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E Weiss

Publications and source records attributed to E Weiss.

At least 325 records · Page 18Linked to original sources
PubMed1965

Adenosine Triphosphate and Other Requirements for the Utilization of Glucose by Agents of the Psittacosis-Trachoma Group.

Weiss, Emilio (Naval Medical Research Institute, Bethesda, Md.). Adenosine triphosphate and other requirements for the utilization of glucose by agents of the psittacosis-trachoma group. J. Bacteriol. 90:243-253. 1965.-The agent of meningopneumonitis cultivated in the allantoic cavity of chick embryos and purified by differential centrifugations was employed for most of the studies of the requirements for glucose utilization. The evolution of C(14)O(2) from glucose-1-C(14) was used as the criterion of metabolic activity in most experiments. The rate of glucose utilization increased somewhat during the first hour of incubation at 34.4 C and became approximately constant during the second hour. Changes in glucose concentration from 1 to 5 mm did not appreciably affect metabolic activity. More vigorous CO(2) production was obtained when the ratio of K(+)-Na(+) was >1 and, under certain conditions, when the concentration of inorganic phosphate was relatively high (0.05 m). Glucose utilization was entirely dependent on added adenosine triphosphate (ATP) and Mg(++). The effect of ATP was greatly reduced when the microorganisms were partially disrupted with sonic energy. Adenosine diphosphate (ADP) could be substituted for ATP, but the activity was reduced to less than 20%. ATP was not required when glucose-6-phosphate was substituted for glucose. With ADP and glucose, glucose-6-phosphate was an effective competitor of glucose utilization. Nicotinamide adenine dinucleotide phosphate (NADP) enhanced CO(2) production from carbon 1, but not from other carbons, with glucose and, especially, glucose-6-phosphate as substrates. ATP and NADP produced the above-described effects only when their concentrations were comparable to those of the substrates. These concentrations always exceeded the amount of CO(2) produced (0.05 to 0.5 mumole/mg of agent protein). The concentration of NADP could be reduced when oxidized glutathione was added. Diphosphothiamine had no effect on CO(2) production. Qualitatively similar results were obtained with the agent of trachoma purified from yolk sac. These experiments furnish evidence that agents of the psittacosistrachoma group, despite their enzymatic capabilities, require an exogenous source of energy.

Journal Article↗
PubMedDate not supplied

Comparative interaction kinetics of two recombinant Fabs and of the corresponding antibodies directed to the coat protein of tobacco mosaic virus.

Two recombinant Fab fragments, 57P and 174P, recognizing peptide 134-146 of the coat protein of tobacco mosaic virus have been cloned, sequenced and expressed in Escherichia coli. They differ by 15 amino acid changes in the sequence of their variable region. The interaction kinetics of the Fabs with the wild-type and four mutant peptides have been compared using a BIAcoreTM biosensor instrument. The recombinant Fab 174P had the same reactivity as the Fab fragment obtained by enzymatic cleavage of monoclonal antibody 174P. The two recombinant Fabs recognized the various peptides in the same ranking order but Fab 174P consistently dissociated somewhat faster from the peptides compared to Fab 57P. The two whole antibodies showed the same relative differences in reactivity as the two recombinant Fabs. The location of amino acid changes was visualized on a model structure of the Fab. Differences in dissociation rates of the two antibodies are most likely due to changes located at the periphery of the antigen-combining site and/or at the interface between the light and heavy chain domains. Our results demonstrate the feasibility of detecting very small differences in binding affinity by the biosensor technology, which is a prerequisite for assessing the functional effect of limited structural changes.

Amino Acid Sequence↗
PubMedDate not supplied

Targetting of the N-terminal domain of the human papillomavirus type 16 E6 oncoprotein with monomeric ScFvs blocks the E6-mediated degradation of cellular p53.

