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Biomedical subjects

H L Lipton

Publications and source records attributed to H L Lipton.

At least 37 records · Page 2Linked to original sources
PubMed1995

Theiler's virus growth in murine macrophage cell lines depends on the state of differentiation.

Theiler's murine encephalomyelitic virus (TMEV) preferentially replicates in macrophages in the central nervous system of mice during the persistent phase of infection. Macrophages accumulate in demyelinating lesions and are evidently the primary cell to harbor virus. To investigate TMEV-macrophage interactions, we studied GDVII infection of three cell lines, M1, P388D1, and RAW264.7, representing various stages of macrophage differentiation/activation. GDVII virus was bound and internalized by RAW264.7 and P388D1 cells, but not by the precursor cell line M1. While infection of P388D1 cells produced a typical lytic cytopathology with marked loss of cellular activity to 10-20% of the uninfected control cells, RAW264.7 cells showed little cytopathology despite a decrease in cellular activity of 50-60%. Morphologic changes in infected RAW264.7 cells were similar to those occurring after cell activation. Although an infectious center assay showed that all P388D1 and RAW264.7 cells were infected, synthesis of viral RNA and proteins was markedly reduced and virus titers were restricted compared to permissive BHK-21 cells. Infected RAW264.7, but not infected P388D1, cells secreted tumor necrosis factor-alpha and nitric oxide. Therefore, depending on the differentiation and/or activation state, murine macrophages may be resistant to TMEV infection (M1), semipermissive and activated to secrete cytokines (RAW264.7), or semipermissive and not activated to secrete cytokines (P388D1).

Animals↗
PubMed1995

Pharmacists as agents of change for rational drug therapy.

We analyze what is known and unknown about the contribution of the pharmacist as patient educator, physician consultant, and agent to affect patient outcomes in ambulatory settings. The need for pharmacist services is discussed, as are the theoretical underpinnings and quality of the scientific evidence to support their efficacy. The analysis is conducted in the context of a shift in pharmacists' roles from product to patient orientation as well as recent U.S. legislation mandating enhanced pharmacists' roles via drug utilization review for all Medicaid patients. We conclude with a research and action agenda, calling for stronger research designs in evaluating pharmacists' interventions. The shifting paradigm in the pharmacy profession, coupled with the implementation of the Omnibus Budget Reconciliation Act of 1990, provide unique opportunities for rigorous evaluations of pharmacists as agents of change for rational drug therapy.

Ambulatory Care↗
PubMed1995

The predominant virus antigen burden is present in macrophages in Theiler's murine encephalomyelitis virus-induced demyelinating disease.

Theiler's murine encephalomyelitis virus (TMEV) produces a persistent central nervous system infection and chronic, inflammatory demyelinating disease in susceptible mice. TMEV antigen(s) and RNA genome have been detected in astrocytes, oligodendrocytes, and macrophages during persistence. Whether there is a predominant cell type in which TMEV persists has not been resolved. Since TMEV-induced demyelinating lesions are infiltrated with macrophages and a number of other persistent viruses show near-exclusive tropism for these phagocytic cells, we used two-color immunofluorescent staining with conventional and confocal microscopy to colocalize TMEV to cells that stain with monoclonal antibodies (MOMA-2) [unknown antigen], Mac-1 [CD11b], FA-11 [CD66], and 2F8 [scavenger receptor]) to macrophages in BeAn-infected SJL mice. A predominant virus antigen burden within macrophages infiltrating demyelinating lesions was seen. A dichotomy of cells staining for virus antigen(s) was found with infected cells containing either a large or small virus antigen load. Ninety percent of cells with a large virus antigen load were large phagocytes (20 to 50 microns) that were readily detected at low power (5x objective). Cells with smaller amounts of virus antigen(s) turned out to be either these same large phagocytic cells or much smaller cells, approximately equal to 10 microns in diameter. Forty percent of cells with a small virus antigen load were macrophages. The unidentified approximately equal to 10-microns cells that are virus antigen positive and macrophage negative in this study could still be macrophages, or they may be oligodendrocytes. The fact that virus was detected in the cytoplasm and not phagolysosomes of macrophages and the sheer mass of fluorescently stained virus proteins in some macrophages suggest that TMEV persists in these phagocytic cells by active virus replication.

Animals↗
PubMed1995

The leader polypeptide of Theiler's virus is essential for neurovirulence but not for virus growth in BHK cells.

A leader polypeptide of unknown function is encoded by cardioviruses, such as Theiler's murine encephalomyelitis virus. Although the deletion of this polypeptide has little effect on the growth of parental GDVII virus in baby hamster kidney (BHK) cells, the mutant virus is completely attenuated and fails to kill mice receiving intracerebral inoculations of high doses of the virus.

