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Biomedical subjects

R Sperling

Publications and source records attributed to R Sperling.

At least 19 recordsLinked to original sources
PubMed1992

Human papillomavirus-associated lesions of the vagina and cervix. Treatment with a laser and topical 5-fluorouracil.

Twenty women with cervical and vaginal human papillomavirus-associated lesions were treated with CO2 laser ablation followed by eight weekly applications of 5-fluorouracil. Viral subtyping in a majority of patients and histology were obtained before and after treatment. After treatment 88% (15 of 17) had normal vaginal biopsies, and 59% (10 of 17) had normal cervical biopsies. There were no treatment failures with subtype 6/11 infection of the cervix or vagina. All the failures were with viral subtypes 16/18 and 31/35/51. The protocol was effective in treating patients with cervical and vaginal human papillomavirus-associated lesions.

Administration, Topical↗
PubMed1992

Zileuton, a 5-lipoxygenase inhibitor in rheumatoid arthritis.

The effects of zileuton, a new 5-lipoxygenase inhibitor, on leukotriene generation and clinical response in rheumatoid arthritis (RA) was studied in a 4-week randomized double blind placebo controlled study at 2 academic rheumatology centers. Zileuton decreased the mean (+/- SEM) ionophore induced synthesis of leukotriene B4 at Week 1 by 70% from 191.2 +/- 28.5 to 57.5 +/- 17.0 ng/ml. A parallel suppression of all major 5-lipoxygenase pathway products was observed. An improvement in clinical variables was observed in the zileuton and placebo treated population. No unique toxicity was identified in this study. Zileuton inhibited 5-lipoxygenase in RA with a suggestion of clinical response with limited toxicity.

Adult↗
PubMed1991

Possible involvement of (2'5')oligoadenylate synthetase activity in pre-mRNA splicing.

The first step in splicing of pre-mRNA involves an intermediate lariat structure, in which a 2'5' phosphodiester bond between the 5' terminal guanosine residue of the intron and a specific adenosine residue near the 3' end of the intron is formed. A mammalian enzyme that generates 2'-5' phosphodiester bonds is (2'-5')oligoadenylate synthetase [(2'-5')OASE]. Although the expression of this enzyme is induced by interferon, low constitutive levels can be detected in untreated cells and tissues. The structural similarity between the lariat branch point and the 2'-5' phosphodiester bond generated by (2'-5')OASE prompted the experiments described here which suggest that this enzyme is involved in pre-mRNA splicing. (i) We show that a (2'-5')OASE activity is associated with 60S spliceosomes in an ATP- and RNA-dependent manner and that it can be indirectly immunoprecipitated by anti-Sm antibodies. (ii) Antibodies against (2'-5')OASE inhibit the lariat formation in the first step of splicing when added directly to a splicing reaction in vitro. (iii) HeLa cell nuclear extracts immunodepleted of (2'-5')OASE activity were also deficient in splicing activity.

2',5'-Oligoadenylate Synthetase↗
PubMed1991

The effects of cyclosporin A on eicosanoid excretion in patients with rheumatoid arthritis.

Alterations in renal eicosanoid levels have been postulated as a factor in cyclosporin A (CSA) nephrotoxicity. The effects of CSA on renal eicosanoid excretion in rheumatoid arthritis were studied over a 24-week period, during which treatment with nonsteroidal antiinflammatory drugs was discontinued. The initial dosage of CSA was 4 mg/kg/day; at week 24, the mean dosage of CSA was 3.9 mg/kg/day. At week 24, the mean (+/- SD) serum creatinine level (1.04 +/- 0.24 mg/dl) was 32% above the baseline value; renal blood flow had decreased by 21% (P less than 0.03) and the glomerular filtration rate had decreased by 16%. There was a significant increase (P less than 0.03) in the 2,3-dinor thromboxane B2 level at week 2, but there was no significant change in the levels of the other eicosanoids. This study demonstrates that after CSA treatment, there is a selective increase in a thromboxane metabolite that parallels an increase in renal vascular resistance, even in the absence of nonsteroidal antiinflammatory drugs, and with unimpaired formation of other vasodilator eicosanoids.

Adult↗
PubMed1991

A novel splicing factor is an integral component of 200S large nuclear ribonucleoprotein (InRNP) particles.

