Induction of peroxisomal beta-oxidation by structural analogues of dehydroepiandrosterone in cultured rat hepatocytes: structure-activity relationships

The structural requirements of dehydroepiandrosterone (DHEA) for the induction of peroxisomal beta-oxidation were studied in cultured rat hepatocytes. The hepatocytes were incubated for 5 days with various steroids, including 3- and 17-substituted analogues and 5-hydrogenated analogues of DHEA, and the activities of peroxisomal beta-oxidation and carnitine acetyltransferase were measured. Among the steroids examined, DHEA, DHEA sulfate (DHEAS), dehydroandrosterone sulfate, androstenediol 3-sulfate, epiandrosterone sulfate and androsterone sulfate significantly induced the enzymes; 4.6- to 14.2-fold for beta-oxidation and 5.1- to 10.9-fold for carnitine acetyltransferase at 50 microM. All of the sulfated steroids were more effective than the corresponding unsulfated forms. DHEAS was the most potent inducer. The 3-sulfuric group was required for the marked induction of peroxisomal beta-oxidation, and the 17-carbonyl group was also important. Furthermore, the relatively planar conformation of the steroidal hydrophobic backbone was crucial for inducing the enzyme. The configuration of the 3-sulfuric group (beta-configuration) and the presence of a double bond at position C5 were not primary determinants for the action of DHEAS. On the other hand, the introduction of bulky substituents to position C17 or aromatization of ring A led to a loss of inducing activity. Thus, there are strict structural requirements for the DHEA induction of peroxisomal beta-oxidation, suggesting the presence of a certain specific recognition site in the cell for DHEAS, which mediates the peroxisome proliferator action of DHEA.

GABA receptor subtypes involved in the neuronal mechanisms of baroreceptor reflex in the nucleus tractus solitarii of rabbits

The role of GABAA and GABAB receptors in neuronal mechanisms of the baroreceptor reflex in the nucleus tractus solitarii (NTS) of the anesthetized and immobilized rabbits were investigated using a microiontophoretic technique. Baroreceptive neurons (BRNs) activated or depressed by baroreceptor stimulation (phenylephrine, 10 micrograms/kg, i.v.) were identified in the NTS (activated BRN (A-BRN) and depressed BRN (D-BRN), respectively). The GABAA antagonist bicuculline (40-80 nA) increased spontaneous activities of these neurons, but the GABAB antagonist phaclofen (80-160 nA) did not. Evoked responses of A-BRNs were potentiated by bicuculline and phaclofen, while the responses of D-BRNs were not clearly affected by these drugs. These results suggest that most of A- and D-BRNs are tonically inhibited by endogenous GABA acting on GABAA receptors, but not on GABAB receptors, and that GABAergic mechanisms suppressively modulate the baroreceptor reflex acting on GABAA and GABAB receptors of A-BRNs, but not of D-BRNs.

Antitumor activity of a new series of platinum complexes: trans(+/-)-1,2-cyclohexanediammineplatinum(II) conjugated to acid polysaccharides

Complexes with trans(+/-)-1,2-cyclohexanediammineplatinum(II) conjugated to acid polysaccharides were synthesized and their antitumor activities were tested in female CDF1 mice with intraperitoneal leukemia L1210 cells. Platinum was released from the polymers under physiological conditions, with half-lives from 3.3 to 19.3 h. A hyaluronic acid-supported complex was the most effective against the tumors (all six mice survived for 60 days). The group given a chondroitin polysulfate-supported complex had five survivors, the chondroitin sulfate A group also had five, the chondroitin sulfate C group had three and the heparan sulfate group had two. Part of the antitumor activity was due to increased efficacy of the polymers. The bioavailability of these complexes is high. Therefore, acid polysaccharides should be a good system for delivering antitumor platinum complexes.

Conformational recognition of RA-XII by 80S ribosomes: a differential line broadening study in 1H NMR spectroscopy

1H NMR spectroscopy has been used to demonstrate specific binding of rat 80S ribosomes to the major conformer of an antitumor bicyclic hexapeptidic glucoside, RA-XII, isolated from Rubia cordifolia, in a fast exchange process.

