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Biomedical subjects

E Weiss

Publications and source records attributed to E Weiss.

At least 73 records · Page 4Linked to original sources

[Changes in the plasma concentration of vitamin A, vitamin E and beta-carotene in polytrauma patients and in patients with osteitis in relation to course of illness].

In 17 patients with osteitis and 16 polytraumatized patients changes in the plasma levels of vitamin A, vitamin E and beta-carotene were investigated. Plasma samples taken preoperatively, daily during the first three days and then twice a week postoperatively were analysed for fat-soluble vitamins by high performance liquid chromatography (HPLC). Significant changes in plasma levels of all three components depending on the outcome of injury were found in all patients. Increased levels were observed in patients that survived the injury, while in those who died a significant decrease was observed. Recommendations regarding the supplementation with these vitamins in clinical practice can not be made based on these results, but substitute might prove beneficial for vitamin E in certain types of injury.

Adult↗

Expression in Escherichia coli of Y5-mutant and N-terminal domain-deleted DNA gyrase B proteins affects strongly plasmid maintenance.

Escherichia coli DNA gyrase B subunit (GyrB) is composed of a 43-kDa N-terminal domain containing an ATP-binding site and a 47-kDa C-terminal domain involved in the interaction with the gyrase A subunit (GyrA). Site-directed mutagenesis was used to substitute, in both the entire GyrB subunit and its 43-kDa N-terminal fragment, the amino acid Y5 by either a serine (Y5S) or a phenylalanine residue (Y5F). Under standard conditions, cells bearing Y5S or Y5F mutant GyrB expression plasmids produced significantly less recombinant proteins than cells transformed with the wild-type plasmid. This dramatic decrease in expression of mutant GyrB proteins was not observed when the corresponding N-terminal 43-kDa mutant plasmids were used. Examination of the plasmid content of the transformed cells after induction showed that the Y5F and Y5S GyrB protein level was correlated with the plasmid copy number. By repressing tightly the promoter activity encoded by these expression vectors during cell growth, it was possible to restore the normal level of the mutant GyrB encoding plasmids in the transformed bacteria. Treatment with chloramphenicol before protein induction enabled large overexpression of the GyrB mutant Y5F and Y5S proteins. In addition, the decrease in plasmid copy number was also observed when the 47-kDa C-terminal fragment of the GyrB subunit was expressed in bacteria grown under standard culture conditions. Analysis of DNA supercoiling and relaxation activities in the presence of GyrA demonstrated that purified Y5-mutant GyrB proteins were deficient for ATP-dependent gyrase activities. Taken together, these results show that Y5F and Y5S mutant GyrB proteins, but not the corresponding 43-kDa N-terminal fragments, compete in vivo with the bacterial endogenous GyrB subunit of DNA gyrase, thereby reducing the plasmid copy number in the transformed bacteria by probably acting on the level of negative DNA supercoiling in vivo. This competition could be mediated by the presence of the intact 47-kDa C-terminal domain in the Y5F and Y5S mutant GyrB subunits. This study demonstrates also that the amino acid Y5 is a crucial residue for the expression of the gyrase B activity in vivo. Thus, our in vivo approach may also be useful for detecting other important amino acids for DNA gyrase activity, as mutations affecting the ATPase activity or the GyrB/GyrB or GyrB/GyrA protein interactions.

Catalysis↗

Intraspinal high-grade astrocytoma in a child--rationale for chemotherapy and more intensive radiotherapy?

Intraspinal high-grade astrocytoma in children is an extremely rare tumor entity with disappointingly short survival times despite multimodality treatment. We report on a girl with anaplastic astrocytoma at level T9-11, who was treated with tumor resection, multidrug chemotherapy and irradiation. Local recurrence was diagnosed after 16 months. With reference to other cases reported in the literature, the course of disease, achievements and limitations of currently available therapeutic options, and potential future strategies are discussed.

Adolescent↗

Cooperative effects of mutations in a recombinant Fab on the kinetics of antigen binding.

