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S Harrington

Publications and source records attributed to S Harrington.

At least 19 recordsLinked to original sources
PubMed2002

Cereal genes similar to Snf2 define a new subfamily that includes human and mouse genes.

Genes from the SNF2 family play important roles in transcriptional regulation, maintenance of chromosome integrity and DNA repair. This study describes the molecular cloning and characterization of cereal genes from this family. The predicted proteins exhibit a novel C-terminal domain that defines a new subfamily designated SNF2P that includes human and mouse proteins. Comparison between genomic and cDNA sequences showed that cereal Snf2P genes consisted of 17 exons, including one only 8 bp long. Two barley alleles differed by the presence of a 7.7-kb non-LTR retrotransposon in intron 6. An alternative annotation of the orthologous Arabidopsis gene would improve its similarity with the other members of the subfamily. Intron 2 was not spliced out in approximately half of the rice Snf2P mRNAs present in leaves, resulting in a premature stop codon. Transcripts from the barley and wheat Snf2P genes were found in apexes, leaves, sheaths, roots and spikes. The Snf2P genes exist as single copies on wheat chromosome arm 5A(m)L and in the colinear regions on barley chromosome arm 4HL and rice chromosome 3. High-density genetic mapping and RT-PCR suggest that Snf2P is not a candidate gene for the tightly linked vernalization gene Vrn2.

Adenosine Triphosphatases↗
PubMed2002

Estrogen status correlates with the calcium content of coronary atherosclerotic plaques in women.

BACKGROUND: Coronary artery calcium, a radiographic marker for atherosclerosis and a predictor of coronary heart disease (CHD), is less extensive in women than in men of the same age. The role of estrogen in the pathogenesis of coronary artery calcification is unknown. We examined the association of estrogen status with extent of calcification and atherosclerotic plaque in coronary arteries of deceased women. METHODS: Coronary arteries were obtained at autopsy from 56 white women age 18--98 yr, 46 postmenopausal and 10 premenopausal. Exclusion criteria included patients with coronary stents, coronary artery bypass surgery, and medical-legal cases. Medical records were reviewed for demographics, CHD risk factors, menstrual status, and use of estrogen replacement therapy. Contact microradiography of coronary arteries assessed true calcium content and atherosclerotic plaque area was analyzed histologically. RESULTS: The coronary arteries from estrogen-treated postmenopausal women had lower mean coronary calcium content (P = 0.002), mean plaque area (P < 0.0001), and calcium-to-plaque area ratio (P = 0.004) than those from untreated menopausal women. Estrogen status, age, diabetes, and hypertension predicted calcium and plaque area by univariate analysis. After controlling for these CHD risk factors, estrogen status remained an independent predictor of both calcium (P = 0.014) and plaque area (P = 0.001) in all women. Mean calcium area (P < 0.05) but not plaque area (P = 0.44) was significantly greater in women treated with estrogen replacement therapy than in premenopausal women. Coronary calcium (P < 0.007) and plaque area (P < 0.03) varied significantly with age in untreated postmenopausal women, but not in the estrogen-treated or premenopausal women (P = 0.33). CONCLUSIONS: Estrogen status is associated with coronary calcium and plaque area independent of age and CHD risk factors. Estrogen may modulate the calcium content of atherosclerotic plaques, as well as plaque area and may slow the progression of atherosclerosis in women.

Adult↗
PubMed2001

Transmission of Mycobacterium tuberculosis through casual contact with an infectious case.

