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Biomedical subjects

L McAlpine

Publications and source records attributed to L McAlpine.

At least 19 recordsLinked to original sources
PubMed1998

The acute effects of prostacyclin on pulmonary hemodynamics in patients with pulmonary hypertension secondary to systemic sclerosis.

OBJECTIVE: To determine whether patients with isolated pulmonary hypertension secondary to systemic sclerosis (SSc) have a pulmonary vasculature that is responsive to treatment with vasodilators. METHODS: Seven SSc patients with pulmonary hypertension underwent right heart catheterization. Pulmonary pressures and cardiac output were measured before and during a systemic intravenous infusion of prostacyclin. RESULTS: Both pulmonary arterial mean pressure and pulmonary vascular resistance decreased significantly with prostacyclin infusion (median decrease 11% and 32%, respectively), with a concomitant increase in cardiac output (median increase 26%). No adverse hemodynamic effects were noted during the infusion. CONCLUSION: Vasospasm contributes to the pulmonary hypertension complicating SSc. This feature may be amenable to treatment with vasodilators.

Adult↗
PubMed1998

CAVH. Principles and practical applications.

While being one of the earliest and simplest forms of continuous renal replacement therapy, CAVH provided a means for treating the azotemic, hypervolemic critically ill patient. In order to deliver care for the patient undergoing CAVH, critical care nurses must demonstrate an understanding of the physiologic mechanism of action as well as knowledge and technical competency regarding circuit management. Multidisciplinary standards are imperative for successful implementation of any CRRT program. Any institution wishing to adopt certain CAVH standards provided within this article should review each particular standard to determine if it meets the specific needs of their unique patient population.

Acute Kidney Injury↗
PubMed1995

Evaluation of a combined HIV-1/2 and HTLV-I/II assay for screening blood donors.

A combined immunoassay for the simultaneous detection of antibodies to HIV-1/2 and HTLV-I/II (Bioelisa, Launch Diagnostics) has been evaluated to determine its suitability for routine use in blood screening. 84,222 donations were tested from 76,452 donors. One HIV- and 1 HTLV-1-positive donor were identified. The specificity was 99.7%, and the sensitivity for anti-HIV-1, anti-HIV-2, and anti-HTLV-1 on 173 positive sera was 100%; 2 of 25 anti-HTLV-II-positive sera were non-reactive. Although the specificity of the assay is not as high as that of HIV-1/2 kits currently in UK transfusion use, the information gained about donor HTLV antibody status makes the test an attractive alternative to them.

Blood Donors↗
PubMed1995

False negative results in enzyme linked immunosorbent assays using synthetic HIV antigens.

The sensitivity of 12 commonly used anti-HIV-1/HIV-2 enzyme immunoassays was evaluated. The assays, each of which utilises at least one synthetic HIV antigen, were tested against a panel of 1092 specimens previously designated anti-HIV positive. In a total of 13 104 tests there were eight false negative results attributable to assay insensitivity: three were on two serum samples collected close to seroconverison and five on another serum specimen. These eight false negative results arose in seven different assays. Five other false results were attributable to technical error. This false negativity rate indicates that all of the assays performed adequately and leads to an estimate of one false negative result in a thousand tests in routine diagnostic practice. Because of the antigenic heterogeneity of HIV strains, similar evaluations would be required in several regions before this satisfactory level of sensitivity in anti-HIV assays incorporating synthetic antigens could be said to be universal.

Enzyme-Linked Immunosorbent Assay↗
PubMed1994

Thirteen current anti-HIV-1/HIV-2 enzyme immunoassays: how accurate are they?

The sensitivity and specificity of 13 current anti-HIV-1/HIV-2 screening enzyme immunoassays (EIA) for the detection of anti-HIV in human serum or plasma were investigated by testing against a panel of 454 well-characterised serum or plasma specimens. The panel included specimens confirmed to contain anti-HIV-1 (n = 96), anti-HIV-2 (n = 26), or low levels of anti-HIV (n = 44) as well as specimens collected during HIV-1 seroconversion (n = 73). Specimens from unselected blood donors (n = 80) and samples from patients with a range of pathological conditions (n = 135) were also included. Observed sensitivities ranged from 96.9% (Biochrom, UBI, and Vironostika) to 100% (Biotest, Cambridge Biotech, IAF Biochem, Ortho, and Vidas). For the seroconversion specimens, Biotest, Cambridge Biotech, Ortho, and Vidas were most sensitive. Observed specificities ranged from 89.9% (UBI) to 100% (Biochrom and Ortho). One assay (Ortho HIV 1+2 EIA) achieved maximum sensitivity and specificity, and was one of four assays to detect anti-HIV-1 early in seroconversion. The accuracy of several of the other EIAs was also quite adequate, so additional factors such as convenience and cost can be considered when choosing an assay from the group evaluated.

