concentration of 4-OH-2,3,3',4',5-pentaCB in blood was >3 times higher than that in liver, lung, or kidney. The ratios of 4-OH-2,3,3',4',5-pentaCB to unchanged CB in blood were 11:1 for CB105 and 7:1 for CB118. The other two metabolites, 4'-OH-2, 3',4,5,5'-pentaCB from CB118 and 4'-OH-2,3,3',4,5,5'-hexaCB from CB156, also exhibited a high blood affinity. Another metabolism of mono-ortho-PCBs PCBs involved methylthiolation in the vicinal ortho and meta unsubstituted positions to give methylthio metabolites, which were detected as methylsulfonyl metabolites in liver and adipose tissue. The tissue retention of these metabolites might contribute to the toxic and biologic effects of mono-ortho-substituted PCBs.

[The Osaka concept. "Dome osteotomy" with of without labrum resection]

Acetabular dysplasia represents the most common aetiology for secondary osteoarthritis of the hip joint in Japan. On radiographs progress of the disease can be classified in four stages (I to IV). Labral lesions are common accompanying findings in acetabular dysplasia, representing an important prognostic factor. Therefore we routinely use conventional arthrography to classify labral lesions in three types (normal, torn and detached). From 1978 to 1983 a modified Chiari osteotomy of the pelvis (dome osteotomy) was performed in 64 hip joints without arthrotomy. The preoperative radiography showed labral lesions in 66%. After an average follow-up of 4 years, 43 of the 44 patients with a normal or torn labrum showed excellent or good results. On contrast, 50% of the 20 patients with a detached labrum showed fair and poor results only. From 1984 to 1989 an arthrotomy was combined with dome osteotomy in 29 hip joints and labral lesions had to be resected in 16 cases. The results were generally good in patients with arthrosis grade I and II, but in stage III they were only fair. Thus, the success of labral surgery can only be achieved in early stages of dysplasia. Based on our findings dome osteotomy combined with arthrotomy and labral surgery can be recommended in patients with labral lesions and hip dysplasia grade I and II.

The glycosylphosphatidylinositol-anchored phosphatase from Spirodela oligorrhiza is a purple acid phosphatase

We recently presented clear evidence that the major low-phosphate-inducible phosphatase of the duckweed Spirodela oligorrhiza is a glycosylphosphatidylinositol (GPI)-anchored protein, and, to our knowledge, is the first described from higher plants (N. Morita, H. Nakazato, H. Okuyama, Y. Kim, G.A. Thompson, Jr. [1996] Biochim Biophys Acta 1290: 53-62). In this report the purified 57-kD phosphatase is shown to be a purple metalloenzyme containing Fe and Mn atoms and having an absorption maximum at 556 nm. The phosphatase activity was only slightly inhibited by tartrate, as expected for a purple acid phosphatase (PAP). Furthermore, the protein cross-reacted with an anti-Arabidopsis PAP antibody on immunoblots. The N-terminal amino acid sequence of the phosphatase was very similar to those of Arabidopsis, red kidney bean (Phaseolus vulgaris), and soybean (Glycine max) PAP. Extracts of S. oligorrhiza plants incubated with the GPI-specific precursor [3H]ethanolamine were treated with antibodies raised against the purified S. oligorrhiza phosphatase. Radioactivity from the resulting immunoprecipitates was specifically associated with a 57-kD band on sodium dodecyl sulfate-polyacrylamide gels. These results, together with previous findings, strongly indicate that the GPI-anchored phosphatase of S. oligorrhiza is a PAP.

[Effective splenectomy in a patient with HIV-associated thrombocytopenia]

A 31-year-old man presented with a 3-month history of petechial hemorrhages. Physical examination revealed no splenomegaly. The patient's platelet count was 1.0 x 10(9)/l and bone marrow aspiration showed an elevated number of megakaryocytes. A diagnosis of HIV-associated thrombocytopenia was made on the basis of HIV seropositive results. The CD4 cell count was 400 x 10(6)/l. No opportunistic infections indicating AIDS were detected. Initially the patient was treated with predonisolone, but showed only a transient response. He also failed to respond to zidovudine, lamivudine, or indinavir. Following splenectomy, however, his platelet count rose above 80 x 10(9)/l (normal level: 150-350 x 10(9)/l).

