Phenotypic characteristics of T cells interacted with synovial cells

We demonstrated the phenotypic characteristics of T cells interacted with synovial fibroblast-like cells. A small percentage of peripheral blood T cells adhered to synovial fibroblast-like cells. When synovial cells were treated with interferon-gamma or interleukin-1 beta, the percentage of T cells that adhered to the treated cells markedly increased in comparison with the value for untreated synovial cells. The kinesis of T cell adherence to treated synovial cells differed from that of HLA-DR antigen expression on synovial cells. T cell adherence was not blocked by mouse monoclonal anti-HLA-DR and anti-HLA-ABC antibodies. The phenotypes of the adherent and nonadherent T cells were investigated with a flow cytometer. The CD29 + subset was more adhesive than the CD45RA + subset to IL-1 beta-stimulated synovial cells. The proportions of high density lymphocyte function associated antigen (LFA)-1 alpha and LFA-1 beta were greater in the adherent than in the nonadherent T cells, and the mean fluorescence intensities of LFA-1 alpha, LFA-1 beta and CD2 molecules on adherent T cells were significantly higher than those on nonadherent T cells. Our results support the concept that an interaction between infiltrating lymphocytes and synovial cells occurs in the synovium, resulting in the initiation and perpetuation of immune responses in synovial tissue in rheumatoid arthritis.

Somatostatin augments long-term potentiation of the mossy fiber-CA3 system in guinea-pig hippocampal slices

The effect of exogenously applied somatostatin (1-14), which is one of the candidates of neuromodulators in the hippocampus, on long-term potentiation (LTP) was investigated in the CA1 and CA3 subfields of guinea-pig hippocampal slices. In the mossy fiber-CA3 pyramidal cell system, the magnitude of LTP of both population excitatory postsynaptic potential (pEPSP) and population spike was significantly augmented by somatostatin (10(-7)-10(-6) M) perfused before and during tetanic stimulation which never affected basal amplitude of population spikes before tetanus. The enhancement of LTP by somatostatin lasted for at least one hour after washout. On the other hand, somatostatin at the most effective concentration (3.2 x 10(-7) M) in the above described system failed to affect the magnitude of the LTP of population spikes in Schaffer collateral-CA1 pathway. The enhancing effect of somatostatin on LTP in the mossy fiber CA3 system was inhibited either by a muscarinic antagonist, scopolamine (10(-6) M), or a beta-adrenoceptor antagonist, timolol (10(-6) M). These results suggest that somatostatin enhances the production of LTP in the mossy fiber-CA3 pathway of the guinea-pig hippocampus through the intervention of cholinergic and noradrenergic neurons.

[Volume reduction and tritium retention factor in electrolytic enrichment of water]

Volume reduction(N), tritium retention factor (R), tritium concentration factor(Z) and apparent separation factor(beta) were measured on the large and small electrolytic cell systems. The relative variation of R was smaller than that of Z. So, it is recommended to use R in calculation of tritium concentrations in water samples. Furthermore, it was empirically revealed that R can be obtained only from N if a reliable beta-value is previously known. Therefore, it is possible to obtain R without electrolysis of the tritium standard solution. Taking into account the above facts, the so-called non-spike analysis of tritium, in which electrolytic enrichment and liquid scintillation counting are combined, becomes practicable.

[Clinical evaluation of bone turnover in patients with bone metastasis of various cancer of urogenital tract]

To study the bone turnover in patients with bone metastasis from cancers of the kidney, bladder, prostate and other organs, Ca metabolism, vitamin D related hormones and various markers, such as bone glaprotein (BGP) and hydroxyproline, were investigated. In the group with osteolytic metastasis of non-prostatic cancer patients, BGP which is a measure of bone absorption was significantly increased and urinary excretion of hydroxyproline, Ca and P was elevated. Serum Ca was also higher and 1 alpha 25 (OH)2D and 250HD, measures of the metabolism of vitamin D, were lower. It was shown that bone absorption was promoted with the osteolytic findings by clinical X-ray examination, but osteoblastic changes which did not depend on osteoblast cells, seemed to exist in this group. On the contrary, in the group with osteoblastic metastasis from prostatic cancer, the level of BGP was not increased, but urinary hydroxyproline was moderately increased. Serum and urinary Ca and P levels were increased. In addition, 1 alpha 25 (OH)2D and 24 x 25 (OH)2D were lower than in the control group. These results indicate that urinary hydroxyproline is a useful marker for patients with bone metastasis, but BGP was correlative with neither the clinical findings of bone metastasis nor the bone turn over and metabolisms.

