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Biomedical subjects

D Englert

Publications and source records attributed to D Englert.

18 recordsLinked to original sources
PubMed2001

DNA microarrays with stem-loop DNA probes: preparation and applications.

We have developed DNA microarrays containing stem-loop DNA probes with short single-stranded overhangs immobilized on a Packard HydroGel chip, a 3-dimensional porous gel substrate. Microarrays were fabricated by immobilizing self-complementary single-stranded oligonucleotides, which adopt a partially duplex structure upon denaturing and re-annealing. Hybridization of single-stranded DNA targets to such arrays is enhanced by contiguous stacking interactions with stem-loop probes and is highly sequence specific. Subsequent enzymatic ligation of the targets to the probes followed by stringent washing further enhances the mismatched base discrimination. We demonstrate here that these microarrays provide excellent specificity with signal-to-background ratios of from 10- to 300-fold. In a comparative study, we demonstrated that HydroGel arrays display 10-30 times higher hybridization signals than some solid surface DNA microarrays. Using Sanger sequencing reactions, we have also developed a method for preparing nested 3'-deletion sets from a target and evaluated the use of stem-loop DNA arrays for detecting p53 mutations in the deletion set. The stem-loop DNA array format is simple, robust and flexible in design, thus it is potentially useful in various DNA diagnostic tests.

DNA Mutational Analysis↗
PubMed2001

Multiplex allele-specific target amplification based on PCR suppression.

We have developed a strategy for multiplex PCR based on PCR suppression. PCR suppression allows DNA target amplification with only one sequence-specific primer per target and a second primer that is common for all targets. Therefore, an n-plex PCR would require only n + 1 primers. We have demonstrated uniform, efficient amplification of targeted sequences in 14-plex PCR. The high specificity of suppression PCR also provides multiplexed amplification with allele specificity. Multiplexed PCR was used to develop assays for genotyping DNA samples from cystic fibrosis-affected individuals. The new approach greatly simplifies primer design, significantly increases the PCR multiplexing level, and decreases the overall primer cost. In addition, this assay is more readily amenable to automation and is therefore suitable for high-throughput genetic diagnostics.

Alleles↗
PubMed1995

Microchannel array detector for quantitative electronic radioautography.

The microchannel array detector provides direct electronic detection and real time imaging of radioactive tracers in samples that traditionally have been imaged by film radioautography. The technology of the detector is described, and the main benefits of this new technology, speed and precise quantitation, are illustrated with practical results. The instrument response to a 14C dilution series (range of 10(5)) was linear over the whole range. Results from the microchannel array detector are compared to results obtained with liquid scintillation counting (LSC) and densitometry of film radioautographs. Because the instrument response is linear and consistent from day to day, it is not necessary to routinely include calibration standards as is required for film. The 14C counting efficiency was found to be essentially constant for different tissues in a whole body microtome section. As with LSC, results reported as counts per min. (CPM) are independent of counting time. Quantitative results were obtained with assays for chloramphenicol acetyl transferase in two min. and little as 0.2 DPM/mm2 of 32P was detected in seven min.

Animals↗
PubMed1993

New instruments for high throughput receptor binding assays.

The TopCount Microplate Scintillation Counter and the Matrix 9600 Direct Beta Counter are microplate compatible instruments developed to meet the needs of investigators using radioisotope assays adapted for very high throughput. This paper describes these instruments and their application to receptor binding assays. When combined with the appropriate sample handling equipment and filter media, use of these multi-detector instruments improves sample handling efficiency and shortens overall counting time. The assay protocols including filtration through glass fiber mats and membrane filters have been investigated. Results obtained from these new instruments are compared to standard techniques using conventional liquid scintillation and gamma counting.

Filtration↗
PubMed1989

[The importance of subclavian vein stenosis for the treatment of Dupuytren's contracture].

The postoperative healing in cases of Dupuytren's contracture is not only influenced by the age of the patient and the progress of the disease, but also by the existence of other accompanying diseases and general and local factors. The appearance of postoperative edema and the so-called hand-finger-syndrome are also especially unfavorable, because these complications determine the duration of treatment and the functional results. As a cause for these postoperative complications a disorder of the subclavian vein could be found and documented by means of phlebography. Preoperative examination of the venous situation is therefore an important diagnostic step to determine indications and to allow an estimation of the postoperative course and the duration of treatment. Demonstration of cases and statistical evaluation of our patients over the last five years show the importance of this observation.

Constriction, Pathologic↗
PubMed1987

Local hemostasis in subarachnoid hemorrhage.

