Differential use of warfarin for secondary stroke prevention in patients with various types of atrial fibrillation.

Anticoagulation therapy significantly reduces the incidence of thromboembolic events in patients with atrial fibrillation (AF), and warfarin therapy at discharge is a class I-indicated drug in patients with ischemic stroke with persistent or paroxysmal AF without contraindications. The aim was to determine whether participation in the Get With The Guidelines-Stroke (GWTG-S) quality improvement program would be associated with improved adherence to anticoagulation guidelines for patients with all types of AF. Adherence to warfarin treatment at hospital discharge was assessed in eligible patients with AF who presented with stroke or transient ischemic attack, based on type of AF.

Modulation of mitogenesis by liver fatty acid binding protein.

Liver fatty acid binding protein (L-FABP), a cytoplasmic 14 kDa protein previously termed Z protein, is conventionally considered to be an intracellular carrier of fatty acids in rat hepatocytes. The following evidence now indicates that L-FABP is also a specific mediator of mitogenesis of rat hepatocytes: a. the synergy between the action of L-FABP and unsaturated fatty acids, especially linoleic acid, in the promotion of cell proliferation; b.

Liver fatty acid-binding protein: specific mediator of the mitogenesis induced by two classes of carcinogenic peroxisome proliferators.

Peroxisome proliferators (PP) are a diverse group of chemicals that induce dramatic increases in peroxisomes in rodent hepatocytes, followed by hypertrophy, hepatomegaly, alterations in lipid metabolism, mitogenesis, and finally hepatocarcinomas. Termed nongenotoxic carcinogens, they do not interact with DNA, are not mutagenic in bacterial assays, and fail to elicit many of the phenotypes associated with classic genotoxic carcinogens. We report here that the mitogenesis induced by the major PP class, the amphipathic carboxylates, and by the tetrazole-substituted acetophenones specifically requires liver fatty acid-binding protein (L-FABP) in cultured rat hepatoma cells transfected with the sense cDNA of L-FABP, in contrast to L-FABP-nonexpressing cells transfected with its antisense cDNA.

Growth promotion of transfected hepatoma cells by liver fatty acid binding protein.

Former studies have linked hepatocyte growth with liver fatty acid binding protein (L-FABP) of rat liver cytosol. In search for the roles of L-FABP in hepatocytes, we previously stably transfected rat L-FABP sense and antisense cDNAs into rat hepatoma HTC cells that do not contain L-FABP RNA or protein, thereby providing a zero-background, homologous cell model of L-FABP-expression suitable for controlled studies of its intracellular functions in hepatocyte-derived cells. The present study demonstrates the abilities of L-FABP to promote DNA synthesis and cell growth, preserve cell morphology, extend survival, and act cooperatively with unsaturated fatty acids in the transfected hepatoma cells in the absence of serum.

Specific growth stimulation by linoleic acid in hepatoma cell lines transfected with the target protein of a liver carcinogen.

The hepatic carcinogen N-2-fluorenylacetamide (2-acetylaminofluorene) was shown previously to interact specifically with its target protein, liver fatty acid binding protein (L-FABP), early during hepatocarcinogenesis in rats. In search of the significance of the interaction, rat L-FABP cDNA in the sense and antisense orientations was transfected into a subline of the rat hepatoma HTC cell line that did not express L-FABP. After the transfections, the basal doubling times of the cells were not significantly different.

Preferential binding of growth inhibitory prostaglandins by the target protein of a carcinogen.

Liver fatty acid binding protein (L-FABP) is the principal target protein of the hepatic carcinogen N-(2-fluorenyl)acetamide (2-acetylaminofluorene) in rat liver. In addition, the cyclopentenone prostaglandins (PG), PGA, PGJ2, and delta 12-PGJ2, inhibit the growth of many cell types in vitro. This report describes the preferential binding of the growth inhibitory prostaglandins by L-FABP and the reversible inhibition of thymidine incorporation into DNA by PGA2 and delta 12-PGJ2 in primary cultures of purified rat hepatocytes.

Specific high affinity binding of lipoxygenase metabolites of arachidonic acid by liver fatty acid binding protein.

Liver fatty acid binding protein (L-FABP) binds avidly the arachidonic acid metabolites, hydroperoxyeicosatetraenoic acids (HPETEs) and hydroxyeicosatetraenoic acids (HETEs). Binding of 15-[3H]HPETE was specific, saturable, reversible, and rapid. Protein specificity was indicated by the following order: L-FABP greater than bovine serum albumin greater than ovalbumin = beta-lactoglobulin greater than ribonuclease.