The E6 protein of cancer-associated human papillomavirus type 16 (HPV16) binds to cellular p53 and promotes its degradation through the ubiquitin pathway. In an attempt to identify the regions of E6 that could be targetted for functional inhibition, we generated monoclonal antibodies to the HPV16 E6 oncoprotein (16E6) and analysed their effect on E6-mediated p53 in vitro degradation. The isolated antibodies recognize the 16E6 oncoprotein expressed in the CaSki carcinoma cell line and strongly inhibit the proteolysis of p53 in vitro by binding specifically to a region of 10 residues located at the N-terminal end of 16E6. The variable regions of these antibodies were cloned and expressed in E. coli as single chain Fvs (scFvs). Purified scFvs were present in monomeric form and totally abolished 16E6-mediated p53 degradation by preventing the formation of E6/p53 protein complexes. Our results demonstrate that monovalent binding of scFvs to the N-terminal end of 16E6 abrogates the biological mechanisms leading to the degradation of p53, and they suggest that this region of 16E6 may be a useful in vivo target for blocking the oncogenic activity of HPV16 E6 protein.

Amino Acid Sequence↗
PubMedDate not supplied

Expression of the CD6 T lymphocyte differentiation antigen in normal human brain.

Antigens shared by the immune and central nervous systems (CNS) have been described repeatedly. The present study reports the expression of the CD6 lymphocyte differentiation antigen in normal human brain evidenced by immunohistochemistry and Northern blot analysis. A panel of various anti-CD6 monoclonal antibodies (mabs) tested on serial cryostat sections identified CD6-positive cells randomly scattered in parenchyma of all examined brain areas. Northern blot analysis with a highly sensitive cRNA probe revealed a 3.1 kb CD6-specific mRNA in various brain regions, especially in basal ganglia and cortex cerebellum. Staining with mabs raised against different hematopoietic cell types, as well as hybridization with probes specific for the beta- and gamma-T cell receptor (TCR) chains support the notion that CD6 is expressed by original brain cells. The nature of the CD6-positive cell type and possible functions of shared antigens in immune and nervous systems are discussed.

Antibodies, Monoclonal↗
PubMedDate not supplied

Use of rabbit Fab'-peroxidase conjugates prepared by the maleimide method for detecting plant viruses by ELISA.

In contrast to antibodies conjugated to enzyme with glutaraldehyde or by the periodate method, monomeric Fab' fragments conjugated to enzyme by means of a maleimide compound are not adversely affected by the conjugation procedure. We used such Fab'-enzyme conjugates prepared with antibody to tobacco mosaic virus (TMV), to TMV coat protein and to rabbit IgG for the detection of different tobamoviruses by direct and indirect double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). Compared to conjugates prepared by other methods, the sensitivity of TMV detection with Fab'-enzyme conjugates by direct DAS-ELISA was markedly increased. However, because of their monomeric nature, these FAb'-enzyme conjugates did not cross-react with serologically related tobamoviruses. Anti-globulin Fab'-enzyme conjugate was found to be the most efficient anti-globulin conjugate for detecting TMV by indirect DAS-ELISA. Because of their high sensitivity and serotype specificity, FAb'-enzyme conjugates are useful for detecting low amounts of contaminating viruses present in crude viral preparations.

Animals↗
PubMedDate not supplied

[In vitro study of a paclitaxel-radiotherapy combination on a human epidermoid tumor cell line].

PURPOSE: Paclitaxel is an agent which stabilizes microtubules, and has been shown to block different cells in the G2/M phase of the cell cycle and thus to modulate their radioresponsiveness. We investigated the radiosensitizing potential of paclitaxel in human head and neck cancer cells. MATERIALS AND METHODS: ZMK-1 cells were incubated with paclitaxel for 3, 9, or 24 h before or during 24 h after irradiation. Paclitaxel concentrations of 70 nM, 7 nM, and 0.7 nM were chosen to obtain equivalent toxicity at the different incubation times: 3 h, 9 h, and 24 h, respectively. Radiation doses ranged from 0 to 8 Gy using 60Co source. Cell survival was measured by a standard clonogenic assay after a 9-day incubation. Flow cytometry was used to measure the capacity of paclitaxel to accumulate cells in the G2/M phase. RESULTS: Paclitaxel alone possessed cytotoxicity dependent on time and concentration. There was a total of 40% of cells accumulated in G2/M after 24-36 h. When combined with radiation, the 9 h preincubation resulted in a radiosensitization. The 3 h pre-incubation as well as the 24 h post-incubation resulted in an infra-additive effect. CONCLUSION: In our cells a radiosensitizing effect of paclitaxel could not be demonstrated unambiguously. The blockage of the cells in the G2/M phase is not the only mechanism to explain the potential radiosensitization of paclitaxel.

