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Biomedical subjects

E Stevenson

Publications and source records attributed to E Stevenson.

At least 19 recordsLinked to original sources
PubMed2000

Interaction of protein kinase C and cAMP-dependent pathways in the phosphorylation of the Na,K-ATPase.

To test the hypothesis that there is cross-talk between the protein kinase C (PKC) and protein kinase A (PKA) pathways in the regulation of the Na,K-ATPase, we measured its phosphorylation in mammalian cell cultures. Phosphorylation of the PKC site, Ser-18, appeared to be due to the activation of the alpha isoform of the kinase. In NRK-52E and L6 cells, this phosphorylation was reduced by prior activation of a cAMP-dependent signaling pathway with forskolin. In principle this would be consistent with direct interaction between the two phosphorylation sites, but further investigation suggested a more indirect mechanism. First, phosphorylation of Ser-938, the PKA site, could not be detected despite the presence of active PKA. Second, there was a major reduction in the phosphorylation of unrelated phosphoproteins as a consequence of elevation of cAMP, suggesting generalized reduction of kinase activity or activation of phosphatase activity. In NRK-52E and L6, phosphorylation of the Na, K-ATPase at Ser-18 paralleled this global change. In C6 cells, in contrast, there was no cAMP effect on Na,K-ATPase phosphorylation at Ser-18 and no global cAMP effect on other phosphoproteins. The cross-talk is evidently mediated by events occurring at the cellular level.

Animals↗
PubMed2000

Internal energies of analyte ions generated from different matrix-assisted laser desorption/ionization matrices

A transfer of energy into the internal modes of the matrix and analyte is expected to occur during matrix-assisted laser desorption/ioniziation (MALDI) processes. Both the physical and thermochemical properties of the MALDI matrix used can influence the ion internal energy and analyte ion fragmentation. Here we report the effect of several MALDI matrices on the relative internal energy of the 2'-deoxyadenylyl-(3',5')-2'-deoxyguanosine (AG) anion. Relative internal energies were probed by low-energy collision-induced dissociation in a Fourier transform ion cyclotron resonance mass spectrometer. Sublimation temperatures of the matrices under study were also determined and found to lie between 409 and 455 K. Analyte ion internal and initial kinetic energies did not correlate with matrix sublimation temperatures. In contrast, a strong correlation between the relative internal energy of the analyte anions and the gas-phase basicity of the matrix anions was found. These results suggest that gas-phase proton transfer reactions play an important role in MALDI analyte ion formation and influence their internal energy and fragmentation behavior. Copyright 2000 John Wiley & Sons, Ltd.

Journal Article↗
PubMed1997

Impact of improved laboratory compliance on notification of genital Chlamydia trachomatis infection in Victoria.

BACKGROUND AND OBJECTIVES: Although regulations in Victoria require notification of chlamydia infection by both clinician and laboratory, review found many reports that were notified only by one source (i.e., were unmatched). GOALS: To identify problems with the notification system and to improve the quality of surveillance for this disease. STUDY DESIGN: All notified cases of chlamydia diagnosed in January or February 1995 were followed up by contacting diagnosing doctors. Identified noncompliant laboratories were asked to provide a list of all diagnoses for the period and institute ongoing reporting. Notification data were reviewed for timeliness and completeness. RESULTS: Clinicians never notified without laboratory confirmation. Soliciting laboratory reports increased total notifications by 30%, and there was a highly significant improvement in reporting by both clinicians and laboratories. Reasons for failure to notify by clinicians included an assumption by some clinicians that laboratories would notify and ignorance that notification was required. CONCLUSIONS: Notified cases generally are now accompanied by a laboratory report, and although nonnotification by clinicians continues, notification has improved. Further improvements in clinician notification may depend on doctors knowing that public health action results from reporting. An alternative to requiring doctors' time to be spent in duplicate notification would be to strengthen laboratory reporting and then check that adequate treatment and partner notification has occurred through contact with the diagnosing doctor.

Adult↗
PubMed1997

Methadone maintenance and hepatitis C virus infection among injecting drug users.