Normal hepatocytes exhibiting histone H3 with antibody accessible sites that are cryptic in carcinogen-altered hepatocytes.

A Mr 14,000 polypeptide (p14), identified as liver fatty acid binding protein, in normal liver cytosol was shown previously to be the principal target of the carcinogen, N-2-fluorenylacetamide (2-acetylaminofluorene), early during hepatic carcinogenesis in rats. Immunohistochemical analyses using rabbit antiserum against pure p14/liver fatty acid binding protein revealed marked increases in the levels of the protein in cytoplasm specifically during mitosis in normal and regenerating hepatocytes, and throughout the cell cycle in hyperplastic and malignant hepatocytes brought about by carcinogen, N-2-fluorenylacetamide (2-acetylaminofluorene) or 3'-methyl-4-dimethylaminoazobenzene. Present also in normal hepatocytes was a nuclear antigen that was not detected in the hyperplastic hepatocytes, benign hepatocytic adenomas, and hepatocellular carcinomas produced by these carcinogens.

Late target protein of the carcinogen N-2-fluorenylacetamide in rat liver.

In previous studies, administration of a radioactive tracer dose of the liver carcinogen, N-2-fluorenylacetamide (2-acetylaminofluorene; FAA), to normal or carcinogen-fed rats led to the presence of one or two principal labeled carcinogen: protein complexes in liver cytosol. The early target Mr 14,000 protein of the carcinogen in normal rats was identified as being liver fatty acid-binding protein and was associated in hepatocytes with normal mitosis and the cell proliferation brought about by either of the two liver carcinogens, FAA or 3'-methyl-4-dimethylaminoazobenzene. Continued ingestion of any of the three hepatocarcinogens, FAA, 3'-methyl-4-dimethylaminoazobenzene, or ethionine, resulted in the progressive loss of the early radioactive complex and the concurrent gain in liver cytosol of the late carcinogen: protein complex (Mr approximately 150,000) formed by the tracer dose of FAA.

Liver fatty acid binding protein is the mitosis-associated polypeptide target of a carcinogen in rat hepatocytes.

Hepatocytes in normal rat liver were found previously to contain a cytoplasmic 14,000-dalton polypeptide (p14) that is associated with mitosis and is the principal early covalent target of activated metabolites of the carcinogen N-2-fluorenylacetamide (2-acetylaminofluorene). The level of immunohistochemically detected p14 was low when growth activity of hepatocytes was low, was markedly elevated during mitosis in normal and regenerating livers, but was very high throughout interphase during proliferation of hyperplastic and malignant hepatocytes induced in rat liver by a carcinogen (N-2-fluorenylacetamide or 3'-methyl-4-dimethylaminoazobenzene). We report here that p14 is the liver fatty acid binding protein.

Elevated expression and cell cycle deregulation of a mitosis-associated target polypeptide of a carcinogen in hyperplastic and malignant rat hepatocytes.

A cytoplasmic polypeptide with a molecular weight of 14,000 (p14) was previously found to be the principal covalent target protein of the carcinogen, N-2-fluorenylacetamide (2-acetylaminofluorene), early during carcinogenesis in rat liver. The level of immunodetected p14 was markedly increased specifically during all stages of mitosis of hepatocytes in normal and regenerating partially hepatectomized livers. In addition, the polypeptide appeared to be immunologically and behaviorally related to a polypeptide with a molecular weight of 17,500 that is tightly bound to nucleosomes of chromatin in hepatocytes.

A new nucleosomal protein in normal liver related to the cytoplasmic polypeptide target of a carcinogen.

Normal adult rat liver contains a nucleosomal protein that is related to the principal target polypeptide of a carcinogen in cytoplasm. Normal rat liver was found previously to contain a 14 000-dalton polypeptide that is the principal cytosolic target of the carcinogen, N-2-fluorenylacetamide (2-acetylaminofluorene; FAA), early during hepatocarcinogenesis. Elevated levels of immunohistochemically detectable target polypeptide in cytoplasm are associated with normal mitosis and carcinogen-induced hyperplasias in adult hepatocytes.

Induction of epidermoid differentiation by cyclic adenine nucleotide in cultured mammary tumors of mice.

In search of the degree of responsiveness of mammary adenocarcinomas to signals of differentiation, mouse mammary tumors were induced to undergo a course of development leading to multiple foci of squamous metaplasia, and subsequently a differentiation manifested by marked keratinization. The mammary tumors had spontaneously arisen in the preneoplastic mammary outgrowths of the transplantable lines, D1, MH5, and MH9, after their long-term implantation in gland-free mammary fat pads of virgin BALB/c mice. The inductions were produced in cultured fragments of mammary tumors by incubation for 9 days in the cyclic adenine nucleotide, N6-O2'-dibutyryl cyclic AMP, at 0.