Analysis of differentiation-induced expression mechanisms of thyrotropin receptor gene in adipocytes

Rat adipose tissue, as well as differentiated 3T3-L1 cells, has been shown to express TSH receptor (TSHR) mRNA in amounts approaching those in the thyroid. We investigated the molecular mechanisms of TSHR gene expression in adipose cells. Primer extension and cloned cDNA sequences showed that transcription of the TSHR gene in rat adipose tissue was from multiple start sites clustered between -89 to -68 bp and almost identical to those in FRTL-5 thyroid cells. By transient expression analysis, we localized, between -146 and -90 bp, a positive regulatory element, the activity of which was markedly increased after the differentiation of 3T3-L1 cells. Deoxyribonuclease I protection showed that nuclear extracts from differentiated 3T3-L1 cells strongly protected two sequences, from -146 to -127 bp, including a cAMP response element-like sequence and from -112 to -106 bp containing a putative Ets-binding sequence. In differentiated 3T3-L1 cells, disruption or deletion of either sequence was found to result in the loss of enhancer activity, suggesting both elements may synergistically activate the TSHR promoter. Electrophoretic mobility shift analysis revealed the induction of new protein/DNA complexes formed either with the cAMP response element-like site or with putative Ets elements after the differentiation into adipocytes. In contrast, nuclear proteins, whose binding to DNA was diminished after the differentiation of 3T3-L1 cells, were found to interact with the site contiguous to the 5'-end of the putative Ets-binding sequence. Mutations of this binding site, which reduced the protein/DNA complex formation, increased TSHR promoter activity in undifferentiated cells. These observations suggested that differentiation-induced diminution of suppressor interactions may allow the enhancers to synergistically activate the transcription of TSHR gene in adipocytes.

Effects of cytokines on expression of thyrotropin receptor mRNA in rat preadipocytes

Cultured rat preadipocytes express thyrotropin receptor (TSHR) during their differentiation. To evaluate the effects of inflammatory cytokines on the expression of TSHR in cultured rat preadipocytes, we cultured those cells in the presence of recombinant human tumor necrosis factor (rhTNF)-alpha, recombinant human interferon (rhIFN)-gamma, and human transforming growth factor (hTGF)-beta1. The effects on the level of TSHR mRNA and signal transduction were evaluated. Addition to the medium of 1 ng/mL TNF-alpha, 1 ng/mL rhIFN-gamma, and 1 ng/mL hTGF-beta1 during the differentiation of rat preadipocytes inhibited the expression of TSHR mRNA. The decrease in TSHR mRNA was accompanied by a decrease in TSH-stimulated cyclic adenosine monophosphate (cAMP) production. Histochemical analysis showed that these cytokines inhibited the morphological differentiation of the cells. These cytokines also decreased the expression of mRNA for such fat-specific proteins as lipoprotein lipase and aP2. Results indicate that the loss of expression and function of the TSHR is closely related to the inhibition of differentiation. This confirms the close relation between the expression of the TSHR and the differentiation of the rat preadipocytes.

Reduction of thyroid hormone levels by methylsulfonyl metabolites of polychlorinated biphenyl congeners in rats

Male Sprague-Dawley rats received four consecutive intraperitoneal doses of four kinds of methylsulfonyl (MeSO2) metabolites of polychlorinated biphenyl (PCB) congeners: 3-MeSO2-2,2',3',4',5,6-hexachlorobiphenyl (3-MeSO2-CB132); 3-MeSO2-2,2',3',4', 5,5'-hexachlorobiphenyl (3-MeSO2-CB141); 3-MeSO2-2,2',4',5,5',6-hexachlorobiphenyl (3-MeSO2-CB149) and 4-MeSO2-2,2',4',5,5',6-hexachlorobiphenyl (4-MeSO2-CB149). The congeners were major MeSO2-PCBs determined in human milk, liver and adipose tissue, and the aim was to determine their effect on thyroid hormone levels. All four tested MeSO2 metabolites (20 micromol/kg once daily for 4 days) reduced serum total thyroxine levels by 22-44% at a much lower dose than phenobarbital (PB; 431 micromol/kg once daily for 4 days) on days 2, 3, 4 and 7 after the final doses. Total triiodothyronine levels were reduced 37% by treatment with 4-MeSO2-CB149 at day 7. A 30% increase in thyroid weight was produced by 3-MeSO2-CB141 treatment. Total cytochrome P450 content was increased by 3-MeSO2-CB132, 3-MeSO2-CB141 and 3-MeSO2-CB149, but not by 4-MeSO2-CB149. Thus, it is likely that the 3-MeSO2-hexachlorobiphenyls and 4-MeSO2-CB149 could influence the thyroid hormone metabolism by different mechanism(s). The results show that tested 3- and 4-MeSO2 metabolites of PCB congeners reduce thyroid hormone levels much more than PB in rats. Our finding suggests that the metabolites may act as endocrine-disrupters.