In previous studies we have shown that nuclear transcripts of several pre-mRNAs can be released from nuclei of mammalian cells in the form of large nuclear ribonucleoprotein (InRNP) particles. By electron microscopy, these particles appeared as compact composite structures, 50 nm in diameter, which invariably sedimented at the 200S region in sucrose gradients. In order to identify putative protein splicing factors associated with the 200S InRNP particles, a panel of monoclonal antibodies directed against these particles were screened for their ability to inhibit splicing of pre-mRNA in vitro. In this study we have focused on a nuclear protein of 88 kd in molecular weight, which is an integral component of the InRNP complex and is recognized by monoclonal antibodies from a specific clone. This protein has been identified here as a novel splicing factor by, (i) antibody inhibition of splicing in vitro and (ii) depletion of splicing activity from HeLa cell nuclear extract after removing the 88 kd polypeptide by immunoadsorption, and complementation of the depleted activity with an affinity-purified 88 kd antigen. This splicing factor has further been shown to be required for the assembly of an active splicing complex.

Animals↗
PubMed1991

HIV/AIDS education in a prenatal clinic: an assessment.

An HIV/AIDS education and counseling program was integrated into the routine medical care of women attending the prenatal clinic of a major urban, inner-city, teaching hospital that serves mostly indigent minority women in an area hard hit by the HIV/AIDS epidemic. Pre- and post-intervention questionnaires were administered to a consecutive historical Control Group (n = 98) who did not receive the HIV/AIDS information and an Intervention Group (n = 515) who received all information. The data support our hypothesis that an HIV/AIDS education program would increase the level of general knowledge, but fail to support our hypothesis of a positive effect on attitudes around HIV-antibody testing and an increase in desire for voluntary testing. Our hypothesis that women reporting more risk behaviors would be more likely to agree to HIV-antibody testing was only partially supported.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Incorporating HIV education and counseling into routine prenatal care: a program model.

This article reports how a prenatal clinic in a major urban teaching hospital has developed and integrated an HIV education and counseling program into routine prenatal care. The patient population served are predominantly minority women living in an inner-city community that has been disproportionately affected by the AIDS epidemic. Implementation of the patient program has required training and support for all professional staff. Staff training served as a foundation for this comprehensive patient program, which has reached all prenatal patients regardless of risk behavior. The program has succeeded in involving a large population of women in an educational program, has identified HIV-1 seropositive pregnant women through voluntary testing, and has provided them with the necessary medical and social work services. Principles of program development are identified for use in other settings.

Ambulatory Care↗
PubMed1990

The effects of a 5-lipoxygenase inhibitor on asthma induced by cold, dry air.

BACKGROUND: The enzyme 5-lipoxygenase catalyzes the metabolism of arachidonic acid to form products that have been implicated in the airway obstruction of asthma. We hypothesized that if products of the 5-lipoxygenase pathway are important in mediating this obstruction, then prevention of their formation should decrease the severity of an induced asthmatic response. METHODS: In a randomized, double-blind, placebo-controlled, crossover study, we examined the effect of A-64077, a 5-lipoxygenase inhibitor, on the bronchoconstriction induced by hyperventilation of cold, dry air in 13 patients with asthma. The completeness of 5-lipoxygenase inhibition was confirmed by examining the profile of eicosanoids produced in whole blood ex vivo after activation with the calcium ionophore A-23187. RESULTS: A-64077 decreased the mean (+/- SEM) ionophore-induced synthesis of leukotriene B4, a 5-lipoxygenase product, by 74 percent (from 265.3 +/- 30.3 to 69.5 +/- 21.5 ng per milliliter, P less than 0.001), but it did not affect the ionophore-induced synthesis of thromboxane B2, a cyclooxygenase metabolite of arachidonic acid (80.0 +/- 17.1 ng per milliliter before A-64077 vs. 75.8 +/- 14.3 ng per milliliter after A-64077). In concert with the selective inhibition of 5-lipoxygenase by A-64077, the amount of cold, dry air (expressed as respiratory heat exchange) required to reduce the forced expiratory volume in one second by 10 percent was increased by 47 percent after A-64077 (3.0 kJ per minute for placebo vs. 4.4 kJ per minute for A-64077, P less than 0.002). Similar results were obtained when minute ventilation was used as an indicator of outcome (27.5 liters per minute for placebo vs. 39.8 liters per minute for A-64077, P less than 0.005). CONCLUSIONS: Selective inhibition of 5-lipoxygenase by A-64077 is associated with a significant amelioration of the asthmatic response to cold, dry air, suggesting that 5-lipoxygenase products are involved in this response. This approach may be useful in the treatment of asthma.

Asthma↗
PubMed1990

Monoclonal anti-La antibody derived from a mouse with experimental SLE is similar to human anti-La antibodies.

