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Biomedical subjects

S Emery

Publications and source records attributed to S Emery.

At least 55 records · Page 3Linked to original sources
PubMed1997

Evolving technology thwarts aim of cost analyses.

Paucity of financial data obscures the risks and rewards of telemedicine and may have public policy implications. Study findings suggest potential private benefits to hospitals that implement the service, but tracking and analysis are critical.

Accounting↗
PubMed1996

CD8+ lymphocyte responses to antiretroviral therapy of HIV infection.

CD8+ T lymphocytes may mediate important host responses to human immunodeficiency virus (HIV) infection by human leukocyte antigen (HLA)-restricted cytotoxicity and production of soluble HIV suppressor factors. CD8+ lymphocytes are also important for the suppression of many latent pathogens responsible for opportunistic disease in HIV-infected patients. There has been no systematic analysis of the responses of CD8+ lymphocyte counts to antiretroviral therapy. We compared CD8+ lymphocyte responses in seven trials of nucleoside or non-nucleoside analog reverse transcriptase inhibitors and in two trials of ritonavir, a HIV protease inhibitor. Nucleoside analog and non-nucleoside analog reverse transcriptase inhibitor monotherapy resulted in no substantial changes in CD8+ counts relative to baseline or placebo. Combination nucleoside analog therapy resulted in variable peak responses (-145 to +240 cells/mm3), which remained significantly above baseline for 0 to 12 weeks. In contrast, ritonavir monotherapy caused a peak increase of 892 CD8+ cells/mm3, which remained significantly above baseline for 32 weeks. There was a significant correlation (Rs 0.61, p = 0.01) between the peak CD4+ cell and CD8+ responses to each therapy, but no significant correlation between the peak viral load responses and peak CD8+ cell responses. These findings suggest that the greater CD8+ response seen with ritonavir may be due to its specific inhibition of HIV protease and also that the CD8+ response is dependent on new CD4+ cell production. The CD8+ lymphocyte proliferation observed with protease inhibitor therapy could result in improved suppression of HIV replication by the immune system and should be confirmed in a prospective trial comparing protease inhibitors with both nucleoside and non-nucleoside analog therapies.

Acetamides↗
PubMed1996

Immune-based therapies in HIV infection: recent developments.

A wide variety of different immunologic approaches have been evaluated as potential therapies for HIV disease. Whether any of these approaches will play a role in clinical management will require the completion of the appropriate clinical trials. Importantly, all clinical trials present opportunities to evaluate aspects of the pathogenesis of HIV infection that are perhaps unevaluable in vitro. Clinical trials of antiretroviral drugs have defined the dynamics of HIV replication [37,38]. The complexities and heterogeneity of the immune system and particularly its responses to HIV are being unveiled in the setting of clinical trials of immune-based therapies. Truly effective treatments for HIV will result in long-term preservation of immune function allied to control of virus replication in infected individuals. Immune-based therapy might well play a significant role in such strategies.

Cytokines↗
PubMed1995

Effect of drink temperature on antropyloroduodenal motility and gastric electrical activity in humans.

There is little information on the motor mechanisms underlying the effects of meal temperature on gastric emptying. The effects on antropyloric pressures and the surface electrogastrogram of ingesting drinks at 4 degrees C, 37 degrees C, and 50 degrees C (350 ml normal saline and 50 ml low calorie (7 kj) orange cordial) given in randomised order were measured over 60 minutes in 12 normal volunteers (10 men and 2 women, aged 18-55 years). The warm and cold drinks suppressed antral pressure waves (p < 0.05), altered the organisation of antropyloric pressure waves (p < 0.05), stimulated isolated pyloric pressure waves (p < 0.05), and increased electrogastrogram frequency (p < 0.05) when compared with the 37 degrees C drink. These changes were greatest in the first 30 minutes after ingestion and greater (p < 0.05) with the 4 degrees C drink. Temperature has major effects on postprandial antropyloroduodenal motility in normal subjects. Both cold and warm drinks stimulate a pattern of motility associated with retardation of transpyloric flow.

Adolescent↗
PubMed1993

Event-related brain potentials and psychology course mean examination grades.

Since 1965 research into the event-related brain potentials of the human electroencephalogram suggests that these EEG components are closely related to human information-processing activities. In this study were tested 21 normal adult university students (12 women, 9 men, ages 19 to 51 years) from the Alaskan subarctic, using both the auditory and visual event-related potential oddball paradigms. The event-related brain potential recordings were analyzed as explanatory variables of academic performance, as measured by the mean of a series of multiple-choice examinations covering lecture and text material. No high association between these brain electrophysiological measures and students' academic performance was observed. At best, one component explained 27.6% of the variation in mean examination grades.

Adult↗
PubMed1991

Babesiosis. Diagnostic pitfalls.

A case of babesiosis complicated by quinine-induced hemolysis is described. A splenectomized woman contracted babesiosis after visiting an endemic area. The patient presented with high fevers and minimal hemolysis. While she was on treatment, the hemolysis increased. The increased hemolysis was initially attributed to babesiosis, but after additional evaluation quinine therapy was found to be the cause. In the setting of this brisk hemolysis, there was an increase in red blood cell inclusions. At first, the inclusions were thought to be Babesia, but iron stain demonstrated that many of the inclusions were hemolysis-induced Pappenheimer bodies. The role of the clinical laboratory in sorting out this confusing picture is presented.

