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Biomedical subjects

L Sherman

Publications and source records attributed to L Sherman.

At least 91 records · Page 5Linked to original sources
PubMed1990

Pattern of transcription of the genome of equine infectious anemia virus.

The pattern of expression of the equine infectious anemia virus (EIAV) genome in a persistently infected canine cell line was determined. Five EIAV-specific transcripts (8.2, 5.0, 4.0, 2, and 1.8 kilobases [kb]) were detected by using subgenomic restriction enzyme fragments of EIAV DNA and EIAV-specific oligonucleotides as probes. The 8.2-kb mRNA could be shown to represent viral genomic RNA, whereas the smaller transcripts were generated by splicing events. Evidence was obtained that indicated that each subgenomic RNA species shared a common 5'-splice donor. The 5.0-kb mRNA was found to be expressed at relatively low levels, was difficult to detect consistently, and appeared to be generated by a single splicing event which linked the 5' exon to the 3' region of pol. The 4.0-kb transcript was concluded to be the env mRNA on the basis of its hybridization pattern with the various probes and its abundance. The 2-kb species was found to be multiply spliced and was encoded by sequences derived from orf2 but was not detected by probes representing 3'-env/3'-orf sequences. The 1.8-kb species was shown to consist of sequences representing orf1, part of orf2, and the 3'-orf/env and may represent the message for the EIAV trans-activator gene.

Amino Acid Sequence↗
PubMed1990

Parent-adolescent problem-solving interactions and drug use.

This study reports on the social problem-solving interactions of young adolescents in single-parent and intact families on substance-specific and nonsubstance-related issues. Although research has shown the impact of families on adolescent substance use, all of the previous results have been based on questionnaire or interview data. A sample of 128 families was selected from a larger sample of 763 within a longitudinal study of adolescent substance use. Parent(s) and one adolescent, aged 11-15, participated in interactions which were videotaped for later coding. In three standard scenarios, the families discussed fictional assignments from a health class teacher about the use of cigarettes, alcohol, and marijuana. In addition, they discussed an issue salient to them that was the source of recent conflict. Results showed that aversive affective behavior was more likely to be displayed by substance-using adolescents, whether or not the issue was drug-related. Mothers' and fathers' alcohol use was also shown to contribute to alcohol and cigarette use among their children, while fathers' smoking contributed to marijuana and hard drug use. These data suggest that such families may not be skilled at resolving issues and coping with life's difficulties whether or not they are drug-related.

Adolescent↗
PubMed1989

Impact of distressed and aggressive behavior.

Two studies examined the hypothesis that distressed behavior induces negative emotions in others but also prompts solicitousness and deters aggression. In Study 1, 48 marital dyads rated various behaviors in terms of their feelings and reactions toward a spouse engaging in each behavior. Distressed behavior prompted both negative and solicitous emotions, but deterred hostile reactions. Aggressive behavior prompted negative feelings and hostile and argumentative reactions. In Study 2, 41 couples rated videotaped examples of a woman engaging in distressed, aggressive, or neutral behavior, with variations in verbal content and nonverbal affect. Examples of distressed behavior prompted more negative feelings and more solicitous feelings than neutral behavior. Aggressive examples prompted more negative feelings and hostile reactions. The studies indicate the importance of distinguishing between distressed and aggressive behavior.

Adaptation, Psychological↗
PubMed1989

Analysis of regulatory elements of the equine infectious anemia virus and caprine arthritis-encephalitis virus long terminal repeats.

We analyzed the equine infectious anemia virus (EIAV) long terminal repeat (LTR) for sequences that influence its promoter activity and ability to be trans-activated by the EIAV tat gene product. A series of LTR deletion mutants and recombinants between LTR and simian virus 40 (SV40) regulatory sequences were used for these studies. We were able to identify the EIAV promoter region and showed that sequences within the U3 region significantly inhibited LTR-directed transcription. However, when placed in a heterologous context (SV40 promoter) these U3 sequences functioned as an enhancer. trans-activation of the EIAV LTR was found to depend upon sequences downstream of the transcription initiation site and also within U3. Deletion mutagenesis experiments showed that the major downstream element was present in a 46-nucleotide stretch (+4 to +50). An SV40 promoter construct containing these sequences could be trans-activated in cells expressing the EIAV tat gene product. For comparative purposes we also examined the LTR of another animal lentivirus, caprine arthritis-encephalitis virus (CAEV), for positive and negative transcriptional regulatory elements and demonstrated the presence of an enhancer within its U3 sequence. There is evidence that trans-activation of the CAEV LTR requires U3 sequences. When the EIAV U3 region was replaced by the CAEV U3 sequence, the promoter activity of the EIAV LTR was markedly elevated, but the responsiveness to the EIAV trans-activator could not be restored.