Mitosis in hepatocytes is generally associated with elevated levels of the target polypeptide of a liver carcinogen.

Rat hepatocytes have previously been found to contain in their cytoplasm a 14,000-dalton polypeptide that: is markedly and specifically increased in concentration during the infrequent mitoses that occur in hepatocytes of adult normal liver; is apparently related to a 17,500-dalton polypeptide that is tightly bound to the chromatin of nuclei of normal adult liver; is the principal covalent target of the carcinogen, N-2-fluorenylacetamide (FAA; 2-acetylaminofluorene), early during liver carcinogenesis; is present at highly elevated levels in the proliferating hepatocytes of hyperplastic foci brought about by the two liver carcinogens, FAA and 3'-methyl-4-dimethylaminoazobenzene; and is present at a greatly depressed level in the mitotically nonresponsive parenchyma that surrounds these hyperplastic foci. In the present investigation, we examined the levels of the two polypeptides in hepatocytes undergoing cell division at different rates in livers of diverse normal and regenerative states. Using immunohistochemical techniques, both polypeptides were detected in developing hepatocytes in as early as 15- and 19-day rat fetuses.

Target polypeptide of a carcinogen is associated with normal mitosis and carcinogen-induced hyperplasias in adult hepatocytes.

Normal rat liver cytosol was found previously to contain a 14,000-dalton polypeptide that is the principal target of the carcinogen N-2-fluorenylacetamide (2-acetyl-aminofluorene) early during hepatocarcinogenesis. By using antiserum that identifies the 14,000-dalton polypeptide in liver cytosol, an immunologically related 17,500-dalton polypeptide was shown to be present in isolated normal liver nuclei, tightly bound to chromatin. We report here that the 14,000-dalton polypeptide is associated with cell multiplication in normal adult hepatocytes.

Normal liver chromatin contains a firmly bound and larger protein related to the principal cytosolic target polypeptide of a hepatic carcinogen.

A 14,000-dalton polypeptide was previously reported to be the principal protein target of the carcinogen N-2-fluorenylacetamide (2-acetylaminofluorene) in liver cytosol at the start of hepatocarcinogenesis in rats. The 14,000-dalton polypeptide was purified to homogeneity according to gel electrophoreses in both NaDodSO4-containing medium and acetic acid/urea and also by immunogenicity. An immunologically related form of the cytosolic target polypeptide has now been found to be present in the nuclei of normal rat liver as a 17,500-dalton polypeptide that is firmly and ionically bound to chromatin.

Persistence of precursor cells of squamous metaplasia in preneoplastic mammary outgrowth lines from mice.

The preneoplastic state is without apparent effect on the induction or prevention of epidermidalization in transplanted mammary outgrowth lines. Development of squamous metaplasia and differentiation (keratinization) were induced in organ cultures of three hyperplastic alveolar and ductular mammary outgrowth lines (D1, MH5, and MH9) that had been extensively passaged in gland-free mammary fat pads of BALB/c virgin mice. The induction was elicited by the mixture of dibutyryl cyclic AMP (0.

Nononcogenic hormone-independent alveoli produced by carcinogens in cultured mouse mammary glands.

Treatment of mouse mammary glands with a high concentration of 7,12-dimethylbenzo(a)anthracene in whole organ culture was reported by Banerjee et al. to transform foci of lobuloalveoli to a hormone-independent state, and to give rise to mammary hyperplastic outgrowths and adenocarcinomas in vivo. In the present study using the identical system, mammary glands of BALB/c mice were exposed to 7,12-dimethylbenzo(a)anthracene or N-2-fluorenylacetamide at low concentrations that bring about maximal incidences of the hormone-independent hyperplastic lobuloalveolar lesions with minimal cytotoxicity.

Induction of squamous metaplasia: requirement for cell multiplication, and competition with lobuloalveolar development in cultured mammary glands.

Mouse mammary glands were previously shown to undergo either of two courses of development and differentiation in whole organ culture. The combination of insulin, prolactin, aldosterone, and hydrocortisone induces a structural development of lobuloalveoli, followed by casein production. In the second course, the mixture of dibutyryl cyclic AMP, prostaglandins E1, E2 and B1, and papaverine brings about an extensive squamous metaplasia and excessive keratinization.