We established a cell-free system in which epinephrine and other lipolytic agents stimulated lipolysis of endogenous lipid droplets from fat cells by hormone-sensitive lipase. The endogenous lipid droplets were prepared by hypotonic treatment of fat cells and their successive washing with buffer containing 0.025% Triton X-100. In the cell-free system, propranolol inhibited lipolysis induced by various lipolytic agents such as norepinephrine, theophylline and cyclic AMP (cAMP), whereas phenoxybenzamine did not inhibit lipolysis. The binding of these lipolytic agents to endogenous lipid droplets was inhibited by propranolol, but not by phenoxybenzamine. The "propranolol-sensitive" binding of these lipolytic agents to the droplets may be involved in lipolysis. Treatment of the droplets with phospholipase C, but not phospholipase D, inhibited the propranolol-sensitive binding of these lipolytic agents to the droplets. These results suggest that the phosphate group of phospholipid in the droplets may be the site of propranolol-sensitive of binding of theophylline, and cAMP in addition to norepinephrine.

Adipose Tissue↗

PubMedDate not supplied

Effects of lead exposure on GnRH and LH secretion in male rats: response to castration and alpha-methyl-p-tyrosine (AMPT) challenge.

Animal and clinical studies suggest that lead exposure disrupts the hypothalamic-pituitary axis. To define more precisely the toxic action of lead on the hypothalamic-pituitary unit, a series of in vivo and in vitro experiments were performed. The first experiment was designed to determine whether lead exposure exerts an inhibitory effect on GnRH secretion as reflected by an enhanced inhibition of luteinizing hormone (LH) secretion in response to the tyrosine hydroxylase inhibitor methyl-p-tyrosine (AMPT). In the control animals, the AMPT dose had no significant effect on LH secretion, whereas LH fell significantly in the lead-treated animals. In experiments designed to evaluate the effects of lead exposure on the pattern of pulsatile release of gonadotropins castrated control and lead-dosed animals were cannulated, and serial blood sampling was performed. Baseline LH and follicle-stimulating hormone values were not statistically different between the control and lead-treated group. There were no significant differences noted in pulsatile patterns when the data were analyzed as groups. Pituitary cells harvested from lead-treated animals released significantly more LH that did the control animals. These data are consistent with the hypothesis that the signals between the hypothalamus and pituitary gland are disrupted by lead exposure in the intact animal. However, the lead-exposed castrated rat's hypothalamic-pituitary unit is able to adapt to the toxic effects of lead.

Adaptation, Physiological↗

PubMedDate not supplied

Lipolytic activities of p-aminophenol and n-decylamine in endogenous lipid droplets from rat adipocytes.

Lipolytic agents such as adrenaline (epinephrine), dibutyryl cyclic AMP (DBcAMP) and theophylline possess common structural characteristics, the existence of a positive charge and a hydrophobic area. p-Aminophenol, which has the same structural characteristics, was found to induce lipolysis in the endogenous lipid droplets from rat adipocytes. It was demonstrated that the positive group and the hydrophobic area of p-aminophenol are essential requirements for its lipolytic activity. Among various amine derivatives, only n-decylamine was found to induce lipolysis in the endogenous lipid droplets. Although the lipolytic action of n-decylamine is fairly low, it possesses remarkable inhibitory effects on both adrenaline- and DBcAMP-induced lipolytic activities. Furthermore, n-decylamine is found to inhibit competitively the DBcAMP-induced lipolysis.

Adipose Tissue↗

PubMedDate not supplied

Effects of phenolic constituents from the mulberry tree on arachidonate metabolism in rat platelets.

The effects of various phenolic compounds isolated from the rootbark of the mulberry tree on rat platelet cyclooxygenase and lipoxygenase products formed from (1-14C)arachiodonic acid were studied. Kuwanons G and H, sanggenon C, and mulberrofuran Q at concentrations of 10(-3) to 10(-4)M inhibited the formation of 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT) and thromboxane B2 (cyclooxygenase products); however, they increased the formation of 12-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) (a lipoxygenase product). Sanggenon D and mulberrofuran J at concentration of 10(-3)M inhibited the formation of HHT, thromboxane B2, and 12-HETE. Mulberrofuran G at a concentration of 10(-3)M inhibited the formation of HHT, thromboxane B2, and 12-HETE, while at 10(-5)M, it inhibited the formation of 12-HETE without affecting the formations of HHT and thromboxane B2. Kuwanon M and mulberroside A did not affect arachidonate metabolism in rat platelets.

Animals↗

PubMedDate not supplied

Studies on the activities of tannins and related compounds, X. Effects of caffeetannins and related compounds on arachidonate metabolism in human polymorphonuclear leukocytes.