Methyl sulphone metabolites of polychlorinated biphenyls (PCBs) in cetaceans from the Irish and the Aegean Seas

The levels of PCBs and PCB methyl sulphone metabolites were determined in the blubber of six species of cetaceans that originated from the Irish Sea and the Aegean Sea (Mediterranean). Burdens ranging from 2.80 to 27.80 microg g-1 (lipid weight) total PCBs and 0.03 to 0.58 microg g-1 (lipid weight) total methyl sulphones were recorded. The highest cetacean methyl sulphone burden (0.58 microg g-1) was in an Irish Sea harbor porpoise (Phocoena phocoena). Methyl sulphone isomer formation capacity, as determined by PCB:MSF ratios, varied considerably between species as follows: harbour porpoise (1:10) > pilot whale (Globicephalus melas), white-sided dolphin (Lagenorhyncus acutus) (1:50) > common dolphin (Delphinus delphis), Risso's dolphin (Grampus griseus), and striped dolphin (Stenella coerueoalba), (1:100), and was related to interspecific variation in PCB methyl sulphone formation capacity.

Intramolecular oxyselenation of (5'S)-C-(4-phenyl-1,3-butadienyl)uridine: synthesis of octosyl nucleosides

(5'S)-C-(4-Phenyl-1,3-butadienyl)uridine (8) was prepared from the (5'S)-C-styryl derivative 2. Intramolecular oxyselenation of 8 proceeded in a 6-endo-trig manner to yield the cyclized product 9. Compound 9, having appropriate substituents at the 5'-, 6'-, and 7'-positions, was found to serve as a key intermediate for the synthesis of octosyl nucleosides.

Transient isolated thyrotropin deficiency associated with cavernous sinus syndrome

The cause and course of isolated thyrotropin (TSH) deficiency are not well understood. We report a 65-year-old man with a transient, probable isolated TSH deficiency associated with cavernous sinus syndrome secondary to tympanitis. On his admission, serum TSH and triiodothyronine levels were very low. No TSH response to thyrotropin releasing hormone (TRH) was observed. However, 6 years later, TSH response to TRH was restored. The present case showed that inflammation in the cavernous sinus could be one of the causes of TSH deficiency. Further, it demonstrated that TSH deficiency is not always permanent and the reevaluation of pituitary function is necessary.

Catalepsy induced by calcium channel blockers in mice

It is known that calcium channel blockers induce Parkinsonism. In this study, amlodipine-, diltiazem-, and verapamil-induced catalepsy was investigated in mice. All of these three calcium channel blockers induced catalepsy. Dopamine D1, D2, and mACh receptor occupancies were estimated under the same conditions, and the affinities of these drugs for each receptor were also estimated in vitro. Intensity of catalepsy was predicted by dopamine D1, D2, and mACh receptor occupancies with the dynamic model which had already been constructed and was compared with the observed values. The predicted and the observed values were comparable (r = 0.98, p < 0.001). In conclusion, the dynamic model considering D1, and D2, and mACh receptor occupancy may be useful for quantitative prediction of drug-induced catalepsy.

Inhibition of cell-cell communication by methylsulfonyl metabolites of polychlorinated biphenyl congeners in rat liver epithelial IAR 20 cells

The effects of three polychlorinated biphenyl (PCB) congeners and their six methylsulfonyl (MeSO2)-metabolites on cell communication have been investigated in the scrape-loading/dye-transfer assay in IAR 20 rat liver epithelial cells. The results demonstrated that at non-cytotoxic concentrations 2,2',4',5-tetrachlorobiphenyl, 2,2',4',5,5'-pentachlorobiphenyl (2,2',4',5,5'-pentaCB), 2,2',4',5,5',6-hexachlorobiphenyl (2,2',4',5,5', 6-hexaCB), and their 3- and 4-MeSO2 derivatives completely inhibited the cell communication within 1 h. 4-MeSO2-2,2',4',5,5'-pentaCB and 4-MeSO2-2,2',4',5, 5',6-hexaCB appeared to inhibit the cell communication at slightly lower concentration than their parental PCB congeners and 3-MeSO2 derivatives. The results show that 3- and 4-MeSO2 derivatives of the PCB congeners tested inhibit gap junction intercellular communication at about the same potency as their parental compounds. Since inhibition of cell communication is often observed after treatment with many tumor promoters, our findings suggest that the metabolites may also act as tumor promoters.

