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Biomedical subjects

A Ross

Publications and source records attributed to A Ross.

At least 145 records · Page 8Linked to original sources
PubMed1993

Characterization of the linker peptide of the single-chain Fv fragment of an antibody by NMR spectroscopy.

A comparison of the single-chain Fv fragment of the antibody McPC603 (scFv) with its corresponding unlinked Fv fragment has been carried out with 15N-edited NMR spectroscopy. The two Fv fragments adopt the same structure, indicating that the linker does not perturb the folding of the domains. This also directly demonstrates that folding in vivo (Fv fragment) and in vitro (scFv fragment) leads to the same structure. The main differences in the spectra of the uniformly 15N-labeled scFv and Fv fragments are due to signals of Gly and Ser from the linker peptide of the scFv fragment. The linker peptide has been mapped with NMR spectra of 15N-glycine- and 15N-glycine/15N-serine-labeled scFv fragments. The 15N T2 relaxation data indicate that the linker peptide is more flexible than the rest of the molecule.

Glycine↗
PubMed1993

[Dietary intake of total lipids and saturated fatty acids of the Geneva population: an unexpected development].

Results of two dietary surveys performed 10 years apart suggest that the Geneva population has a lower caloric intake and a lower proportion of total fat and saturated fat in the total caloric intake. These changes are observed in all ages, sexes or nationalities. They may indicate that prevention campaigns promoting a healthier diet with a lower content of calories and fat have had some impact. However, because of methodological differences between the two surveys we cannot conclude that these dietary changes are real.

Adult↗
PubMed1993

Low birthweight in twins: black and white differences.

Washington State birth certificate data for the years 1984-1988 were analyzed for 2,804 mothers of twins in order to determine whether black mothers of twins have a higher risk of delivering a low birthweight twin infant than white mothers. Seventy four percent of black mothers of twins gave birth to an infant weighing < 2500 grams (white 52.9%), while slightly less than 20% gave birth to an infant weighing < 1500 grams (white 9.4%). After adjustment for maternal age, parity and marital status, the risk of black mothers giving birth to at least one twin infant < 2500 grams relative to white mothers was 1.3 (95% confidence interval, 1.2, 1.5). When this analysis was restricted to very low birthweight babies (< 1500 grams), the relative risk for infants of black mothers compared to white mothers adjusted for the same factors was 2.1 (95% confidence interval, 1.5, 3.0). The frequency of neonatal mortality in the study population was also assessed. The overall frequency of mortality in black twin infants was double that in white twin infants. When stratified by birthweight category, the frequency was higher in white infants (30.2%) than in black infants (24.1%) weighing less than 1500 grams at birth. However, within higher birthweight categories, (> or = 1500 grams to < 2500 grams and > 2500 grams), relative frequencies of neonatal mortality were higher in black infants. This analysis reveals that black mothers of twins are more likely to deliver low birthweight twin infants than white mothers. The increased risk is even more pronounced in very low birthweight twin pairs. However, the additional risks for low birthweight black twin pairs and very low birthweight twin pairs found in this study are lower than the risk increase commonly reported for the respective birthweight categories in black singleton infants relative to white singleton infants. This implies that while black twin pregnancies require many of the same special antepartum considerations given to black singleton pregnancies, the increased baseline risks associated with low birthweight and very low birthweight twin deliveries offset racial disparities traditionally seen in singleton infants.

Adolescent↗
PubMed1993

Comparability and reliability of ELISA, immunofluorescence, and indirect hemagglutination assays for Trypanosoma cruzi and Trypanosoma rangeli.

Serum samples and filter paper spot samples from 48 adults were assayed in three laboratories for Trypanosoma cruzi and Trypanosoma rangeli by ELISA, immunofluorescence (IF), and indirect hemagglutination (HA) in a controlled, blind experiment. IF (serum samples) attained higher levels of comparability necessary for validity than did ELISA (serum samples) in these laboratories. ELISA was inferior to IF and HA (spot samples) in testing for T. cruzi. ELISA was not reliable (intrasubject r = .51) and was not in agreement between two laboratories (kappa = .09). The experiment indicates that ELISA is not the best choice of assay for T. cruzi in epidemiologic surveys. Assays for T. rangeli by ELISA and IF lacked comparability to the extent that those two techniques could not be considered useful for T. rangeli.

Adult↗
PubMed1993

The role of angioplasty in acute myocardial infarction.

The role of primary angioplasty versus thrombolytic therapy for the treatment of coronary thrombosis has been the subject of recent randomised trials. They have shown a higher early patency rate after angioplasty with no differences in later patency. Recurrent ischaemia was more frequent after thrombolysis, but the one study that examined myocardial salvage showed no difference. There were fewer intracerebral bleeds in the angioplasty group, but owing mostly to much higher than usual stroke occurrence in the thrombolysis group. With less than 800 patients in all the studies, no final conclusions can yet be drawn about effects on mortality and larger studies are needed. Primary angioplasty is an option when operators are skilled and the procedure can be done quickly.

Angioplasty, Balloon, Coronary↗
PubMed1993

Epidural analgesia and fetal heart rate abnormalities.

Lumbar epidural analgesia is frequently associated with fetal heart rate abnormalities. Fluid preloading prior to the procedure significantly reduces the incidence of abnormal fetal heart rate patterns (p = 0.02). The mechanisms of these changes are discussed and the importance of maternal hypotension is evaluated. Fluid preloading and continuous electronic fetal monitoring should be considered routine for all women undergoing this procedure.

Analgesia, Epidural↗
PubMed1992

Secondary structure of human granulocyte colony-stimulating factor derived from NMR spectroscopy.