As part of a series of biological examinations of various tannins and related compounds, the present paper reports the effects of caffeetannins and related compounds isolated from medicinal plants on arachidonate metabolism in human peripheral polymorphonuclear leukocytes (PMN-L). The formation of leukotriene B4 (LTB4) induced by calcium ionophore A 23187 (A 23187) in human PMN-L was inhibited by 3,5-, 4,5-, and 3,4-di-O-caffeoylquinic acid, caffeoylmalic acid, caffeoyltartric acid, rosmarinic acid, and caffeic acid. Rosmarinic acid strongly inhibited the formation of 5-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE) and LTB4 (5-lipoxygenase products) at concentrations of 10(-5)-10(-3) M. On the other hand, the formation of prostaglandin E2 (PGE2) was enhanced in a concentration-dependent fashion by caffeic acid, caffeoylmalic acid, caffeoyltartaric acid, and 3,4-di-O-caffeoylquinic acid. On the basis of experimental results, it seems likely that caffeoyl derivatives could be developed as therapeutic drugs for treatment of allergic inflammation such as asthma.

Arachidonic Acid↗

PubMedDate not supplied

Inhibitory effects of various flavonoids isolated from leaves of persimmon on angiotensin-converting enzyme activity.

The leaves of the persimmon Diospyros kaki, have been traditionally used for treatment of hypertensive diseases in Japan. We have studied the inhibitory effects of four flavonoids isolated from the leaves of the persimmon on angiotensin-converting enzyme activity. The four flavonoids astragalin [1], kaempferol-3-O-(2"-O-galloyl)-glucoside [2], isoquercitrin [3], and quercetin-3-O-(2"-O-galloyl)-glucoside [4] inhibited the angiotensin-converting enzyme activity in a dose-dependent fashion. Compounds 1-4 produced 67%, 53%, 33%, and 48% inhibition at a concentration of 300 micrograms/ml, respectively. The 50% inhibitory concentrations (IC50) of 1 and 2 for the angiotensin-converting enzyme were 180 micrograms/ml and 280 micrograms/ml, respectively. On the other hand, 2 and 4 were shown to have tannin activities, but 1 and 3 had no tannin activities. These results suggest that there is no relationship between the inhibition for angiotensin converting enzyme activity and the tannin activity for the four flavonoids.

Angiotensin-Converting Enzyme Inhibitors↗

PubMedDate not supplied

Selective covalent binding of the active sulfate ester of the carcinogen 5-(hydroxymethyl)chrysene to the adenine residue of calf thymus DNA.

5-(Hydroxymethyl)chrysene (5-HCR) sulfate, an active metabolite of the carcinogen 5-HCR, bound significantly in a covalent manner to the purine bases of calf thymus DNA through its 5-methylene carbon with loss of a sulfate anion when incubated at pH 7.4 and 37 degrees C. From the DNA were isolated two purine base adducts by high-pressure liquid chromatography, and they were identified as N6-[(chrysen-5-yl)methyl]adenine and N2-[(chrysen-5-yl)methyl]guanine with the corresponding synthetic specimens. The purine base adducts, appearing in the ratio 1 to 27 for guanine to adenine in the chromatogram, accounted for about 60% of the total covalent binding of 5-HCR sulfate to the DNA. 5-HCR sulfate also reacted specifically with the exocyclic amino groups of the purine bases of 2'-deoxyadenosine 5'-phosphate and 2'-deoxyguanosine 5'-phosphate at much lower rates than did with those of calf thymus DNA. Denaturing the DNA by heating followed by rapid cooling, covalent binding of 5-HCR sulfate to it markedly decreased with the increasing ratio of N2-guanine to N6-adenine adducts (1:3.6). These results strongly suggest that secondary structure of DNA has an influence on the covalent binding of 5-HCR sulfate and that intercalation of the sulfate ester into DNA base pairs plays an important role in its preferential binding to N6 of the adenine residue of native DNA.

Adenine↗

PubMedDate not supplied

Vitamin K-dependent proteins and hepatocellular carcinoma.

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Biomarkers↗

PubMedDate not supplied

Prevalence of primary sclerosing cholangitis and other liver diseases in Japanese patients with chronic ulcerative colitis.

An association between primary sclerosing cholangitis (PSC) and chronic ulcerative colitis (CUC) is well known in Western countries, but there have been no reports on this association in Japan. We reviewed 163 consecutive CUC patients (91 males and 72 females) diagnosed from 1984 to 1990 at Tokyo Women's Medical College. Abnormal liver function tests were found in 42 patients with CUC (25.8%), but chronic liver disease was only diagnosed in seven patients (4.3%). Among these seven patients, there were four with PSC, one with small-duct PSC, one with transfusion-associated chronic hepatitis and one with Type B liver cirrhosis. No relationship was found between the documented colonic manifestations of CUC and the presence of PSC. The four PSC patients did not have a longer history of CUC at the time of diagnosis of PSC than CUC patients without PSC. At the time of PSC diagnosis, two patients were asymptomatic, one presented with right upper quadrant pain, and the other had fatigue. Three patients were diagnosed as having CUC before the onset of PSC (range 2-13 years), and the other patient had both diseases simultaneously. All four had a good prognosis. Thus PSC was the most common chronic liver disease associated with CUC in our series, and it was present in all our CUC patients with alkaline phosphatase levels exceeding twice the upper limit of normal and mild transaminase elevation.

Adolescent↗

PubMedDate not supplied

Immunohistochemical detection of proliferating cell nuclear antigen in hepatocellular carcinoma: relationship to histological grade.

