The benzene metabolite p-benzoquinone forms adducts with DNA bases that are excised by a repair activity from human cells that differs from an ethenoadenine glycosylase

Benzene is a ubitiquous human environment mental carcinogen. One of the major metabolites is hydroquinone, which is oxidized in vivo to give p-benzoquinone (p-BQ). Both metabolites are toxic to human cells. p-BQ reacts with DNA to form benzetheno adducts with deoxycytidine, deoxyadenosine, and deoxyguanosine. In this study we have synthesized the exocyclic compounds 3-hydroxy-3-N4-benzetheno-2'-deoxycytidine (p-BQ-dCyd) and 9-hydroxy-1,N6-benzetheno-2'-deoxyadenosine (p-BQ-dAdo), respectively, by reacting deoxycytidine and deoxyadenosine with p-BQ. These were converted to the phosphoamidites, which were then used to prepare site-specific oligonucleotides with either the p-BQ-dCyd or p-BQ-dAdo adduct (pbqC or pbqA in sequences) at two different defined positions. These oligonucleotides were efficiently nicked 5' to the adduct by partially purified HeLa cell extracts--the pbqC-containing oligomer more rapidly than the pbqA-containing oligomer. In contrast to the enzyme binding to derivatives produced by the vinyl chloride metabolite chloroacetaldehyde, the oligonucleotides up to 60-mer containing p-BQ adducts did not bind measurably to the same enzyme preparation in a gel retardation assay. Furthermore, there was no competition for the binding observed between oligonucleotides containing 1,N6-etheno A deoxyadenosine (1,N6-etheno-dAdo; epsilon A in sequences) and these oligomers containing either of the p-BQ adducts, even at 120-fold excess. When highly purified fast protein liquid chromatography (FPLC) enzyme fractions were obtained, there appeared to be two closely eluting nicking activities. One of these enzymes bound and cleaved the epsilon A-containing deoxyoligonucleotide. The other enzyme cleaved the pbqA- and pbqC-containing deoxyoligonucleotides. One additional unexpected fact was that bulk p-BQ-treated salmon sperm DNA did compete effectively with the epsilon A-containing oligonucleotide for protein binding. This raises the possibility that such DNA contains other, as-yet-uncharacterized adducts that are recognized by the same enzyme that recognizes the etheno adducts. In summary, we describe a previously undescribed human DNA repair activity, possibly a glycosylase, that excises from DNA pbqC and pbqA, exocyclic adducts resulting from reaction of deoxycytidine and deoxyadenosine with the benzene metabolite, p-BQ. This glycosylase activity is not identical to the one previously reported from this laboratory as excising the four etheno bases from DNA.

Molecular and biochemical characterization of two meta-cleavage dioxygenases involved in biphenyl and m-xylene degradation by Beijerinckia sp. strain B1

Beijerinckia sp. strain B1 is able to grow on either biphenyl or m-xylene as the sole source of carbon and is capable of cooxidizing many polycyclic aromatic hydrocarbons. The catabolic pathways for biphenyl and m-xylene degradation are coinduced and share common downstream enzymatic reactions. The catabolic pathway for biphenyl degradation involves two meta-cleavage steps, one for 2,3-dihydroxybiphenyl and a second for catechol. The catabolic pathway for m-xylene involves one m-cleavage step for 3-methylcatechol. The genes for two meta-cleavage dioxygenases were cloned from Beijerinckia sp. strain B1 on a single fragment of genomic DNA. The two genes are located approximately 5.5 kb away from one another. Expression of each gene separately in Escherichia coli and analysis of the meta-cleavage dioxygenase produced showed that one enzyme was more specific for 2,3-dihydroxybiphenyl while the second was more specific for catechol. The genes for the two meta-cleavage enzymes were thus labeled bphC and xylE for 2,3-dihydroxybiphenyl 1,2-dioxygenase and catechol 2,3-dioxygenase, respectively. Nondenaturing polyacrylamide gel electrophoresis followed by enzyme activity staining showed that the two meta-cleavage dioxygenases could be easily separated from each other. Similar analyses of Beijerinckia sp. strain B1 grown on succinate, biphenyl, or m-xylene indicate that both meta-cleavage enzymes are induced when cells are grown on either biphenyl or m-xylene. The nucleotide sequence was determined for both bphC and xylE. The two genes are transcribed in opposite directions, demonstrating that at least two operons must be involved in biphenyl degradation by Beijerinckia sp. strain B1. Analysis of the deduced amino acid sequence indicates that 2,3-dihydroxybiphenyl 1,2-dioxygenase (BphC) falls into the class of meta-cleavage dioxygenases acting on dihydroxylated polycyclic aromatic hydrocarbons and is somewhat distinct from the main group of meta-cleavage dioxygenases acting on 2,3-dihydroxybiphenyl. Catechol 2,3-dioxygenase (XyIE) falls into the class of meta-cleavage enzymes acting on dihydroxylated monocyclic aromatic hydrocarbons but shows little similarity to the canonical TOL plasmid-encoded catechol 2,3-dioxygenase.

RIP: a novel protein containing a death domain that interacts with Fas/APO-1 (CD95) in yeast and causes cell death

Ligation of the extracellular domain of the cell surface receptor Fas/APO-1 (CD95) elicits a characteristic programmed death response in susceptible cells. Using a genetic selection based on protein-protein interaction in yeast, we have identified two gene products that associate with the intracellular domain of Fas: Fas itself, and a novel 74 kDa protein we have named RIP, for receptor interacting protein. RIP also interacts weakly with the p55 tumor necrosis factor receptor (TNFR1) intracellular domain, but not with a mutant version of Fas corresponding to the murine lprcg mutation. RIP contains an N-terminal region with homology to protein kinases and a C-terminal region containing a cytoplasmic motif (death domain) present in the Fas and TNFR1 intracellular domains. Transient overexpression of RIP causes transfected cells to undergo the morphological changes characteristic of apoptosis. Taken together, these properties indicate that RIP is a novel form of apoptosis-inducing protein.