Animals↗
PubMed1995

Mutation of a major histocompatibility class I locus, H-2D, leads to an increased virus burden and disease susceptibility in Theiler's virus-induced demyelinating disease.

Genetic studies have demonstrated that susceptibility to Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease is multigenic with linkage to the MHC class I locus, H-2D. We have analyzed the effect of mutations (H-2bm13 and H-2bm14) in the H-2Db gene on central nervous system (CNS) virus replication, virus-specific delayed type hypersensitivity (DTH) and disease induction in mutant [bm14D2F1 and bm13D2F1] and parental B6D2F1 hybrids. The results indicate that substitutions of only a single residue (bm14D2F1) or three residues (bm13D2F1) in H-2D in the mutant leads to a sequence of events culminating in disease susceptibility. Mutation of the H-2D gene is associated with reduced or delayed virus clearance following the acute phase of exponential CNS virus growth and an increased level of virus persistence. Concomittant with the greater virus antigen burden, mutant mice respond with higher levels of virus-specific DTH and develop inflammatory demyelinating lesions.

Animals↗
PubMed1994

The impact of clinical pharmacists' consultations on geriatric patients' compliance and medical care use: a randomized controlled trial.

This study assessed the impact of clinical pharmacists' consultations on drug regimens, compliance, and health service use of geriatric hospitalized patients (N = 706) discharged on 3 or more medications. Pharmacists consulted with experimental patients at discharge and 3 months thereafter, and with physicians as needed. Controls received usual care. At 6-8 weeks after enrollment, experimental patients were more knowledgeable about regimens than controls. At 12-14 weeks, they were on fewer medications and less complex regimens, and had better compliance scores. There was no effect on service use or charges, perhaps due to inadequate sample size and lack of targeted drug groups analysis. The authors conclude that clinical pharmacists' consultations can improve geriatric patients' drug regimens and compliance. Findings further suggest the need for replication among large cohorts of patients at high risk, due to the use of medications most likely to have a potential for serious outcomes and to be vulnerable to physician prescribing error.

Aged↗
PubMed1994

Popular films do not reflect current tobacco use.

This study examined trends in tobacco use in a random sample of 2 of the 20 top-grossing US films each year from 1960 through 1990 (62 films). The overall rate of tobacco use did not change. Films continue to portray smokers as successful, attractive White males. Smoking groups became larger, smoking alone declined, hostility and stress reduction were increasingly associated with smoking, and smoking by minor characters increased. Although smoking among elite characters fell, it remained nearly three times as prevalent as in actual population data during the 3 decades. Events involving young people more than doubled. Films do not accurately represent smoking in the United States.

Female↗
PubMed1993

Crystallization and preliminary X-ray diffraction studies of Theiler's virus (GDVII strain).

Theiler's murine encephalomyelitis virus (TMEV) is a member of the picornavirus family. Mice infected with TMEV serve as models for the study of human neurological diseases including multiple sclerosis. Preparations of the GDVII strain of Theiler's virus have been crystallized using the hanging drop technique. When exposed to high intensity synchrotron radiation, these monoclinic crystals diffracted X-rays to at least 3.0 A resolution. The unit cell has a C-centered lattice with dimensions: a = 575.2 A, b = 324.0 A and c = 558.4 A, beta = 108.2 degrees. The molecular mass and cell dimensions imply that there is an entire virus particle per asymmetric unit, suggesting the presence of 60-fold non-crystallographic redundancy. This GDVII crystal form appears to be suitable for high-resolution structure determination.

Crystallization↗
PubMed1993

Drug utilization review in ambulatory settings: state of the science and directions for outcomes research.

There are escalating national pressures to analyze pharmaceutical outcomes and to develop drug-related clinical guidelines. These interests coincide with passage of the Medicaid Rebate Law (OBRA, 1990), which mandates the implementation of prospective and retrospective drug utilization review (DUR) programs by Medicaid in 1993. This report investigates DUR programs that target outpatient drug therapies. The authors present a conceptual framework that identifies the factors influencing drug prescribing and the range of potential patient outcomes. Current types of DUR interventions and their applications are described, in addition to problems that hinder implementation or evaluation of DUR programs. DUR evaluation studies are reviewed, and a critique identifies the limitations of available DUR research. The authors recommend an expanded DUR policy research agenda, strongly suggesting that priority be given to studies in the following areas: DUR criteria development and validation; prevalence of prescribing problems and their association with patient outcomes; efficacy, toxicity and costs of therapeutic alternatives; and DUR program evaluation. The overall conclusion is that the state of the science pertaining to DUR is not well developed. The potential of DUR may not be realized due to the lack of resources needed to design, implement, and evaluate effective programs. Instead, DUR efforts may be limited to cost-containment issues without due consideration of quality-of-care outcomes. The authors call for rigorous evaluation efforts to inform DUR design and implementation, thereby assuring more rational prescribing and enhancing patient outcomes.