Recombinant Fabs, 57P and 174P, recognizing peptide 134-151 of the coat protein of tobacco mosaic virus, differ by 15 amino acid changes in the sequence of their variable region. Kinetic analysis using BIAcore showed that they recognized five peptide variants in the same ranking order, but that Fab 174P consistently dissociated faster from the peptides compared to Fab 57P. In order to identify amino acid substitutions that are responsible for differences in dissociation rates of the two Fabs, six hybrid Fabs have been constructed by exchanging three DNA segments. Four single and five multiple mutants were obtained by site-directed mutagenesis. All Fabs recognized variant peptides in a similar ranking order. The high precision of biosensor measurements made it possible to detect small contributions to dissociation kinetics of at least five substitutions, as well as the presence of small-magnitude non-additive effects of multiple substitutions. Our results demonstrate the cooperative influence on dissociation kinetics of amino acid residues located away from each other and away from the Fab combining site.

Antigens↗

Durometer measurements of skin induration in venous disease.

BACKGROUND: The degree of skin induration (lipodermatosclerosis) around venous ulcers has prognostic significance; however, objective measurements are needed to assess the induration. The durometer, an engineering instrument used to measure the hardness of metals and plastic, has recently been adapted to assess skin induration. OBJECTIVE: The purpose of this study was to measure skin induration and its relationship to skin ulceration by the use of a durometer, and to determine the influence of edema, if any, on durometer measurements. METHODS: The degree of skin induration on the medial leg was determined in six sequential, nonselected patients with lipodermatosclerosis and leg ulcers, and in five normal volunteers by using a blinded observer's clinical score (0 = normal to 3 = maximal induration) and a hand-held Type 0 durometer. In addition, durometer readings in 14 patients with edema and eight control subjects were taken on the tibia, the dorsum of the foot, and behind the ankle. RESULTS: Durometer readings in patients with leg ulcers and lipodermatosclerosis diminished as one measured from the superior edge of the ulcer to the knee (r = 0.925). The higher the clinical skin score the higher were the durometer readings (P = 0.0062). The presence of edema did not influence durometer measurements. CONCLUSION: The durometer is an effective and reliable instrument for measuring the degree of skin induration in venous ulceration and its readings are not affected by edema. Ulcers occur in skin most affected by lipodermatosclerosis.

Dermatology↗

Characterization of the proliferation state in canine mammary tumors by the standardized AgNOR method with postfixation and immunohistologic detection of Ki-67 and PCNA.

Paraffin-embedded tissue sections of 96 surgically removed mammary tumors from female dogs were analyzed for their proliferation state using three different methods. The AgNOR method, originally developed by Ploton and coworkers in 1986, modified and standardized by the AgNOR committee, is an easy, inexpensive silver-staining procedure used to determine cell proliferation and prognosis of various tumors. Due to the standardized staining protocol of the AgNOR method and a postfixation step, results obtained were of excellent quality for image-analysis processing. The growth fraction was evaluated by counting of immunohistologically positive-stained cells for Ki-67 or proliferating-cell nuclear antigen (PCNA). The values determined were, in general, lower with Ki-67 (MIB1) than with PCNA (PC10). Nevertheless, the labeling indices of these antigens correlated significantly (P < 0.001). Though the differences of the means between the tumor groups according to the classification system of the World Health Organization were significant for all three investigated methods (P < 0.001), there was a considerable overlap between the tumor groups concerning all investigated parameters. An exploratory data analysis (multivariate analysis) as performed to evaluate the prognostic relevance of the three methods including further anamnestic, clinical, gross, and histopathologic variables. Besides the histopathologic diagnosis (survival P < 0.001; survival time P < 0.05; reappearance of tumor growth P < 0.05), only the PCNA-labeling index (time until reappearance of tumor growth P < 0.001) was of prognostic significance.

Adenoma↗

Activation of the budding yeast spindle assembly checkpoint without mitotic spindle disruption.