Analysis of the kinetics and voltage-dependency of transient and delayed K+ currents in muscle fibers isolated from the flatworm Schistosoma mansoni

There are two distinct voltage-dependent K+ currents in muscle fibers freshly isolated from the human flatworm parasite S. mansoni. Present is a delayed rectifier current with a tau act of 17 msec and tau inact > 3 sec. The delayed rectifier is very resistant to steady-state inactivation, with over 40% of the current non-inactivating, and over 15 sec required for the maximum inactivation of the other portion. The current is resistant to block by extracellular tetraethylammonium, is half-blocked by 10 mM 4-aminopyridine, and is insensitive to dendrotoxin. Also present is an "A" current with tau act < 1 msec and tau inact < 15 msec. The "A" current, like the delayed rectifier current, is resistant to block by external tetraethylammonium and is insensitive to dendrotoxin. Three micromoles of 4-aminopyridine produce a half-blockade of the "A" current. These two K+ currents are very similar to a delayed rectifier and "A" currents that have been described in a number of lower and more advanced animals.

Depression and anxiety in an 85-year-old woman with a toxic nodular goiter

Depression is commonly encountered in medical settings and often may be a symptom of an underlying medical illness. This case report illustrates the disabling symptoms of anxiety and depression that can accompany a toxic nodular goiter, and underscores the importance of both accurate psychiatric diagnosis and appropriate medical evaluation in the assessment of psychiatric disorders in the elderly.

Cloning and functional expression of a Shaker-related voltage-gated potassium channel gene from Schistosoma mansoni (Trematoda: Digenea)

We have isolated a cDNA (SKv1.1) encoding a Shaker-related K+ channel from an adult cDNA library of the human parasitic trematode Schistosoma mansoni. The deduced amino acid sequence (512 aa, 56.5 kDa) contains 6 putative membrane-spanning domains (S1-S6) and a pore-forming domain (H5). SKv1.1 is grouped in the Shaker family, but forms a unique branch within this family, on the basis of dendrogram analysis. SKv1.1 shows significant sequence identity with most other Shaker channels, with 64-74% identity in the core region (S1-S6). It has the highest sequence identity with the K+ channel (Ak01a) from Aplysia. Northern blot analysis detected a single primary transcript of 2.8 kb. Southern blot analysis indicated that SKv1.1 is present as a single copy in the genomic DNA of S. mansoni. Expression of SKv1.1 in Xenopus oocytes produced a rapidly activating and inactivating outward K+ current which is highly sensitive to 4-aminopyridine, but is insensitive to tetraethylammonium, mast cell degranulating peptide, dendrotoxin and charybdotoxin. The presence of a Shaker homologue in Schistosoma suggests that Sh subfamilies may exist in other lower invertebrates as well as platyhelminths.

Iron(II) is a modulator of ryanodine-sensitive calcium channels of cardiac muscle sarcoplasmic reticulum

Iron is examined for its ability to modify Ca2+ transport across sarcoplasmic reticulum (SR) and to alter the binding of [3H]ryanodine to its high-affinity site on the Ca2+ release channel complex of SR preparations from rat heart. Iron(III) (added as ferric chloride) has negligible activity on active Ca2+ accumulation into SR and on the binding of [3H]ryanodine. In contrast, Fe(II) (added as ferrous sulfate) is a potent inhibitor of both Ca(2+)-induced Ca2+ release (IC50 of 29 microM) and DXR-induced Ca2+ release (IC50 of 14 microM). Iron(II) enhances the rate of active Ca2+ uptake into SR vesicles, mimicking the actions of the known SR Ca2+ channel blocker ruthenium red. The underlying mechanism of Fe(II) on SR Ca2+ transport is shown to be a direct and potent action on the ryanodine receptor. Fe(II) inhibits the binding of [3H]ryanodine when assayed in the presence of 5 microM Ca2+ with an IC50 of 4 microM and in an apparently cooperative manner (nH = 1.7). In the presence of physiological (1 mM) Mg2+, Fe(II) decreases the sensitivity of ryanodine receptors toward activation by Ca2+ shifting EC50 from 18 to 35 microM in the absence and presence of 5 microM Fe(II), respectively, without significant decrease in maximum [3H]ryanodine occupancy. In the presence of 5 microM Ca2+ and 1 mM Mg2+, Fe(II) decreases the potency of doxorubicin (DXR) on [3H]ryanodine binding (shifts EC50 from 8 to 24 microM in the absence and presence of 5 microM Fe(II)). These results suggest that Fe(II) competes with Ca2+ at the activator sites on the channel complex. The actions of Fe(II) on ryanodine receptor function is not correlated with membrane lipid peroxidation of SR vesicles since Fe(II) does not produce detectable changes in malondialdehyde using the thiobarbituric acid assay. These results demonstrate a direct inhibition of the Ca2+ release channel of cardiac SR by Fe(II) which may be important in pathological states of the heart during iron overload.

Localization of the human stem cell tyrosine kinase-1 gene (FLT3) to 13q12-->q13

We have previously reported the cloning of stem cell tyrosine kinase-1 (STK-1, gene symbol FLT3), the human homolog of the mouse Flk2/Flt3 gene (Small et al., 1994). This growth factor receptor is expressed in CD34+ human bone marrow (stem/progenitor) cells. We have mapped the gene for STK-1 using PCR screening of a human-rodent somatic cell hybrid panel, and fluorescence in situ molecular hybridization (FISH) of STK-1 genomic probes to mitotic chromosomes of normal human lymphocytes. The results of both analyses show that the gene for STK-1 (FLT3) localizes to chromosome 13q12-->q13.