Evaluation Studies as Topic↗
PubMed1993

Prevalence of antibodies to human T cell leukaemia/lymphoma virus in blood donors in north London.

OBJECTIVES: To determine the prevalence of antibodies to the human T cell leukaemia/lymphoma viruses (HTLV-I and HTLV-II) in blood donors in north London in order to assess the economic impact and the logistic effects that routine screening would have on the blood supply. DESIGN: All donations collected by the north London blood transfusion centre between January 1991 and June 1991 were screened for antibodies to HTLV-I and HTLV-II by modified, improved Fujirebio gel particle agglutination test. Positive samples were titrated and retested as necessary. SUBJECTS: 96,720 unpaid volunteers, who gave 105,730 consecutive donations of blood and plasma. SETTING: North London blood transfusion centre. MAIN OUTCOME MEASURE: Observed numbers of donors confirmed to be seropositive for HTLV by reference laboratories. RESULTS: Of 2622 (2.5%) initially reactive samples, 414 (0.4% of all samples) gave a titre of > or = 1 in 16 on the modified agglutination test. Thirty five of the 414 serum samples yielded positive results on one of two enzyme linked immunosorbent assays (ELISA (Cambridge Biotech and Abbot)), and none of these results were confirmed by either reference laboratory. Five samples yielded positive results on both ELISAs and all five of these were confirmed to contain antibodies to HTLV. One of the five contained antibodies to HTLV-II and the others antibodies to HTLV-I. Four seropositive donors were white women whose only risk factor for infection was sexual contact. The fifth (positive for antibodies to HTLV-II) was an Anglo-Caribbean man who admitted to previous misuse of intravenous drugs. CONCLUSION: The prevalence of antibodies to HTLV in blood donors in north London was one in 19,344 (0.005%). Up to 100 donors a year might be identified in the United Kingdom as being infected with HTLV, although prevalence in different regions may vary considerably.

Adult↗
PubMed1993

Influence of cigarette smoking on the efficacy of radiation therapy in head and neck cancer.

BACKGROUND: Smoking is a risk factor for several cancers and may also limit the efficacy of treatment. In this study, we evaluated the influence of cigarette smoking during radiation therapy on the efficacy of treatment in patients with head and neck cancer. METHODS: Using a questionnaire, we obtained information on smoking behavior at base line and weekly during therapy in 115 patients with head and neck cancer who were treated with radiation therapy with or without fluorouracil. The side effects of therapy were evaluated weekly, and response was assessed 13 weeks after treatment was completed. The main outcomes measured were treatment response and survival. RESULTS: The prognostic variables were similar among the patients who smoked and those who did not smoke during treatment. The 53 patients who continued to smoke during radiation therapy had a lower rate of complete response (45 percent vs. 74 percent, P = 0.008) and poorer two-year survival (39 percent vs. 66 percent, P = 0.005) than the 62 patients who did not smoke or who had quit before treatment. Among the nonsmoking patients, mortality was influenced by the length of time between quitting and treatment, with a risk reduction (relative to that for patients who continued to smoke) of 40 percent for patients who had quit less than 12 weeks before diagnosis and of 70 percent for patients who had quit more than 1 year before diagnosis. After adjustment for other variables with proportional-hazards regression analysis, smoking remained an independent prognostic factor (P = 0.002), with a relative risk of 2.5 (95 percent confidence interval, 1.4 to 4.4) favoring the patients who abstained from smoking. The results could not be explained by the type of chemotherapy received, the presence of coexisting morbid conditions, differences in the side effects of radiation, or the number of interruptions of treatment. CONCLUSIONS: Patients with head and neck cancer who continue to smoke during radiation therapy have lower rates of response and survival than patients who do not smoke during radiation therapy.

Aged↗
PubMed1993

Serological speciation of human T-cell leukaemia virus infections using synthetic peptide antigens.

In order to assess the specificity and sensitivity of two peptide-based assays (Synth HTLV-I and HTLV-II enzyme-linked immunoassay [EIA] [UBI] and Select-HTLV EIA [IAF]) in discriminating between antibody to HTLV-I and HTLV-II infection, a panel of 186 well-characterised serum/plasma samples was tested by the two assays. The panel comprised 160 samples that by Western blot were confirmed to contain antibodies to HTLV-I/II and 26 samples that showed reactivity with gag but not env gene products. Both assays were found to be specific in that they did not misclassify any of the 80 specimens from cases of tropical spastic paraparesis or adult T-cell leukaemia/lymphoma, diseases believed to be HTLV-I associated, as anti-HTLV-II positive. Of the 160 specimens confirmed as anti-HTLV-I/II positive by Western blot, 6.2% were negative or untypable in the Synth EIA compared with 13.7% in the Select EIA. Of the 26 Western blot indeterminate samples, 16 were negative by both assays. Five were typed as anti-HTLV-I by both assays and 5 as anti HTLV-II by Select EIA only. The peptide based EIAs offer an economical and, in most cases, reliable means of discriminating between anti-HTLV-I and anti-HTLV-II. However, they should only be applied to sera that have been confirmed by Western blot or other methods as anti-HTLV-I/II positive. Even then they may fail to speciate sera from non-Japanese, non-Afrocaribbean populations.