BACKGROUND: An ongoing restriction fragment length polymorphism study of Mycobacterium tuberculosis isolates from tuberculosis cases showed an identical 12-band IS6110 pattern unique to 3 unrelated patients (Patients A-C) diagnosed as having tuberculosis within a 9-month period. METHODS: In an attempt to identify epidemiologic links between the 3 patients, we performed site visits to the retail business work site of patient A and conducted detailed interviews with all 3 patients and their contacts. RESULTS: Patient B had visited patient A's work site 3 times during patient A's infectious period, spending no more than 15 minutes each time. Patient C visited patient A's work site on 6 to 10 occasions during this period for no more than 45 minutes at any one time. There were no other epidemiologic links between these 3 cases other than the contact at the store. Contact investigation identified 4 tuberculin skin test conversions among 8 (50%) of patient A's coworkers, 6 positive tests among 15 household contacts (40%), and 8 positive tests among 16 identified customers who were casual contacts (50%). Patient B and patient C were most likely infected by patient A during one of their brief visits to patient A's work site. CONCLUSIONS: These data demonstrate that some tuberculosis is spread through casual contact not normally pursued in traditional contact investigations and that, in certain situations, M tuberculosis can be transmitted despite minimal duration of exposure. In addition, this outbreak emphasizes the importance of DNA fingerprinting data for identifying unusual transmission in unexpected settings.

Adult↗
PubMed2001

Binding of human immunodeficiency virus type 1 gp120 to CXCR4 induces mitochondrial transmembrane depolarization and cytochrome c-mediated apoptosis independently of Fas signaling.

Apoptosis of CD4(+) T lymphocytes, induced by contact between human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (gp120) and its receptors, could contribute to the cell depletion observed in HIV-infected individuals. CXCR4 appears to play an important role in gp120-induced cell death, but the mechanisms involved in this apoptotic process remain poorly understood. To get insight into the signal transduction pathways connecting CXCR4 to apoptosis following gp120 binding, we used different cell lines expressing wild-type CXCR4 and a truncated form of CD4 that binds gp120 but lacks the ability to transduce signals. The present study demonstrates that (i) the interaction of cell-associated gp120 with CXCR4-expressing target cells triggers a rapid dissipation of the mitochondrial transmembrane potential resulting in the cytosolic release of cytochrome c from the mitochondria to cytosol, concurrent with activation of caspase-9 and -3; (ii) this apoptotic process is independent of Fas signaling; and (iii) cooperation with a CD4 signal is not required. In addition, following coculture with cells expressing gp120, a Fas-independent apoptosis involving mitochondria and caspase activation is also observed in primary umbilical cord blood CD4(+) T lymphocytes expressing high levels of CXCR4. Thus, this gp120-mediated apoptotic pathway may contribute to CD4(+) T-cell depletion in AIDS.

Apoptosis↗
PubMed2000

Thermal conductance and wettability of xenon on resorcinol-formaldehyde aerogels.

We have performed thermal conductivity and adsorption isotherm measurements to investigate the system formed by Xe adsorbed on resorcinol-formaldehyde (RF) aerogel. Below 80 K, the thermal conductivity of the Xe/RF-aerogel system is essentially identical to that of the bare RF aerogel; however, above this temperature the thermal conductivity of the system increases significantly above that of the bare aerogel. Adsorption isotherm measurements indicate that Xe incompletely wets the RF aerogel below Xe's bulk triple point temperature. The thickness of the Xe film that forms on the RF aerogel decreases with decreasing temperature. By 80 K the total amount of Xe present on the aerogel in equilibrium with the saturated vapor pressure is less than the amount needed to form about 1.5 atomic layers of Xe on the substrate. We attribute the observed changes in the thermal conductivity of the Xe/aerogel system to changes in the wettability of the aerogel by the Xe film.

Journal Article↗
PubMed2000

General practice. Hit and miss.

A survey of practices in a primary care group in outer London found many were poorly prepared for implementing clinical governance. More than half consisted of one doctor, and a quarter of practices were not computerised. Only a third had a staff development plan. Only a minority had sought patients' views about new services. Although three-quarters of practices were using guidelines, few had been trained in the use of protocols and guidelines.

Clinical Audit↗
PubMed2000

A multi-state outbreak of tuberculosis among members of a highly mobile social network: implications for tuberculosis elimination.