Adult↗
PubMed1990

Studies on the hyperplasia ('regeneration') of the rat liver following partial hepatectomy. Changes in lipid peroxidation and general biochemical aspects.

Using the experimental model of partial hepatectomy in the rat, we have examined the relationship between cell division and lipid peroxidation activity. In rats entrained to a regime of 12 h light/12 h dark and with a fixed 8 h feeding period in the dark phase, partial hepatectomy is followed by a rapid regeneration of liver mass with cycles of synchronized cell division at 24 h intervals. The latter phenomenon is indicated in this study by pulses of thymidine kinase activity having maxima at 24 h, 48 h and 72 h after partial hepatectomy. Microsomes prepared from regenerating livers show changes in lipid peroxidation activity (induced by NADPH/ADP/iron or by ascorbate/iron), which is significantly decreased relative to that in microsomes from sham-operated controls, again at 24 h, 48 h and 72 h after the operation. This phenomenon has been investigated with regard to possible underlying changes in the content of microsomal fatty acids, the microsomal enzymes NADPH:cytochrome c reductase and cytochrome P-450, and the physiological microsomal antioxidant alpha-tocopherol. The cycles of decreased lipid peroxidation activity are apparently due, at least in part, to changes in microsomal alpha-tocopherol content that are closely associated in time with thymidine kinase activity.

Animals↗
PubMed1990

Antigenic heterogeneity in human ovarian cancer.

Primary and metastatic tumor tissues from 21 patients with ovarian epithelial cancer were studied with a panel of 8 monoclonal antibodies. Primary tumors reacted with 1 to 7 antibodies (mean, 3.5). Heterogeneity was observed even within histologic subtypes. Comparison of metastases (including ascites) with their respective primaries revealed differences in antigen profile in each of 10 cases studied. In one patient variable antigen expression was observed in five ascites samples collected over a 12-month period. These observations of antigenic heterogeneity and modulation with respect to site and time suggest that single monoclonal antibody immunotherapy would not be appropriate for all patients or even for a single patient over time.

Adenocarcinoma↗
PubMed1988

Studies on lipid peroxidation in normal and tumour tissues. The Yoshida rat liver tumour.

Reduced rates of lipid peroxidation have been observed in Yoshida hepatoma cells and microsomes when compared with appropriate control tissue (normal rat liver) under the same pro-oxidant conditions. The pro-oxidant conditions used were incubation with NADPH+ADP+iron or ascorbate+iron or exposure to gamma-irradiation. As previously shown with the Novikoff hepatoma, the relative concentrations of alpha-tocopherol and polyunsaturated fatty acids are important in conferring resistance to lipid peroxidation in the Yoshida hepatoma. Furthermore, NADPH-cytochrome c reductase and the NADPH-cytochrome P-450 electron transport chain, which are involved in the initiation and propagation of certain types of lipid peroxidation, are found at very much reduced levels in the Yoshida hepatoma. The relative importance of these aberrations are discussed.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1987

Effects of alpha-tocopherol on carbon tetrachloride metabolism in rat liver microsomes.

alpha-tocopherol is the major lipid-soluble radical-scavenging antioxidant in rat liver. It has long been used as a putative protective agent in CCl4 induced liver injury but with variable results. We have used alpha-tocopherol loaded rat liver microsomes to study the effect of this vitamin on CCl4 metabolism in vitro. As expected, alpha-tocopherol inhibits CCl4-dependent microsomal lipid peroxidation and, at a very high concentration, will inhibit the covalent binding of CCl3 to microsomal protein by up to 50%. No inhibitory effect was observed towards CCl3 production as measured by the electron spin resonance technique of spin-trapping but this apparent discrepancy may represent a limitation of the technique. The high levels required to inhibit covalent binding probably preclude the likelihood of alpha-tocopherol significantly affecting that phenomenon at endogenous concentrations but may be relevant to other experiments employing high doses of alpha-tocopherol as an experimental hepatoprotective agent.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1985

The effect of cimetidine and ranitidine on paracetamol glucuronidation and sulphation in cultured rat hepatocytes.

Cimetidine and ranitidine have been investigated for their ability to inhibit conjugation reactions in cultures of rat hepatocytes. Neither compound had any appreciable effect on rates of paracetamol sulphation. However, both cimetidine and ranitidine inhibited the glucuronidation of paracetamol in a dose-dependent manner. No adverse effects on cellular viability were noted utilizing enzyme leakage (lactic dehydrogenase) or protein synthesis measurements. The kinetics of inhibition by ranitidine were studied in more detail. At 0.25 mM ranitidine, the inhibition appeared to be purely competitive. However, at higher concentrations decreases in Vappmax were noted suggesting a more complex mechanism of inhibition. The relevance to inhibition in vivo by cimetidine and ranitidine and possible interactions between paracetamol and these histamine H2-receptor antagonists are discussed.

Acetaminophen↗