Search PubMed⌕ Search

Biomedical subjects

E Weiss

Publications and source records attributed to E Weiss.

At least 145 records · Page 8Linked to original sources
PubMed1989

[Pulsed Doppler sonography of the umbilical artery and fetoplacental resistance. A histometric study of gestosis placentas in comparison with a normal sample].

Histometric data from placentas after EPH gestosis, in cases with normal (n = 15) or pathological (n = 13) foetal umbilical artery flow velocity wave forms, are compared with data from uncomplicated pregnancies (n = 17). The cross-sectional areas of the villi were increased in both gestosis groups, whereas the diffusion capacity, the degree of vascularisation, the foetal placental blood volume and the length of epithelial plates and their quota of the circumference of the villi are decreased only in cases of gestosis with pathological flow velocity wave forms. In this group a high rate of caesarean sections for foetal distress was necessary and the foetal outcome was poor. We were able to prove the possibility of estimation of "placental risk" with pulsed Doppler ultrasound of an umbilical artery with morphometric data.

Asphyxia Neonatorum↗
PubMed1989

[Doppler sonography of the umbilical artery: differential diagnosis in intrauterine growth retardation].

50 fetuses with IUGR were differenciated by pulsed Doppler-wave velocimetry of an umbilical artery. All cases with a normal A/B-ratio according to Stuart had spontaneous vaginal delivery and normal fetal outcome. Pathological flow velocity waveforms led to early delivery and a significantly high rate of cesarean section for fetal asphyxia and to a poor fetal outcome. The umbilical artery flow velocity waveform showed a high sensitivity and specificity with regard to fetal risk and indicated the latter earlier than the oxytocin challenge test. A positive correlation between elevated umbilical placental resistance and histomorphological disorders of the fetal placenta was found. Screening for fetal perinatal risk by means of pulsed Doppler ultrasound of the umbilical arteries is discussed in cases of IUGR.

Blood Flow Velocity↗
PubMed1989

Energy metabolism of monocytic Ehrlichia.

We investigated if the monocytic Ehrlichia are totally dependent on their host cells for energy, or, as Rickettsia, are capable of some ATP synthesis in vitro. The Miyayama strain of Ehrlichia sennetsu and the Maryland and Illinois strains of Ehrlichia risticii were cultivated in a mouse macrophage cell line, separated from host cell constituents by procedures that included Renografin or Percoll gradient centrifugation, and tested after cryopreservation. Cells incubated without a metabolizing substrate contained little, if any, ATP. When the Ehrlichia cells were incubated for 1 hr at 34 degrees C with glutamine, significant amounts of ATP were detected. The amounts of ATP attained with glutamine were decreased in some instances by the addition of atractyloside, an inhibitor of adenine nucleotide translocase in mitochondria, and were decreased consistently and to a greater extent by 2,4-dinitrophenol. When ATP, instead of glutamine, was added to the ehrlichiae, upon incubation the amount of ATP was markedly decreased. Comparable responses under all these conditions were obtained with Rickettsia typhi, although the final ATP levels were higher. Control preparations derived from uninfected mouse macrophages or from the discards of the Ehrlichia purification procedures contained negligible amounts of ATP, which were not increased by incubation with glutamine. We conclude that with respect to ATP metabolism, the monocytic Ehrlichia resemble Rickettsia more closely than Chlamydia, even though Ehrlichia resemble Chlamydia in their intracellular location in the phagosomes and in possibly having a developmental cycle.

2,4-Dinitrophenol↗
PubMed1989

Phylogenetic diversity of the Rickettsiae.