SETTING: Baltimore, Maryland. OBJECTIVE: To describe a tuberculosis (TB) outbreak among a highly mobile population and the efforts required to control it. DESIGN: Epidemiologic outbreak investigation. RESULTS: Between June 1998 and January 2000, 20 TB outbreak cases were identified, of which 18 were culture-confirmed. Seventeen isolates of Mycobacterium tuberculosis had an identical 11-band DNA fingerprint; another isolate had one additional band and was considered a match. Two cases were diagnosed in New York City; another patient lived primarily in Atlanta, but was diagnosed in Baltimore. Persons in the outbreak were predominantly young (median age 24 years), black, male, infected with the human immunodeficiency virus (HIV), and gay, transvestite or transsexual. Activities common among many TB cases included attending two nightclubs, membership in one of three social 'Houses', attending balls or pageants in East Coast cities, marijuana use, and prostitution. Community outreach, extended contact tracing, DNA fingerprinting, directly-observed therapy, and expanded use of preventive therapy were utilized to assess and control the outbreak. During the outbreak period the Baltimore City TB rate declined by 10%. However, additional public health personnel were required to control the outbreak, resulting in a 17% increase in TB clinic staff. CONCLUSION: As TB rates decline, remaining cases are likely to occur in difficult-to-reach populations. Increased resources per case of TB treated will be required to eliminate TB.

AIDS-Related Opportunistic Infections↗
PubMed1999

Effects of physisorption of xenon on the thermal conductivity of resorcinol-formaldehyde aerogels.

The effects of adsorption of xenon to the thermal conductivity of a resorcinol-formaldehyde aerogel were investigated in a temperature range from 20 to 120 K. It was found that at temperatures below 75 K, the adsorbed xenon has little effect on the thermal conductivity. Rapid rises of the thermal conductivity develop at temperatures around 75-80 K with magnitudes roughly proportional to the amount of xenon adsorbed. The effect is explained as due to adsorbed xenon atoms that enhance the neck connection between aerogel particles.

Journal Article↗
PubMed1998

Molecular and geographic patterns of tuberculosis transmission after 15 years of directly observed therapy.

CONTEXT: Recent studies suggest that one third of tuberculosis cases in urban areas result from recent transmission. Improved tuberculosis control measures such as uniform implementation of directly observed therapy might reduce the proportion of cases resulting from recent transmission. OBJECTIVE: To determine patterns of tuberculosis transmission in Baltimore, Md, after 15 years of community-based directly observed therapy. DESIGN: A 30-month (January 1994-June 1996), prospective, city-wide study of all cases of tuberculosis using traditional contact investigations, geographic information systems data, and molecular epidemiologic comparison of Mycobacterium tuberculosis isolates with 2 DNA probes. PATIENTS: One hundred eighty-two patients with culture-positive tuberculosis. MAIN OUTCOME MEASURES: Proportion of disease defined as recently transmitted based on epidemiologic linkage by traditional contact tracing and molecular linkage by DNA fingerprint analysis of isolates; geographic foci of transmission based on linkage of residences by geographic information systems data. RESULTS: Of the 182 patients who had isolates of M tuberculosis available, 84 (46%) showed molecular clustering with 58 (32%) defined as being recently transmitted. Only 20 (24%) of 84 cases with clustered DNA fingerprints had epidemiologic evidence of recent contact. Geographic analysis showed significant spatial aggregation of the 20 clustered cases with epidemiologic links (P<.001), occurring in areas of low socioeconomic status and high drug use. The 64 cases with clustered DNA fingerprints but without epidemiologic links shared common risk factors and demographic features with the 20 clustered patients who did have epidemiologic links. CONCLUSIONS: Recently transmitted tuberculosis accounts for a high proportion of tuberculosis cases in Baltimore. Recently transmitted cases occur in geographically distinct areas of Baltimore, and location-based control efforts may be more effective than contact tracing for the early identification of cases.