Fibrinopeptide A (FPA), platelet-secreted protein, platelet factor 4 and beta-thromboglobulin were determined in the cerebrospinal fluid of patients who had suffered from subarachnoid hemorrhage and were treated with 6 g tranexamic acid or 4 million KIU aprotinin to prevent rebleeding. Platelet-secreted proteins and FPA were cleared from the cerebrospinal fluid within 3 days after bleeding. Their vasoactive and thrombotic capability is limited to the initiation period of vasospasm that usually comes to clinical observation 3-8 days after bleeding. Increased thrombotic activity of the cerebrospinal fluid, as reflected by high levels of FPA and platelet-secreted protein, seemed to promote the occurrence of neurological deficits.

Fibrinogen↗
PubMed1984

Light microscopic observations on the release of vesicles by isolated chromaffin cells.

Cultured bovine adrenal medullary chromaffin cells were stimulated with the secretogogues Ba2+ or carbamyl choline plus Ca2+. With video-enhanced contrast, differential interference contrast microscopy, small vesicles were found to appear on the cell surface during stimulation. The structures were of lower refractive index than the cytoplasm, and their appearance required several tenths of a second. The vesicles are thought to correspond to omega figures seen with electron microscopy due to exocytosis. Many of the structures disappeared within a few seconds, but some appeared to coalesce into larger structures. The large structures may lead to the vacuoles that have been demonstrated to be present following stimulation. The nature of the cellular elements responsible for the vesicle which appeared on the surface was not found with either differential interference or interference reflection microscopy. The simplest explanation is that the refractive index of the elements is similar to that of the cell, and therefore the elements cannot be seen.

Adrenal Medulla↗
PubMed1983

Immunofluorescent evidence for exocytosis and internalization of secretory granule membrane in isolated chromaffin cells.

Cultured bovine adrenal medullary chromaffin cells were stimulated with the secretogogues Ba2+ or carbamyl choline plus Ca2+ in the presence of a monospecific rabbit IgG fraction directed against bovine dopamine beta-hydroxylase. The anti-dopamine beta-hydroxylase was labeled either with fluorescent protein A or with a fluorescent second antibody to rabbit IgG. Stimulation produced a patchy cell surface distribution of fluorescence. There was no noticeable internalization of the fluorescence for up to 2 h. In similar experiments using fluorescent monovalent fragments (Fab) of the same monospecificidopamine-beta-hydroxylase IgG, a more uniform distribution of the fluorescence was observed. A few min after a 5 min period of stimulation with Ba2+, the fluorescence appeared to be on or near the cell surface; however, after 20 min or more it was distributed throughout the cytoplasm except that the cell nuclei were not labeled. Thus, dopamine beta-hydroxylase which appeared on the cell surface as a consequence of exocytosis was internalized in the presence of monovalent antibody fragments, but not in the presence of the divalent (polyclonal) antibody, presumably because endocytosis of dopamine beta-hydroxylase was inhibited by crosslinking of the dopamine beta-hydroxylase molecules. The internalized anti-dopamine beta-hydroxylase Fab fragments were found to reappear on the cell surface during a second secretory response. It is concluded that the interior of the chromaffin granule membrane, for which dopamine beta-hydroxylase is a marker, becomes exposed on the surface of the cell during secretion and that the membrane is then retrieved back into the cell where it can be re-used in a further secretory cycle.

Animals↗
PubMed1981

Myelin basic protein in cerebrospinal fluid of patients with multiple sclerosis and other neurological diseases.

Cerebrospinal fluid (CSF) from 105 patients was analyzed by radioimmunoassay for the presence of material cross-reactive with peptide 89-169 of bovine myelin basic protein (BP). In a group of 72 multiple sclerosis patients, 52 showed higher BP content than the control group, i.e. more than 2 ng/ml CSF. Increased BP or BP fragments could be detected in CSF from almost all patients who recently (within 2 weeks) had had an acute episode, or after deterioration in the progressive form of the disease. Fifteen to 30 days after the onset of exacerbation or in a stable period, BP content decreases and in the slowly progressive form was in the range of the control group with one exception. BP content was also elevated in the CSF of patients with other neurological diseases. The presence of BP in the CSF from patients with isolated retrobulbar neuritis is of particular interest. Thus the presence of material cross-reactive with BP fragment 89-169 is not specific for multiple sclerosis, but is a useful parameter in diagnosis and evaluation of MS.

Cerebrovascular Disorders↗
PubMed1981

Demonstration of oligoclonal immunoglobulin G in Guillain-Barré syndrome and lymphocytic meningoradiculitis by isoelectric focusing.