Outcome of extremely low-birth-weight infants: 1980-1990

Neonatal and follow-up data of infants from the special care nursery whose birth weights were < 750 g, born between 1980 and 1990, were reviewed. There was a 20% relative improvement in the odds of surviving the neonatal period, a 16% improvement in the odds of being discharged and a 19% improvement in the odds of surviving until 2 years of age with each consecutive year. Home oxygen use increased significantly over the study period. The neurodevelopmental outcomes of infants were similar over the 11-year period, with 53% being classified as neurologically normal, with a mean developmental index of 83 at 1 to 2 years of age. We conclude that there has been an improved survival of infants with birth weights < 750 g in our institution, and that the overall incidence of serious neurodevelopmental deficits among survivors has remained stable.

Scintigraphic appearance of albuterol-induced inhibition of hypoxic pulmonary vasoconstriction

Alveolar hypoxia is known to result in localized pulmonary arterial vasoconstriction. As a consequence, blood is diverted from poorly ventilated alveoli, maintaining ventilation-perfusion (V/Q) matching and thereby reducing the deleterious effects on gas exchange. An incomplete alveolar hypoxic vasoconstrictive response can be easily demonstrated by radionuclide V/Q lung scanning. A case of albuterol-induced inhibition of hypoxic pulmonary vasoconstriction is described in a patient with steroid-dependent asthma. The utility of V/Q lung scanning as a simple, noninvasive test to detect this phenomenon in patients with primary airway disorders who deteriorate despite appropriate therapy is also briefly discussed.

"Normal" control subjects are hard to find: a model for centralized recruitment

A central program for recruiting "normal" control subjects is examined by considering the yield of subjects who meet criteria for "healthy" as defined by their personal and family histories of mental disorders. Of the 267 applicants, 30.3% have no lifetime diagnoses, 41.2% are currently healthy with a history of mental illness, and 27.7% are currently mentally ill. Only 16.1% met Research Diagnostic Criteria for "never mentally ill" and reported no family history of mental disorders. Benefits of a central recruitment program for studies of mental disorders include increased information on a large subject pool and decreased volunteer bias.

Effects of thyroid hormone on the calcium current and isoprenaline-induced background current in rabbit ventricular myocytes

The majority of previous studies have been performed to explain the effects of thyroid hormone on the heart in chronic hyperthyroidism that was usually induced by eight to 10 daily injections of thyroid hormones. However, it is unclear whether or not the electrophysiological effects result from the chronic manifestations of hyperthyroidism and whether thyroid hormone acts directly or indirectly on cardiac myocytes to alter cardiac electrophysiological properties. In order to examine the acute term electrophysiological effects of thyroid hormone applied in vitro and the mechanisms responsible for some of these effects, we investigated the modulatory effects of thyroid hormone on the calcium current and isoprenaline-induced background current in L-triiodothyronine-treated ventricular myocytes of the rabbit. The major findings were as follows. Over 5 h (range, 5-24 h) after treatment of L-triiodothyronine (1 microM) in vitro, the calcium current was increased significantly. Isoprenaline (1 microM) and cyclic AMP (100 microM) caused an increase in the calcium current in both euthyroid and hyperthyroid myocytes. The hyperthyroid myocytes were more sensitive to the effect of beta-adrenergic stimulation on the calcium current and isoprenaline-activated background current. In euthyroid myocytes, acetylcholine (1 microM) produced no or little changes in the amplitude of the calcium current. In hyperthyroid myocytes, acetylcholine markedly reduced the calcium current, however, acetylcholine was ineffective in the presence of sufficient intracellular cyclic AMP (100 microM). Our results suggest that thyroid hormone can affect the cardiac myocytes directly. Furthermore, our results demonstrate that thyroid hormone affects the calcium current and isoprenaline-activated background current. These electrophysiological changes may explain, at least in part, the occurrence of positive inotropy and cardiac arrhythmias that is associated with hyperthyroidism.

Postmortem distribution of zipeprol

The abuse of zipeprol, an antitussive agent, is prevalent among young people in Korea. For its hallucinogenic effects, abusers have taken overdoses of the drug; thus, fatalities from zipeprol overdose have risen since 1991. In order to determine the postmortem distribution of zipeprol, tissues and blood from 23 decedents who had histories of drug abuse were examined. Homogenized tissue (1 g) and 1 mL blood were extracted by ethyl acetate. Cinnarizine was used as an internal standard. A Varian GC 4600 equipped with a thermionic specific detector was used to quantitate the drug using a DB-5 megabore column, and a Finnigan GC-MS model 4021 was used to obtain mass spectral identification of the extracts. The blood zipeprol concentrations varied from 2.3 to 38.3 micrograms/mL. The highest concentration of zipeprol was found in stomach tissue. Zipeprol concentrations in tissues were higher than the corresponding blood concentrations.

Cloning and analysis of the genes for polycyclic aromatic hydrocarbon degradation

Bacterial degradation of polycyclic aromatic hydrocarbons initially proceeds through monooxygenase or dioxygenase attack on the aromatic ring. The dihydroxylated compounds formed are substrates for ring cleavage and further catabolism to tricarboxylic acid cycle intermediates. A number of microbial strains, both gram positive and gram negative, have been isolated that have the metabolic capability to degrade polycyclic aromatic hydrocarbons to carbon dioxide and water. In addition, many of these strains have the ability to cometabolize structurally similar aromatic compounds that may not normally serve as metabolic inducers or as carbon sources. The genes from several of these strains have been cloned for the purpose of analyzing in more detail their structure and function. The cloned genes were used to determine the range of substrates that can be metabolized by the genetically encoded pathway. For instance, the cloned genes from Pseudomonas sp. XPW-2 placed in E. coli encoded for the oxidation of such polycyclic aromatic hydrocarbons as naphthalene, biphenyl, anthracene, phenanthrene, acenaphthylene, fluorene, fluoranthene, chrysene, and pyrene. The cloned genes were also used as genetic probes to determine the degree of homology, if any, there is between different microbial strains capable of degrading polycyclic aromatic hydrocarbons. These experiments indicated significant homology among the class of terrestrial naphthalene and phenanthrene-degrading strains. Nevertheless, little homology was seen across species lines or among strains capable of degrading higher molecular weight polycyclic aromatic hydrocarbons. This indicates that there is a diversity of genetically distinct pathways for polycyclic aromatic hydrocarbon degradation.