Experimental investigations concerning a new liquid embolization method: combined administration of ethanol-estrogen and polyvinyl acetate

A new embolization agent combining ethanol-estrogen and polyvinyl acetate was evaluated angiographically and histologically in 18 canine renal arterial systems. Peripheral vessels of less than 100 microns diameter were obliterated by thrombus induced by ethanol-estrogen, and larger vessels were obliterated by polyvinyl acetate casts and/or thrombus. This embolization method is easily controlled and has fewer adverse effects, so is suitable for intravascular applications, especially in the head and neck regions.

Complication of parenteral nutrition composed of essential amino acids and histidine in adults with renal failure

This is a case report on six patients with hyperammonemia that developed while they were receiving total parenteral nutrition (TPN) as a component of renal failure therapy. Clinically, the hyperammonemia presented as mental status changes in all six cases. Four of the six patients with renal failure initially received 400 mL Amiyu in 1400 mL 17% glucose (total = 1800 mL TPN-A) administered over each 24-hour period. Two patients had been placed on 400 mL complete amino acid in 1400 mL 17% glucose (total = 1800 mL TPN-C over each 24-hour period) prior to therapy with TPN-A. Approximately 3 weeks after initiation of TPN therapy with TPN-A, episodes of mental status changes of increasing duration and paroxysms were documented in five of the six patients. In one of the patients receiving TPN-C prior to TPN-A therapy, toxicity was clinically evident only 4 days after initiation of TPN-A. Serum ammonia levels were obtained and found to be elevated in the acute (ie, presenting) stage in all patients. With the discontinuance of TPN-A, ammonia levels normalized uniformly. Mental status also improved in all cases except for the patient with rapid clinical presentation who died 2 weeks after first evidence of clinical toxicity. In cases 1, 2, and 6, serum amino acid analysis in the acute phase showed reduced levels of ornithine and citrulline, the substrate and product, respectively, of condensation with carbamyl phosphate at its entry into the urea cycle. Moreover, levels of arginine, precursor to ornithine, were found to be elevated.(ABSTRACT TRUNCATED AT 250 WORDS)

Lack of stereoselectivity in rat liver peroxisomal enzyme induction by optically active phenoxyacetic acids

To ascertain if there is stereoselectivity in peroxisomal proliferation induced by chiral peroxisome proliferators, induction by stereoisomers of 2-methyl-4'-chlorophenoxyacetic acid and 2-methyl-2-(2'-4'-dichlorophenoxy)acetic acid were studied in rat in vivo and in vitro with isolated rat hepatocytes. No significant differences in the inducing potencies of the stereoisomers of the above two phenoxyacetic acid derivatives were found for cyanide-insensitive fatty acyl-CoA oxidizing system, fatty acyl-CoA oxidase, carnitine acetyltransferase or carnitine palmitoyltransferase. There was also no significant difference in the degree of hepatomegaly or lipid-lowering effect between the isomers. The findings with cultured rat hepatocytes agreed with those of the studies in vivo.

Induction of peroxisomal beta-oxidation enzymes by dehydroepiandrosterone and its sulfate in primary cultures of rat hepatocytes

Treatment of cultured rat-hepatocytes with 50 microM dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) for up to 5 days resulted in a progressive increase in peroxisomal beta-oxidation and carnitine acetyltransferase activity. After 5 days, the increases in activity were 2.6- and 4.8-fold for peroxisomal beta-oxidation and 11.7- and 17.1-fold for carnitine acetyltransferase over the initial activity, in DHEA- and DHEAS-treated cells, respectively. The stimulation of the activity of these enzymes by the respective agents was dose-related; it was maximum with 50 to 100 microM DHEA and 50 to 250 microM DHEAS, although DHEAS was more effective for stimulation than DHEA. Western blot analyses revealed the induction of acyl-CoA oxidase, enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase bifunctional enzyme and carnitine acetyltransferase in the treated cells. Moreover, induction of fatty acid omega-hydroxylase proteins (P-450IVAS) was also revealed. These results indicate that DHEA and DHEAS act directly on hepatocytes. The induction of hepatic peroxisomal beta-oxidation enzymes and several other enzymes in rats administered with DHEA could be accounted for, at least in part, by the direct action of DHEA and its sulfate-conjugate (DHEAS) on liver cells.

