Inhibition of duck hepatitis B virus replication by 2',3'-dideoxycytidine. A potent inhibitor of reverse transcriptase.

The effect of 2',3'-dideoxycytidine, a potent antiviral agent, which, following anabolic phosphorylation, inhibits the reverse transcriptase of the human immunodeficiency virus in vitro, was assessed in 16 Pekin ducks chronically infected with the duck hepatitis B virus. Nine ducks were given 11 mg/m2 of dideoxycytidine intravenously every 6 h, and 7 ducks received no treatment. Serum duck hepatitis B virus deoxyribonucleic acid and deoxyribonucleic acid polymerase activity decreased in every duck treated with dideoxycytidine.

Elevation of factor VII activity and mass in young adults at risk of ischemic heart disease.

The Northwick Park Heart Study found that elevation of factor VII in middle-aged subjects was an independent risk factor for subsequent ischemic heart disease. The present study was designed to determine whether factor VII elevation is present at a younger age and whether zymogen or activated factor VII is responsible for this elevation. A group of 20 asymptomatic first degree relatives (mean age 34.

Rapid and sensitive method for the detection of serum hepatitis B virus DNA using the polymerase chain reaction technique.

We have developed a rapid procedure for the detection of serum hepatitis B virus (HBV) DNA using the polymerase chain reaction (PCR) technique. HBV DNA is released from virions by incubating serum with 0.1 M NaOH for 60 min at 37 degrees C.

Mutation rate of the hepadnavirus genome.

An essential factor for charting the evolution of hepadnaviruses is an estimation of the mutation rate of the virus genome during replication in the host. In order to determine the mutation rate of the hepadnavirus genome under defined experimental conditions, we transfected 10 neonatal woodchucks with an infectious molecular clone of woodchuck hepatitis virus (WHV). By 4 months post-transfection, all 10 animals showed serological evidence for WHV infection.

Effect of bovine growth hormone on incorporation of [14C]acetate into lipids by co-cultures of bovine mammary, liver, and adipose tissue explants.

Incorporation of [14C]acetate into lipids was measured in 24 hr co-cultures of mammary, liver and adipose tissue from Holstein cows at 53, 210 and 318 d of lactation in the presence or absence of bovine growth hormone. Little (less than 1%) of the labeled lipids appeared in the media relative to that incorporated into the tissue. In mammary tissue, incorporation of [14C]acetate was highest into triglycerides (16,298 cpm/mg mammary tissue), followed by phospholipids (1,887 cpm), free fatty acids (1,252 cpm), diglycerides (708 cpm), free cholesterol (360 cpm) and monoglycerides (93 cpm).

One-step preparation of competent Escherichia coli: transformation and storage of bacterial cells in the same solution.

We have developed a simple, one-step procedure for the preparation of competent Escherichia coli that uses a transformation and storage solution [TSS; 1 x TSS is LB broth containing 10% (wt/vol) polyethylene glycol, 5% (vol/vol) dimethyl sulfoxide, and 50 mM Mg2+ at pH 6.5]. Cells are mixed with an equal volume of ice-cold 2 x TSS and are immediately ready for use.

A Novel Type of Glial Cell Associated with Nodes of Ranvier in Rat Optic Nerve.

Using Golgi impregnation and intracellular injection of horseradish peroxidase, we show that the adult rat optic nerve contains two distinct types of astrocyte-like glial cells: one has mainly radially oriented processes that terminate on blood vessels or on the pial surface; the other has mainly longitudinally oriented processes that associate with, and often terminate at, nodes of Ranvier, but do not end on blood vessels or the pial surface. The sequence of appearance of the two types of glial cells in the developing nerve, taken together with previous immunocytochemical findings, suggests that these cells may correspond to the two types of astrocytes previously described in cultures of perinatal optic nerve cells-those with mainly radially oriented processes corresponding to type-1 astrocytes and those with mainly longitudinally oriented processes corresponding to type-2 astrocytes. To our knowledge, this is the first description of a class of central nervous system (CNS) glial cell whose processes are primarily associated with nodes of Ranvier.

Complete nucleotide sequence of a molecular clone of woodchuck hepatitis virus that is infectious in the natural host.

Woodchuck hepatitis virus (WHV) DNA was cloned from viral particles obtained from the serum of a woodchuck with a naturally acquired infection. The complete nucleotide sequence of the virus genome was determined and found to be 3323 base pairs long. Transfection experiments demonstrated that the recombinant WHV DNA was infectious in each of 18 woodchucks tested and established a chronic carrier state in 1 of 13 neonates and 3 of 5 adult animals.

Covalent DNA damage in tissues of cigarette smokers as determined by 32P-postlabeling assay.

Covalent DNA addition products (adducts) formed by the reaction of chemical carcinogens or their metabolites with DNA are critically involved in the initiation of chemical carcinogenesis and may serve as molecular markers and dosimeters for environmental carcinogen exposures. Using a highly sensitive 32P-postlabeling assay for DNA adduct analysis, we studied DNA damage elicited by cigarette smoke in tissues of smokers. A multitude of characteristic smoking-induced, presumably aromatic DNA adducts were found to occur in a dose- and time-dependent manner in the lung, bronchus, and larynx of smokers with cancer of these organs and to decline only slowly after cessation of smoking.