Activation of serum response factor in the liver of Long-Evans Cinnamon (LEC) rat

We have studied the DNA binding activities of transcription factors in the liver of Long-Evans Cinnamon (LEC) rats, an animal model of Wilson's disease. Owing to a genetic defect, this strain of rats accumulates excessive copper in the liver and develops severe hepatitis and hepatocellular carcinoma. We found that the DNA binding activity of the serum response factor (SRF) was higher in the liver of LEC rats (approximately 2-fold) than in that of Wistar rats. There was a close correlation between the intensity of the activity and the concentrations of copper in the nuclear protein. The DNA binding activity of Sp1, on the other hand, showed similar levels in both LEC and Wistar rats. SRF may play an important role in the development of hepatocellular carcinoma in LEC rats by mediating the proto-oncogene c-fos induction. We suggest that the copper in nuclear protein may be involved in the activation of SRF.

Iodide uptake and experimental 131I therapy in transplanted undifferentiated thyroid cancer cells expressing the Na+/I- symporter gene

131I therapy is a widely accepted treatment for differentiated thyroid cancers which can accumulate iodide. We evaluated the efficiency of 131I therapy against tumors which are transfected with the Na+/I- symporter (NIS) gene. We transfected the rat NIS cDNA expression vector into malignantly transformed rat thyroid cells (FRTL-Tc) which do not concentrate iodide. The resultant cell line (Tc-rNIS) accumulated 125I 60-fold in vitro. The FRTL-Tc cells formed solid tumors after injection of cells into subcutaneous tissues of Fischer 344 rats. Tumors formed with Tc-rNIS cells accumulated up to 27.3% of total 125I administered, and concentrated 125I 11 to 27-fold in the tumors. Extracorporeal measurement of radioactivity in the tumors revealed that 125I accumulation peaked at 90 min, and decreased to half levels 6 h after the injections. To investigate the effect of 131I administration on the tumor growth, we injected Na131I 2 and 3 weeks after the transplantation of the cells. The Na131I did not change the tumor volume significantly in either the FRTL-Tc or the Tc-rNIS-induced tumors. The short (6 h) effective half life of 131I in the tumors diminished the radiation dose to the tumor cells. However, this approach may prove beneficial in the treatment of radiosensitive cancers, and could be employed diagnostically.

Epstein-Barr virus-positive multiple early gastric cancers and dysplastic lesions: a case report

Epstein-Barr virus (EBV) has been implicated as a causal virus of gastric cancer with episomal monoclonality, elevated antibodies and a unique morphologic expression in the early intramucosal stage, but the infection mechanisms have not been demonstrated. EBV has been shown only in the cancerous lesions by the highly sensitive EBV-encoded small RNA in situ hybridization (EBER-ISH) method, not in the dysplastic mucosa adjacent to the cancer. A case is presented of multiple EBV-positive gastric cancer and dysplastic epithelium observed in a 52-year-old man. Serial cut sections of the gastrectomy specimen showed four small cancerous lesions, three of which were EBER-positive, and three EBER-positive, minute, non-cancerous dysplastic lesions. The three cancerous lesions were intramucosal cancer, with one having minimal submucosal invasion forming a lymphoepithelioma-like histology. All of these EBER-positive cancerous and dysplastic lesions showed intense CD8 T-lymphocytic infiltration. There was no such findings in the EBV-negative cancerous lesion. It was concluded that EBV infection may occur in the epithelial cells of atrophic gastric mucosa, and progress to cancer with monoclonal expansion through the EBV-positive dysplastic change. Cytotoxic T-lymphocytic reactions can occur even in the dysplastic lesions. Multifocal EBV infection in the gastric mucosa may occur and, if necessary, total gastrectomy is recommended in such a case.

Tissue distribution kinetics of a new nonsteroidal 5 alpha-reductase [correction of 5 A-reductase] inhibitor, 4-[3-[3-[bis(4-isobutylphenyl)methylamino]benzoyl]-1H-indol-1-YL ]-butyric acid, in rats

The disposition of a new nonsteroidal 5alpha-reductase inhibitor, 4-[3-[3-[bis(4-isobutylphenyl)methylamino]benzoyl]-1H-indol-1-yl]-butyric acid (FK143), was investigated in rats. After intravenous administration of FK143 at 1 and 5 mg/kg, total body clearance, elimination half-life, and volume of distribution at steady-state were, respectively, 6.96 and 8.76 ml/min/kg, 10.31 and 9.83 hr, and 4.11 and 3.33 liters/kg. There were no essential differences between the two doses in any parameters. The serum protein binding in vitro was very high (>99%). The unidirectional uptake clearance (CL1) to 13 tissues was determined by integration plot until 10 min after intravenous administration of 1 mg/kg. CL1 values were much smaller than blood flow rate in all tissues, including the prostate, the target organ, indicating that FK143 was transported from blood to tissues by a membrane-limited process. Since the elimination rates of FK143 from the liver, kidney, lung, epididymis, seminal vesicle, and prostate were slower than from the blood, the efflux rate constant (k2) and rate constants at a binding compartment (k3 and k4) were assumed in the pharmacokinetic model. A correlation was found between the binding potential of binding compartment (k3/k4) and V(max) of steroid 5alpha-reductase, the target enzyme, suggesting that the levels of 5alpha-reductase activity or that of associated substances are a primary determinant of the specific binding of FK143 in these tissues.