Animals↗
PubMed1989

Low incidence of thrombocytopenia with porcine mucosal heparin. A prospective multicenter study.

We treated 193 patients either intravenously (94) or subcutaneously (99) for at least 5 days with porcine intestinal mucosal heparin and followed them up prospectively with frequent platelet counts to determine the incidence of heparin-related thrombocytopenia and arterial thrombosis. None of the patients in the study developed severe thrombocytopenia (platelet count, less than 100 x 10(9)/L) or arterial thrombosis. Eight patients had a platelet count of 100 to 140 X 10(9)/L on one occasion, with a count of greater than 140 x 10(9)/L on the subsequent measurement. The mean (+/- SD) values of the initial and lowest platelet counts during therapy in all patients were 288 +/- 100 x 10(9)/L and 253 +/- 88 x 10(9)/L, respectively, with the lowest counts occurring on day 4.1 +/- 4.2. A least-squares line was computed for each patient to fit the day and counts; the slopes were significantly different from zero and negative in 7.8% of patients and positive in 14.5%. This multicenter study confirms the reports that the incidence of heparin-related severe thrombocytopenia and arterial thrombosis is distinctly low in patients treated with porcine-mucosal heparin.

Aged↗
PubMed1988

Typing of HLA class II and class I antigens using PHA-activated, IL-2-propagated T lymphocytes.

We describe here a simple procedure, by which HLA class II antigens can be accurately and reliably identified in those patients where there is minimal or absent expression of HLA-DR,DQw antigens on B cells, or when the total number of leukocytes recovered from the patients do not permit reliable typing. Ficoll-Hypaque-separated peripheral blood mononuclear leukocytes, fresh or cryopreserved, were activated by PHA and then propagated in IL-2-containing medium until enough cells for typing were obtained (usually 7-14 days). At this stage, the cultured cells were shown to be primarily T cells (greater than 90% CD3+). Since the activated T cells propagate in the presence of IL-2, even a small number (10(4] of fresh or cryopreserved patients' cells suffice for this protocol. To date we have been able to successfully HLA-DR,DQw type 34/34 bone marrow transplantation candidates and 12/12 long-term dialysis patients, who were untypable using fresh cells. HLA-DR,DQw antigens on activated T cells from normal individuals were identical to those found on their uncultured B cells. In addition, class I antigens that were undetectable on the uncultured cells of one patient could be identified on activated T cells. The HLA antigens identified on the patients' activated T cells were confirmed by phenotypic analysis of cells from family members.

B-Lymphocytes↗
PubMed1988

Localization of sequences responsible for trans-activation of the equine infectious anemia virus long terminal repeat.

We used the Escherichia coli chloramphenicol acetyltransferase gene (cat) to study sequences that influence expression of the equine infectious anemia virus (EIAV) genome. The EIAV long terminal repeat (LTR) directed CAT activity in a canine cell line, but at levels much lower than those achieved with other eucaryotic viral promoters. In the same cells infected with EIAV or cotransfected with molecularly cloned EIAV genomic DNA, LTR-directed activity was markedly enhanced. Comparison of cat mRNA and protein levels in these cells indicated that this trans-activating effect could be accounted for by a bimodal mechanism in which both transcriptional and posttranscriptional events are enhanced. trans-Activation but not promoter activity was abolished by deletion of the R-U5 region of the EIAV LTR. EIAV sequences responsible for the trans-activating function could be localized to a region encompassing the 3' and 5' termini of the pol and env genes, respectively (nucleotides 4474 to 5775). Interestingly, this stretch harbors a short open reading frame with some amino acid sequence similarity to the human immunodeficiency virus type I tat gene product.