Cross-lineage gene rearrangements in human leukemic B-precursor cells occur frequently with V-DJ rearrangements of IgH genes

Gene configurations of immunoglobulin (Ig), T-cell antigen receptor (TCR) beta chain, and T-cell rearranging gene gamma (TRG gamma) were studied in human B-precursor lymphoblastic leukemic cells. These cells were phenotypically classified into three developmental stages (stages II through IV) according to Nadler's criteria. All of them showed the Ig heavy chain (IgH) gene rearrangement, and 67% of the cells in stage IV had the rearranged TRG gamma, albeit seldom in other stages. We further analyzed IgH gene rearrangements in detail using upstream to DH (diversity region of IgH) region probe to distinguish DJ from V-DJ recombination. All dual genotyped cells in each stage except one case in stage II showed the V-DJ rearrangements. This suggests the cross-lineage involvement of the putative recombinase, particularly in the process of V-DJ rearrangements. We next examined the transcriptional status of Ig genes as an indirect reflection of the accessibility of these genes to the recombinase. Properly spliced IgH transcripts of normal size were observed in stage IV and surface Ig positive stage, but not in stage II nor III. However, IgH transcripts of aberrant sizes were seen in stage II, III, and also IV. Cross-lineage gene rearrangements were shown to occur frequently when normally spliced IgH gene begins to be transcribed or just before this. These findings may implicate that V-DJ or V-VDJ gene rearrangements forming functional IgH genes, induce frequently TCR or TRG gene rearrangements. We propose these dual genotypes are different in origin from those observed in stem cell leukemia.

Dyslipoproteinemia and an inhibitor of lipolytic enzymes in Weber-Christian disease

Hyperlipidemia of initially Type V and finally of Type III was observed in a patient with Weber-Christian disease. The lipoprotein lipase (LpL) and hepatic triglyceride lipase (HTGL) activities of the post-heparin plasma were low, but detectable. Both lipase activities were higher when assayed with 20 microliters of post-heparin plasma than with more than 30 microliters, indicating the presence of some inhibitory factor in the plasma. This plasma inhibited purified LpL and HTGL from human post-heparin plasma. Zonal ultracentrifugation studies showed that the inhibitor of hepatic lipase was associated with the middle fraction of intermediate lipoprotein and low density lipoproteins (1.020 less than d less than 1.040). These results are consistent with the idea that dyslipoproteinemia in this patient was partially due to dysfunction of the catabolic system caused with an inhibitor of lipolytic enzymes.

Surface and cytoplasmic expression of CD2, CD13, and CD25 antigens in human T lymphotropic virus type I infected cell line. An immunoelectron microscopic study

Immunoperoxidase electron microscopy revealed intracellular expression of CD2, CD13, and CD25 antigens in a unique human T lymphotropic virus type I infected cell line, TI-CL. This cell line is thought to be derived from cord mononuclear cells in the bifurcation stage of T cell and myelomonocytic lineage, based on cytochemical, immunologic, and molecular genetic analyses. Each antigen expression was observed on the plasma membranes, the cisternae of rough endoplasmic reticulum, and the perinuclear cisternae. Surface and cytoplasmic expression of CD25 antigen in adult T cell leukemia/lymphoma cells have been reported, but similar events concerning CD2 and CD13 antigens have not been described previously. CD13 antigen is a marker of myelomonocytic lineage, and biochemical analyses have demonstrated that monoclonal antibodies belonging to CD13 precipitated two glycoprotein molecules of 130,000 and 150,000 molecular weight and that the former molecule (gp130) is the precursor protein of the latter (gp150). In our findings, CD13-positive reaction in the cisternae of rough endoplasmic reticulum and the perinuclear cisternae may correspond to the precursor protein of CD13. CD2 antigen, a 50 kilodalton sheep erythrocyte rosette receptor protein, is the early T lineage antigen and plays an important role in T cell activation. The detection of CD2 antigen on the cell surface and in the cytoplasm may morphologically confirm that this antigen is synthesized in the cytoplasm and inserted into the plasma membrane.