Proliferating cell nuclear antigen (PCNA), also known as cyclin, is an auxiliary protein of DNA polymerase-delta and is found only in the nuclei of proliferating cells in the late G1 and S phases. The proliferation of hepatocellular carcinoma (HCC) by immunohistochemical staining for PCNA using paraffin sections of 20 surgically resected HCC specimens was analysed. The mean percentage of PCNA-positive nuclei in the HCC tissue was 10.3% in grade I of Edmondson and Steiner's classification, 25.5% in grade II, 28.4% in grade III and 41.5% in grade IV. In early HCC, we observed only a few PCNA-positive tumour cells. However, PCNA-positive nuclei were numerous in the tumour thrombi found in portal vein branches, in regions of extracapsular tumour growth, and in the inner nodules of tumours with a nodule-in-nodule formation. Proliferating cell nuclear antigen positivity was correlated with an increase of the nucleocytoplasmic ratio of tumour cells as determined by image analysis. Our findings showed that PCNA positivity was correlated with the histological grade and invasiveness of HCC, suggesting that this antigen may be used as an indicator to predict tumour invasion in patients with HCC.

Adult↗

PubMedDate not supplied

Levels of vitamin K, immunoreactive prothrombin, des-gamma-carboxy prothrombin and gamma-glutamyl carboxylase activity in hepatocellular carcinoma tissue.

To clarify the mechanism of production of des-gamma-carboxy (abnormal) prothrombin (DCP) by hepatocellular carcinoma (HCC), we measured the levels of vitamin K, DCP, immunoreactive prothrombin and the activity of gamma-glutamyl carboxylase in liver tissues from HCC patients and in the medium of cultured human hepatoma cells. There was no significant difference in vitamin K (K1, MK-4) contents between HCC and non-HCC cirrhotic liver tissues. The activity of gamma-glutamyl carboxylase per unit amount of endogenous microsomal prothrombin precursor was decreased in HCC tissue compared with non-HCC liver tissue (positive plasma DCP: 335 +/- 72 vs 372 +/- 67, negative plasma DCP: 370 +/- 84 vs 393 +/- 56 nmol/min per mg prothrombin precursor, P > 0.05), although the total incorporation of 14COOH into microsomal precursor protein was higher in the former. By contrast, levels of DCP and immunoreactive prothrombin in HCC tissue were greater (P < 0.05) than those in non-HCC cirrhotic liver tissue. Furthermore, production of large amounts of immunoreactive prothrombin was observed in human hepatoma cells huH-1 and huH-2, which produced large amounts of DCP. These results suggest that there was excessive synthesis of prothrombin precursors by human HCC tissue and hepatoma cell lines huH-1 and huH-2. Thus, excessive synthesis of prothrombin precursors seems to be the main mechanism of DCP production by HCC.

Aged↗

PubMedDate not supplied

A new experimental model for drug studies: effects of phenobarbital and phenytoin on photosensitivity in the lateral geniculate-kindled cat.

Photosensitivity was acquired as a result of kindling in the lateral geniculate body (GL), and the GL-kindled cat pretreated with DL-allylglycine showed a stable level of photosensitivity. To test the usefulness as a model for the evaluation of anticonvulsant drugs, the effects of phenobarbital (PB) and phenytoin (PHT) on photosensitivity were studied in the GL-kindled cat under DL-allylglycine. PB (5 and 10 mg/kg intravenously, i.v.) completely suppressed photically induced seizures in most subjects at plasma concentrations of 7-16 micrograms/ml, and this anticonvulsant action persisted for at least 4 h after the injection. PHT (15 mg/kg, i.v.) at plasma concentrations of 9-15 micrograms/ml produced toxic signs, e.g., pupil dilatation, hypersalivation, and tachypnea. At this dose, PHT was inactive against photically induced myoclonus but prevented the elicitation of a generalized tonic-clonic convulsion. From these results showing that the effects of anticonvulsant drugs on photically induced seizures can be assessed in relation to plasma concentration and acute neurologic toxicity, we suggest that the GL-kindled cat is a potentially useful animal model of epilepsy for testing the efficacy of anticonvulsant drugs.

Allylglycine↗

PubMedDate not supplied

Platelet-derived endothelial cell growth factor is not implicated in progression of cervical cancer.

We examined the expression of platelet-derived endothelial cell growth factor (PD-ECGF) mRNAs in 47 invasive cervical cancer tissues by semi-quantitative RT-PCR and addressed its association with clinicopathological features including microvessel density. Squamous cell carcinomas expressed higher levels of PD-ECGF mRNA than non-squamous cell carcinomas (P=0.014). We found no association between FIGO stage and levels of PD-ECGF mRNA. A subset of 31 patients with stage Ib-II cervical cancer underwent radical hysterectomy and pelvic lymphadenectomy. There were no significant differences in PD-ECGF mRNA levels with respect to tumor size, degree of stromal invasion, lymphvascular space involvement, parametrial involvement, vaginal involvement or lymph node metastasis among these patients. There was no correlation between microvessel density and the levels of PD-ECGF mRNA. These findings suggest that PD-ECGF expression is not associated with progression and metastasis of cervical cancer.

Disease Progression↗