Blotting, Western↗
PubMed1993

Psychologic perspectives on pediatric pain.

Pain has always been a salient feature for children because it occurs frequently in their everyday lives. We are only beginning to understand childhood pain. Yet, it is this understanding that influences our assessment and treatment of their pain. As with adults, pain in children is a complex matrix of biologic, psychologic, and sociologic phenomena. This article reviews what we know today about childhood pain and focuses on the psychologic perspectives that affect that pain experience. It outlines the psychologic elements that include: cognition, coping strategies, ability to communicate pain, fear, temperament, and personality as well as the sociologic factors, such as the family, culture, and economics, that influence children's perceptions and reactions to pain. The article concludes with a review of psychologic treatments of pain and an exploration of the effects of the psychology of adults, including professional anxiety and beliefs about pain and medication, on how pain is experienced by children.

Child↗
PubMed1992

Evaluation of an enzyme immunoassay for the combined detection of antibodies to HIV-1, HIV-2, HTLV-I and HTLV-II.

OBJECTIVE: To assess the sensitivity and specificity of a newly-developed assay (Bioelisa HIV-1 + 2, HTLV-1 + 2) for the simultaneous detection of HIV-1, HIV-2, HTLV-I and HTLV-II antibodies in human serum or plasma specimens. METHODS: A panel of 775 well characterized serum or plasma samples was studied. This included samples confirmed to contain antibodies to HIV-1 (n = 46), HIV-2 (n = 19), HTLV-I (n = 49) and HTLV-II (n = 12), samples containing low titres of anti-HIV antibody (n = 14) and samples collected during HIV seroconversion (n = 36). Eighty-three sera samples which were reactive in one or more HIV or HTLV screening assays, but which could not be confirmed to contain anti-HIV-1/2 or anti-HTLV-I/II antibodies, were also examined. RESULTS: Excluding the seroconversion samples and those selected on the basis of false reactivity in other screening assays, the Bioelisa kit had a sensitivity of 100% for antibody to all four viruses and a specificity of 98.8%. The ability of the kit to detect anti-HIV during seroconversion was similar to that of several other synthetic HIV-antigen-based screening kits currently in use. CONCLUSIONS: Our findings indicate that the Bioelisa kit is sufficiently accurate to screen for both HIV and HTLV infections and that it warrants larger scale trials. Its use might allow blood donor screening for HTLV infection to be introduced more widely at modest extra cost [corrected].

Enzyme-Linked Immunosorbent Assay↗
PubMed1990

The use of the polymerase chain reaction for the detection of Simian immunodeficiency virus in experimentally infected macaques.

A rapid, non-radioactive assay for the detection of proviral Simian immunodeficiency virus (SIV) in tissue-culture cells is described. The assay is based on the co-amplification of the SIV env and gag genes by the polymerase chain reaction (PCR). When the gag PCR product is blotted onto a nylon membrane and hybridised to a radioactive oligonucleotide probe, the assay can also be used to detect the SIV gag gene in DNA isolated directly from experimentally infected cynomolgus macaque lymphocytes. This provides a valuable assay for the presence of proviral SIV during animal trials of AIDS vaccines and chemotherapeutics.

Animals↗
PubMed1990

Sensitivity of six commercial enzyme immunoassay kits that detect both anti-HIV-1 and anti-HIV-2.

The sensitivities of six commercial combined anti-HIV-1/anti-HIV-2 enzyme immunoassays (EIAs) were evaluated, one assay (ELAVIA) based on whole virion antigen, two assays (Abbott, Wellcozyme) based on antigens expressed from recombinant DNA, and three assays (Biochrom, IAF Biochem and Pharmacia) based on synthetic peptides as antigens. All the kits investigated performed well on a panel of 47 routine anti-HIV-1-positive specimens, but on series of anti-HIV-1-seroconversion specimens from seven plasmapheresis donors, two of the peptide assays, Biochrom and Pharmacia, performed less well than the other assays. On a panel of anti-HIV-2-positive specimens, all the assays except Biochrom detected all 33 positive sera, though the reactions of some of them in the Abbott assay were relatively weak. In deciding whether to introduce a combined assay in place of an anti-HIV-1 assay, cost, specificity, the availability of confirmatory tests and the prevalence of HIV-2 in the locality, as well as sensitivity, should be considered.

Acquired Immunodeficiency Syndrome↗