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Biomedical subjects

J Piette

Publications and source records attributed to J Piette.

At least 127 records · Page 7Linked to original sources
PubMed1992

Molecular analysis of mutations induced by 4'-hydroxymethyl-4,5',8-trimethylpsoralen and UVA in the mouse HPRT gene.

The effects of the reaction photosensitized by 4'-hydroxymethyl-4,5'-8-trimethylpsoralen (HMT) on a mouse lymphoma cell line have been examined. Using the hypoxanthine phosphoribosyltransferase (HPRT) locus as target gene, a mutagenic effect of the photoreaction can be detected concomitantly with a loss of cell viability. Isolation of HPRT deficient clones has permitted a molecular characterization of the mutational pattern induced by the photosensitization reaction mediated by HMT. Southern blotting analysis demonstrated that the HPRT deficiency could not be correlated with gene deletions larger than 300 bp. Using polymerase chain reaction on both DNA and cDNA, amplification products have been cloned into M13mp18 and sequenced. Base transversions targeted on thymine residues have been located in exon 2, 3, 8 and 9 together with spontaneous frameshift mutations occurring in a run of guanine residues in exon 3. HPRT deficiencies owing to mutations arising in the HPRT promoter region have also been observed. Dot and Northern blot analysis revealed that the photoreaction could lead to either a reduced level of gene transcription or to a complete absence of HPRT m-RNA. Using polymerase chain reaction (PCR) amplification and agarose gel electrophoresis, deletions in the HPRT promoter have been observed and correlated to deficient enzyme expression.

Amino Acid Sequence↗
PubMed1992

Physical symptoms and depressive symptoms among individuals with HIV infection.

The authors investigate the importance of physical symptoms as a correlate of depressive symptoms and suicidal thoughts in a large (N = 881) community-based sample of persons infected with human immunodeficiency virus. The study overcomes limitations of prior research by minimizing overlap in measures of affective and physical symptoms, studying a more diverse population, and including correlates such as measures of social support, function, employment, insurance coverage, and cognitive impairment in the analysis. The authors' data support the notion that in diagnosing depression in the medically ill, concern over isolating physical symptoms as either "affective" or "physical" may be exaggerated.

Acquired Immunodeficiency Syndrome↗
PubMed1992

The structure and process of AIDS case management.

This article presents observations of case management in the Robert Wood Johnson Foundation AIDS Health Services Program. Case management is discussed in terms of assessment, care plan development, client links with services, monitoring, and advocacy. Recommendations are proposed to ensure that AIDS case management is delivered in a standard and equitable manner that can be monitored by quality assurance agencies.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Variation in health service use among HIV-infected patients.

The effects of sociodemographic factors on health service use among people with human immunodeficiency virus (HIV) infection are assessed. Data are from a survey of 939 clients of the Robert Wood Johnson Foundation's AIDS Health Services Program in nine communities across the country. Dependent variables are the number of outpatient visits, use of the emergency room, and whether the respondent had been admitted as an inpatient. In the 3 months before the interview, the sample averaged 7.46 outpatient physician/clinic visits: 35.9% reported an emergency room visit, and 29.9% had been hospitalized. The data suggested differential patterns of health service use, such that those who are white, male, and non-intravenous drug users have higher rates of outpatient clinic/physician use, whereas those who are nonwhite, female, and intravenous drug users have higher rates of emergency room use. Whether these observed differences are attributable to the system's response to different socioeconomic groups, or to differences in individual orientations toward use of medical care is discussed.

Black or African American↗
PubMed1992

Singlet oxygen quantum yield of sulfur and selenium analogs of psoralen.

The quantum yield of singlet oxygen production by eight newly synthesized sulfur and selenium analogs of psoralen irradiated with UV-A (366 nm) has been determined in CCl4 with the help of the steady state luminescence technique. The new psoralen derivatives are generally better singlet oxygen producers than psoralen itself. In particular, the replacement of selenophene for furan and/or of thiopyrone for pyrone induces an important enhancement of the singlet oxygen quantum yield.

Furocoumarins↗
PubMed1992

Antibodies to varicella-zoster virus modulate antigen distribution but fail to induce viral persistence in vitro.

Varicella-zoster virus (VZV) persists in human sensory ganglia. One of the hypotheses to explain the induction or the maintenance of VZV latency is that it could be promoted by the immune response itself. It is known that in the case of viruses which bud off the infected cell membrane, virus-specific antibodies can induce antigenic modulation, i.e., spatial redistribution of viral antigens and modulation of their synthesis. To determine whether antigenic modulation occurs during VZV infection in vitro and could possibly be involved in viral persistence, we have grown infected cells in the presence of anti-VZV antibodies either transiently or permanently. The distribution of immune complexes and viral proteins was then analyzed. In transient immunomodulation experiments, the distribution of one or more viral antigens was modified not only in the cytoplasmic membranes but also in the cytoplasm and nucleoplasm of infected cells. When infected cells were kept permanently in the presence of antibodies, the same pattern of redistribution of immune complexes was observed and the localization of internal viral glycoproteins was significantly modified. However, antibodies did not prevent the lytic effect of infection; they altered neither the infectious virus yield nor the Western immunoblot pattern of viral proteins, suggesting that immunomodulation is not the primary effector of viral persistence.