Immunogenotypes of lymphoid malignancies; the rearrangement of T cell receptor beta chain gene can occur before the gamma chain gene rearrangement

Immunoglobulin (Ig) and T cell receptor (TcR) gene rearrangements were analyzed in 101 cases of lymphoid malignancies in association with a surface phenotype study. In leukemias/lymphomas with mature phenotype, there is a good correlation between phenotypes and genotypes. However, in leukemias/lymphomas with immature phenotype, we found many discordances between phenotypes and genotypes, suggesting the stochastic nature of hematopoietic cell differentiation at the early stage. As for TcR beta and gamma chains, the rearrangement of gamma chain gene is considered to occur slightly prior to that of beta chain gene. However, we observed a mature T cell malignancy, adult T-cell leukemia, with rearranged beta chain gene and germ line gamma chain gene, showing the possible existence of another pathway of T cell differentiation.

[Clinical feature of male non-gonorrhoea urethritis and minocycline treatment of Chlamydia or Ureaplasma-infected urethritis]

Thirty-nine male patients with urethritis were studied for gonorrhoea or non-gonorrhoea infections. Only 2 patients were infected with N. gonorrhoeae, the other 37 patients were non-gonorrhoea urethritis (NGU). In 9 of these patients, C. trachomatis was identified and in 6 patients, U. urealyticum was isolated. No chlamydial urethritis was combined with ureaplasma. There was no clinical difference between chlamydia and ureaplasma infection, such as serous urethral discharge or mild pyuria. Minocycline was given orally at the dose of 200 mg daily for 7 to 42 days to these patients. Seven of the 9 patients (78%) with C. trachomatis and 7 of the 6 patients (67%) with U. urealyticum infection showed improvement of subjective and objective symptoms after minocycline. In no case, was an adverse reaction noted. Minocycline was effective in the treatment of both C. trachomatis and U. urealyticum urethral infection.

[Single-agent trial with epirubicin in hematological malignancies]

Twelve patients with hematological malignancies were treated with epirubicin and ten patients were evaluable. One out of our four patients with ALL, who had a previous therapy of anthracycline, achieved a partial remission (PR: 25%). In two patients with AML, remission was not obtained. Of four patients with NHL, one with B-cell lymphoma achieved complete remission (CR) and one with ATLL partial remission (CR + PR: 50%). Stomatitis was observed as a major side effect in three patients with acute leukemia and in one with NHL. In conclusion, our trial seems to show the efficacy of epirubicin in lymphoid malignancies.

Twenty-four hour ambulatory ECG monitoring of junior high school students in Miki City

To evaluate incidence of serious arrhythmias among school age youths, 24-hour ambulatory ECG monitoring was performed in 100 junior high school students, including 60 subjects with some ECG abnormalities and 40 without. With this monitoring 2 cases with multifocal VPCs and 2 cases with paired VPCs or nonsustained ventricular tachycardia were found; the case with VT died suddenly after having been lost during careful follow up. It is emphasized from these results that ambulatory ECG monitoring is quite useful in selected cases in this age group and careful follow up of students with advanced grade VPCs is very important.

[Clinical effects of TA-077 in non-Hodgkin's lymphomas]

Ten patients with non-Hodgkin's lymphomas (NHL), six untreated and four with previous chemotherapy, were treated with TA-077, a new derivative of nitrosourea. Partial remission was observed in three untreated cases (30%) of NHL [Case 1: 71-year-old female with B cell lymphoma/diffuse small cell type, Case 2: 79-year-old male with T cell lymphoma/diffuse large cell type, and Case 3: 64-year-old female with adult T cell leukemia lymphoma (ATLL)]. Remission durations were as follows: Case 1; 33 days, Case 2; 38 days and Case 3; 14 days. Side effects were transient anorexia (40%), nausea & vomiting (30%), liver dysfunction (10%) and delayed hematological toxicities (80%). Hematological toxicities consisted of leukocytopenia (80%), thrombocytopenia (60%) and anemia (20%). Our study suggests that TA-077 is a useful agent as one of the drugs used in combination chemotherapy against NHL, since it was effective for refractory T cell malignancies such as ATLL.

[Treatment of malignant lymphoma under consideration of its biological behavior]

Malignant lymphoma is very heterogeneous in terms of its biological behavior. A strategy for the treatment of malignant lymphoma fundamentally requires a multidisciplinary field of treatment including mainly chemotherapy and radiotherapy in collaboration with surgical procedure and immunotherapy. The expressions of biological behavior such as histologic type, immunologic type, and stage of disease which influence the therapeutic effect and prognosis are actually very important in deciding a plan of treatment. Recent advances in chemotherapy have made it possible to cure advanced lymphoma patients, especially those with Hodgkin's disease. In this article the present state of treatment for malignant lymphoma is briefly reviewed from the viewpoint of its biological behavior.