Antithetical actions of mitoxantrone and doxorubicin on ryanodine-sensitive Ca++ release channels of rat cardiac sarcoplasmic reticulum: evidence for a competitive mechanism

The anthracenedione mitoxantrone (MTX) is examined for activity toward ryanodine-sensitive Ca++ release channels (i.e., ryanodine receptors; RyR) from rat cardiac SR singly or in combination with doxorubicin (DXR). MTX and DXR exhibit antithetical activities toward RyR. Under conditions promoting channel closure, DXR enhances the binding of [3H]ryanodine (EC50 = 44 microM), whereas MTX has higher affinity (EC50 = 25 microM) but > 10-fold lower activity towards activating RyR. Unlike DXR, MTX assayed under conditions promoting channel activation inhibits the binding of [3H]ryanodine (IC50 = 3.3 microM) and does not alter the potency with which Ca++ activates RyR in the presence or absence of Mg++. In the presence of Mg++, MTX does not alter kobs and slows k-1 for [3H]ryanodine binding, whereas DXR accelerates kobs with little change in k-1. The antithetical behavior of MTX and DXR at the RyR raises the possibility that MTX antagonizes the ability of DXR to activate the RyR when the drugs are present in combination. In consonance with this hypothesis, MTX inhibits DXR (60 microM)-sensitized [3H]ryanodine-binding sites in a dose-dependent manner (IC50 = 8.4 microM) and shifts the EC50 for DXR-activated [3H]ryanodine-binding without reducing the maximum occupancy attained at high DXR concentration, revealing the competitive nature of the interaction of DXR and MTX. MTX singly does not alter active Ca++ accumulation by SR but is shown to fully inhibit DXR-induced Ca++ release. The results suggest that MTX antagonizes DXR-activated RyR by binding to mutually exclusive sites and may provide a rational basis for combination therapy aimed at extending the current dose limits of DXR.

Increased production of paired helical filament epitopes in a cell culture system reduces the turnover of tau

To investigate the regulation of posttranslational modifications of tau that might be pertinent to the production of the paired helical filament (PHF) of Alzheimer's disease, we incubated human neuroblastoma cells with the protein phosphatase inhibitor okadaic acid. This treatment results in increased immunoreactivity of tau with the monoclonal antibodies Alz-50, PHF-1, T3P, and NP8, a reduction in Tau-1 immunoreactivity, and an elevation in apparent molecular weight of tau. Moreover, our data demonstrate that accumulation of phosphates in tau leads to a decrease in the turnover rate of tau in the neuroblastoma cells. It is suggested that similar build-up of hyperphosphorylated tau in the neuronal perikarya may represent an early event in PHF formation. The present system facilitates the investigation of regulatory mechanisms governing the occurrence of PHF epitopes, their effects on neuronal cell metabolism, and possible pharmacological intervention.

All four known cyclic adducts formed in DNA by the vinyl chloride metabolite chloroacetaldehyde are released by a human DNA glycosylase

We have previously reported that human cells and tissues contain a 1,N6-ethenoadenine (epsilon A) binding protein, which, through glycosylase activity, releases both 3-methyladenine (m3A) and epsilon A from DNA treated with methylating agents or the vinyl chloride metabolite chloroacetaldehyde, respectively. We now find that both the partially purified human epsilon A-binding protein and cell-free extracts containing the cloned human m3A-DNA glycosylase release all four cyclic etheno adducts--namely epsilon A, 3,N4-ethenocytosine (epsilon C), N2,3-ethenoguanine (N2,3-epsilon G), and 1,N2-ethenoguanine (1,N2-epsilon G). Base release was both time and protein concentration dependent. Both epsilon A and epsilon C were excised at similar rates, while 1,N2-epsilon G and N2,3-epsilon G were released much more slowly under identical conditions. The cleavage of glycosyl bonds of several heterocyclic adducts as well as those of simple methylated adducts by the same human glycosylase appears unusual in enzymology. This raises the question of how such a multiple, divergent activity evolved in humans and what may be its primary substrate.

STK-1, the human homolog of Flk-2/Flt-3, is selectively expressed in CD34+ human bone marrow cells and is involved in the proliferation of early progenitor/stem cells

We cloned the cDNA for stem cell tyrosine kinase 1 (STK-1), the human homolog of murine Flk-2/Flt-3, from a CD34+ hematopoietic stem cell-enriched library and investigated its expression in subsets of normal human bone marrow. The cDNA encodes a protein of 993 aa with 85% identity and 92% similarity to Flk-2/Flt-3. STK-1 is a member of the type III receptor tyrosine kinase family that includes KIT (steel factor receptor), FMS (colony-stimulating factor 1R), and platelet-derived growth factor receptor. STK-1 expression in human blood and marrow is restricted to CD34+ cells, a population greatly enriched for stem/progenitor cells. Anti-STK-1 antiserum recognizes polypeptides of 160 and 130 kDa in several STK-1-expressing cell lines and in 3T3 cells transfected with a STK-1 expression vector. Antisense oligonucleotides directed against STK-1 sequences inhibited hematopoietic colony formation, most strongly in long-term bone marrow cultures. These data suggest that STK-1 may function as a growth factor receptor on hematopoietic stem and/or progenitor cells.