DNA Mutational Analysis↗
PubMed1987

Absence of thrombosis in subjects with heterozygous protein C deficiency.

Protein C deficiency has been thought to be associated with an increased risk of venous thrombosis. To establish a normal range of values, we used a two-site monoclonal-antibody assay to measure protein C levels in 699 healthy adults. The distribution was log normal; 95 percent of the values ranged from 70 to 140 percent of the overall mean (4.03 micrograms per milliliter). Two subjects had levels more than 3.5 SD below the mean (34 and 50 percent), consistent with heterozygous deficiency. We also screened 4723 other blood donors and found 8 additional unrelated subjects with levels from 33 to 51 percent of normal. Autosomal inheritance of heterozygous protein C deficiency was confirmed in them by a detailed study of four families. Levels from 55 to 65 percent of normal are consistent with either heterozygous deficiency or the lower end of the distribution of normal values, and were found in 79 of 5422 subjects when the two groups were combined. None of the subjects had any history of venous thrombosis. We conclude that heterozygous deficiency of protein C has a prevalence of 1 in 200 to 300, a figure consistent with the known number of homozygous infants recently identified, and that levels consistent with heterozygous deficiency are found in 1 in 60 healthy adults but are not detectably associated with a risk of thrombosis.

Adult↗
PubMed1987

Nucleotide sequence analysis of equine infectious anemia virus proviral DNA.

The nucleotide sequence of the integrated form of the genome of the equine infectious anemia virus was determined. By comparison with LTR sequences of other retroviruses, signals for the control of viral gene transcription and translation could be identified in the EIAV LTR. Open reading frames for gag and pol genes were identified and their sequences matched very closely to those determined previously by others. However, in the present study, the pol gene reading frame was open throughout its entire length. The open reading frame for the env gene product was constructed from the sequences of two independent EIAV clones. Thus, a noninfectious genomic-length clone was shown to contain a frameshift mutation approximately in the middle of the presumed env gene coding sequence, whereas the sequence of another clone was open in this region. The deduced amino acid sequences of the EIAV gag and pol products showed closer evolutionary relationships to those of known lentiviruses than to other retroviruses. There was also partial sequence homology between predicted env gene products of EIAV, visna virus, and HTLV-III/LAV. Sequences analogous to the sor region of other lentiviruses could not be identified in our EIAV clone. A short open reading frame at the 3' end of the genome that overlapped env but not the 3' LTR was present but lacked significant sequence similarity to the 3' open reading frames of other lentiviruses. Thus, the sequence and general structure of EIAV most closely resemble those of known lentiviruses.

Amino Acid Sequence↗
PubMed1987

Detection of disease-specific restriction fragment length polymorphisms in pemphigus vulgaris linked to the DQw1 and DQw3 alleles of the HLA-D region.

Pemphigus vulgaris in Israeli Ashkenazi and non-Ashkenazi Jews and in Austrian non-Jewish patients is strongly associated with the DR4 and DRw6 alleles of the HLA-D region class II genes. Restriction fragment length polymorphism analysis was undertaken with DQ beta, DQ alpha, and DR beta cDNA probes. Hybridization with the DQ beta probe identifies Pvu II, BamHI, and EcoRV fragments that absolutely discriminate pemphigus vulgaris patients from healthy DR-, DQ-, and ethnic-matched controls. In contrast the DQ alpha and DR beta probes failed to identify disease-specific restriction fragment length polymorphism fragments. These studies indicate that DQw1 and DQw3 polymorphisms carried by pemphigus vulgaris patients may be directly involved in predisposition to the disease or may be tightly linked to the susceptibility gene itself. To our knowledge, this is the first example of an HLA restriction fragment length polymorphism that is highly associated with susceptibility to autoimmune disease.

Alleles↗
PubMed1987

Distribution of selenium in human milk.

The present studies were designed to characterize selenium distribution in human milk. These studies reveal that most selenium in human milk is protein bound. Percentage dialyzable selenium varied proportionally with total selenium content of milk but not with stage of lactation. Neither rate of freezing nor frozen storage of samples for one month influenced distribution profiles. At least nine selenoproteins were detected in dialyzed milk samples following molecular sieve (Sephadex) chromatography. Glutathione peroxidase accounted for approximately 15-30% of selenium found in milk. Approximately half of peroxidase activity in human milk was associated with selenium dependent glutathione peroxidase activity.