Isoelectric focusing (IEF) of serum and CSF revealed oligoclonal IgG in 13 out of 16 patients with the Guillain-Barré syndrome (GBS), in 10 of them in serum only and in 3 in serum and CSF. Seventeen out of 19 patients with lymphocytic meningoradiculitis (LMR) showed oligoclonal IgG, 12 of them in CSF only. These findings, together with additional results, mean that in GBS oligoclonal IgG is synthesized mainly outside the CNS and in LMR within the CNS. Follow-up studies revealed changes in the oligoclonal IgG during the course of GBS and LMR. After treatment by plasma exchange the disappearance of oligoclonal IgG bands was followed by an improvement of GBS symptoms. The oligoclonal IgG bands returned in correlation with worsening of the disease. We were not able to elucidate the antibody character of oligoclonal IgG in GBS or LMR. No antibodies against the myelin basic protein (fragment 89-169) were detectable in the sera and CSF in any of the patients tested.

Adolescent↗
PubMed1981

Suppression of experimental allergic encephalomyelitis by transfer of lymph node cells from Lewis rats pretreated with complete Freund's adjuvant.

Experimental allergic encephalomyelitis (EAE) in Lewis rats was suppressed by pretreatment with complete Freund's adjuvant (CFA) 14-16 days before immunization with basic protein (BP) in CFA. Suppression of active EAE was also accomplished clinically and even histologically if lymph node cells from CFA-treated donors were passively transferred. Obviously this depends first on a certain amount of transferred lymph node cells (about 3 X 108) and secondly on the interval between CFA application and cell harvest (more than 14 days). No suppression was obtained by transfer of serum from CFA-treated donors. This indicates that there is a suppressor cell population which can be raised or stimulated by CFA and which is capable of suppressing the immune response EAE.

Animals↗
PubMed1979

Decrease in motor activity - an early symptom in the course of experimental allergic encephalomyelitis (EAE).

Motor activity has been followed in rats during an experimental allergic encephalomyelitis (EAE). The disease was produced by transfer of lymph node cells from sensitized syngenic donors. Small and large movements were permanently registered by an electric activity meter. It could be demonstrated that a decrease of the motility is an early symptome of the disease. Therefore the measurement of the motoric activity might be a useful parameter in the classification of EAE.

Animals↗
PubMed1977

Effect of increased potassium concentrations on particle motion within a neurosecretory structure.

Intensity fluctuation spectroscopy was used to detect particle motion within the pericardial organ of the crab Carcinus while it was perfused with media with increased potassium concentrations. Replacement of some or all of the sodium ions of the normal medium with potassium ions caused a graded increase in motion. Evidence is presented which indicates that this effect is not a consequence of membrane depolarization or calcium ion influx, but is due to the flux of potassium chloride and water into the cytoplasm of the cells.

Animals↗
PubMedDate not supplied

Selenium status of seven chronic intravenous hyperalimentation patients.

Selenium status was determined on seven patients receiving long-term intravenous hyperalimentation (IVH) and they were followed monthly for 4 to 17 months. Analysis of the IVH solutions for selenium revealed no detectable amounts. The selenium indices measures were (1) erythrocyte selenium levels, (2) erythrocyte glutathione peroxidase activities (GSH-Px), and (3) plasma selenium levels. In general, the IVH population had significantly lower values (p less than 0.001) for these selenium indices than a healthy population (n = 275). The plasma selenium levels decreased to below the normal range within one to two months after initiation of IVH. The below normal ranges varied by patient: three patients by three months, one patient by nine months, and three patients had low and normal values throughout the study. No consistent correlation of individual patient's erythrocyte GSH-Px activities and erythrocyte selenium levels existed, but a positive correlation (r = 0.51, p less than 0.01) occurred between plasma selenium levels and erythrocyte GSH-Px activities. Thus, erythrocyte GSH-Px activities decrease parallel to decreases in plasma selenium levels but not with changes in erythrocyte selenium levels. These data suggest that some of these IVH patients may be at risk for selenium deficiency and that selenium supplementation of IVH solutions may be required. Furthermore, these data suggest that the measurement of erythrocyte GSH-Px activity or selenium levels in some IVH patients may not be related to available body selenium.

Adult↗
PubMedDate not supplied

Nutrition education in schools of nursing in the United States. Part 2: The status of nutrition education in schools of nursing.

To explore whether nurses in academic institutions are being adequately educated to care for patients' nutritional needs, we conducted a survey of National League for Nursing accredited baccalaureate programs in the United States and their associated graduate programs. Data indicate that nutrition content is an integral part of baccalaureate nursing programs. Less emphasis is reported on nutrition content at the graduate level. Recommendations include revision of the substantive nutritive content and increased clinical experience in nutrition in both undergraduate and graduate nursing education.

Curriculum↗