Existence of lipoprotein lipase in rat brain microvessels

To clarify the possibility that brain microvessels could utilize very low density lipoprotein (VLDL)-triglyceride, the hydrolysis of [14C] triolein in VLDL by rat brain microvessels was examined. The rat brain microvessels were prepared under microscopy. In the homogenate, triolein hydrolyzing activity was observed only in the presence of apolipoprotein C-II. That activity was diminished by the addition of 1 M NaCl. [14C] triolein incorporated in VLDL was hydrolyzed time- dependently. These results suggested that there exists lipoprotein lipase in brain microvessels and the brain can utilize VLDL triglyceride as a source of fatty acids.

[Clinical trial of bestrabucil (KM 2210) on hematopoietic malignancies]

Twenty-one patients were entered for a clinical study of KM 2210, the benzoate of an estradiol-chlorambucil conjugate, in the treatment of hematopoietic malignancies. These included 4 cases of chronic lymphocytic leukemia (CLL), 5 cases of chronic myelogenous leukemia (CML), 5 cases of malignant lymphoma (ML) and 7 cases of multiple myeloma (MM). Twelve cases had prior chemotherapy. KM 2210 was given orally at a dose of 50-300 mg daily. Of 19 evaluable cases, two cases with CLL achieved complete response and 6 cases including 2 with CLL, 2 with CML and 3 with ML achieved partial response. There were no responders among the cases of MM. The partial and complete response rate was 47%. Toxicity included mild breast or nipple pain (28.6%), genital bleeding (9.5%), appetite loss (9.5%) and gynecomastia (4.8%). These side effects may have been due to increased levels of estrogen. Hematopoietic toxicity was mild and well tolerated. No cardiac, hepatic or renal toxicity was observed in this study. These results suggest that KM 2210 might be an effective candidate for the treatment of hematopoietic malignancies, especially CLL.

Effects of dextran sulfate on stabilization of milk lipoprotein lipase and VLDL triglyceride hydrolysis in vitro

The effects of dextran sulfate (DS), which has various molecular numbers, on hydrolysis of very low density lipoprotein triglyceride (VLDL-TG) by bovine milk lipoprotein lipase (LPL) and the stability of LPL were studied. VLDL-TG hydrolysis was increased by the addition of DS; DS caused linear increase in the Vmax for VLDL-TG with increase in its sulfate content, but did not change the Km value for VLDL-TG. DS also stabilized LPL, but this effect was not dependent on its sulfate content. These results suggest that the mechanism of action of DS in LPL stabilization may be different from that in enhancement of VLDL hydrolysis.

A fly, Drosophila melanogaster, forms 11-cis 3-hydroxyretinal in the dark

All-trans and 11-cis 3-hydroxyretinals were synthesized and the presence of these substances in the head of Drosophila melanogaster was shown by using high performance liquid chromatography. Even when the head extract was prepared in the dark from the flies reared successively in the dark, both of the 3-hydroxyretinal isomers were detected. In the culture medium, they were not present. D. melanogaster must have an 11-cis 3-hydroxyretinal forming-system that does not need light.

Metabolism of n-3 polyunsaturated fatty acids and modification of phospholipids in cultured rabbit aortic smooth muscle cells

The metabolism of the linolenic acid family (n-3) of fatty acids, e.g., linolenic, eicosapentaenoic, and docosahexaenoic acids, in cultured smooth muscle cells from rabbit aorta was compared to the metabolism of linoleic and arachidonic acids. There was a time-dependent uptake of these fatty acids into cells for 16 hr (arachidonic greater than docosahexaenoic, linoleic, eicosapentaenoic greater than linolenic), and the acids were incorporated mainly into phospholipids and triglycerides. Eicosapentaenoic and arachidonic acids were incorporated more into phosphatidylethanolamine and phosphatidylinositol plus phosphatidylserine and less into phosphatidylcholine than linolenic and linoleic acids. Docosahexaenoic acid was incorporated into phosphatidylethanolamine more than linolenic and linoleic acids and into phosphatidylinositol plus phosphatidylserine less than eicosapentaenoic and arachidonic acids. Added linolenic acid accumulated mainly in phosphatidylcholine and did not decrease the arachidonic acid content of any phospholipid subfraction. Elongation-desaturation metabolites of linoleic acid did not accumulate. Cells treated with eicosapentaenoic acid accumulated both eicosapentaenoic and docosapentaenoic acids mainly in phosphatidylethanolamine and the arachidonic acid content was decreased. Added docosahexaenoic acid accumulated mainly in phosphatidylethanolamine and decreased the content of both arachidonic and oleic acids. The following conclusions are drawn from these results. The three n-3 fatty acids are utilized differently in phospholipids. The arachidonic acid content of phospholipids is reduced by eicosapentaenoic and docosahexaenoic acids, but not by linolenic acid. Smooth muscle cells have little or no desaturase activity, but have significant elongation activity for polyunsaturated fatty acids.

