Biomedical subjects

D Sanford

Publications and source records attributed to D Sanford.

9 recordsLinked to original sources

PubMed2001

A human mitochondrial ferritin encoded by an intronless gene.

Ferritin is a ubiquitous protein that plays a critical role in regulating intracellular iron homoeostasis by storing iron inside its multimeric shell. It also plays an important role in detoxifying potentially harmful free ferrous iron to the less soluble ferric iron by virtue of the ferroxidase activity of the H subunit. Although excess iron is stored primarily in cytoplasm, most of the metabolically active iron in cells is processed in mitochondria. Little is yet known of how these organelles regulate iron homeostasis and toxicity. Here we report an unusual intronless gene on chromosome 5q23.1 that encodes a 242-amino acid precursor of a ferritin H-like protein. This 30-kDa protein is targeted to mitochondria and processed to a 22-kDa subunit that assembles into typical ferritin shells and has ferroxidase activity. Immunohistochemical analysis showed that it accumulates in high amounts in iron-loaded mitochondria of erythroblasts of subjects with impaired heme synthesis. This new ferritin may play an important role in the regulation of mitochondrial iron homeostasis and heme synthesis.

Amino Acid Sequence↗

PubMed2001

Modulation of fine specificity of anti-DNA antibody by CDR3L residues.

The light chain of 2C10, an anti-double stranded DNA (dsDNA) autoantibody, is not favorable for DNA binding and it was suggested that the light chain might modulate the specificity of the antibody in DNA binding. We studied several mutant scFvs expressing mutated VL and normal VH of 2C10 to explore the role of the light chain in determining the fine specificity of the antibody, which we define as the preferential binding to a specific sequence of bases or a helical conformation compared to dsDNA from calf thymus. The wild-type Fab and scFv of 2C10 bind to poly(dA-dC).(dG-dT) better than to dsDNA. However, in the absence of the light chain domain, the VH domain bound dsDNA better than poly(dA-dC).(dG-dT), indicating the possible involvement of the light chain in determining the fine specificity in DNA binding. The mutations we studied were located in either CDR1L or CDR3L of the antibody. The CDR1 mutants, D28A, D30A, D31A, and D32A have been previously shown to cause an increase in the affinity of 2C10 scFv to DNA. The fine specificity of 2C10 was not affected by the CDR1 mutants which bound to poly(dA-dC).(dG-dT) better than dsDNA. However, CDR3L mutants, D92A and N93A, which had been shown to be involved in direct interaction with DNA, preferred dsDNA to poly(dA-dC).(dG-dT) in their binding. Our results indicate that the fine specificity of 2C10 in DNA binding is modulated primarily by Asp at 92 and Asn at 93 in CDR3L. The effects of CDR1L mutations indicate that this region affects only the affinity but not the fine specificity of 2C10.

Animals↗

PubMed2000

Prednisolone plus albuterol versus albuterol alone in mild to moderate bronchiolitis.

To evaluate combination therapy of mild to moderate bronchiolitis with bronchiodilators and corticosteroids, we treated 51 young children with first-time wheezing and symptoms of respiratory tract infection with albuterol plus either prednisolone or placebo for 5 days. Disease severity was scored on days 0, 2, 3, and 6. On day 2, prednisolone resulted in significantly lower scores (2.7 +/- 1.4 vs. 4.0 +/- 1.5 in all patients evaluated, p < 0.05) than placebo, whereas there was no detectable difference on day 6, suggesting that addition of prednisolone to albuterol transiently accelerates recovery from bronchiolitis. The clinical significance of this effect needs to be evaluated in further studies.

Albuterol↗

PubMed1998

The structural basis for DNA binding by an anti-DNA autoantibody.

We have used single and multiple site-directed mutagenesis, and molecular modeling, to identify critical residues in the DNA binding site of MAb 2C10, an IgG anti-dsDNA autoantibody from an MRL/lpr lupus mouse. Simultaneous replacement of four Arg residues in the CDR3H abolished binding activity. With one exception, replacement of any one of these Arg residues reduced the activity to 20-50% of the unmutated scFv activity. Arg to Asp replacements had a slightly greater effect than Arg to Ala replacements. In the one exceptional case, replacement of Arg99 with Ala actually increased DNA binding five-fold and replacement by Asp had little effect. Mutation of Phe32 and Asn35 to A1a in CDRIH decreased DNA binding, whereas replacement of Arg31 with A1a had negligible effect. Ala substitution of any one of a cluster of Asp residues in CDR1L increased DNA binding three to six-fold, confirming previous findings that the L-chain of MAb 2C10 is not favorable for DNA binding. The L-chain does participate in shaping the selectivity of antigen binding, and mutation of CDR3L residue Asp92 or Asn93 caused a decrease in DNA binding activity. Directed mutagenesis, consistent with a molecular model, indicates that: several CDR amino acids contribute to DNA binding, without one residue dominating; both VH and VL CDR3 domains contribute to specificity of binding whereas the CDR1L hinders DNA binding. The results suggest a significant role for electrostatics in the interaction of DNA with MAb 2C10.

Amino Acid Sequence↗

PubMed1997

Back to a Future: One Man's AIDS Tale Shows How Quickly Epidemic Has Turned.