cDNAs and deduced amino acid sequences of subunits in the binding component of mouse bactericidal factor, Ra-reactive factor: similarity to mannose-binding proteins

The complement-dependent bactericidal factor, Ra-reactive factor, binds specifically to Ra polysaccharide, which is common to some strains of Gram-negative enterobacteria, and its is a complex of proteins composed of a polysaccharide-binding component and a component that is presumably responsible for the complement activation. The former component consists of two different 28-kDa polypeptides, P28a and P28b. We determined the partial amino acid sequences of P28a and P28b, and the results indicated that these polypeptides were similar to two species of mannose-binding protein, MBP-C and MBP-A (alternative names, liver and serum mannan-binding proteins, respectively), which have been isolated from rat liver and/or serum [Drickamer, K., Dordal, M. S., & Reynolds, L. (1986) J. Biol. Chem. 261, 6878-6887; Oka, S., Itoh, N., Kawasaki, T., & Yamashina, I. (1987) J. Biochem. 101, 135-144]. Thus, we cloned the respective cDNAs, using as probes synthetic oligonucleotides for which the sequences had been deduced from the amino acid sequences of P28a and P28b and of rat MBP cDNAs. The primary structures of P28a and P28b deduced from the cloned cDNAs are homologous to one another. They have three domains, a short NH2-terminal domain, a collagen-like domain, and a domain homologous to regions of some carbohydrate-binding proteins, as has been reported for rat MBPs. Southern and Northern blotting analyses using these cDNAs indicated that the P28a and P28b polypeptides are the products of two unique mouse genes which are expressed in hepatic cells.

[Experimental study of aneurysmal occlusion with fibrin glue]

The authors report an experimental trial of intra-aneurysmal occlusion using fibrin glue. Nowadays, with the development of microsurgical techniques and aneurysmal clips, results of direct radical operations have been improving. But quite a few aneurysms cannot be clipped because of their size, location, broad neck etc. Some authors have treated these aneurysms with innovative techniques (detachable balloon techniques etc). In these methods, the occlusive state of the aneurysms is not always obtainable because of the size of their neck. Besides, it is not always possible to preserve the parent arteries of the aneurysms. Experimental aneurysms in cervical carotid arteries of dogs are treated by direct injection with fibrin glue. During its injection, influx of fibrin glue was prevented by occlusion of the aneurysmal orifices with inflated polyethylene angioplastic balloons. The aneurysms which were completely (100%) filled by the injection of fibrin glue (100% infused group) were totally obliterated in 10 (71%) of the 14 cases. The parent arteries were completely preserved in all instances. Follow-up study demonstrated satisfactory maintenance of this occluded state in the aneurysms in the 100% infused group. In completely occluded cases, all aneurysms maintained this state. On the other hand, 1 of the 4 incompletely obliterated aneurysms recanalized partially. These occluded aneurysms were studied by a light microscope (LM) and a scanning electron microscope (SEM). At day 7 after the occluding procedure, the margin of the aneurysmal orifice was covered by a layer of fibroblasts. At day 21, almost half of the aneurysmal cavity had been substituted with connective tissue. The orifice of the aneurysms was covered with an endothelial layer.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of sympatho-adrenal system on insulin sensitivity using the euglycemic clamp technique