Drug Screening Assays, Antitumor↗
PubMedDate not supplied

Delivery room resuscitation decisions for extremely low birthweight infants in California.

OBJECTIVE: To characterize physician-parent counseling and delivery room resuscitation of extremely low birthweight (ELBW) infants. STUDY DESIGN: Cross-sectional survey of 473 California neonatologists detailing counseling patterns, resuscitation thresholds, and acceptance of parental decision making. RESULTS: The response rate was 61%. After 23 weeks' gestation, > 80% of neonatologists counseled parents expecting ELBW infants. All (> 99%) counseled parents about mortality; > 25% reported not discussing limiting resuscitation or death despite resuscitation. Decisions to limit resuscitation were affected by congenital anomalies, parents' wishes, or perceptions of pain, suffering, and quality of life. Nearly 70% of neonatologists supported parental decision making at 22 to 23 weeks, whereas 66% to 74% responded that parents should not be allowed to make nonresuscitation decisions after 26 weeks. Median resuscitation thresholds were 23 weeks (range 20-28) and 500 g (range 350-1000). CONCLUSIONS: Neonatologists' failure to discuss nonresuscitation options, variations in resuscitation thresholds, and unwillingness to accept nonresuscitation decisions for more mature ELBW infants may restrict parental decision making.

Adult↗
PubMedDate not supplied

Bone marrow response to acute and chronic Trypanosoma congolense infection in multimammate rats (Mastomys coucha).

The femoral bone marrow of multimammate rats (n=90), aged 3-8 weeks, experimentally infected with different doses of Trypanosoma congolense was examined by light and electron microscopy. Some animals died from trypanosomosis, but groups of 10 were killed at 4-8, 9-16, 20-24, 30, 40, 50 and 60 days post-infection (dpi). In the acute stage of infection (4-8 dpi) the bone marrow invariably showed a striking increase in erythropoiesis, characterized by an increase in the number of mitotic figures and erythroblastic islands and by a marked decrease in the myeloid:erythroid cell ratio. Later in the infection, erythropoietic activity decreased, while erythrophagocytosis, granulopoiesis, megakaryopoiesis and plasma cell population increased. In chronic infection (16-60 dpi), erythropoietic activity decreased, while intra- and extra-vascular erythrophagocytosis greatly increased. There was also an increase in the bone marrow stroma cells. Excessive erythrophagocytosis by these cells led to the formation of myelin figures and cytoplasmic telephagolysosomes. Degeneration and necrosis of neutrophils lining the adluminal surfaces of the blood sinuses were observed. It is concluded that in the acute stage of the infection, the bone marrow is responsive to the anaemia and that in the chronic stage, dyserythropoiesis and increased erythrophagocytosis by the expanded and activated cells of the mononuclear phagocytic system play an important role in the production of anaemia.

Acute Disease↗
PubMedDate not supplied

Case report: echocardiographic observations in patients with Friedreich's ataxia.

Echocardiography was performed on 11 patients with Friedreich's Ataxia. Eight of 11 had asymmetric septal hypertrophy and systolic anterior motion of the anterior leaflet of the mitral valve at rest or after inhalation of amyl nitrite. Two patients had concentric left ventricular hypertrophy. In view of this high incidence of hypertrophic cardiomyopathy, echocardiography is suggested as part of the routine evaluation of the patient with Friedreich's Ataxia.

Adolescent↗
PubMedDate not supplied

Immunohistological and immuno-electron microscopic localization of fibronectin in chicken bone marrow.

Fibronectin (FN) was immunolocated in chicken bone marrow with the PAP-technique by light and electron microscopy. A pre-embedding method was employed for immunolabelling the specimen for electron microscopy. Blood vessels and lining cells of capillaries and sinusoids were labelled for FN. Monocytes, intrasinusoidal macrophages, and stromal elements in the extrasinusoidal compartment. The distribution of FN in the chicken bone marrow supports the assumption that FN facilitates extravascular haematopoiesis, especially migratory processes, whereas its contribution to intravascular haematopoiesis seems less likely and needs further investigation.