Ambulatory Care Facilities↗
PubMed1993

A three-nucleotide insertion in the H stem-loop of the 5' untranslated region of Theiler's virus attenuates neurovirulence.

The highly structured 5' untranslated region (5' UTR) of Theiler's murine encephalomyelitis virus is involved in cap-independent translation of the viral RNA. Previously, we reported that the bicistronic mRNA chloramphenicol acetyltransferase-5' UTR-luciferase (Luc) efficiently expressed Luc both in a rabbit reticulocyte lysate and when transfected into BHK-21 cells. Insertion of 3 nucleotides at position 665 in the 5' UTR of this bicistronic mRNA resulted in greatly reduced Luc expression in BHK-21 cells but had little effect on expression of Luc in rabbit reticulocyte lysate. This mutation was also introduced into a virulent Theiler's murine encephalomyelitis virus chimera, Chi-VL. The kinetics of viral RNA and protein synthesis and virus production in BHK-21 cells were slower for the mutant chimera [Chi-VL(IN668)] than for Chi-VL; however, the final virus yields were comparable. Intracerebral inoculation of mice with the chimeras revealed that Chi-VL(IN668) was completely attenuated in neurovirulence. The reduced neurovirulence of Chi-VL(IN668) may be ascribed to its reduced growth in the central nervous system, most likely due to an impaired ability to synthesize viral proteins.

Animals↗
PubMed1993

Assembly of Theiler's virus recombinants used in mapping determinants of neurovirulence.

A major determinant of neurovirulence for the GDVII strain of Theiler's virus, a murine picornavirus, was mapped to the P1 capsid protein region. Chimeric viruses were constructed by using sequences from the 5' noncoding and P1 regions of the virulent GDVII strain to replace equivalent regions of the less virulent BeAn strain. Neurovirulence in mice progressively increased as larger regions of BeAn capsid protein-encoding sequences were replaced. The in vitro growth characteristics of the chimeras showed that some chimeras were growth delayed in BHK-21 cells even though the viral constructs exhibited larger plaque sizes, were less temperature sensitive, and were more thermally stable than BeAn. Examination of assembly intermediates revealed an altered pentamer conformation and delayed empty capsid formation for the growth-compromised viruses. For these constructs, their chimeric nature inadvertently resulted in virion assembly defects that complicated finer-scale mapping of the determinants of virulence within the capsid region. These results demonstrate the importance of determining in vitro growth characteristics of chimeras to correctly decipher the significance of their phenotypes. VP1 does not contain a complete determinate for virulence because a chimera with VP1-encoding sequences from GDVII in an otherwise BeAn virus has an attenuated phenotype but is not growth compromised in vitro. The source of sequences, BeAn or GDVII, in the 5' noncoding region had only slight effects on the virulence of recombinant constructs.

Animals↗
PubMed1992

Three-dimensional structure of Theiler murine encephalomyelitis virus (BeAn strain).

Depending on the strain, Theiler murine encephalomyelitis virus (TMEV) may cause acute encephalitis or chronic demyelinating disease, which is associated with viral persistence in mice. Persistent central nervous system infection and demyelination by the less-virulent TMEV has provided a useful animal model for the human demyelinating disease multiple sclerosis. The less-virulent BeAn strain of TMEV was crystallized and its atomic structure was determined by x-ray crystallography. The alpha-carbon coordinates of the closely related Mengo virus were used to calculate the initial phases to 3.5 A resolution and the interpretable electron density map was produced by 10 cycles of 30-fold noncrystallographic molecular replacement averaging. The structure revealed a high degree of overall structural similarity to Mengo virus as well as substantial differences in the surface loops. These structural changes might be correlated with TMEV host-specific recognition, pH-related stability, and neurovirulence.

Animals↗
PubMed1992

Nucleotide sequence identifies Vilyuisk virus as a divergent Theiler's virus.

The Vilyuisk virus, originally thought to be the cause of a degenerative neurological disease of inhabitants of Siberia, has been characterized by sequence analysis of its 5' noncoding and coat protein coding regions. In the 5' noncoding, leader, and VP4 regions, the nucleotide identity between the sequences of known strains of Theiler's virus and Vilyuisk virus is about 90%. In the VP1-encoding region, the similarity drops to about 66% compared to the 50% similarity between sequences of Theiler's virus and encephalomyocarditis virus. Using the known crystal structure of one Theiler's virus strain, it is shown that the sequence heterogeneities generally occur at exposed surface residues. Vilyuisk virus is the most divergent Theiler's virus known. A tissue culture-adapted isolate has been propagated and found to exhibit low neurovirulence in CD-1 mice.