The La antigen is a highly conserved protein, originally defined by sera of patients with Sjögren's syndrome or systemic lupus erythematosus (SLE). In the present study, we have produced and characterized a monoclonal anti-la antibody derived from mice with experimental SLE. The induction of SLE in these mice was achieved by their immunization with a murine monoclonal anti-idiotypic antibody against a common idiotype (16/6 Id) found in SLE patients. The monoclonal anti-La antibody derived from these mice was found to be virtually identical to the anti-La antibodies found in human autoimmune sera. First, its binding to different nuclear extracts, as well as to protease-digested HeLa nuclear protein extracts, was found to be identical to that of human anti-La antibodies. Second, an inhibition study on blotted proteins demonstrated a very close relationship between the epitopes recognized by the murine monoclonal anti-La antibody and the human anti-La serum. Third, the monoclonal anti-La antibody was found by immunofluorescence to be directed against a nuclear antigen that gave a speckled pattern. Finally, the monoclonal anti-La antibody immunoprecipitated the La-associated small RNAs. This report provides evidence for the similarity of murine anti-La antibody produced in experimental SLE and human anti-La antibodies formed in autoimmunity.

Animals↗
PubMed1979

Low resolution models of self-assembled histone fibers from X-ray diffraction studies.

X-ray diffraction data from self-assembled histone fibers are presented for three systems: H4, H3-H4, and the four core histones H2A, H2B, H3 and H4. These data have been obtained under conditions of high ionic strength and high protein concentration which are thought to promote histone conformation similar to that found in intact chromatin. The low angle equatorial scattering (R less than .05 A-1) is analysed, and, with additional constraints imposed by electron microscopy data, four low resolution fibrillar models are derived. Two features common to all the possible models are a maximum outer diameter of approximately 60 A and a subfibril diameter of approximately 25 A. It is the interference of the protein subfibrils across a central region of low electron density - a 10 A "hole" - which gives rise to the characteristic diffraction peak at 36 A. Possible relationships of the models of the histone fibers to the structure of the histone component of chromatin are suggested.

Histones↗
PubMed1978

Photochemical cross-linking of histones to DNA nucleosomes.

Ultraviolet (UV)-induced cross-linking was utilized in order to identify histone-DNA interacting regions in the chromatin repeating unit. Fractionated mononucleosomes which contained 185 base pairs of DNA and a full complement of the histones, including histone H1, were irradiated with light of lambda greater than 290nm in the presence of a photosensitizer. Equimolar amounts of histones H2A and H2B were found, by two independent labeling experiments, to be cross-linked to the DNA. Based on previous finding that the UV irradiation specifically cross-links residues which are in close proximity, irrespective of the nature of the amino acid side chain or the nucleotide involved, our results indicate that the four core histones are not positioned equivalently with respect to the DNA. This arrangement allows histones H2A and H2B to preferentially cross-link to the DNA. A water soluble covalent complex of DNA and histones was isolated. This complex was partially resistant to mild nuclease digestion, it exhibited a CD spectrum similar to that of chromatin, and was found to contain histone H1. These results are compatible with a model which suggests that histone H1, though anchored to the linker, is bound to the DNA at additional sites. By doing so it spans the whole length of the nucleosome and clamps together the DNA fold around the histone core.

Animals↗
PubMed1977

Molecular homogeneity of the histone content of HeLa chromatin subunits.

Interaction of affinity chromatographically purified antihistone H3 and antihistone H4 with isolated HeLa core particles, followed by separation of unreacted and reacted particles by sedimentation, demonstrates that every core particle contains these histones. Taken together with our previous data indicating the presence of H2B in every nucleosome (Simpson, R. T., and Bustin, M. (1976), Biochemistry 15, 4305), these data lead to the conclusion that each core particle contains two each of the four smaller histones. In contrast to the lack of interference in binding of more than one molecule of antibody to a single species of histone to the core particle, steric hindrance exists when attempts are made to bind both anti-H3 and anti-H4 to core particles.

Antibodies↗
PubMed1977

Arrangement of subunits in assembled histone H4 fibers.

The structure of assembled histone H4 fibers has been studied by analysis of electronmicrographs, including optical diffraction. An individual fiber has the appearance of an 80-A wide ribbon, twisted at intervals of about 330 A. Thicker fibers which have been observed seem to be bundles of ribbons. In diffraction patterns from both kinds of fiber, layer lines at axial spacings of about 1/55 A-1, 1/37 A-1, and 1/27 A-1 were most consistently observed. The possible arrangements of molecules within the twisted ribbons have been deduced and are found to be fairly closely related. The ribbons appear to consist of two parallel, unstaggered rows of repeating units, which are probably H4 dimers. The similarity between the observed layer line spacings of the H4 fibers and the spacings of the maxima in x-ray diffraction patterns from whole chromatin suggests that the H4 fibers have a structure related to that of chromatin. Since homogeneous preparations of histones H2A, H2B, and H3, or any mixture of these four histones, can form similar structures, it seems likely that the basic organization of chromatin is determined by a fibrous histone core around which the DNA is wrapped.

Histones↗