Treatment of organic bipolar mood disorders in Parkinson's disease

Two patients with long-standing idiopathic Parkinson's disease (PD), without individual or family histories of affective disorders, developed bipolar mood disorders. Both were treated with lithium and clozapine, and one responded favorably. These may be the first reported cases in which mania was treated with clozapine in PD patients.

Suprageneric classification of peptidoglycan group B actinomycetes by nucleotide sequencing of 5S ribosomal RNA

5S ribosomal RNA sequences were determined for thirteen actinomycetes mainly representatives with the rare group B type peptidoglycan. The primary and secondary structure of the resultant sequences were of the type characteristic of Gram-positive bacteria with DNA rich in guanine plus cytosine. The sequencing and associated chemotaxonomic data provide compelling grounds for classifying actinomycetes with a group B type peptidoglycan in a single family. The family Microbacteriaceae fam. nov. is proposed to accommodate actinomycetes classified in the genera Agromyces, Aureobacterium, Clavibacter, Curtobacterium and Microbacterium.

Comparison of the effects of the dopamine D2 agonist quinelorane on tuberoinfundibular dopaminergic neuronal activity in male and female rats

The purpose of the present study was to examine the effects of quinelorane (LY163502), a potent and selective D2 dopaminergic (DA) receptor agonist, on the activity of tuberoinfundibular DA neurons in male and female rats as estimated by determining the concentration of the primary metabolite of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), in terminals of these neurons in the median eminence (ME). In males, quinelorane produced dose- and time-related increases in the concentration of DOPAC in the Me which was blocked by the D2 receptor antagonist raclopride. The activity of tuberoinfundibular neurons in female rats is higher than it is in males because circulating levels of prolactin tonically stimulate these neurons in the female. In female rats, quinelorane markedly lowered plasma concentrations of prolactin but failed to alter DOPAC concentrations in the ME. Pretreatment of female rats with prolactin antiserum induced hypoprolactinemia and reduced DOPAC concentrations in the ME; in these animals quinelorane increased ME DOPAC concentrations. These results indicate that by acting on D2 receptors quinelorane is able to stimulate tuberoinfundibular DA neurons in both male and female rats, but in female rats the ability of quinelorane to reduce circulating levels of prolactin indirectly reduces the activity of tuberoinfundibular DA neurons and thereby masks the stimulatory action of this drug on these neurons.

Hantavirus: an old bug learns new tricks

Hantaviruses are a diverse group of RNA arboviruses in the Bunyaviridae family. Although their role as the causative agents of HFRS has been well established, the recent outbreak of a new disease in the Southwest clearly demonstrates the protein clinical manifestations that this pathogen can produce. Furthermore, whereas hantaviruses have been characterized largely as focal agents in the production of geographically delimited diseases, recent trends indicate that endemic areas for the virus are expanding. Outbreaks often occur in clusters as a result of the epizoology of rodent hosts, but isolated cases of hantavirus-related disease also may be observed. Although hantaviruses have proven their pathogenic capability in other areas of the world, it was perceived widely that they were of little consequence to public health in the United States. However, as more is learned about the nature of this truly global infectious agent, its potential danger to mankind becomes increasingly apparent. It is hoped that continued research will elucidate all the facets of hantavirus-induced disease.

Characterization of the mouse FTZ-F1 gene, which encodes a key regulator of steroid hydroxylase gene expression

The cytochrome P450 steroid hydroxylases are coordinately regulated by steroidogenic factor 1 (SF-1), a protein expressed selectively in steroidogenic cells. Based on its expression in steroidogenic tissues and DNA-binding specificity, we isolated a putative SF-1 cDNA from an adrenocortical cDNA library. As evidence that this cDNA encodes SF-1, we now show that it is selectively expressed in steroidogenic cells, that an antiserum against its protein product specifically abolishes the SF-1-related gel-shift complex, and that its coexpression increases promoter activity of the 21-hydroxylase 5'-flanking region in transfection experiments. Sequence analyses of the SF-1 cDNA revealed that it is the mouse homolog of fushi tarazu factor I (FTZ-F1), a nuclear receptor that regulates the fushi tarazu homeobox gene in Drosophila. A second FTZ-F1 homolog, embryonal long terminal repeat-binding protein (ELP), was recently isolated from embryonal carcinoma cells. SF-1 and ELP cDNAs are virtually identical for 1017 base pairs, including putative DNA-binding domains, but diverge at their 5'- and 3'-ends. One genomic clone contained both SF-1- and ELP-specific sequences, confirming their origin from a single gene. Characterization of this gene defined shared exons encoding common regions and alternative promoters and 3'-exons leading to differences between the two FTZ-F1 transcripts. We used in situ hybridization with transcript-specific probes to study the ontogeny of SF-1 and ELP expression. ELP transcripts were not detected from embryonic day 8 to adult, consistent with its previous isolation from embryonal carcinoma cells and its postulated role in early embryonic development.(ABSTRACT TRUNCATED AT 250 WORDS)

[The study of senile symptoms and home care on the elderly living in Korea]

The purpose of this study is to investigate the daily life and care condition of elderly people living in Korea, and to observe the symptom of senile dementia among them. In the first survey, 713 subjects were screened and 42 subjects were diagnosed as suffering from senile dementia. In the second survey, 26 elderly and their caregivers who agreed to participate in this program, were interviewed. The results were as follows. 1. About 25% of the 713 subjects needed some kind of help in their daily life. 2. 85% of the subjects could go out and about their houses without help. Only 5% of them had a complete or a partial loss of activity. 3. Of all the subjects, 42 were diagnosed as suffering from senile dementia. The prevalence of this disease was calculated at 5.6% in the survey. 4. Each demented elderly person had 5.3 mental symptoms on the average. Depression was observed more among women and violence was observed more among men. 5. The elderly who had a lower CPR score (Caretaker-Patient Relationship Score), indicating a poor relationship between the patient and caretaker, had a higher prevalence of mental symptoms than those who had a higher CPR score.