Amino Acid Sequence↗
PubMed1992

The impact of clinical pharmacists' consultations on physicians' geriatric drug prescribing. A randomized controlled trial.

The impact of clinical pharmacists' consultations on geriatric drug prescribing was studied in a prospective randomized controlled trial of patients 65 years of age and over discharged on 3 or more medications for chronic conditions from a 450-bed community hospital. The pharmacists provided consultation to experimental patients and their physicians at hospital discharge and at periodic intervals for 3 months postdischarge. Using a standardized tool, a physician-pharmacist panel, blinded to study group assignment of patients, evaluated the appropriateness of prescribing for a random sample of 236 patients. Eighty-eight percent had at least one or more clinically significant drug problems, and 22% had at least one potentially serious and life-threatening problem. Drug-therapy problems were divided into six categories: 1) inappropriate choice of therapy; 2) dosage; 3) schedule; 4) drug-drug interactions; 5) therapeutic duplication; and 6) allergy. Experimental patients were less likely to have one or more prescribing problems in any of the categories (P = 0.05) or in the appropriateness (P = 0.02) or dosage (P = 0.05) categories. A summary score, measuring the appropriateness of the patient's total drug regimen, indicated that experimental patients' regimens were more appropriate than those of controls (P = 0.01). Results of this trial reveal that clinical pharmacists can improve the appropriateness of geriatric drug prescribing in outpatient settings.

Aged↗
PubMed1992

Cap-independent translation by the 5' untranslated region of Theiler's murine encephalomyelitis virus.

The RNA genome of Theiler's murine encephalomyelitis viruses, a picornavirus belonging to the genus Cardiovirus, is translated in infected cells to a polyprotein. Unlike cellular messages, the 5' end of the RNA is not capped, and the untranslated region (UTR) is quite long (1,064 nucleotides in size). In poliovirus and encephalomyocarditis virus, the 5'UTR is thought to mediate cap-independent translation. We report here experiments to determine the role of the Theiler's murine encephalomyelitis virus 5'UTR in translation. Recombinant DNAs were constructed that were transcribed into bicistronic mRNAs encoding 5' chloramphenicol acetyltransferase intercistronic sequences linked to luciferase and a poly(A) 3' tail. The sequences of the 5'UTR, either complete or with sequential 5' deletions, were inserted into the intercistronic region. Bicistronic RNA transcripts were translated in a rabbit reticulocyte lysate or used to transfect BHK-21 cells, and chloramphenicol acetyltransferase and luciferase synthesis was quantitated. The results strongly suggest that the Theiler's virus 5'UTR promotes cap-independent translation and that the 5' boundary of the relevant signals resides 3' to nucleotide 500. Monocistronic mRNAs were synthesized by using an expression vector in which the 5'UTR containing deletions at the 3' terminus was inserted 5' to the coding sequences for luciferase. Analysis of luciferase translation in a rabbit reticulocyte lysate suggests that the 3' end of the translation initiation signal lies between nucleotides 1043 and 1053.

Animals↗
PubMed1992

A single base deletion in the 5' noncoding region of Theiler's virus attenuates neurovirulence.

Viral chimeras have been constructed through in vitro manipulations of the infectious cDNA clones of two prototypes of Theiler's murine encephalomyelitis virus: (i) the virulent GDVII strain and (ii) the less virulent BeAn and VL strains. Previous studies have suggested that the phenotypic differences in virulence between the BeAn and GDVII strains map to both the 5' noncoding and the coat protein regions of these viral genomes. It is shown here that attenuation mapped to the 5' noncoding region is due, at least in part, to an inadvertent deletion resulting from a cloning artifact of one C nucleotide out of four between positions 876 and 879 in the BeAn sequences. The in vitro growth characteristics in BHK-21 cells, however, do not reflect the large differences in neurovirulence between chimeras that are identical except for the deleted C. Another chimera with a mutation at position 877 and a deletion at 976 is also attenuated. The wild-type sequences from the less virulent strains BeAn and VL between nucleotides 1 and 933, in an otherwise GDVII chimera, do not attenuate virulence. Sequences of the 500 nucleotides of the 5' noncoding region proximal to the translation initiation codon were obtained for nine additional Theiler's virus strains. The attenuating deletions are discussed in the context of these sequences and the proposed secondary structures for the 5' noncoding region.

Animals↗