The aim of the present study was to further investigate the role of the adrenergic system on insulin action using the euglycemic clamp technique. Whole-body glucose metabolism (GM) was calculated as the glucose infusion rate for maintaining euglycemia under insulin infusion and used as an indicator of insulin sensitivity. Euglycemic clamps were performed in adrenodemedullated, epinephrine-treated, phentolamine-treated (alpha-blockade), propranolol-treated (beta-blockade), and epinephrine plus phentolamine and/or propranolol-treated rats. The following results were obtained at an insulin level of approximately 80 mU/l. GM in adrenodemedullated rats (13.97 +/- 0.98 mg/kg/min) was significantly higher than that of the control rats (10.26 +/- 0.50 mg/kg/min, P less than 0.01). GM in epinephrine-treated rats (1.7 mg/kg body weight/h) was 2.12 +/- 0.49 mg/kg/min (P less than 0.001 vs. control). Dose-response curves for phentolamine and propranolol established maximally effective doses (3.0 mg and 12 mg/kg body weight/h, respectively). Using these doses, GM in epinephrine plus phentolamine-treated rats (4.90 +/- 0.39 mg/kg/min) was significantly higher than that of epinephrine alone and GM in epinephrine and propranolol-treated rats (4.49 +/- 0.47 mg/kg/min) was also significantly higher than that of the epinephrine alone. GM in the epinephrine plus both propranolol and phentolamine (5.94 +/- 0.45 mg/kg/min) was significantly higher than that of the epinephrine alone, but not different from either treatment alone and was not additive. Neither phentolamine alone (9.48 +/- 1.45 mg/kg/min), propranolol alone (10.36 +/- 0.55 mg/kg/min) or the combination of blockades (11.14 +/- 0.65 mg/kg/min) had any effect on GM.(ABSTRACT TRUNCATED AT 250 WORDS)

Study on stereospecificity of enzyme reaction related to peroxisomal bile acid synthesis in rat liver

We examined stereoselectivities of enzymes related to bile acid formation in hepatic peroxisomes using two stereoisomers of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid (THCA) and its coenzyme A (CoA) derivatives. The activity of acyl-CoA synthetase for 25 S-THCA was 1.4-times higher than that for 25 R-THCA. The difference was also observed after clofibrate-treatment. This activity was located in microsomes, differing from palmitoyl-CoA synthetase located in mitochondria, peroxisomes and microsomes. There was no stereoselectivity in the reaction of peroxisomal fatty acyl-CoA oxidase for THCA isomers, and the activity was one tenth of that for acyl-CoA synthetase. Considering the overall reaction of peroxisomal bile acid formation, the stereoselective difference observed in THCA-CoA synthesis should be denied. Thus, the previous finding that the overall formation of bile acid from THCA was not stereoselective was further confirmed. Furthermore, the activity for THCA oxidation was not induced by clofibric acid, suggesting that there would be different isozymes of peroxisomal acyl-CoA oxidase against THCA-CoA and palmitoyl-CoA.

[Clinical significance of serum CA 125 values in patients with gastric cancers--especially correlation with peritonitis carcinomatosa]

A study of 387 patients with gastric cancers revealed elevation of CA 125 in sera of 7.2% of the patients. Patients with Borrmann 1 and 2 in gross type, poorly differentiated adenocarcinoma in histological type and stage 4 in stage grouping of gastric cancer, showed a higher positive rate than patients with the others. In patients with peritonitis carcinomatosa, positive rate of serum CA 125 was 42.9% of patients with synclonus metastasis, 72.2% with metaclonus metastasis. Elevation of serum CA 125 was observed earlier than detection by image diagnosis in almost all cases. These results indicate that CA 125 is an useful tumor marker for detection and follow up of patients with peritonitis carcinomatosa from gastric cancers.

Involvement of calmodulin- and protein kinase C-related mechanism in an induction process of peroxisomal fatty acid oxidation-related enzymes by hypolipidemic peroxisome proliferators

Trifluoperazine, a calmodulin antagonist, suppressed the clofibric acid-evoked induction of the peroxisomal cyanide-insensitive fatty acyl-CoA oxidizing system and carnitine acetyltransferase in rat liver and also in cultured rat hepatocytes. H-7, a potent inhibitor of protein kinase C, also suppressed the induction of these enzymes by clofibric acid, bezafibrate, Wyl4,643 or mono(2-ethylhexyl)phthalate in cultured rat hepatocytes. This suppressive effect was also confirmed by the protein composition of hepatocytes treated with clofibric acid and these antagonists, where the increase in the amount of peroxisomal bifunctional enzyme by peroxisome proliferator was markedly suppressed by above two antagonists. Profile of the time-dependent changes in the activities of the two enzymes after clofibric acid treatment showed that there might be two phases in the induction process. The initial phase (0-3 days after the treatment) showed a relative low inducing rate and subsequent phase (3-5 days after the treatment) showed an abrupt induction. The suppressive effect of the above two antagonists was significant in the later phase. In a time course study of the induction process of peroxisomal catalase, bifunctional enzyme or 69 kDa integral membrane protein using immunochemical detection, the induction of the membrane protein by clofibric acid was delayed compared with that of the bifunctional enzyme, where the induction was inhibited almost completely by nicardipine. These experimental results suggest that calmodulin- and protein kinase C-dependent processes play an important role in the process of marked induction of peroxisomal enzymes and membrane protein by drugs in rat liver.