Gene organization and primary structure of a ribosomal RNA gene cluster from Streptomyces griseus subsp. griseus

The Streptomyces griseus subsp. griseus KCTC 9080 genome contains six rRNA-encoding gene (rDNA) clusters. One rDNA cluster (rrnE), contained in an 8.7-kb BamHI fragment, was cloned and sequenced. The rDNA were arranged in the order 16S-23S-5S, and separated by small intergenic spacers. No tRNA-encoding sequences were found in the spacer regions. The lengths of the mature 16S, 23S and 5S rRNAs were 1528, 3120 and 120 nucleotides (nt), respectively. The G + C content of the gene cluster was lower than that of the chromosomal DNA. In general, the primary and secondary structures of the three rRNAs showed good agreement with those from other Streptomyces species. However, in comparison with Escherichia coli, two noticeable changes (mismatches and deletions) and two large insertions were identified in the 16S and 23S rRNAs, respectively. On the other hand, regions showing considerable heterogeneity, even within the genus Streptomyces, were found in both rRNAs. Putative primers and processing signals showing high sequence similarity to those from other Streptomyces species were located in the region upstream from the 5' end of the mature 16S rRNA. A potential hairpin loop structure reminiscent of a Rho-independent terminator was located just downstream from the 5S rRNA. A considerable degree of sequence conservation and variation within rDNA gene clusters was revealed in this study, both at the infra- and suprageneric levels.

The structure of the chloramphenicol resistance gene on a transferable R plasmid from the fish pathogen, Pasteurella piscicida

The chloramphenicol resistance gene (pp-cat) was cloned from a transferable R plasmid of Pasteurella piscicida, pSP9351, and the sequence of the gene was determined. Subcloning and deletion analysis localized the resistance gene, pp-cat, to within a 2.3 kb HincII-BamHI fragment. The fragment as a probe hybridized with the type I chloramphenicol acetyltransferase (CAT) gene and did not hybridize to CAT types II, III, and CAT-VA. The fragment hybridized to transferable R plasmids encoded with resistance to chloramphenicol, which were detected from P. piscicida isolated in different years. Nucleotide sequences of the coding and flanking regions of pp-cat (2031 bp) identified an open reading frame coding type I CAT of a molecular mass of about 25,000 Da. Comparison analysis of the sequences outside the cat open reading frame showed also that pp-cat has homology, in part, with the gene that coding for the endonuclease EcoRII and those that flank the cat gene derived from the Acinetobacter baumannii chromosome.

Characterization of the mouse FTZ-F1 gene, which encodes a key regulator of steroid hydroxylase gene expression

The cytochrome P450 steroid hydroxylases are coordinately regulated by steroidogenic factor 1 (SF-1), a protein expressed selectively in steroidogenic cells. Based on its expression in steroidogenic tissues and DNA-binding specificity, we isolated a putative SF-1 cDNA from an adrenocortical cDNA library. As evidence that this cDNA encodes SF-1, we now show that it is selectively expressed in steroidogenic cells, that an antiserum against its protein product specifically abolishes the SF-1-related gel-shift complex, and that its coexpression increases promoter activity of the 21-hydroxylase 5'-flanking region in transfection experiments. Sequence analyses of the SF-1 cDNA revealed that it is the mouse homolog of fushi tarazu factor I (FTZ-F1), a nuclear receptor that regulates the fushi tarazu homeobox gene in Drosophila. A second FTZ-F1 homolog, embryonal long terminal repeat-binding protein (ELP), was recently isolated from embryonal carcinoma cells. SF-1 and ELP cDNAs are virtually identical for 1017 base pairs, including putative DNA-binding domains, but diverge at their 5'- and 3'-ends. One genomic clone contained both SF-1- and ELP-specific sequences, confirming their origin from a single gene. Characterization of this gene defined shared exons encoding common regions and alternative promoters and 3'-exons leading to differences between the two FTZ-F1 transcripts. We used in situ hybridization with transcript-specific probes to study the ontogeny of SF-1 and ELP expression. ELP transcripts were not detected from embryonic day 8 to adult, consistent with its previous isolation from embryonal carcinoma cells and its postulated role in early embryonic development.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of substrate and inhibition of oxidative metabolism on contraction and myosin phosphorylation in ASM

Steady-state active stress in smooth muscle is maintained by cross bridges which undergo continuous cycling and myosin phosphorylation, and the two processes both consume ATP. In this study, we investigated whether energy utilization by cross-bridge cycling and myosin phosphorylation is compartmentalized and examined their relative affinities for ATP in airway smooth muscle. We measured active stress, myosin phosphorylation, O2 consumption, and tissue ATP content in bovine tracheal smooth muscle activated by K+ depolarization when glucose was replaced by pyruvate and when oxidative metabolism was inhibited by hypoxia or uncoupled by 2,4-dinitrophenol. The results indicate that ATP produced from both glycolysis and oxidative metabolism is available to both cross-bridge cycling and myosin phosphorylation. However, steady-state myosin phosphorylation was insensitive to the inhibition of oxidative metabolism by hypoxia and mitochondrial uncoupling when steady-state isometric stress and tissue ATP content were significantly reduced. These results suggest that, relative to actomyosin adenosine 5'-triphosphatase, myosin light chain kinase has a higher affinity for ATP in intact airway smooth muscle. However, peak myosin phosphorylation associated with the initial rapid stress development was sensitive to inhibition of oxidative metabolism, probably reflecting a lower content of intracellular calcium store as a result of metabolic inhibition.