Post-heparin plasma hepatic triacylglycerol lipase-catalyzed hydrolysis of tributyrin. Effect of lipid interface

The mechanism of action of hepatic triacylglycerol lipase (EC 3.1.1.3) was examined by comparing the hydrolysis of a water-soluble substrate, tributyrin, with that of triolein by hepatic triacylglycerol lipase purified from human post-heparin plasma. The hydrolyzing activities toward tributyrin and triolein were coeluted from heparin-Sepharose at an NaCl concentration of 0.7 M. The maximal velocity of hepatic triacylglycerol lipase (Vmax) for tributyrin was 17.9 mumol/mg protein per h and the Michaelis constant (Km) value was 0.12 mM, whereas the Vmax for triolein was 76 mumol/mg per h and the Km value was 2.5 mM. The hydrolyses of tributyrin and triolein by hepatic triacylglycerol lipase were inhibited to similar extends by procainamide, NaF, Zn2+, Cu2+, Mn2+, SDS and sodium deoxycholate. Triolein hydrolysis was inhibited by the addition of tributyrin. Triolein hydrolysis was also inhibited by the addition of dipalmitoylphosphaidylcholine vesicles. In contrast, the additions of triolein emulsified with Triton X-100 and dipalmitoylphosphatidylcholine vesicles enhanced the rate of tributyrin hydrolysis by hepatic triacylglycerol lipase. In the presence of dipalmitoylphosphatidylcholine, the Vmax and Km values of hepatic triacylglycerol lipase for tributyrin were 41 mumol/mg protein per h and 0.12 mM, respectively, indicating that the enhancement of hepatic triacylglycerol lipase activity for tributyrin by dipalmitoylphosphatidycholine vesicles was mainly due to increase in the Vmax. The enhancement of hepatic triacylglycerol lipase activity for tributyrin by phospholipid was not correlated with the amount of tributyrin associated with the phospholipid vesicles. On Bio-Gel A5m column chromatography, glycerol tri[1-14C]butyrate was not coeluted with triolein emulsion, and hepatic triacylglycerol lipase activity was associated with triolein emulsion even in the presence of 2 mM tributyrin. These results suggest that hepatic triacylglycerol lipase has a catalytic site for esterase activity and a separate site for lipid interface recognition, and that on binding to a lipid interface the conformation of the enzyme changes, resulting in enhancement of the esterase activity.

Hydrolysis of cholesterol ester in artificial lipid mixtures by cholesterol esterase released from particulate fractions of rat arterial wall

Acid and neutral cholesterol esterase activities in rat arterial wall were released from the lysosomal fraction and microsomal fraction respectively into the 105,000 X g supernatant fraction by treatment with Triton X-100, heparin and dextran sulfate. The percentage releases of acid cholesterol esterase by Triton X-100 (0.1%), heparin (50 micrograms/ml) and dextran sulfate (1 mg/ml) were 21%, 18% and 4%, respectively, while those of neutral cholesterol esterase were 66%, 56% and 39%, respectively. The cholesterol esterase released by dextran sulfate, especially that from the microsomal fraction, hydrolyzed cholesterol ester in artificial lipid mixtures with similar lipid compositions to those of the deposits in fatty streaks and fibrous plaques of atheromatous lesions.