Small subunit rRNA sequences have been determined for representative strains of six species of the family Rickettsiaceae: Rickettsia rickettsii, Rickettsia prowazekii, Rickettsia typhi, Coxiella burnetii, Ehrlichia risticii, and Wolbachia persica. The relationships among these sequences and those of other eubacteria show that all members of the family Rickettsiaceae belong to the so-called purple bacterial phylum. The three representatives of the genus Rickettsia form a tight monophyletic cluster within the alpha subdivision of the purple bacteria. E. risticii also belongs to the alpha subdivision and shows a distant yet specific relationship to the genus Rickettsia. However, the family as a whole is not monophyletic, in that C. burnetii and W. persica are members of the gamma subdivision. The former appears to show a specific, but rather distant, relationship to the genus Legionella.

Bacteria↗
PubMed1988

Anti-asthmatic effects of onions. Alk(en)ylsulfinothioic acid alk(en)yl-esters inhibit histamine release, leukotriene and thromboxane biosynthesis in vitro and counteract PAF and allergen-induced bronchial obstruction in vivo.

Five alk(en)ylsulfinothioic acid alk(en)yl-esters isolated from onions and four synthetic thiosulfinates inhibited 5-lipoxygenase of porcine leucocytes, histamine release and leukotriene B4 and C4 biosynthesis of human polymorphonuclear leucocytes, thromboxane B2 biosynthesis by human platelets and allergen- and PAF-induced bronchial obstruction of guinea-pigs. The anti-asthmatic and anti-inflammatory effects of onions depend in part on the thiosulfinate moiety: (Formula: see text).

Allergens↗
PubMed1988

Differential expression of c-myc and the transferrin receptor in G1 synchronized M1 myeloid leukemia cells.

We have studied the transcriptional activity, steady-state mRNA levels, and steady-state protein levels of the c-myc and transferrin receptor (TfR) genes in murine M1 myeloid leukemia cells arrested in G1 phase of the cell cycle by different methods. When cells are growth-arrested by density inhibition, a technique that places the majority of cells in early G1, c-myc protein, as detected by Western analysis, is expressed at 80% of the level seen in proliferating cells. Steady-state mRNA levels and, to a lesser extent, transcriptional activity of the c-myc gene, parallel the protein findings. Under these conditions, TfR gene expression is much lower than in normally cycling cells. We have previously demonstrated that density-inhibited M1 cells, released from density inhibition and treated with the DNA polymerase alpha inhibitor aphidicolin, remain in G1, but at a point temporally closer to S phase. Cells treated in this manner demonstrate reduced transcriptional activity and expression of the c-myc gene, but TfR gene expression approximates the level found in proliferating cells. These data suggest that neither c-myc nor TfR gene expression is constant throughout the G1 phase of the cell cycle in M1 cells. c-myc gene expression is highest in early G1 and falls to low levels by late G1, while the reverse is true for TfR gene expression.

Animals↗
PubMed1988

A gingival guard for crown preparation.

A device for subgingival margin preparation is presented. The gingival guard consists of a clamp attached to the high-speed handpiece supporting a stainless steel shank terminating in a sphere. The guard permits nontraumatic subgingival margin preparation.

Crowns↗
PubMed1988

Atrial natriuretic peptide administration to normal and salt depleted rats--effects on digoxin-like immunoreactive factor, aldosterone, ACTH, and renal function.

In view of the known interrelationships between renin, aldosterone, and atrial natriuretic peptide (ANP), we sought to examine whether there also exists an interaction between ANP and digoxin-like immunoreactive factor (DLIF). We therefore studied the effects of ANP administration on normal and salt-depleted rats, and measured the effects on blood pressure, urine output, glomerular filtration rate, sodium excretion, aldosterone, ACTH, and DLIF levels. ANP administration resulted in a significant elevation of sodium excretion and glomerular filtration rate and a fall in blood pressure. DLIF concentrations in plasma rose significantly, as did urinary DLIF excretion. ANP administration resulted in a fall in aldosterone as well as ACTH. These observations suggest that ANP has a direct inhibitory effect on ACTH secretion. Our findings support the concept of an interrelationship between ANP and DLIF.