Purification and characterization of the acid soluble 26-kDa polypeptide from soybean seeds

Whey proteins from soybean seeds of Japanese varieties were analyzed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Among 11 varieties of soybean, three green and one black soybeans lacked a 26-kDa band that was found in all yellow soybeans. In this paper, the 26-kDa protein was named AS26k (acid soluble 26-kDa protein) temporarily. The AS26k protein was purified from Glycine max cv. Nattosyoryu, which is yellow soybean, through four purification steps: 30-35% saturated ammonium sulfate fractionation, ion exchange chromatography on S Sepharose Fast Flow, gel filtration on Sephadex G-100, and hydrophobic chromatography on phenyl Sepharose CL-4B. Purified AS26k was cleaved with V8 proteinase from Staphylococcus aureus or CNBr. The cleaved polypeptide contained two typical dehydrin motif sequences: DEYGNPV and (M)DKIKEKLPG, and a 19 amino acids sequence similar to a pea dehydrin. Native AS26k had a molecular mass of 32 kDa on gel filtration and a pl of 7.2 on two-dimensional PAGE. Similarly to other dehydrins and late embryogenesis abundant (LEA) proteins, AS26k was rich in hydrophilic amino acids, and highly heat stable. These results showed that AS26k was a dehydrin, a group II LEA protein in soybean seeds.

Metabolism of 3,3',4,4'-tetrachlorobiphenyl via sulphur-containing pathway in rat: liver-specific retention of methylsulphonyl metabolite

1. Single doses of 3,3',4,4'-tetrachlorobiphenyl (TCB) were administered intraperitoneally to the male Wistar rat for metabolism studies. 2. Seven sulphur-containing metabolites of TCB were isolated from faeces, in addition to previously reported 4-hydroxy-3,3',4',5-tetrachlorobiphenyl and 5-hydroxy-TCB. Major sulphur-containing metabolites were 5- and 6-methylthio-TCBs, and 6-methylsulphonyl-3-methylthio-3',4,4'-trichlorobiphenyl. 3. The faecal excretions of hydroxy metabolites, methylthio metabolites and unchanged TCB accounted for 7.1, 0.5 and 0.3% of the dose respectively within 4 days after administration. 4. 5-Methylsulphonyl-TCB was detected and selectively retained in liver. The concentration ratio of 5-methylsulphonyl-TCB and unchanged TCB in liver was 1:4. 5. Following administration of 5- and 6-methylsulphonyl-TCBs to rat, 5-methylsulphonyl-TCB was localized in liver, whereas 6-methylsulphonyl-TCB was rapidly biotransformed to 6-methylsulphonyl-3-methylthio-3',4,4'-trichlorobiphenyl and excreted in the faeces.

Comparative study on formation of hydroxy and sulfur-containing metabolites from different chlorinated biphenyls with 2,5-substitution in rats

2,4',5-Trichlorobiphenyl (TriCB), 2,3',4',5-tetrachlorobiphenyl (TetraCB), 2,2',4',5,5'-pentachlorobiphenyl (PentaCB), and 2,2',3',4',5,5'-hexachlorobiphenyl (HexaCB) were studied with regard to the fecal excretion and tissue distribution of their metabolites after intraperitoneal injection to rats. Major fecal metabolites were 3- and 4-hydroxy and 3- and 4-methylthio derivatives, the substitution ratios depending largely on the degree of chlorination. As the degree of chlorination increased, hydroxy products were more efficiently excreted, whereas the formation of methylthio metabolites greatly decreased. As a result, the excretion ratios of methylthio and hydroxy products varied with 2.8 for TriCB, 1.3 for TetraCB, 0.04 for PentaCB, and 0.02 for HexaCB. The 3-/4-hydroxy substitution ratios were 0.6 for TriCB, 1.4 for TetraCB, 21 for PentaCB, and 35 for HexaCB, whereas the 3-/4-methythio substitution ratios were 1.2 for TriCB, 0.8 for TetraCB, 0.18 for PentaCB, and 0.12 for HexaCB. The formation rate of 3- and 4-methylthio metabolites from each congener was correlated to the accumulation and distribution of 3- and 4-methylsulfonyl derivatives in tissues. The tissue/blood concentration ratios of methylsulfonyl metabolites showed that the 3-methylsulfonyl derivatives from higher chlorinated biphenyls had a relatively high affinity for liver and adipose tissue, whereas the 4-methylsulfonyl derivatives were selectively retained in the lung in all cases.