Effect of niceritrol on lipid metabolism of aorta in atherosclerotic rats

Atherosclerotic lesions were formed in the aorta of rats given a high cholesterol diet containing propylthiouracil (PTU) and vitamin D2 (atherogenic diet) for 8 weeks. The effects of niceritrol (pentaerythritol tetranicotinate), which lower the plasma lipid level, on lipid metabolism in the arterial wall of the atherosclerotic rats were studied. Niceritrol significantly decreased the plasma cholesterol level of atherosclerotic rats, which was 823 mg/100 ml, or about ten times that of control rats. On treatment with niceritrol, the cholesterol level was reduced most in the very low density lipoprotein (VLDL) fraction (d less than 1.006). Heparin-releasable lipoprotein lipase activity in epididymal adipose tissue, lipoprotein lipase activity in post-heparin plasma, and VLDL-triolein hydrolyzing activity in adipose tissue stromal vessels were all higher in niceritrol-treated atherosclerotic rats. Of the enzymes in the arterial wall concerned with cholesterol ester metabolism, acid cholesterol esterase activity was decreased in atherosclerotic rats, while niceritrol treatment increased this activity. The ratio of acyl-CoA cholesterol acyltransferase activity (ACAT) to neutral cholesterol esterase activity was higher in atherosclerotic rats than in control rats, but was lower in niceritrol-treated rats than in atherosclerotic rats. From these results, it is concluded that niceritrol modifies enzyme activities in such a way as to reduce the cholesterol ester content of the arterial wall and lower plasma VLDL and LDL cholesterol levels.

Lipid metabolism in nephrotic rats induced by daunomycin injection

Lipid metabolism in the blood and liver of rats was investigated to clarify the mechanism of dyslipoproteinemia in the nephrotic syndrome. The nephrotic syndrome was induced in rats by a single injection of daunomycin. The serum total cholesterol, triglyceride, and phospholipid levels in nephrotic rats 14 days after the injection were increased 3.1-fold, 2-fold, and 2.7-fold, respectively, over the control values. The cholesterol, triglyceride, and phospholipid contents of high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very-low-density lipoprotein (VLDL) were also increased, increase in VLDL lipids being the greatest. The serum HDL cholesterol level decreased gradually after day 14, returning to the normal level on day 37, whereas the LDL and VLDL cholesterol levels continued to increase until day 37. The mechanism of dyslipoproteinemia in the nephrotic syndrome was examined by comparing lipid metabolism in the liver of nephrotic rats induced by daunomycin with that of rats fed on high-cholesterol diet. The contents of to total lipids, triglyceride, and cholesterol ester in the liver were significantly less in nephrotic rats than in controls. The contents of total lipids and cholesterol ester in the liver were much higher in rats fed on high-cholesterol diet than in controls. The contents of total lipids, triglyceride, cholesterol ester, and phospholipid in the liver were significantly lower in nephrotic rats fed on high-cholesterol diet than in normal rats fed on high-cholesterol diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of cholesterol metabolism in rat adrenal glands: effect of adrenocorticotropin, cholesterol, and corticosteroids on acyl-coenzyme A synthetase and cholesterol ester hydrolases

The regulation of cholesterol metabolism in rat adrenal glands, especially the effect of ACTH, cholesterol, and corticosteroids on acyl-coenzyme A (CoA) synthetase and cholesterol ester hydrolases was investigated. A significant increase in acyl-CoA synthetase activity and decrease in cholesterol ester hydrolase activities were observed in 24-h hypophysectomized rats. Acute injection of ACTH, however, reversed these changes, whereas dexamethasone administration had no effect. When 4-aminopyrazolo[3,4-d]pyrimidine was given to rats, adrenal cholesterol ester content and the acyl-CoA synthetase activity declined and the activities of the cholesterol ester hydrolases were increased in association with the rise of plasma ACTH concentration. When dexamethasone, which suppresses ACTH secretion, was simultaneously administered with 4-aminopyrazolo[3,4-d]pyrimidine no changes except for a decrease in plasma cholesterol level occurred. In hyperlipidemic rats the acyl-CoA synthetase activity increased when a high cholesterol diet was given and the plasma cholesterol level was increased. These results suggest that acyl-CoA synthetase is under the influence of ACTH and also the plasma cholesterol concentration, and that cholesterol ester hydrolases are mainly regulated by ACTH.

[Effect of mazindol on free fatty acid metabolism in the brain of rats]

The effects of mazindol which is known as a anorexigenic agent on the free fatty acid metabolism in the brain were studied. One-half mg of mazindol was orally administered to rats weighing 500 g for 5 days. Body weight was reduced by 10%, compared to the control. Serum levels of free fatty acid, triglyceride, total cholesterol and phospholipid were decreased. The effect of mazindol on the incorporation of [1-14C] palmitic acid into various lipids in the brain were studied. When mazindol (5 mg) was administered one hr before injection of [1-14C] palmitic acid to the internal carotid artery of rats ad libitum, incorporation of [1-14C] palmitic acid into free fatty acids in the cerebrum and diencephalon was lower than that of the control, but incorporation into phospholipid and triglyceride were higher than that of the control. When mazindol was injected into fasting rats, incorporation into free fatty acid in cerebrum and diencephalon was increased compared with the control, and the incorporations into phospholipid and triglyceride were decreased.