A specific method for determination of peroxisomal beta-oxidation activity in cultured human skin fibroblasts using a specific substrate, C9: a possible application for screening of peroxisomal disorders

We developed a specific method for direct determination of peroxisomal beta-oxidation activity in cultured human skin fibroblasts. When control fibroblasts were incubated with N-(alpha-methylbenzyl)azelaamic acid (C9), a specific peroxisomal substrate, C5 and C7, the chain-shortened products, were detected with cell concentration and incubation time dependencies and no other products including C3 were detected. In glutaric aciduria type I and type II fibroblasts, the formation rates of C2 units liberated from C9 were almost similar to that in control cells. In contrast to these cell types, the fibroblasts from patient of Zellweger syndrome, in which peroxisomal beta-oxidation was impaired, showed no conversion of C9 to C5 and C7. The lack of the C2 units liberation in Zellweger fibroblasts was not due to an impairment of mitochondrial beta-oxidation and/or activation of C9 to C9-CoA derivative for subsequent beta-oxidation reaction, but rather, appeared to be due to the specific defect of peroxisomal beta-oxidation system. These results indicate that C9 is a useful substrate for the estimation of peroxisomal beta-oxidation activity in cultured human skin fibroblasts.

Comparison of the inducing effect of dehydroepiandrosterone on hepatic peroxisome proliferation-associated enzymes in several rodent species. A short-term administration study

The in-vivo effect of dehydroepiandrosterone (DHEA) on hepatic enzyme activities of rats, mice, hamsters and guinea pigs was investigated. After DHEA treatment (300 mg/kg body weight, per os, 14 days), the activities of peroxisomal beta-oxidation, catalase, carnitine acetyltransferase, carnitine palmitoyltransferase, lauric acid omega-hydroxylation, 1-acylglycerophosphocholine acyltransferase, malic enzyme and cytosolic palmitoyl-CoA hydrolase were increased in rats and in mice although to a smaller extent in the latter. These enzyme activities, however, were unchanged in hamsters with the exception of omega-hydroxylation (2.5-fold increase) and 1-acylglycerophosphocholine acyltransferase (2.0-fold increase). No significant changes were observed in any of these enzyme activities in guinea pigs. Immunoblot analysis confirmed the induction of peroxisomal acyl-CoA oxidase and enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase bifunctional enzyme in rats and mice. These results indicate that there are species differences in the inducing effect of DHEA on hepatic peroxisome proliferation-associated enzymes, which correlates well with the enzyme induction observed with other peroxisome proliferators.

Experimental investigation of a new liquid embolization method: enhancing effect of 25% ethanol on conjugated estrogen

A new liquid embolization material applicable to intracranial lesions was evaluated by selective renal artery embolization in mongrel dogs. Absolute and diluted ethanol, estrogen, and estrogen in 25% ethanol (ethanol-estrogen) were injected. The embolization and side effects were investigated angiographically and histologically. Ethanol-estrogen caused similar embolization to absolute ethanol, but no direct damage to perivascular tissue, and is considered a promising embolization agent in intravascular surgery.

Loss of peroxisomal enzyme expression in preneoplastic and neoplastic lesions induced by peroxisome proliferators in rat livers

Immunohistochemical staining of enoyl CoA hydratase (ECH), a key peroxisomal enzyme, revealed that the putative preneoplastic lesions induced in livers by administration of the peroxisome proliferator (PP) clofibrate (0.3% in diet) to rats for 60 weeks or more, lacked this enzyme so that they could be detected as ECH-negative foci. ECH and other peroxisomal enzymes such as acyl CoA oxidase, catalase and carnitine-dependent acetyltransferase were also either not or only weakly expressed in most hepatic hyperplastic nodules and hepatomas induced by ciprofibrate (0.025% in diet), Wy-14,643 (0.1%) or BR-931 (0.2%), while being strongly induced in surrounding hepatocytes. These results indicate that the expression of ECH and other peroxisomal enzymes is repressed in putative preneoplastic and neoplastic lesions induced by PPs in rat livers and that these peroxisomal enzymes might therefore be used as negative markers.