Adult↗
PubMed1997

Transmission of Mycobacterium tuberculosis by a fiberoptic bronchoscope. Identification by DNA fingerprinting.

CONTEXT: An ongoing restriction fragment length polymorphism (RFLP) study of Mycobacterium tuberculosis isolates from tuberculosis (TB) cases revealed an identical 10-banded IS6110 RFLP pattern unique to 2 patients diagnosed as having TB 6 months apart. Their only identifiable link was care at the same hospital. OBJECTIVE: To determine if nosocomial transmission had occurred. DESIGN: Traditional and molecular epidemiologic investigation. MEASUREMENTS: We reviewed medical charts and bronchoscopic records, examined hospital locations visited by both patients, evaluated hospital ventilation systems, and observed cleaning and disinfection of bronchoscopes. RESULTS: A patient with cough, hoarseness, and fever underwent bronchoscopy and was diagnosed as having TB. A second patient with a mediastinal mass underwent bronchoscopy 2 days later and was diagnosed as having small cell carcinoma. Following 6 months of chemotherapy and radiation therapy, the second patient developed fever and an infiltrate of the right upper lobe of the lung. Bronchoscopic washings revealed acid-fast bacilli and were culture positive for M tuberculosis. Both patients had undergone bronchoscopy with the same instrument in the same operating room with no intervening bronchoscopies. Bronchoscope cleaning and disinfection procedures were inconsistent with national guidelines. CONCLUSIONS: A contaminated bronchoscope was the most likely source of M tuberculosis transmission between these 2 patients. The RFLP analysis of M tuberculosis isolates was responsible for detecting this nosocomial source of transmission and led to the implementation of public health measures to prevent further spread of infection and disease. This study emphasizes the need for continued vigilance in endoscope cleaning techniques.

Adult↗
PubMed1996

Resistance patterns of Streptococcus pneumoniae and Haemophilus influenzae isolates recovered in Egypt from children with pneumonia. The Antimicrobial Resistance Surveillance Study Group.

Treatment of childhood pneumonia in developing countries requires knowledge of susceptibility patterns for Streptococcus pneumoniae and Haemophilus influenzae. Between October 1991 and April 1993, a surveillance survey of antimicrobial resistance was performed at two fever hospitals in Egypt; nasopharyngeal swab and blood specimens obtained from 1,635 children with pneumonia were cultured for these organisms. Susceptibility testing of these organisms was performed. At least one of these organisms was isolated from nasopharyngeal swab specimens from 73% of the children; 3.7% of blood cultures were positive. For S. pneumoniae strains, 70.9% of nasopharyngeal isolates were calculated to be susceptible to penicillin vs. 77.6% of blood isolates; the percentages of isolates susceptible to co-trimoxazole were 73.0% and 75.0%, respectively. For H. influenzae strains, 93.0% of nasopharyngeal isolates were calculated to be susceptible to ampicillin vs. 100% of blood isolates; the percentages of isolates susceptible to co-trimoxazole were 84.9% and 100%, respectively. Although most S. pneumoniae and H. influenzae strains associated with childhood pneumonia in Cairo were susceptible to penicillins and co-trimoxazole, antimicrobial resistance did not occur.

Ampicillin↗
PubMed1996

A hypervariable region in VP1 of chicken infectious anemia virus mediates rate of spread and cell tropism in tissue culture.