Role of aging in lipid metabolism in the aorta of rats

To clarify the intrinsic process of aging in aorta, the lipid metabolism was investigated in serum, aorta, and liver of 24-month-old rats in comparison to 10-month-old animals. Serum total cholesterol and the lipid content of low-density lipoprotein slightly increased in aged animals. Enzyme activities which hydrolyze or synthesize cholesterol ester or triglyceride in aorta were enhanced in aged animals. The increase in hydrolysis overcame that in synthesis, suggesting that enzyme activities were not changed in order to accumulate cholesterol ester and triglyceride in the aorta with aging. Phospholipid content and choline phosphotransferase activity were low both in the aorta and liver of aged animals. Moreover the phospholipid to free cholesterol ratio was decreased in aged animals, suggesting a change of membrane property with aging.

In vivo effects of cis-5,8,11,14,17-20:5 (n-3) and cis-4,7,10,13,16,19-22:6(n-3) on serum lipoproteins, platelet aggregation, and lipid metabolism in the aorta of rats

Highly purified cis-5,8,11,14,17-20:5 (n-3) or cis-4,7,10,13,16,19-22:6 (n-3) was administered to rats for 2 weeks, and serum lipoprotein lipid levels, platelet aggregation, and lipid metabolism in the aorta in vivo were investigated. 20:5 (n-3) decreased the level of low density lipoprotein phospholipid. 22:6 (n-3) increased the level of high density lipoprotein cholesterol and decreased those of low density lipoprotein triglyceride and phospholipid. Both 20:5 (n-3) and 22:6 (n-3) markedly inhibited platelet aggregation. 20:5 (n-3) decreased the acid and neutral cholesterol esterase activities, but did not affect either acyl-CoA synthetase or acyl-CoA: cholesterol acyltransferase activity. 22:6 (n-3) had no effect on any of these enzyme activities. From these results, the roles of 20:5 (n-3) and 22:6 (n-3) in the formation of atheromatous lesions and the mechanism of the decrease in cholesterol esterase activity by 20:5 (n-3) were discussed.

Lipid metabolism in the aorta of daunomycin-induced nephrotic rats

Several enzyme activities involved in lipid hydrolysis (acid and neutral cholesterol esterase and lipase) or synthesis (acyl-CoA synthetase, acyl-CoA: cholesterol acyltransferase and cholinephosphotransferase) were assayed in the aortas of rats with nephrosis induced by daunomycin and of rats fed on high cholesterol diet. In nephrotic rats activities of some enzymes involved in lipid hydrolysis, but not in synthesis, were increased. On the contrary, in rats fed on high cholesterol diet, the activities of all enzymes involved in lipid synthesis were significantly increased, with some increase in those involved in lipid hydrolysis. In nephrotic rats fed on high cholesterol diet all enzyme activities were markedly increased. From the view point of accumulation of cholesterol ester (CE), the ratio of hydrolysis of CE in lysosomes to CE incorporated from the blood and the ratio of hydrolysis of CE to reesterification of free cholesterol in microsomes were considered to be important. From this point of view, nephrotic hyperlipidemia was not so atherogenic as hyperlipidemia induced by the diet. The role of serum high density lipoproteins in lipid metabolism in the aorta was discussed.

Effects of gamma-oryzanol on lipid metabolism in rats fed high-cholesterol diet

The lipid contents of the plasma and liver and enzyme activities in the aorta were determined in rats given the following diets: Group I, normal diet (ND); Group II, high cholesterol diet (HCD, ND plus 1% cholesterol and 0.5% cholic acid); Group III, HCD plus 0.5% gamma-oryzanol; Group IV, HCD plus 2% gamma-oryzanol in the last days of the 4th, 8th and 12th week of the feeding period. Total cholesterol, low-density lipoprotein-cholesterol and very low-density lipoprotein-cholesterol in the plasma were significantly higher in rats in groups III and IV than in those in group II. High-density lipoprotein-cholesterol was increased in groups III and IV. There were no differences in the triglyceride or phospholipids concentrations in the plasma of rats in the four groups. The liver weight was higher in the HCD groups (groups II, III and IV) than in the ND group (group I). The cholesterol ester and triglyceride contents of the liver were higher in the HCD groups than in the ND group, and the increase was the least in group IV of the HCD groups. Changes in acid cholesterol esterase activity and acyl CoA: cholesterol acyltransferase activity in rat aorta homogenates to compensate for lipid deposition were greater in groups III and IV than in group II.