Adult↗
PubMed1987

N-methylisatin-beta-4',4'-diethylthiosemicarbazone, an inhibitor of Moloney leukemia virus protein production: characterization and in vitro translation of viral mRNA.

The mode of inhibition of N-methylisatin-beta-4',4'-diethylthiosemicarbazone (M-IBDET) on Moloney leukemia virus production was studied. Drug treatment of infected cells did not alter the amounts or sizes of the 35S and 22S subgenomic viral RNAs. The translation abilities of poly(A)+ RNA derived from M-IBDET-treated cells was also unaffected, as judged by cell-free translation analysis. Poly(A)+ RNA derived from M-IBDET-treated cells directed translation of equal amounts of viral gag precursors, gPr-80gag and Pr-65gag, as did poly(A)+ RNA prepared from untreated cells. The addition of M-IBDET to a cell-free translation system programmed with either total poly(A)+ RNA extracted from infected cells or hybrid-selected viral RNA inhibited the synthesis of viral protein precursors. An examination of the effect of M-IBDET on polysomes engaged in the translation of viral proteins revealed a fourfold accumulation of polysomal virus-specific RNA in drug-treated cells. These results suggest that the inhibition of Moloney leukemia virus by M-IBDET involves a block in the translation of viral RNA rather than interference with viral RNA transcription.

Gene Products, gag↗
PubMed1987

Factors affecting conditional discrimination learning by pigeons.

In Experiment 1 (within subjects) and Experiment 2 (between subjects) it was shown that the sequential training of pigeons on a color discrimination and then on its reversal, each in a different floor-tilt/texture context, failed to produce conditional control of discriminative performance by those contexts. Daily alternation between the two problems (with correlated contexts) was successful, however. In each of these experiments conditional control was better reflected in generalization test performance in extinction than during sessions of training with reinforcement.

Journal Article↗
PubMed1986

Molecular cloning and physical characterization of integrated equine infectious anemia virus: molecular and immunologic evidence of its close relationship to ovine and caprine lentiviruses.

Molecular clones of the integrated form of the genome of equine infectious anemia virus (EIAV), the etiologic agent of a naturally occurring, worldwide disease of horses, were obtained. The restriction map of a full-length genome was determined. Additional evidence for the close evolutionary relationship between EIAV and a prototype lentivirus (caprine arthritis encephalitis virus) was acquired by Southern blotting and immunological analyses. An interspecies radioimmunoassay was developed in which EIAV and ovine and caprine lentiviruses could be detected equally well. These studies make available precisely defined reagents to pursue the study of the mechanisms of pathogenesis of lentiviral induced diseases.

Animals↗
PubMed1986

Nucleotide sequence analysis of the long terminal repeat of integrated caprine arthritis encephalitis virus.

The nucleotide sequence of the long terminal repeat (LTR) of caprine arthritis encephalitis virus (CAEV), a prototype lentivirus was determined. 6-bp directly repeated host cell sequences flank the 376-bp proviral LTRs. By comparison with other retroviral sequences, the CAEV LTR likely contains U3, R and U5 regions 207, 86 and 83 base-pairs in length, respectively. Sequences conforming to consensus transcriptional promoter sites were identified in the U3 region upstream of a potential transcription initiation site. A consensus polyadenylation signal is present 20 bases upstream of the putative R-U5 border and a potential poly(A) addition site. Sequence comparisons of the CAEV LTR with those of other retroviruses uncovered significant similarities with that of visna virus. No other global homologies with other retrovirus LTRs could be detected. CAEV utilizes a primer binding site complementary to lysine tRNA as does visna, AIDS associated retroviruses, and mouse mammary tumor virus. The putative primer for positive-strand DNA synthesis identified in the CAEV sequence is identical to that of visna virus and very similar to those of AIDS retroviruses and MMTV. In addition, a stretch that includes the TATA box of the CAEV LTR resembles closely the corresponding region in the AIDS retrovirus. These and other findings further strengthen the classification of AIDS retrovirus as a lentivirus.

Animals↗