Harm reduction strategies for the prevention of transmission of human immunodeficiency virus (HIV) transmission among injecting drug users (IDUs) have been widely implemented in Australia and are seen to have been effective in preventing the spread of HIV. A major strategy has been increasing the availability of and accessibility to methadone maintenance therapy (MMT) programmes. We have reviewed the experience of a major MMT general practice with hepatitis C virus (HCV) infection from 1991 to 1995. Of 1741 individuals tested for HCV antibodies at least once 66.7% were positive. Of 73 IDUs who were initially seronegative and were retested at least once, 19 were subsequently seropositive. Seroconverters to HCV were younger than non-seroconverters, and were more likely to have evidence of previous hepatitis B infection. The overall HCV incidence rate was 22 cases per 100 person-years, and this did not differ between those on MMT programs (continuous or interrupted) between HCV tests and those not on MMT. These findings suggest that the role of MMT in the control of the spread of HCV infection among IDUs needs further assessment, and that control of the current epidemic of HCV infection among IDUs in Australia will be very difficult.

Adult↗
PubMed1994

Milk composition and lactation of beta-casein-deficient mice.

beta-Casein is a major protein component of milk and, in conjunction with the other caseins, it is assembled into micelles. The casein micelles determine many of the physical characteristics of milk, which are important for stability during storage and for milk-processing properties. There is evidence that suggests that beta-casein may also possess other, nonnutritional functions. To address the function of beta-casein, the mouse beta-casein gene was disrupted by gene targeting in embryonic stem cells. Homozygous beta-casein mutant mice are viable and fertile; females can lactate and successfully rear young. beta-Casein was expressed at a reduced level in heterozygotes and was completely absent from the milk of homozygous mutant mice. Despite the deficiency of beta-casein, casein micelles were assembled in heterozygous and homozygous mutants, albeit with reduced diameters. The absence of beta-casein expression was reflected in a reduced total protein concentration in milk, although this was partially compensated for by an increased concentration of other proteins. The growth of pups feeding on the milk of homozygous mutants was reduced relative to those feeding on the milk of wild-type mice. Various genetic manipulations of caseins have been proposed for the qualitative improvement of cow's milk composition. The results presented here demonstrate that beta-casein has no essential function and that the casein micelle is remarkably tolerant of changes in composition.

Animals↗
PubMed1994

Surveillance for sexually transmissible diseases in Victoria, 1983 to 1992.

Surveillance systems have been developed in Victoria to determine trends in sexually transmissible diseases (STDs). Notifications to the Health Department (including laboratory notification since May 1990) have been supplemented by data about strains of Neisseria gonorrhoeae and cultures for Chlamydia trachomatis processed by the Microbiological Diagnostic Unit, enhanced laboratory surveillance of syphilis, and data on genital herpes and genital warts from the Melbourne Sexual Health Centre. During the period under review the incidence of gonorrhoea declined, rapidly at first, and then more slowly. For women, this trend has continued, while gonorrhoea acquired abroad by men has become relatively more important. Since 1988, gonorrhoea in homosexual men has increased, and rectal isolates have increased concurrently, raising concerns about HIV risk behaviour. Cases of syphilis are likely to be ascertained through STD, antenatal and refugee screening, rather than because of symptoms or contact tracing. Chlamydia is a the most common notifiable STD, despite underreporting and underdiagnosis. In 1991, 832 cases were notified, increasing to 1377 in 1992. In 1992, of the 73 cases (65 per cent of notifications) where the doctor identified a risk, 15 per cent was attributed to homosexual contact, and 27.4 per cent to heterosexual exposure. Limitations in the data include inadequate standard case definitions for many STDs, changes in the statutory requirement for notifications in 1990, underreporting, changes in diagnostic and screening patterns, and lack of detailed demographic data. Education of general practitioners is needed to improve diagnosis and notification of chlamydia.

Adult↗
PubMed1993

The epidemiology of HIV-1 infection in Victoria. The Victorian Collaborative Group on HIV and AIDS Surveillance (VCGHAS).