Recombinant 15N-, 13C-labeled human granulocyte colony-stimulating factor (rh-metG-CSF) has been studied by 2D and 3D NMR using uniformly labeled protein as well as residue-specific 15N-labeled samples. Assignment of the 1H, 15N backbone, and 60% 1H sidechain resonances has enabled the determination of the secondary structure of the protein. The secondary structure is dominated by alpha-helical regions with four stretches of helices between residues 11-41, 71-95, 102-124 and 144-170.

Amino Acid Sequence↗
PubMed1992

Developmental pattern and distribution of nerve growth factor low-affinity receptor immunoreactivity in human spinal cord and dorsal root ganglia: comparison with synaptophysin, neurofilament and neuropeptide immunoreactivities.

Immunocytochemical expression of the low-affinity nerve growth factor receptor was studied in human fetal and adult tissues using the monoclonal antibody ME20.4. In dorsal root ganglia, a few immunoreactive neurons were first detected in nine-week-old fetuses and many more were found in the following weeks of gestation. However, none was present in adult ganglia. The ME20.4-positive cells were larger than neurons immunostained by substance P, calcitonin gene-related peptide or galanin antibodies. In the spinal cord, fibres immunostained by ME20.4 appeared in a characteristic pattern that differed from the spatial and temporal distributions of synaptophysin- and neurofilament-immunoreactive fibres. Those expressing the low-affinity nerve growth factor receptor were only detected in regions containing collaterals of primary sensory axons: (i) in the dorsal funiculus between seven and 18 weeks of gestation; (ii) in a ventrodorsal bundle reaching the ventral horn from weeks 12-14; (iii) in the medial region of the dorsal horn between weeks 12 and 20; (iv) in the superficial layers and lateral portion of the dorsal horn after the 14th week of gestation and also in adult spinal cord. During the fetal period, ME20.4 immunoreactivity was also found in motoneurons and peripheral nerve fibres in the skin, myotomes and gut. Sheaths of peripheral nerves and the adventitia of blood vessels were stained both in fetal and adult tissues. Thus, the low-affinity nerve growth factor receptor is: (i) strongly expressed in the developing human nervous system; (ii) transiently associated with a subset of large primary sensory neurons and with motoneurons; (iii) transiently and sequentially expressed by various groups of sensory afferents to the spinal cord; (iv) permanently expressed by fibres in the superficial layers of the dorsal horn, Clarke's column, nerve sheaths and the adventitia of blood vessels.

Adult↗
PubMed1992

Quality control of cathepsin-D measurement by the EORTC Receptor Study Group.

Cathepsin-D is a lysosomal protease that can serve as an important prognostic cytosolic factor in breast cancer. To evaluate the performance of a commercially available immunoradiometric assay kit, 15 lyophilised cytosol participating EORTC laboratories for preparations containing various levels of cathepsin-D have been sent to 13 participating EORTC laboratories for quality control purposes. The between-laboratory variation, when expressed as coefficient of variation, did not exceed 24%. The within-laboratory variation was assessed by analysing five samples of the 15 specimens containing lyophilised material from a homogeneous cytosol pool. The mean within-laboratory coefficient of variation was 7%. Analysis of human breast tumour cytosols in one of the participating EORTC laboratories resulted in a median within-assay variation between duplicate measurements of 2.1% (n = 408), with a between-assay variation of a pooled human breast tumour cytosol of 4.6% (n = 11).

Breast Neoplasms↗
PubMed1992

Predictors of early morbidity and mortality after thrombolytic therapy of acute myocardial infarction. Analyses of patient subgroups in the Thrombolysis in Myocardial Infarction (TIMI) trial, phase II.

BACKGROUND: Thrombolysis has altered treatment of acute myocardial infarction (AMI). Therefore, reevaluation of predictors of outcome and treatment strategies is appropriate. METHODS AND RESULTS: Clinical variables collected prospectively for the 3,339 patients of the Thrombolysis in Myocardial Infarction II study were analyzed retrospectively to identify predictors of clinical events at 42 days and earlier and to identify subgroups in which an invasive or conservative strategy might be superior. Pulmonary edema/cardiogenic shock presented as the strongest independent correlate with death (relative risk, 6.0). In two subgroups, mortality differed between the invasive and conservative strategies: 1) Patients with versus without prior AMI had a higher mortality in the conservative strategy (11.5% versus 3.5%, p less than 0.001); in the invasive strategy, the mortality rates were similar (6.0% and 5.1%). 2) Patients with diabetes mellitus and no prior AMI had a higher mortality in the invasive than in the conservative strategy (14.8% versus 4.2%, p less than 0.001). Reinfarction was not independently correlated with baseline characteristics except with history of angina (relative risk, 1.9). Mortality was lower in current smokers and ex-smokers versus never-smokers (3.6% and 4.8% versus 8.0%, p less than 0.001). Current smokers had a lower risk profile (p less than 0.001), including age, pulmonary edema/cardiogenic shock, history of hypertension, and diabetes. The rate of reinfarction was lower in current smokers versus ex-smokers and never-smokers (4.6% versus 8.3% and 8.8%, p less than 0.001). "Not current smoker" was an independent correlate with reinfarction (relative risk, 1.9). The coronary anatomy did not differ among the current smokers, ex-smokers, and never-smokers. CONCLUSIONS: The strong independent correlation of pulmonary edema/cardiogenic shock with death suggests that thrombolysis is not sufficient to improve survival in these patients. The higher mortality in patients with versus without prior AMI in the conservative strategy suggests that early catheterization and revascularization of these patients might be beneficial. Conversely, the higher mortality in diabetes without prior AMI in the invasive than in the conservative strategy suggests that early aggressive management might not be suitable in this subgroup except for clinical indications. Reinfarction was not predictable by clinical variables except by history of angina. The finding that "not current smoker" was an independent correlate with reinfarction was unexpected.

Female↗