Structure-dependent induction of CYP2B1/2 by 3-methylsulfonyl metabolites of polychlorinated biphenyl congeners in rats

The effects of eleven 3-methylsulfonyl (3-MeSO(2))-metabolites of polychlorinated biphenyl (PCB) congeners (which were reported to remain in Swedish mother's milk and Japanese Yusho patient's tissues) and their two structurally similar 3-MeSO(2)-PCBs on the hepatic drug-metabolizing enzyme activities were compared with those of phenobarbital (PB) and 3-methylcholanthrene (3-MC).The induction profile of the drug-metabolizing enzymes, CYP2B1 and CYP2B2 in the hepatic microsomes of rats treated with nine 3-MeSO(2) derivatives, namely 3-MeSO(2)-2,4',5-trichlorobiphenyl, 3-MeSO(2)-2,2',4',5-tetrachlorobiphenyl (3-MeSO(2)-2,2',4',5-tetraCB), 3-MeSO(2)-2,2',5,5'-tetraCB, 3-MeSO(2)-2,3',4',5-tetraCB, 3-MeSO(2)-2,2',3',4',5-pentachlorobiphenyl (3-MeSO(2)-2,2',3',4',5-pentaCB), 3-MeSO(2)-2,2',4',5,5'-pentaCB, 3-MeSO(2)-2,2',3',4',5,5'-hexachlorobiphenyl (3-MeSO(2)-2,2',3',4',5,5'-hexaCB), 3-MeSO(2)-2,2',3',4',5,6-hexaCB and 3-MeSO(2)-2,2',4',5,5',6-hexaCB, was similar to that of rats treated with PB, but was different from that of rats treated with 3-MC. These findings indicate that 3-MeSO(2) metabolites derived from nine PCBs are PB-type inducers of microsomal drug-metabolizing enzymes. The relative inducing potencies of 3-MeSO(2) derivatives on the hepatic drug-metabolizing enzyme activities differed with the extent of chlorination and the positions of chlorine substituent on the phenyl rings. The results of present study show that the structure-CYP2B1/2 induction relationship exists for the 3-MeSO(2) derivatives studied. The inducing abilities of 3-MeSO(2)-2,2',4',5-tetraCB and 3-MeSO(2)-2,2',4',5,5'-pentaCB (2 μmol/kg) on the content of cytochrome P450 were higher than those of 2,3',4,4',5-pentaCB (mono-ortho-substituted PCB) (80 μmol/kg), 3,3',4,4'-tetraCB (coplanar PCB) (80 μmol/kg) and 3,3',4,4',5-pentaCB (coplanar PCB) (0.5 μmol/kg). The inducing effects of the administration of 3-MeSO(2)-2,2',4',5-tetraCB and 3-MeSO(2)-2,2',4',5,5'-pentaCB at 2 μmol/kg on the contents of total cytochrome P450, CYP2B1 and CYP2B2 corresponded to those of PB at 431 μmol/kg twice at a 24 h interval. It is noticeable that 3-MeSO(2)-2,2',4',5-tetraCB and 3-MeSO(2)-2,2',4',5,5'-pentaCB have highly potent PB-type inducing activity on drug-metabolizing enzyme systems.

Prediction of drug-induced catalepsy based on dopamine D1, D2, and muscarinic acetylcholine receptor occupancies