Antibodies, Viral↗
PubMed1992

Characterization of regulatory functions of the varicella-zoster virus gene 63-encoded protein.

Varicella-zoster virus (VZV) gene 63 encodes a protein (IE63) with a predicted molecular mass of 30.5 kDa which has amino acid similarities to the immediate-early (IE) protein 22 (ICP22) of herpes simplex virus type 1. ICP22 is a polypeptide synthesized in herpes simplex virus type 1-infected cells, and as is the case for its VZV counterpart, its regulatory functions are unknown. On the basis of the VZV DNA sequence, it has been shown that IE63 exhibits hydrophilic and acidic properties, suggesting that this protein could play a regulatory role during the infectious cycle. We report in this article cotransfection experiments which demonstrate that the VZV gene 63 protein strongly represses, in a dose-dependent manner, the expression of VZV gene 62. On the other hand, transient expression of the VZV gene 63 protein can promote activation of the thymidine kinase gene but cannot affect the expression of the genes encoding glycoproteins I and II. The results of transient expression experiments strongly suggest that the VZV gene 63 protein could play a pivotal role in the repression of IE gene expression as well as in the activation of early gene expression.

Animals↗
PubMed1991

Biological consequences associated with DNA oxidation mediated by singlet oxygen.

Singlet oxygen is a major oxidative species that can be generated by numerous biological processes such as photosensitization. This oxidant can react with deoxyguanosine and with guanine in deoxyribonucleic acid (DNA) leading to the induction of at least four different reaction products such as 4,8-dihydro-4-hydroxy-8-oxodeoxyguanosine and 7,8-dihydro-8-oxodeoxyguanosine. The induction of true single-stranded breaks in the oxidated DNA is still a matter of controversy and is not yet clearly established. This paper focuses mainly on several biological consequences which can be associated with the induction of DNA lesions by singlet oxygen. Oxidated DNA loses its transformation efficiency probably because unrepaired lesions can partially inhibit DNA replication. Mutagenesis is one of the main effects induced by guanine oxidation products. Molecular analysis of mutated genes reveals that G to T transversions are the most frequent mutations; these are probably introduced in DNA by misincorporation of deoxyadenosine monophosphate (dAMP) opposite to the lesion. Efficient repair of these oxidated guanine residues can take place via specific glycosylase, endonuclease or the SOS network. However, the data concerning the toxicity of singlet oxygen for eukaryotic cells are not frequent enough in the literature to draw a clear picture of the effects of this activated species in several biologically revelant phenomena.

DNA Damage↗
PubMed1991

Photosensitized production of singlet oxygen by merocyanine 540 bound to liposomes.

The production of singlet oxygen by merocyanine 540 was studied in dimyristoyl-phosphatidylcholine liposomes using two singlet oxygen probes: 9,10-anthracenedipropionic acid (water soluble) and 9,10-dimethylanthracene (liposoluble). Upper and lower limits of singlet oxygen quantum yield for bound merocyanine 540 were determined to be 0.055 and 0.015 respectively. The diffusion characteristics of singlet oxygen were examined using the isotropic enhancement effect of D2O and the inhibitory effect of sodium azide. It was shown that 1O2 spent more than 87% of its lifetime in a vesicle environment. When the singlet-reacting substrate and the dye were both located in the bilayer, approximately 40% of the singlet oxygen remained in the liposomes where it was originally generated.

Dimyristoylphosphatidylcholine↗
PubMed1991

Influence of innervation of myogenic factors and acetylcholine receptor alpha-subunit mRNAs.

The mRNA levels of the acetylcholine receptor alpha-subunit gene and of four members of the MyoD1 gene family, which code for candidate transcriptional activators of the former gene, were compared in the mouse during post-natal development and after denervation in the adult. During post-natal development, mRNA levels of myogenin, MyoD1, and Myf5 decrease in parallel with alpha-subunit mRNA whereas MRF4 mRNA level remains nearly constant. After denervation, increases in the levels of mRNAs coding for myogenin, MyoD1 and MRF4 accompany that of alpha-subunit mRNA, while Myf5 mRNA level varied little. A possible role of these myogenic genes in mediating nerve influence on the state of muscle differentiation and AChR alpha-subunit gene expression is discussed.

Animals↗
PubMed1991

Perceived need for dental care among persons living with acquired immunodeficiency syndrome.