Animals↗
PubMedDate not supplied

[Brain-specific creatine kinase (CKBB) in umbilical cord blood. A prognostic parameter in chronic intrauterine hypoxia?].

Elevated levels of brain type creatine isoenzyme (CKBB) have been demonstrated in serum after brain cell injury in neonates. A hypoxic lesion of the membrane permeability of the CKBB rich brain cells may lead to an increased enzyme leakage into the serum. As an increased release from the fetal brain as a result of intermittent compression and decompression of the fetal head during labour and after rupture of membranes may occur without hypoxic damage, only pregnancies which were terminates by cesarean section were studied. No mother went into first stage of labour and no rupture of membranes occurred. Three study groups were defined. The control group (elective cesarean section for breech presentation) showed CKBB enzyme activities below 15 U/l. A group with emergency cesarean sections had low CKBB values too, despite acidotic pH-values (pH < 7.20) at birth. The third group included fetuses which were delivered by cesarean section because of a pathological fetal heart rate tracing and intrauterine growth retardation. 6 out of 40 umbilical cord sera in this group showed elevated CKBB enzyme activities. If there was an additional fetal acidosis an increased neurological morbidity and neonatal mortality was seen.

Asphyxia Neonatorum↗
PubMedDate not supplied

Electron-microscope studies on the pathogenesis of infectious bursal disease after intrabursal application of the causal virus.

Intrabursal application of infectious bursal disease virus (IBDV) is of advantage in studying sequential morphological events since the time of infection of the bursa is exactly known. A highly pathogenic strain caused first clinical symptoms 12 hr postinfection (PI) and death 24-30 hr PI. These are respectively 12 and 18 hr earlier than after per-oral infection. Numerous virus particles 53-58 nm in size, arrayed in a crystalline pattern and not surrounded by a membrane, are first found 6 hr PI in the cytoplasm of normal-looking lymphoid cells and macrophages. Some of the particles are less electron-dense and obviously immature; others have no core and therefore are regarded as incomplete. However, there is no evidence for the presence of more than one type of virus particle. Seven hr PI a membrane to segregate the virus clusters is formed, finally leading to autophagic vacuoles containing virus particles and cellular remnants. Within these vacuoles virus degradation takes part, though most of the infected cells, particularly the lymphoid cells, undergo cellular lysis, release the virions, and spread the infection to other cells of the bursa. At 18 hr PI the follicles are almost depleted of lymphoid cells. The findings show that early replication of IBDV is in the lymphoid cells and macrophages. These cells represent the main areas of virus multiplication, but the virions also can replicate in heterophils, reticulum cells, and reticular epithelial cells of the bursa.

Animals↗
PubMedDate not supplied

[Clinical management of fetuses with diastolic zero or negative flow of the umbilical arteries: duration of clinical observation and fetal outcome].

40 fetuses with diastolic zero flow or diastolic reverse flow of the umbilical arteries were examined in a longitudinal analysis. While 35 fetuses had to be delivered by cesarean section, three fetuses showed intrauterine death which seemed to be inevitable, and two fetuses were delivered vaginally without signs of fetal distress. In one third of our study group the cesarean section was necessary immediately after admittance to the obstetrical ward. The remaining two thirds were clinically observed up to one or up to four weeks respectively. The shorter the interval between diagnosis of the zero flow and delivery the larger was the gestational age, the amount of severe fetal acidosis, and the number of emergency cesarean section. The clinically observed groups were delivered significantly earlier and fetal blood gases were normal. Only one case of emergency cesarean section was observed. The bad fetal outcome of fetuses with diastolic zero flow of the umbilical arteries is therefore caused by the hypoxia and asphyxia of the not hospitalized and clinically observed high risk pregnancies. The early diagnosis of this flow pattern and the immediate clinical admittance and surveillance with doppler flow measurements and CTG-monitoring including the oxytocin challenge test allows to reduce the amount of fetal acidosis by adequate timing of the delivery. Acute placental insufficiency in cases with diastolic zero or reverse flow commonly occurs before the 33. week of pregnancy.

Asphyxia Neonatorum↗