Suprageneric classification of thermoactinomyces vulgaris by nucleotide sequencing of 5S ribosomal RNA

The 5S rRNA nucleotide sequence of Thermoactinomyces vulgaris was determined and compared with published sequences of representative Gram-positive bacteria. The primary and secondary structure of the sequence is of the type characteristic of Gram-positive bacteria that have DNA with a low proportion of guanine plus cytosine. It was evident from the phylogenetic trees that T. vulgaris has little in common with actinomycetes but is related to the genus Bacillus, showing a moderately high relationship with B. stearothermophilus. The taxonomic implications of these relationships are discussed and an emended description of the family Bacillaceae is given.

Recognition of oxidized DNA bases by sera of patients with inflammatory diseases

Chronic inflammatory conditions result from or contribute to many diseases. Prominent among them is systemic lupus erythematosus (SLE). Sera of SLE patients contain an array of various auto-antibodies (Ab), including antinuclear Ab of unknown etiologies. The most puzzling is formation of Ab directed against autologous DNA. Our hypothesis was that increased oxidant production causes oxidation of DNA bases, which provide antigenic determinants that elicit antioxidized DNA Ab. To test this hypothesis, we used oxidized DNA nucleoside (5-hydroxymethyl-2'-deoxyuridine [HMdU]) conjugated to bovine serum albumin (HMdU-BSA) as the antigen. The results of the enzyme-linked immunosorbent assay showed that these Abs are sensitively detectable in SLE sera and sera of various other inflammatory autoimmune diseases. The titers of anti-HMdU Ab were significantly higher (p < .01) than those present in the control sera. Anti-HMdU Ab were predominantly of the IgM isotype, with low levels of IgG and no IgA. Anti-HMdU Ab bound to the HMdU-BSA-coated wells in a concentration- and time-dependent manner. That binding was inhibited by HMdU-BSA and to a lesser extent by thymidine-BSA, a normal nucleoside conjugate. The specific binding appears to be inversely related to the age of the patients, but no significant differences were observed between the sexes of the same age.

Computer modelling of glycolipids at membrane surfaces

Interactions of membrane anchored molecules such as glycolipids with a membrane surface are important in determining headgroup conformation. It is therefore essential to represent these membrane surface interactions in molecular modeling studies of glycolipids and other membrane bound molecules. We introduce here an energy term that represents the interaction of molecules with a membrane bilayer. This membrane interaction energy term has been added to the potential energy function of a molecular dynamics and mechanics program and has been parameterized using partition coefficients between an aqueous solution and a vesicular membrane for two model glycolipids.

Development of a PHC nursing information system in Korea

WHO has established collaborating centres at educational institutions throughout the world to assist with WHO research. In 1988 a WHO Collaborating Centre was inaugurated at Yonsei University College of Nursing in Korea. Since then two important research projects have been completed for establishing a data bank of human resources of nursing for primary health care (PHC) in Korea. Both projects strengthen the PHC nursing information systems in Korea and, as such, are beginning to develop PHC networks throughout Korea, passing on information to an international network system. Below, the rationale behind the two projects, the methodology and the results.

Effects of tobacco smoking on the topographic EEG II

1. Tobacco smokers are well aware of the long term hazards of tobacco smoking, yet they continue to smoke. Presumably people smoke because of short term gains due to nicotine. 2. The mechanism by which nicotine is a drug reinforcer still needs a great deal of study. The specific aim of the present study was to determine the effects of tobacco smoking on the topographic EEG of 12 hr deprived heavy tobacco smokers. 3. Seven normal adult tobacco smokers of mixed sex were recruited into the study and compared with six normal nonsmokers of similar age and sex. 4. A Grass Model 8-24D EEG and 16 different scalp monopolar electrodes were used to record the EEG using both ears as reference before and after smoking. EKG lead II was recorded on channel 17. Blood pressure was measured by auscultation. Exhaled CO was measured using a CO detector. Computer analysis of the EEG data was run of line on a Zenith 386/25 microcomputer using RHYTHM 7.1. The same system was used to store the EEG in digitized form. The maximum number of 4 sec artifact free epochs in a 3 min recording period with eyes open and then closed was used before and after low and high nicotine tobacco or sham smoking. 5. The hypothesis of this research was confirmed, i.e., that tobacco smoking of high nicotine cigarettes (about 2.0 mg/cigarette) would cause a shift in EEG alpha rhythm to higher frequencies in more diffuse midline cortical structures. In other studies an increase in alpha rhythm has been correlated with an awake relaxed behavioral state. 6. A heart rate increase was a more sensitive index of tobacco smoking than an increase in arterial blood pressure. Exhaled smoking CO levels correlated with the nicotine and tar content of the cigarette.

Regional and generalized changes in cytosolic free calcium in monocytes during phagocytosis

We measured and visualized cytosolic free calcium ([Ca2+]i) in individual human peripheral blood monocytes during phagocytosis by using the fluorescent indicator fura-2. Monocytes exhibit a rapid rise in [Ca2+]i from a basal level of 75 +/- 11 nM to a peak level of 676 +/- 78 nM (means +/- standard errors of the means; P less than 0.001) by 34 +/- 5 s after contact with opsonized zymosan particles, and a thin rim of high [Ca2+]i was observed surrounding the ingested particle.

Cognitive processing of emotional information in panic disorder

Panic-disordered (PD) patients, obsessive-compulsive (OCD) patients, and normal control subjects were exposed to either a high (i.e. exercise) or low arousal manipulation prior to performing a computerized version of the modified Stroop color-naming paradigm. Subjects named the colors of neutral nonlexical stimuli, positive words, and threat words associated with fear, bodily sensations, and catastrophes. After the Stroop task, subjects rated the personal emotional significance of the words. Inconsistent with the emotionality hypothesis of Stroop interference, PD patients rated positive words as more emotional than catastrophe words, but took longer to color-name the latter than the former. Yet consistent with the emotionality hypothesis, PD patients took as long to color-name positive words as to color-name fear and bodily sensation words. Contrary to expectation, OCD patients resembled PD patients in terms of interference, and arousal did not enhance interference for threat words in PD patients.

