Biomedical subjects
S Quick
Publications and source records attributed to S Quick.
Fetal alcohol syndrome: the nurse practitioner perspective.
Fetal alcohol syndrome is the leading cause of mental retardation in the United States. The tragedy is that while FAS is irreversible, it is 100% preventable. FAS is caused by maternal consumption of alcohol during pregnancy. Alcohol is a teratogen and acts in different ways to produce physical and central nervous system malformations and defects in the developing embryo and fetus. FAS is characterized by a history of maternal alcohol ingestion, central nervous system dysfunction, growth deficiencies, and specific physical anomalies. Adolescents and adults with FAS have behavioral problems that differentiate them from other mentally disabled individuals. Nurse practitioners can have an impact on the prevalence of FAS by educating clients about FAS and its relationship to alcohol consumption. NPs need to carefully identify high-risk women and their partners before a pregnancy occurs and assist with interventions to stop active alcoholism or alcohol use during pregnancy. NPs have the capability to decrease the severity of alcohol's effects during pregnancy through education, counseling, and intervention. NPs have the skills to work with case-finding and early identification of infants and children who display signs and symptoms of FAS. With such case-finding, early identification, and prompt referral to the appropriate diagnostic and/or supportive community agencies, individuals with FAS can receive timely intervention to minimize the effects of FAS. Adults with behavioral problems can be assessed for FAS and referred for appropriate assistance as well. Finally, NPs can facilitate public awareness of FAS through educational efforts with individuals, families, and communities.
Recombinant iron-regulatory factor functions as an iron-responsive-element-binding protein, a translational repressor and an aconitase. A functional assay for translational repression and direct demonstration of the iron switch.
The translation of ferritin and erythroid 5-aminolevulinate synthase mRNAs is regulated via a specific high-affinity interaction between an iron-responsive element in the 5' untranslated region of ferritin and erythroid 5-aminolevulinate synthase mRNAs and a 98-kDa cytoplasmic protein, the iron-regulatory factor. Iron-regulatory factor was expressed in vaccinia-virus-infected HeLa cells (hIRFvac) and in Escherichia coli (hIRFeco). An N-terminal histidine tag allowed a rapid one-step purification of large quantities of soluble recombinant protein. Both hIRFvac and hIRFeco bound specifically to iron-responsive elements and were immunoprecipitated by iron-regulatory-factor antibodies. Using in-vitro-transcribed chloramphenicol-acetyltransferase mRNAs bearing an iron-responsive element in the 5' untranslated region, specific repression of chloramphenicol-acetyltransferase translation by hIRFvac and hIRFeco was demonstrated in wheat-germ extract. In addition, hIRFvac and hIRFeco were shown to display aconitase activity. Treatment of hIRFvac and hIRFeco with FeSO4 resulted in a drastic reduction in iron-responsive-element-binding of iron-regulatory factor, but caused a strong stimulation of its aconitase activity. The results establish that recombinant iron-regulatory factor is a bifunctional protein; after purification, it binds to iron-responsive elements and represses translation in vitro. Following iron treatment, iron-responsive-element binding is lost and aconitase activity is gained. No eukaryotic co-factor seems to be required for the conversion of the iron-responsive-element binding to the aconitase form of the protein.
Modulation of the RNA-binding activity of a regulatory protein by iron in vitro: switching between enzymatic and genetic function?
The iron-responsive element-binding protein (IRE-BP) is an RNA-binding protein that regulates the expression of several mRNAs in response to availability of cellular iron. The iron-dependent control of IRE-BP activity has been reconstituted in vitro. Incubation of purified IRE-BP with iron salts in the presence of the reducing agent cysteine decreases IRE-BP binding to the cognate RNA element. The specificity of this effect is established by several parameters: (i) the interaction of the spliceosomal protein U1A with its U1 small nuclear RNA target sequence as an internal control is unaffected by iron perturbations, (ii) non-iron metals fail to mimic the iron effect, and (iii) iron chelator activates the IRE-binding activity of IRE-BP and titrates the effect of iron salts. Modulation of IRE-BP activity by chelatable iron is reversible and thus does not involve permanent alterations of the integrity of the protein. These findings accurately mirror the physiological basis for iron regulation of transferrin receptor mRNA stability as well as ferritin and erythroid 5-aminolevulinate synthase mRNA translation in vivo. We discuss these data vis-a-vis the structural homology of IRE-BP with the iron-sulfur protein aconitase and propose a mechanism by which the same cytoplasmic protein serves a dual function as an RNA-binding factor and an enzyme.
Mutational analysis of the human T-cell leukemia virus type I trans-acting rex gene product.
Expression of the human T-cell leukemia virus type I (HTLV-I) rex gene is a prerequisite for the expression of the retroviral structural proteins. We have generated internal deletion mutants of this 27-kDa nucleolar trans-acting gene product to define functional domains in the Rex protein. The phenotype of the various mutant proteins was tested on the homologous HTLV-I rex response element sequence and the heterologous human immunodeficiency virus type 1 (HIV-1) rev response element sequence. Our results indicate that a region between amino acid residues 55 and 132 in the 189-amino-acid Rex protein is required for Rex-mediated trans activation on both retroviral response element sequences. In addition, substitution of the Rex nuclear localization signal by a sequence of the HIV-1 rev gene product targets the Rex protein to the correct subcellular compartment required for Rex function.