Effects of pantethine and its metabolites on fatty acid oxidation in rat liver mitochondria

The mechanism of the activating effect of pantethine [D-bis-(N-pantothenyl-beta-aminoethyl)disulfide] on fatty acid oxidation was investigated in rat liver mitochondria. Pantethine, pantetheine and 4'-phosphopantetheine activated three steps of fatty acid oxidation, i.e., acyl-CoA synthetase, carnitine, acyltransferase and intramitochondrial oxidation, to various extents. Although their effects may have been partly due to CoASH derived from them, they also had specific effects.

Effect of pantethine on fatty acid oxidation in microvessels of rat brain

Fatty acid oxidation in brain microvessels decreased greatly when persistent hypertension developed in spontaneously hypertensive rats (SHR). Treatment of SHR with pantethine [D-bis-(N-pantothenyl-beta-aminoethyl) disulfide] in vivo for 4 weeks restored their fatty acid oxidation activity to the control level. The mechanism of the activating effect of pantethine on fatty acid oxidation was investigated in brain microvessels. Pantethine and its metabolites (pantetheine and 4'-phosphopantetheine) activated three steps of fatty acid oxidation, i.e., acyl-CoA synthetase, carnitine acyltransferase and intramitochondrial oxidation. The relation between changes in fatty acid oxidation activities and injuries of brain microvessels and the protective effect of pantethine against such injuries is discussed.

Evidence for the homology of hexose 6-phosphate dehydrogenase and glucose 6-phosphate dehydrogenase: comparison of the amino acid compositions

Amino acid compositions of hexose 6-phosphate dehydrogenase and glucose 6-phosphate dehydrogenase from crucian carp and rat, and that of sea-urchin glucose 6-phosphate dehydrogenase were compared in order to ascertain if they are homologous enzymes. The results demonstrated that the overall amino acid compositions of the two enzymes remarkably resemble each other, and that the composition divergence (D = 0.038) of the crucian carp enzymes is in the range of those for homologous proteins so far reported. These findings strongly support our previous prediction that the two enzymes have diverged from a common ancestral molecule.

Effect of phospholipids on lipase activity in rat arterial wall homogenate

Triolein hydrolyzing activity in homogenates of the rat arterial wall was studied. Two optimal pH values were observed around 5.0 (acid lipase) and 7.0 (neutral lipase). Neutral lipase activity was enhanced by serum and was inhibited by 1 M NaCl but was not inhibited by protamine. Heparin decreased the acid lipase activity. A 1-mM solution of Cu2+ ion and Zn+2 ion decreased both lipase activities. The activities of both acid and neutral lipases were increased by the addition of rat serum (2 micrograms protein serum/ml) and were decreased by the addition of more than 5 micrograms protein serum/ml. The activities of neutral and acid lipases were increased by the addition of 0.25 mM phosphatidylcholine and phosphatidylserine. Both lipase activities were decreased by the addition of 0.25 mM phosphatidylethanolamine. The addition of 0.25 mM sphingomyelin increased neutral lipase activity and decreased acid lipase activity. At concentrations higher than 2 mM, these phospholipids decreased the activities of both lipases. These results suggest that at least acid and neutral lipases exist in the arterial wall cells, and their activities might be modified by phospholipids.

Effect of dextran sulfate on the interaction between very low density lipoprotein and lipoprotein lipase

The effect of dextran sulfate on the interaction between very low density lipoprotein (VLDL) and purified bovine milk lipoprotein was studied. Dextran sulfate increased VLDL-triacylglycerol hydrolysis by lipoprotein lipase about 2-fold, but did not alter the Km value for triacylglycerol in VLDL. Strong association of dextran sulfate with the VLDL-lipoprotein lipase complex was demonstrated by gel filtration on BioGel A-5m, although dextran sulfate did not bind to VLDL and only very slightly to lipoprotein lipase. These findings suggest that dextran sulfate increases triacylglycerol hydrolysis in VLDL by binding to the VLDL-lipoprotein lipase complex.