Dilatation of the temporal horn in subarachnoid haemorrhage

CT studies of 50 patients with spontaneous subarachnoid haemorrhage (SAH) and 100 randomly selected patients were reviewed with regard to the size of the frontal and temporal horns of the lateral ventricles. The temporal horn was classified into four grades, based on the size of its posterior portion at the level of the midbrain. The horn was clearly visible in 66% of patients with SAH, but in only 2% of controls. In the SAH group, the temporal horn tended to dilate sooner than the frontal horn after haemorrhage and could be seen clearly in a larger proportion of patients. Thus, assessment of the size of the temporal horn appears to be a simple and sensitive method for assessing ventricular dilatation. In addition, dilatation of the temporal horn may prove to be an important indirect sign suggesting SAH in patients in whom no high density clot is seen on CT.

Minimum requirements for renal biopsy size for patients with IgA nephropathy

In order to clarify the minimum requirements for renal biopsy size for a more accurate interpretation of renal biopsy information by light microscopy, we reanalyzed 92 open renal biopsy specimens in 92 patients with IgA nephropathy retrospectively. The mean number of functioning glomeruli per square millimeter in open renal biopsy specimens from 38 patients with a poor outcome was 1.2 +/- 0.4. In contrast, the mean number in 54 biopsy specimens from 54 patients with stable conditions for 10 years was 3.0 +/- 0.6. Therefore, there was a significant reduction (p less than 0.0001) in the numbers of functioning glomeruli in patients with a poor outcome. We found that the most important point in predicting the severity of tissue damage was detection not of the total numbers of glomeruli but of the density of glomeruli in given specimens in patients with IgA nephropathy. A biopsy sample of 1 mm x 7 mm in size of cortical origin is the minimum necessary to confidently interpret biopsy specimens from patients with IgA nephropathy.

Assay of fatty acid omega-hydroxylation using high-performance liquid chromatography with fluorescence labeling reagent, 3-bromomethyl-7-methoxy-1,4-benzoxazin-2-one (BrMB)

A sensitive nonradioisotopic method is reported for measuring microsomal lauric acid omega-hydroxylation activity. The assay is based upon separation and detection of 12-hydroxylauric acid formed by means of high-performance liquid chromatography following fluorescence labeling of the carboxyl group with 3-bromomethyl-7-methoxy-1,4-benzoxazin-2-one (BrMB). The use of 10-hydroxycapric acid as an internal standard affords the accurate and reproducible assay. The differential effect of dehydroepiandrosterone, a peroxisome proliferator, on the omega-hydroxylation activity in the liver and kidney of rats is also reported.

Infection of rats with HTLV-1: a small-animal model for HTLV-1 carriers

A human T-cell line producing human T-cell leukemia virus type I (HTLV-I), MT-2, was injected intravenously into female F344 rats aged 5 weeks to make HTLV-I carrier rats. Antibody against HTLV-I was detected at the 5th week after MT-2 injection, and its titer reached a high plateau which continued from the 15th to the 27th week. The antibodies were against p19, p24, p28 and p53 of HTLV-I antigens from MT-2 cells. The gag, pX and LTR nucleotide sequences of HTLV-I provirus were demonstrated by using polymerase chain reaction (PCR) in the peripheral-blood mononuclear cells of 3 rats at the 44th week and 2 at the 66th to 68th week out of 8 F344 rats injected with MT-2 cells. Quantification of the HTLV-I proviral sequence revealed that 30 to 60 molecules were present in 10(5) peripheral-blood mononuclear cells, indicating that the rats were chronically infected with HTLV-I. HTLV-I-infected rats could serve as a small-animal model for studying the pathophysiological state of HTLV-I carriers and also that of HTLV-I infection on various HTLV-I-related diseases, including adult T-cell leukemia and HTLV-I-associated myelopathy.