WHEN IT WAS CALLED 'GRID': One year ago today, I told my colleagues that I was dying of AIDS. I had been fighting it for years-the illness and the telling. I had been taking AZT, and briefly even a drug given to lepers. But now I was gaunt, tired and rather sure I was losing the battle. I gave my boss an obituary I had written-I'm a features editor on Page One of The Wall Street Journal, so I certainly didn't want anybody else writing it-sent a note to my boss's boss and started saying my goodbyes. Last week, my doctor, Jerome E. Groopman, noticed that I am getting fat and said it wouldn't be a bad idea if I went on a modest diet. At age 53, I am going to the gym again. I need to buy some new clothes. I am planning to one day retire with my partner of 28 years, who is HIV-negative. What has happened in the past year, at least for me, is a miracle that couldn't have taken place at any other moment. The year 1996 is when everything changed, and very quickly, for people with AIDS. I have been grappling with this disease for nearly a decade and a half, almost since the beginning, when it was called Gay Related Immune Deficiency, or GRID. I've outlived friends and peers, and now I find myself in the unusual position of telling people how I've survived this scourge, something I never thought would happen. My condition could change for the worse tomorrow. But today I feel well again. Thanks to the arrival of the new drugs called protease inhibitors, I am probably more likely to be hit by a truck than to die of AIDS. In coming alive again, I've learned the value of a good doctor and good friends-and the importance of being honest with yourself, your co-workers and the people you love. My battle with AIDS, I'm certain, began in December 1982, at a bathhouse in Manhattan's East Village during a sexual encounter with a man whose name I didn't catch. Like other gay men, I had kept up with newspaper reports, beginning with a July 3, 1981, New York Times story with the fateful headline: "Rare Cancer Seen in 41 Homosexuals." Nevertheless, going to the baths was a big part of gay culture back then, and here I was. Old habits die hard. At the time, the federal Centers for Disease Control and medical authorities were saying little about this being an infectious disease. Indeed, they at first thought it probably wasn't. But it was pretty clear that GRID was caused either by the cumulative effects of too much sex (so many men, so many germs) or too much butyl nitrite (poppers), a sexual stimulant sniffed from little vials available for $5 at newsstands. The third possibility was that it was a sex-borne plague.

Journal Article↗

PubMed1996

NMR analysis of interactions of a phosphatidylinositol 3'-kinase SH2 domain with phosphotyrosine peptides reveals interdependence of major binding sites.

The interactions of the N-terminal src homology (SH2) domain (N-SH2) of the 85 kDa subunit of phosphatidylinositol 3'-kinase (PI-3K) with phosphotyrosine (ptyr) and a series of ptyr-containing peptides have been examined by NMR spectroscopy. HSQC (heteronuclear single-quantum coherence) NMR spectra of 15N-labeled SH2 were used to evaluate its interactions with ptyr-containing ligands. The ability of ligands to cause chemical shift changes was compared to their potency as competitors in in vitro binding experiments using polyoma virus middle T antigen (MT). The results suggest the interdependence of SH2 binding elements. Chemical shifts of residues involved in the ptyr binding were altered by variations of the sequence of the bound peptide, suggesting that the ptyr fit can be adjusted by the peptide sequence. Perturbations of chemical shifts of residues coordinating the methionine three residues C-terminal to the ptyr (the +3 residue) were affected by substitution in the binding peptide at +1 and vice versa. Such results show synergistic interplay between regions of the SH2 binding residues C-terminal to the ptyr.

Amino Acid Sequence↗

PubMed1990

A continuously variable field of view surface coil.

A new type of surface coil is described which allows the user to continuously vary the size of the field of view. This utilizes a modified radiofrequency trombone for size adjustment that results in a stable frequency over a wide range of dimensions. Results show that the coil may be increased in area by as much as 60% while maintaining frequency stability to ca. 1 MHz at 63.5 MHz. Images of the human spine are presented to demonstrate the clinical utility of the new design.

Equipment Design↗

PubMed1987

Epicardial electrical activation analyzed via frequency-wavenumber spectrum estimation for the characterization of arrhythmiagenic states.

The application of a new signal processing methodology to the analysis of epicardial array ECG signals is presented as an alternative to isopotential or isochrones mapping by the use of a zero-delay wavenumber spectrum (ZDWS) estimation technique. The methodology "explains" the array data as the sum of modulated wideband (non-sinusoidal) propagating waves projected onto the array plane and provides an accurate estimate of their number and bearing. The slowness distribution of each of the waves is then obtained by estimating their temporal spectrum. In this experimental study the effects of localized noninfarcting reversible low flow ischemia, digoxin toxicity and verapamil reversal of digoxin toxicity are quantified via the ZDWS methodology and are compared with the information that can be extracted from isopotential mapping. It is demonstrated that the ZDWS methodology permits the epicardial electric activation to be decomposed into a number of quantification parameters which possess a hierarchical "tree" structure and therefore provide a means for an objective and robust characterization of the effects of agents which alter myocardial conduction and arrhythmia generation.

Animals↗

PubMedDate not supplied

Participants and nonparticipants of a mass media self-help smoking cessation program.

Differences in demographic and smoking-related characteristics were examined among an ethnically heterogeneous sample of participants and nonparticipants of a self-help media-enhanced smoking cessation program which had been aired in seven cities in California. Subjects had been prompted or not prompted to view the mass media smoking cessation broadcast as an experimental manipulation. Written self-help smoking cessation materials were provided as supplements in local Sunday newspapers. Predictors of viewing the smoking cessation broadcasts and reading the self-help manual were examined separately. Across conditions, more smokers read the manual than viewed the broadcast. Nonredundant predictors of viewing the smoking cessation broadcasts included being prompted to view the broadcast, and self-reports of a tendency to read or listen to self-help material. Nonredundant predictors of reading the self-help smoking cessation manual included city of residence, older age, being a heavier smoker, planning to quit in the next 3 months, and receiving a newspaper at home (in which the self-help material appeared). Apparently, a televised cessation program can reach smokers who vary widely in characteristics. Prompting viewing increases participation, but only to a limited extent. Distribution of a written cessation manual in Sunday newspapers tends to be utilized by a relatively larger population, but especially by those persons who are motivated to quit.

Adolescent↗