Septic bursitis: experience in a community practice

We reviewed 47 episodes of septic bursitis occurring in a private community medical practice. Most patients were male (85%), and roughly half (49%) the cases were related to recreational or occupational trauma. About 72% of cases were located in the olecranon bursa, while the remaining cases were prepatellar. Prepatellar bursitis patients were more likely to be hospitalized. Staphylococcus aureus was isolated from 70% of bursal fluid aspirations; other etiologic organisms included gram negative bacteria and Mycobacterium marinum. The majority of patients were able to be treated as outpatients with oral antibiotics. All patients were eventually cured without serious complications.

Nephrotoxicity of sodium dichromate depending on the route of administration

A comparison of the effects of intraperitoneal and subcutaneous routes of administration of sodium dichromate on nephrotoxicity in rats was studied. Dichromate when injected subcutaneously (SC group) produced a higher degree of nephrotoxicity than when administered intraperitoneally (IP group). It caused severe progressive proteinuria followed by polyuria and glucosuria, reaching maximum levels at 3 days after treatment in the SC group, whereas it produced mild proteinuria without glucosuria in the IP group. The dose-dependent increases in blood urea nitrogen (BUN) and creatinine concentrations, shown in the SC group, were not observed in the IP group. However, between the two groups, there were no great differences in either the urinary excretion rate of chromium or the electrophoretic patterns of urinary protein in the day 1 urine specimens. Pretreatment of phenobarbital (PB) had no remarkable effect on the dichromate-induced nephrotoxicity. In contrast, it potentiated dichromate-induced hepatotoxicity, the indices of which were the elevation in serum alanine aminotransferase (ALT) activity and hepatic lipid peroxide formation. These results suggest that the dependence of dichromate-induced nephrotoxicity on the route of administration is related to the chemical forms of chromium reaching the kidney, and the necrotizing property of dichromate results from its metabolic fate in vivo.

Classification of acidophilic, neutrotolerant and neutrophilic streptomycetes by nucleotide sequencing of 5S ribosomal RNA

Complete 5S ribosomal RNA sequences were obtained for four acidophilic actinomycetes, seven neutrophilic streptomycetes and a strain of Streptoverticillium baldaccii. All of the organisms contained RNAs belonging to the 120 nucleotide type. An evolutionary tree was generated after combining the test data with results from similar studies on representative Gram-positive bacteria. The acidophilic, neutrotolerant and neutrophilic actinomycetes were recovered in a distinct cluster that was equated with the genus Streptomyces. The sequence data support the view that the genera Chainia, Elytrosporangium, Kitasatoa and Microellobosporia should be considered as synonyms of the genus Streptomyces. The recovery of the Streptoverticillium baldaccii strain on the fringe of the Streptomyces cluster is also consistent with current trends in the taxonomy of these organisms. Further work is needed to determine the taxonomic status of the two streptomycete subgroups that comprised the streptomycete cluster.

Effect of sodium dichromate on carbohydrate metabolism

Subcutaneous injection of sodium dichromate into male Sprague-Dawley rats immediately produced a variety of metabolic changes in a dose-dependent manner. Serum lactate and glucose were significantly increased after dichromate treatment, reaching maximum levels at 15 and 30 min, respectively. Then, the toxicity progressively diminished. In contrast, a steady increase in blood urea nitrogen (BUN) concentration was caused by dichromate, reaching maximum levels at 60 min after the administration; elevated BUN levels were sustained for several hours thereafter. Unlike KCN (5 mg/kg, ip) and As2O3 (5 mg/kg, ip), dichromate rapidly decreased serum insulin within 15 min after intoxication in doses of 20 and 40 mg/kg; hypoinsulinemia lasted 60 min. However, insulin levels returned to the normal range at 120 min after treatment. Dichromate-induced metabolic disturbance was also observed in the 24 hr-fasted rats, the response of which was similar to normal rats except for later hyperglycemia. In both cases, the duration time was short (30 to 60 min). Adrenalectomy and insulin pretreatment had no effect on dichromate-induced hyperglycemia. These results suggest that dichromate-induced metabolic disturbance results from the concomitant effects of a sudden decrease in serum insulin level and its direct inhibitory effect on carbohydrate metabolism. In addition, the characteristic biphasic pattern of metabolic disturbance might be related to metabolic fate of dichromate in vivo.

Association of Helicobacter pylori with gastritis and peptic ulcer diseases

The occurrence of Helicobacter pylori(H.pylori) and its relationship with gastric mucosa were studied by light and electron microscopy and culture of biopsy specimens from gastric mucosa of 160 patients with upper gastrointestinal symptoms. H. pylori were present in 96.6% of patients with active chronic gastritis, 100% of patients with duodenal ulcer and 76.9% of patients with gastric ulcer, while present in only 6.3% of individuals with histologically normal gastric mucosa. The bacteria colonized the antral mucosa more frequently than the body or than the duodenal cap mucosa. The bacteria were rarely seen in the intestinalized epithelium per se, but there was no significant difference in prevalence of H. pylori between gastritis with intestinal metaplasia and gastritis without intestinal metaplasia. H. pylori could be seen in close association with the surface of gastric epithelial cells below the mucus layer without evidence of intracellular parasitism, All of the strains tested were susceptible to penicillin, erythromycin, and most of them susceptible to tinidazole and bismuth salts. It is concluded that H. pylori are highly associated with gastritis and peptic ulcer diseases and its prevalence rates in patients with those diseases is higher than in developed countries. This strong association of H. pylori infection with gastritis and peptic ulcer diseases suggest a possible etiologic role for the bacterium in those diseases.