OBJECTIVE: To describe the epidemiology of infection with the human immunodeficiency virus type 1 (HIV-1) in Victoria from 1980 to 1991. DESIGN: Data on HIV-1 infection in Victoria, obtained through routine laboratory-based surveillance, were entered in a database. Missing information was sought by contacting the referring doctor where possible. SETTING: In Victoria, the acquired immunodeficiency syndrome (AIDS) is notifiable to Health Department Victoria by diagnosing doctors, and laboratories are required to notify new diagnoses of HIV-1 infection, without identifiers. All confirmatory testing for HIV-1 has taken place at the State HIV Reference Laboratory at Fairfield Hospital. MAIN OUTCOME MEASURES: Diagnoses of HIV-1 infection, as confirmed at the State HIV Reference Laboratory by western blot immunoassay, and notifications of AIDS to Health Department Victoria. RESULTS: Over six years the annual number of diagnoses of HIV-1 infection in Victoria remained constant despite a substantial increase in the number of tests performed. To the end of 1991, 2679 people had been diagnosed with HIV-1 infection, 686 of whom had developed AIDS. Information on exposure was available for 2379 (88.8%). Homosexual and bisexual men made up 75.5% (85.0% of those for whom exposure had been ascertained); 3.4% were female or heterosexual male injecting drug users; and 3.7% were heterosexuals with no history of injecting drug use. The latter two groups contributed 2.0% in 1985 to the proportion of all new diagnoses for which exposure was known, and 14.3% in 1991; for recipients of contaminated blood or blood products before 1985 this proportion fell from 12.4% to 1.0%. The cumulative incidence of HIV-1 diagnoses was highest in the age group 25-29 years, and 20% of all HIV-1 infected people were under 25 at the time of diagnosis. In 1991, 81 of the 311 people who had been diagnosed with HIV-1 infection had had previous negative or indeterminate results of tests; half of these had acquired infection in the previous year. CONCLUSION: Most HIV-1 infections in Victoria have been acquired through male homosexual contact, with a small but increasing proportion of diagnoses occurring in heterosexuals. Laboratory-based surveillance of voluntary testing, despite its limitations, has provided valuable information on the extent of the HIV-1 epidemic in Victoria. Surveillance of all HIV-1 test results and of seroconverters now supplements routine surveillance of HIV diagnoses and will ensure a more accurate picture of the epidemic in coming years.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Reassessment of lead exposure in New Jersey using GIS technology.

In order to prevent children's exposure to lead, a variety of sources must be controlled. The New Jersey Department of Environmental Protection and Energy (NJDEPE) is using its Geographic Information System to identify areas within Newark, East Orange, and Irvington, New Jersey, where there may be greater environmental exposure to lead. Sensitive populations are identified through the U.S. Bureau of the Census information. Blood screening data provided by the New Jersey Department of Health (NJDOH) provide reported patterns of elevated blood lead in the study area. Comparisons of these spatial patterns will assist the NJDEPE in its soil sampling activities and lead exposure research, will provide information for public education, and will provide valuable information on sections of the study area where further screening and public education may be needed.

Air Pollutants↗
PubMed1991

Advocacy. Necessary to achieve cancer control goals.

As resources become increasingly scarce, oncology professionals and consumers of oncology services are increasingly engaging in advocacy efforts to achieve goals in cancer control. Effective advocacy includes both legislative and direct educational efforts.

Aged↗
PubMed1991

Patient education: history, development, and current directions of the American Cancer Society and the National Cancer Institute.

With their unique perspectives in the identification, design, promotion, and evaluation of cancer patient education programs and services, the National Cancer Institute and the American Cancer Society have the abilities to meet a wide variety of cancer patient education needs. With federal support and connections to national organizations and the comprehensive and clinical cancer center networks, the National Cancer Institute has access to nationwide experts in medical care and the resources to develop, design, and promote quality, state-of-the-art education programs. The American Cancer Society, with its strong volunteer community base, can pull together local expertise and collaborate with local organizations to meet the special needs of local population groups. In addition, the American Cancer Society volunteer committees have the flexibility to individualize programming and resources to answer specific patient/family education problems. As the number of people affected by cancer continues to raise, and as organizations realize the need to maximize their resources with collaborative efforts, the National Cancer Institute and the American Cancer Society are challenged to focus their energies on the patient education initiatives that build upon and combine their unique strengths.

American Cancer Society↗
PubMed1986

Agitated depression, alprazolam, and panic anxiety.

Three patients with agitated depression showed rapid and persistent response to alprazolam. At least two of the patients had prior panic disorder. Several lines of evidence suggest that agitated depression may sometimes be caused by unremitting panic anxiety.

Adult↗
PubMed1968

The carnitine-independent oxidation of palmitate plus malate by moth flight-muscle mitochondria.

Mitochondria isolated from the flight muscle of the southern armyworm moth, Prodenia eridania, can oxidize palmitate+malate very rapidly. Added carnitine had no effect on the rate of oxidation of palmitate+malate by flight-muscle mitochondria from two species of moths, and carnitine palmitoyltransferase could not be detected in Prodenia by direct assay. Palmitoylcarnitine was not oxidized by moth mitochondria, but when added in low concentrations it reversibly suppressed the oxidation of palmitate. The evidence indicates that carnitine is not involved in fatty acid degradation by moth flight muscle. Added thiols, including CoA, also suppressed palmitate+malate oxidation. An ATP-dependent fatty acyl-CoA synthetase is present in moth mitochondria.

Animals↗