Detection of serum hepatitis B virus DNA in patients with chronic hepatitis using the polymerase chain reaction assay.

We compared the sensitivity of the polymerase chain-reaction (PCR) assay to that of slot-blot hybridization for detecting hepatitis B virus (HBV) DNA in the serum of 31 patients with chronic hepatitis. Of 14 chronic hepatitis patients positive for both HBV surface and HBV e antigens, 9 were positive for HBV DNA by slot-blot hybridization and all 14 by PCR. Also, of 9 patients positive for HBV surface antigen and antibody against HBV e antigen, 2 were positive for HBV DNA by slot-blot analysis and 8 by PCR.

The epidemiology of the postpericardiotomy syndrome: a common complication of cardiac surgery.

PPS is a major cause of morbidity after cardiac surgery and may cause bypass graft closure and fatal cardiac tamponade. Little is known about its incidence and cause. To better define this syndrome characterized by postoperative fever, pericardial friction rub, and pericardial pain, we used two out of three of the preceding criteria to diagnose PPS.

X-region-specific transcript in mammalian hepatitis B virus-infected liver.

In vitro gene expression systems for hepatitis B virus have demonstrated that the virus genome is capable of producing an X-region-specific transcript of approximately 0.7 kilobases (kb). However, this transcript has not been detected in virus-infected cells.

Regulation of valine and alpha-ketoisocaproate metabolism in rat kidney mitochondria.

Activities of branched-chain amino acid (BCAA) aminotransferase (BCAT) and alpha-keto acid dehydrogenase (BCKD) were assayed in mitochondria isolated from kidneys of rats. Rates of transamination of valine and oxidation of keto acids alpha-ketoisocaproate (KIC) or alpha-ketoisovalerate (KIV) were estimated using radioactive tracers of the appropriate substrate from amounts of 14C-labeled products formed (14CO2 or [1-14C]-keto acid). Because of the high mitochondrial BCAT activity, an amino acceptor for BCAT, alpha-ketoglutarate (alpha-KG) or KIC, was added to the assay medium when valine was the substrate.

X gene-related sequences in the core gene of duck and heron hepatitis B viruses.

The genomes of all known mammalian hepadnaviruses contain an open reading frame (ORF), designated X, located just upstream from the gene encoding the major viral nucleocapsid polypeptide. This gene is believed to have one or more roles central to the life cycle of these viruses. Consequently, it is surprising that avian hepadnaviruses appear to lack this ORF.

Sources of variation introduced into a phagocytosis assay as a result of the isolation of neutrophils from bovine blood.

A study was conducted to examine sources of variation introduced into a phagocytosis assay as a result of the isolation of neutrophils from bovine blood, including variation attributable to isolation of neutrophils from blood, variation between duplicate determinations of percentage phagocytosis, and the variation in the ability of neutrophils isolated from blood (over repeated collections from the jugular vein) to phagocytose. For the phagocytosis assay, jugular venous blood from each of 4 cows was divided into 2 equal portions. The neutrophils were isolated by lysis of red blood cells with 0.

Choanal atresia and associated anomalies: the CHARGE association.

Over the past few years there has been increasing awareness of the association of choanal atresia with other congenital defects. Thirty-one cases of choanal atresia were reviewed and other congenital anomalies were documented in 19 patients. These other anomalies were identified in 75% of the 20 patients with bilateral choanal atresia but in only 36% of the 11 patients with unilateral choanal atresia.

Lipid composition of bovine teat canal keratin.

Keratin was obtained by scraping the teat canals of excised teats from 12 lactating and 12 dry cows immediately after slaughter. Teats from four lactating and four dry cows were also stored at -20 degrees C for 2 wk to assess whether keratin composition was affected by frozen storage. Lipids were extracted from keratin of individual teats with 2:1 chloroform-methanol.

Close evolutionary relatedness of the hepatitis B virus and murine leukemia virus polymerase gene sequences.

Previous work indicates that hepatitis B virus (HBV) and retroviruses utilize a unique mechanism for genome replication by reverse transcription of RNA and share homology in biologically important nucleotide and protein sequences. The data presented here extend previous findings of sequence homology among the genomes of the members of these virus families. HBV was found to possess sequences homologous to the retrovirus protease and reverse transcriptase gene sequences.

Human immunodeficiency virus may encode a novel protein on the genomic DNA plus strand.

The genome of the human immunodeficiency virus (HIV) is known to contain eight open reading frames (ORFs) on the minus strand of the double-stranded DNA replicative intermediate. Data presented here indicate that the DNA plus strand of HIV contains a previously unidentified ORF in a region complementary to the envelope gene sequence. This ORF could encode a protein of approximately 190 amino acid residues with a relative molecular mass of 20 kilodaltons if translation began from the first initiation codon.