It is known that catalepsy serves as an experimental animal model of parkinsonism. In this study, the relationship between in vivo dopamine D1 and D2 receptor occupancies and catalepsy was investigated to predict the intensity of catalepsy induced by drugs that bind to D1 and D2 receptors nonselectively. 3H-SCH23390 and 3H-raclopride were used for the labeling of D1 and D2 receptors, respectively. The ternary complex model consisting of agonist or antagonist, receptor, and transducer was developed, and the dynamic parameters were determined. After coadministration of SCH23390 and nemonapride, catalepsy was stronger than sum of the values predicted by single administration of each drug, and it was intensified synergistically. This finding suggested the existence of interaction between D1 and D2 receptors, and the necessity for constructing the model including this interaction. To examine the validity of this model, catalepsy and in vivo dopamine receptor occupancy were measured after administration of drugs that induce or have a possibility to induce parkinsonism (haloperidol, flunarizine, manidipine, oxatomide, hydroxyzine, meclizine, and homochlorcycilzine). All of the tested drugs blocked both dopamine D1 and D2 receptors. Intensity of catalepsy was predicted with this dynamic model and was compared with the observed values. In contrast with haloperidol, flunarizine, manidipine, and oxatomide (which induced catalepsy), hydroxyzine, meclizine, and homochlorcyclizine failed to induce catalepsy. Intensities of catalepsy predicted with this dynamic model considering the interaction between D1 and D2 receptors overestimated the observed values, suggesting that these drugs have catalepsy-reducing properties as well. Because muscarinic acetylcholine (mACh) receptor antagonists inhibit the induction of catalepsy, the anticholinergic activities of the drugs were investigated. After SCH23390, nemonapride and scopolamine were administered simultaneously; catalepsy and in vivo mACh receptor occupancy were measured to evaluate quantitatively the anticholinergic activity. Relationship between mACh receptor occupancy and change in catalepsy was used as the measure of catalepsy-reducing effects of the drugs. Measurement of in vivo mACh receptor occupancy revealed a significant blockade of mACh receptor by all of the tested drugs except for haloperidol. The predicted values of catalepsy, when corrected for the mACh receptor-related reduction, approached the observed values. This finding indicates the possibility that mACh receptor antagonism of drugs may contribute to the reduction of catalepsy. In conclusion, the dynamic model considering D1, D2, and mACh receptor occupancies and synergism between D1 and D2 receptors may be useful for quantitative prediction of drug-induced catalepsy.

[Tissue distribution of methylsulfonyl metabolites derived from Kanechlor 400 in mice]

Kanechlor 400, which caused the "Yusho disease", was i.p. administered to mice and methylsulfonyl (MeSO2) metabolites were investigated with respect to the concentration in liver and lung during 28 days after the administration. Major components were 3- and 4-MeSO2 derivatives from seven PCBs (IUPAC no. #31, #49, #64, #70, #101, #110, #132). In the liver, similar concentration ratio of 3- and 4-MeSO2 derivatives was observed, whereas seven 4-MeSO2 derivatives were selectively retained in the lung. Methylsulfone metabolites of triCB (#31) were rapidly formed and eliminated. The highest concentration of the metabolites in the lung was 4-MeSO2-2, 2', 4', 5-tetraCB. Concentration ratio of MeSO2-CBs to residual PCBs was 1:2.1 in the liver whereas 4.6:1 in the lung 28 days after the administration.

[The condition of PCBs and PCDFs in the blood of Yusho patients 20 years after the onset]

Blood samples of Yusho and control persons were analyzed for individual congeners of PCDDs, PCDFs, and PCBs by high resolution GC/MS. Concentrations of 2,3,4,7,8-penta-CDF, 1,2,3,4,7,8-hexa-CDF and 2,3,3',4,4',5-hexa-CB in Yusho blood were up to 56 times higher than the corresponding concentrations in the control blood. These high concentrations have persisted for 23 years after the incident. Concentrations of 3,3',4,4',5-penta-CB and 2,3',4,4',5-penta-CB in some Yusho blood were lower than the control blood. In Yusho blood, 2,3,4,7,8-penta-CDF contributed the highest toxicity (TEQ 77-248 ppt in lipid) among the congeners determined and toxic contribution of PCDFs was very large (41-77%) in the chlorinated pollutants. Thirty PCB congeners were identified in the blood of Yusho patients in 1996 by GC/MS. The average total PCB concentration in Yusho blood were 4.9 times higher than that of the controls. Characteristic PCB congeners in Yusho patients were 2,2',3,4,4',5-hexa-CB, 2,3,3',4,4',5-hexa-CB and 2,3,3',4,4',5'-hexa-CB and their concentration ratios to the controls were 8-19.

Regulation of thyrotropin receptor gene expression in 3T3-L1 adipose cells is distinct from its regulation in FRTL-5 thyroid cells