Adrenocorticotropic Hormone↗
PubMed1988

Visualization by electron microscopy of the location of tobacco mosaic virus epitopes reacting with monoclonal antibodies in enzyme immunoassay.

The binding of monoclonal antibodies obtained after immunization with tobacco mosaic protein was analyzed by electron microscopy. A method was developed for visualizing the viral antigen reacting in different ELISA procedures. It was found that the use of a pH 9.6 buffer during the coating of ELISA plates led to the dissociation of virions into subunits which bound preferentially to the solid phase. MAbs that reacted with both virions and subunits in ELISA were found to bind to one of the two extremities of viral rods. These MAbs also reacted with viral protein aggregated in the form of disks. In contrast, MAbs reacting only with virions in ELISA were found to bind over the entire surface of the virus.

Antibodies, Monoclonal↗
PubMed1988

Substrate utilization by Ehrlichia sennetsu and Ehrlichia risticii separated from host constituents by renografin gradient centrifugation.

The in vitro metabolic activities of two monocytic species of Ehrlichia were investigated. The Miyayama strain of Ehrlichia sennetsu and two strains of Ehrlichia risticii, isolated in Illinois and Maryland, were cultivated in a P388D1 mouse macrophage cell line. The ehrlichia particles from heavily infected cultures were separated from host constituents by a Renografin gradient centrifugation procedure modified from those employed for rickettsiae and chlamydiae. The metabolic activities of the isolated ehrlichiae were measured by their formation of CO2 after incubation for 1 h or longer at 34 degrees C with 14C-labeled substrates. Of the substrates tested, glutamine was utilized most vigorously. The greatest activity was obtained at pH 7.2 to 8.0, while the activity rapidly declined at pH below 7. The most favorable buffer was one that contained 0.05 M potassium phosphate as well as 0.2 M sucrose, thus affording some osmotic protection. Glutamate was utilized to a much lesser extent than glutamine, and glucose was not utilized at all. No consistent differences in metabolic activities among the three strains were observed.

Amino Acids↗
PubMed1988

Detection of rheumatoid factors of different isotypes by ELISA using biotinylated avian antibodies.

An enzyme-linked immunosorbent assay (ELISA) using biotinylated avian antibodies has been developed for the detection of rheumatoid factors (RF) of various isotypes in human sera. The avian antibodies were obtained from the egg yolks of hens immunized with human IgA, IgG and IgM and were purified by affinity chromatography. These reagents made it possible to detect each of the three isotypes of RF present in the same serum and avoided false positives since the Fc epitopes of avian immunoglobulins are not recognized by the antibody combining site of RF.

Animals↗
PubMed1988

Leukocyte subsets in the granulomatous response produced after inoculation with Mycobacterium leprae-BCG in lepromatous patients.

Leukocyte subsets present in the granulomatous response produced after the inoculation of a mixture of Mycobacterium leprae and BCG in lepromatous leprosy patients were characterized in situ using monoclonal antibodies and an immunoperoxidase technique. The granuloma produced after M. leprae-BCG inoculation showed a distribution pattern similar to tuberculoid granulomas. T lymphocytes bearing the CD8 phenotype (T cytotoxic/suppressor) were sequestered to the periphery of the epithelioid tubercles and T helper-inducer CD4+ lymphocytes were distributed throughout the infiltrate. Langerhans cells CD1+ were increased in the epidermis, and in dermis they were localized mainly in the mantle surrounding the granuloma. Most of the dermal infiltrate produced after the inoculation or M. leprae-BCG expresses the HLA-DR antigen. Similarly, most keratinocytes were also positive to this MHC antigen. The granulomatous response to BCG was similar to the inoculation of a mixture of M. leprae-BCG, however acid-fast bacilla were still present. The inoculation of M. leprae produced a macrophage granuloma with no clearing of the bacilla which resembles the lepromatous leprosy granuloma.

Antibodies, Monoclonal↗