Compromised oral health holds significant implications for the general health of medically vulnerable, HIV infected individuals. Past studies have reported that these individuals frequently suffer from oral opportunistic infections and have a tendency to develop severe periodontal disease. This study extends past research by examining the prevalence of oral infections according to patient characteristics and by reporting, for the first time, the level of perceived dental need in a large, multi-site sample of individuals with symptomatic HIV disease. Data for this study come from a survey of 857 clients of the Robert Wood Johnson Foundation's AIDS Health Services Program in 9 U.S. cities. More respondents (52%) reported a need for dental care than for any other service need. Multivariate analysis showed that clients who were white, in low-income groups, used intravenous drugs, or had a past history of oral opportunistic infections were more likely to report dental need. Relations between age, gender, insurance status, or disease status and perceived need were statistically nonsignificant. Forty-seven percent of the clients reported they had an oral opportunistic infection, the second outcome variable examined in this study. Statistically significant differences (P less than 0.05) were found in the prevalence of oral opportunistic infections among race and disease severity groups. Whites and the more severely ill were more likely to report an infection than their respective counterparts.

AIDS-Related Complex↗
PubMed1991

Mechanism of DNA cleavage mediated by photoexcited non-steroidal antiinflammatory drugs.

DNA damage photoinduced by four nonsteroidal antiinflammatory drugs (NSAID) have been investigated by neutral agarose gel electrophoresis. Upon irradiation at 300 nm, in phosphate buffered solution, benoxaprofen, naproxen, ketoprofen, tiaprofenic acid photosensitized the formation of single-strand breaks (SSB) in double stranded supercoiled phi X174 DNA. The efficiency of the cleavage is higher in argon saturated solutions than in aerated solutions and it is not correlated with the quantum yield of photodegradation of the drugs. Simultaneously with the DNA strand breaks, NSAID promote a weak reduction of the electrophoretic mobility of the supercoiled form that may be attributed to the formation of pyrimidine dimers or other DNA unwinding products. These photodimerization processes suggest the involvement of a triplet-triplet energy transfer between NSAID and DNA. Addition of mannitol and superoxide dismutase decreases the efficiency of the cleavage suggesting that HO. and O2.- are involved in the DNA cleavage. Unexpectedly, addition of sodium azide quenches the cleavage both in aerated or in deaerated solutions. Substituting H2O by D2O does not change the number of SSB thus suggesting that 1O2 does not take an important place in the cleavage of DNA. From our data we tentatively assume that the cleavage occurs through a radical mechanism that may involve in a first step an energy or an electron transfer. Gel sequencing on NSAID-photoinduced DNA breakage exhibits no particular specificity except in the case of benoxaprofen where a slight selectivity for cytosine is observed.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1991

Patterns of survival with AIDS in the United States.

We examined patterns of survival with AIDS (acquired immune deficiency syndrome) using the Centers for Disease Control (CDC) "AIDS Public Information Data Set." Analyses used a census of 23,271 cases diagnosed between January 1, 1984 and December 31, 1986. Three Cox proportional hazards models were fit to the data. The first used clinical and demographic parameters only in an effort to replicate Rothenberg's analysis of survival for patients diagnosed in New York City prior to 1986. The second model included variables that capture the effect of time of diagnosis in order to determine whether temporal trends exist. The third model included variables indicating the geographic region from which the cases were reported. The results of these models support earlier findings of demographic and clinical survival correlates. Controlling for covariates, patients diagnosed during 1986 lived significantly longer than those diagnosed earlier; the difference was most profound when Pneumocystis carinii (PCP) was present. Last, we observed large regional differences; their implications for health services planning are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1991

AIDS case management: the client's perspective.

The Robert Wood Johnson Foundation's AIDS Health Services Program uses case management to provide community-based care for people with AIDS. This article reports data concerning implementation of case management, based on interviews with program clients in nine communities. Some clients receive case management from a community-based organization (CBO), while others have clinic-based case managers. Clinic clients are more likely to be disadvantaged. Over 25 percent of respondents report having no case manager at either site, and 10 percent report having two case managers. Those who need social services are more likely to have a case manager. Between 18 and 25 percent have had no contact with their case manager in a month, but over 50 percent have had multiple contacts. Frequency of contact is positively related to having needs for social services. Evaluations of case managers are favorable, but there is some dissatisfaction with ease of access. Having a case manager is positively related to having service needs met. Results suggest that (1) efforts to coordinate care through case management must deal with the existence of clinics and CBOs as distinct treatment sites with differing clientele, and (2) explicit policies concerning eligibility for case management and frequency of monitoring must be developed.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Two adjacent MyoD1-binding sites regulate expression of the acetylcholine receptor alpha-subunit gene.

Several genes encoding putative myogenic regulatory factors have been isolated on the basis of their ability to convert nonmuscle cells into myoblasts. Four of these genes code for nuclear proteins that belong to a larger family characterized by a conserved helix-loop-helix motif required for DNA-binding and dimerization. At least one protein, MyoD1, can function as a transcription factor and activate muscle-specific genes during differentiation. But the promoter of the delta-subunit gene of the mouse acetylcholine receptor (AChR) was recently reported to be functional in the absence of MyoD1 binding sites and it has been suggested that the genes coding for the AChR could be regulated independently of MyoD1 protein. Here, we identify two functional MyoD1-binding sites in the muscle-specific enhancer of the chicken AChR alpha-subunit gene that are essential for full activity in transfected myotubes.

Animals↗