We previously have demonstrated that rat adipose tissue expresses TSH receptor (TSHR) messenger RNAs (mRNAs) at levels approaching those detected in the thyroid. Furthermore, we recently reported that TSHR mRNA is detected in fibroblast-like 3T3-L1 cells after their hormone-induced differentiation into adipocytes. TSH induces cAMP formation and lipolysis in differentiated 3T3-L1 cells. We now show that, in Northern blot analyses, TSH-induced down-regulation of TSHR mRNA levels, which can be duplicated by forskolin and dibutylyl cAMP, i.e. which is cAMP-mediated. We also have demonstrated that a beta-adrenergic stimulant, which stimulates cAMP formation in adipocytes, induces a down-regulation of TSHR mRNA levels in 3T3-L1 adipocytes. Nuclear run-on assays show that the ability of TSH/cAMP to decrease TSHR mRNA levels in 3T3-L1 cells reflects transcriptional regulation. This report also demonstrates that TSHR gene expression in 3T3-L1 adipocytes is regulated in a manner distinct from that observed in thyroid cells. Thus, in fully differentiated 3T3-L1 adipocytes, TSH-induced down-regulation of TSHR mRNA levels is evident within 1 h and is near maximum within 4 h after addition of TSH. A transient increase of TSHR gene expression, which has been demonstrated in FRTL-5 thyroid cells, was not observed in 3T3-L1 adipocytes. The down-regulation of TSHR gene expression induced by TSH/cAMP in 3T3-L1 cells is cycloheximide-insensitive, suggesting that continuous protein synthesis is not required for this process. In contrast, the down-regulation of TSHR gene expression observed in FRTL-5 cells is sensitive to cycloheximide. In both FRTL-5 thyroid cells and 3T3-L1 adipocytes, insulin or serum increased TSHR mRNA levels. Although insulin or serum was required for the TSH-induced down-regulation of TSHR mRNA levels in FRTL-5 thyroid cells, neither insulin nor serum was required for TSHR down-regulation in 3T3-L1 adipocytes. These findings demonstrate that TSH/cAMP regulates TSHR mRNA levels in adipocytes via a regulatory system distinct from that used in FRTL-5 cells. This report further demonstrates that adipose cells do not express thyroid transcription factor-1, which interacts with the TSHR promoter region in FRTL-5 cells, and that 3T3-L1 nuclear extracts exhibit a different binding activity to the cAMP-response element-like element in the TSHR promoter region compared with extracts from FRTL-5 cells.

Socioeconomic factors and dental caries in developing countries: a cross-national study

The purpose of the present study was to analyze statistically correlations between socioeconomic factors and the prevalence of dental caries in developing countries. The DMFT index, which evaluates the incidence of dental caries, showed a positive correlation (P < 0.01) with several socioeconomic factors, such as life expectancy, adult literacy rate, school attendance rate, population employed in the service sector, population aged 15-64 years, and urban population. According to multiple regression analysis, population aged 15-64 years, population employed in the service sector, and urban population were the most influential independent socioeconomic variables, in descending order, with a regression coefficient of 0.635 and a coefficient of determination of 0.404 (P < 0.001). This finding suggests that the prevalence of dental caries in developing countries increases with the degree of urbanization.

Differentiation of rat preadipocytes is accompanied by expression of thyrotropin receptors

To investigate the regulation of expression of the TSH receptor (TSHR) in extrathyroidal tissues, the level of TSHR messenger RNA (mRNA) and TSH-dependent signal transduction were determined in isolated rat adipocytes and cultured preadipocytes. The epididymal, sc, and perirenal, but not the interscapular brown adipose tissues, possessed TSHR mRNA and increased cAMP responses to TSH and were thus used as the source of preadipocytes. Morphological analysis revealed that the combination of insulin and T3 most effectively caused the differentiation of rat preadipocytes. These differentiated preadipocytes exhibited increased cAMP production in response to TSH. The addition of FCS to the culture medium inhibited the differentiation of rat preadipocytes as well as TSH-stimulated production of cAMP. The stimulation of differentiation was associated with an increased expression of TSHR mRNA levels, whereas the inhibition of differentiation was associated with a decreased expression of TSHR mRNA, as detected by Northern blot analysis. The results indicate that the expression and function of the TSHR in cultured rat preadipocytes are closely related to cellular differentiation. Cultured rat preadipocytes appear to provide a useful system for studying the mechanism of extrathyroidal expression of TSHR.

Functional expression of thyrotropin receptor in differentiated 3T3-L1 cells: a possible model cell line of extrathyroidal expression of thyrotropin receptor

Thyrotropin receptor (TSHR) in extrathyroidal tissue, especially fat tissue, is supposed to have important roles in the development of extrathyroidal manifestations of Graves' disease. However, the molecular mechanism of TSHR expression is not known. Expression of TSHR mRNA and TSH-dependent cAMP production were observed in differentiated but not in undifferentiated 3T3-L1 cells. Maximal expression was obtained when the cells were differentiated in the presence of insulin, dexamethasone, and isobutylmethylxanthine (IBMX). Dexamethasone and IBMX were indispensable for the first three days. On the other hand, after day 4, insulin was indispensable for the expression of TSHR. 3T3-L1 cell is the first non-thyroidal cell line reported that expresses TSHR and whose expression can be induced. 3T3-L1 cell can be a good model to investigate the mechanism of expression of TSHR and extrathyroidal manifestations of Graves' disease.