Chicken infectious anemia virus (CIAV) is a unique infectious agent with an amino acid composition that has been found to be remarkably conserved even in isolates from different parts of the world. We have characterized field isolates of CIAV which vary significantly in terms of their abilities to replicate in culture, demonstrating a biological difference between isolates. Two sublines of MDCC-MSB1 cells that differ in their abilities to support CIAV were identified. In the MSB1(S) subline the CIA-1 isolate of CIAV was found to be less cytopathogenic than the prototype Cux-1(C) isolate; the MSB1(L) subline, which supports Cux-1(C) replication, was found to be nonpermissive for CIA-1. Alignments of the VP1 sequences of previously examined isolates with those of the field isolates CIA-1 and L-028 and the culture-adapted ConnB isolate revealed a previously unreported hypervariable region spanning amino acid positions 139 to 151. Chimeras of Cux-1(C) and CIA-1 were constructed to examine the potential for this region to affect cytopathogenicity. Transfer of a 316-bp region of Cux-1(C) open reading frame 1 into CIA-1 produced a virus with a cytopathogenic profile typical of Cux-1(C), indicating that one or both of the amino acid differences at positions 139 and 144 affect the rate of replication or the spread of infection. Transfection experiments with additional chimeras indicated that the inability of CIA-1 to replicate in MSB1(L) cells is mediated by a larger region of the genome which contains the hypervariable region in addition to upstream amino acid differences. Analysis of chimeras excluding the entire region of open reading frame 1 suggested the presence of a secondary mediator in the progression of infection in culture that was localized to a region containing a single nucleotide difference which results in amino acid differences in both VP2 (V-153) and the nuclear localization signal of VP3 (C-118). Immunofluorescence assays indicated an increased cytoplasmic distribution of VP3 and a general lack of VP3-associated apoptotic bodies in infections of CIA-1 and chimeras containing V-153 or C-118, as opposed to a primarily nuclear distribution and association with well-formed apoptotic bodies in Cux-1(C)-infected cells.

Amino Acid Sequence↗
PubMed1992

Early detection of antibody to human immunodeficiency virus type 1 by using an antigen conjugate immunoassay correlates with the presence of immunoglobulin M antibody.

Sequential plasma samples obtained from 16 individuals who seroconverted were tested for the presence of antibody to human immunodeficiency virus type 1 (HIV-1) by an antigen conjugate enzyme immunoassay (EIA) and a conventional antibody conjugate assay. In 11 of these individuals, the antigen conjugate assay detected antibody to HIV-1 2 to 11 days (mean, 5.5 days) earlier than the antibody conjugate assay. In 11 individuals, HIV-1 p24 antigen was detected a median of 6.5 days (range, 3 to 14 days) prior to positivity by the antigen conjugate EIA. Using class-specific probes, we determined the profiles of immunoglobulin M (IgM), IgG, and IgA antibodies for each individual and correlated these profiles with the EIA signals from both assays. In general, the appearance of IgM exhibited a peak at about 1 week postseroconversion, which was followed by gradually declining levels. Absorbance levels for IgG antibody, however, rose steadily and reached a plateau after 3 to 5 weeks. The levels of IgA were generally low and variable. In contrast to the progressive increase in EIA absorbance observed by the antibody conjugate assay, the antigen conjugate assay displayed a rapid early rise in absorbance which generally coincided with the transient expression of IgM antibody. The subsequent gradual increase coincided with rising levels of IgG. Because the configuration of the antigen conjugate EIA allows for an increased sensitivity for IgM compared with that for other classes of immunoglobulins, these results suggest that earlier detection of antibody to HIV-1 is due to the detection of IgM antibody during the early phase of seroconversion.

Biomarkers↗
PubMed1992

Screening and genetic counselling for relatives of patients with breast cancer in a family cancer clinic.

Family history is the major risk factor in the aetiology of breast cancer. Breast screening is currently available to women from the age of 50 to 64 through the National Breast Screening Programme. There is, however, an equivalent risk of developing breast cancer below 50 for first degree relatives of women diagnosed with breast cancer premenopausally. We have estimated the risk of breast cancer for relatives of women affected at different ages and used these to establish a family cancer clinic offering breast screening based on individual risk. In three years we have seen 851 patients. Compliance for annual radiology was in excess of 83% over this period and of five cancers detected one had a lump at presentation, two developed interval breast lumps, and two were asymptomatic.

Adult↗