Comparison of persistence of seven bovine viruses on bovine embryos following in vitro exposure.
The ability of seven cytopathic strains of bovine viruses to adhere to the zona pellucida of six-to-eight day-old bovine embryos were compared. Embryos were exposed to virus by placing them either in virus suspensions or by culturing them on infected bovine turbinate cultures for 18-24 h. After exposure to bovine virus diarrhea virus (BVDV), infectious bovine rhinotracheitis virus (IBV), bluetongue virus (BTV), pseudorabies virus (PRV), vesicular stomatitis virus (VSV), parainfluenza 3 virus (PI3), or bovine enterovirus virus (BEV), the embryos were tested for virus by culture in bovine turbinate cells and by morphological examination using electron microscopy (EM). A special technique to minimize loss of embryos processed for EM was developed. More embryos had viral particles on the surface of the zona pellucida after exposure to 18-24 hour infected cell cultures than did embryos exposed to viral culture suspensions. The most dramatic finding was that BTV adhered in large numbers to the surface of the zona pellucida of exposed embryos. IBRV, PRV, and VSV comprised an intermediate group, with virions occasionally detected on the surface of exposed embryos after 5 washes. Therefore, extensive washing is required. The PI3 and BEV were easily removed from embryo-exposed virus by washing. BVD was difficult to identify morphologically, making assessment by EM unreliable. There was no evidence that any one of the seven viruses penetrated the intact zona pellucida. Using a micromanipulator, 42 embryos were also directly inoculated through the zona pellucida with +/- 50 picoliters of virus inoculum or medium.(ABSTRACT TRUNCATED AT 250 WORDS)
Experimental transmission of bovine viral diseases by insemination with contaminated semen or during embryo transfer.
Three experimental approaches were used to study transmission of blue tongue (BT), infectious bovine rhinotracheitis (IBR) and bovine virus diarrhoea (BVD) viruses. These were insemination with contaminated semen, experimental infection of embryo donor cows, or transfer of embryos experimentally exposed to virus in vitro to normal recipients. Parameters assessed included number and quality of embryos produced, virus detection (isolation and electron microscopy), serology and histopathology. All superovulated sesceptible cows inseminated with semen containing blue tongue virus (BTV) (n = 2) or infectious bovine rhinotracheitis virus (IBRV) (n = 2) became infected. One cow inseminated with semen containing BTV produced seven virus-free seven-day-old embryos; the second cow failed to produce any embryos. One of two cows inseminated with semen containing IBRV produced two underdeveloped, virus-free embryos while no embryos were produced by the second cow. One of two cows inseminated with semen containing bovine viral diarrhoea virus (BVDV) became infected. Two poorly developed, virus-free seven-day-old embryos were recovered from one of these cows. Superovulated susceptible cows inoculated either intramuscularly with BTV (n = 3) or intranasally with IBR virus (n = 2) became infected. Virus was isolated from some tissues of two BTV-infected cows, neither of which produced embryos. A third BTV-infected cow produced two virus-free embryos collected at necropsy five days after inoculation. One of two cows experimentally infected with IBR virus, produced three embryos but virus was not detected either by electron microscopy (1 embryo) or in cell culture by cytopathic alterations (1 embryo).(ABSTRACT TRUNCATED AT 400 WORDS)
Isolation and characteristics of an equine reovirus type 3 and an antibody prevalence survey to reoviruses in horses located in New York State.
Reoviruses have been isolated from a number of species including human, bovine, feline, canine and equine. In most species they seem to produce mild to inapparent disease. We have isolated a reovirus type 3 from a foal with diarrhea. The virus designated the Ralph strain has been propagated in both the MA-104 and A-72 cell lines. The strain produced cytoplasmic inclusion bodies in these cell cultures. Tissue-cultured virus fixed complement in the presence of reovirus antibodies, but failed to do so in the presence of rotavirus antiserum. By electron microscopy the viral particle measured +/- 65 nm. The virus hemagglutinated pig erythrocytes, but not human O, human A, calf, cow, chicken or guinea pig erythrocytes. In the hemagglutination test there was complete reciprocal crossing between the Ralph strain and the NIH reovirus type 3, but there was no crossing with the NIH reovirus types 1 and 2. A limited serological survey was completed on serum samples from New York State horses collected in 1976-1977 and 1981 using the hemagglutination-inhibition test. The percentage with antibodies to reovirus types 1, 2 and 3 for 1976-1977 was 24.5, 42.2 and 3.9% and in 1981, 8.8, 9.8 and 3.9%, respectively.
Experimental infection of horses and ponies by oral and intranasal routes with New York State reovirus type 3 and German reovirus types 1 and 3 equine isolates.
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Foreign medical graduates and board certification: myths and realities.
The participation of foreign medical graduates (FMGs) in American medicine is a longstanding phenomenon, yet the documentation of their role has been mainly impressionistic and anecdotal, particularly in psychiatry. Using the results of a survey on Board certification, the authors compared FMGs with U.S. medical graduates (USMGs) on several variables: demographic characteristics, attitudes toward certification, performance, and personal experience with the examination process. They found that FMGs are more similar than dissimilar to USMGs in attitudes, values, and opinions about certification. The authors conclude that the differences are not sufficiently remarkable to warrant some of the prevalent misconceptions about FMGs.