The spindle assembly checkpoint keeps cells with defective spindles from initiating chromosome segregation. The protein kinase Mps1 phosphorylates the yeast protein Mad1p when this checkpoint is activated, and the overexpression of Mps1p induces modification of Mad1p and arrests wild-type yeast cells in mitosis with morphologically normal spindles. Spindle assembly checkpoint mutants overexpressing Mps1p pass through mitosis without delay and can produce viable progeny, which demonstrates that the arrest of wild-type cells results from inappropriate activation of the checkpoint in cells whose spindle is fully functional. Ectopic activation of cell-cycle checkpoints might be used to exploit the differences in checkpoint status between normal and tumor cells and thus improve the selectivity of chemotherapy.

Carrier Proteins↗

The Saccharomyces cerevisiae spindle pole body duplication gene MPS1 is part of a mitotic checkpoint.

M-phase checkpoints inhibit cell division when mitotic spindle function is perturbed. Here we show that the Saccharomyces cerevisiae MPS1 gene product, an essential protein kinase required for spindle pole body (SPB) duplication (Winey et al., 1991; Lauze et al., 1995), is also required for M-phase check-point function. In cdc31-2 and mps2-1 mutants, conditional failure of SPB duplication results in cell cycle arrest with high p34CDC28 kinase activity that depends on the presence of the wild-type MAD1 checkpoint gene, consistent with checkpoint arrest of mitosis. In contrast, mps1 mutant cells fail to duplicate their SPBs and do not arrest division at 37 degrees C, exhibiting a normal cycle of p34CDC28 kinase activity despite the presence of a monopolar spindle. Double mutant cdc31-2, mps1-1 cells also fail to arrest mitosis at 37 degrees C, despite having SPB structures similar to cdc31-2 single mutants as determined by EM analysis. Arrest of mitosis upon microtubule depolymerization by nocodazole is also conditionally absent in mps1 strains. This is observed in mps1 cells synchronized in S phase with hydroxyurea before exposure to nocodazole, indicating that failure of checkpoint function in mps1 cells is independent of SPB duplication failure. In contrast, hydroxyurea arrest and a number of other cdc mutant arrest phenotypes are unaffected by mps1 alleles. We propose that the essential MPS1 protein kinase functions both in SPB duplication and in a mitotic checkpoint monitoring spindle integrity.

CDC28 Protein Kinase, S cerevisiae↗

Nocturnal periodic breathing and the development of acute high altitude illness.

We tested the hypothesis that periodic breathing (PB) at high altitude is more frequent and arterial oxygen desaturation more severe during sleep in subjects developing high altitude pulmonary edema (HAPE) or acute mountain sickness (AMS) compared with subjects remaining healthy. We registered thoraco-abdominal movement, electro-encephalogram and oxygen saturation by pulse oximeter (pSao2) in 21 subjects during the first night spent at the altitude of 4,559 m. During the subsequent stay at 4,559 m, eight subjects remained well (controls), five subjects developed AMS and eight subjects developed HAPE. PB was found in all sleep stages and the percentage PB in any sleep stage was not significantly different between groups. There was a trend towards more PB in the HAPE vs. AMS and control group lasting 80 +/- 5 (mean +/- SE), 58 +/- 7, 57 +/- 9% of analyzable time, respectively (p = 0.09). The mean nocturnal decrease of pSao2 for these groups was 8.7 +/- 1.9, 5.4 +/- 2.1, 4.8 +/- 1.2%; (p = 0.36) and the median nocturnal pSao2 was 49 +/- 3, 63 +/- 3, and 63 +/- 4% (p = 0.02). Arterial blood gas analysis before and after sleep recordings indicate that the significantly lower Sao2 in the HAPE group is secondary to gas exchange rather than ventilation. The nocturnal decrease of pSao2 did not correlate with the time of PB nor the number of desaturation events > or = 4%. These findings suggest that more frequent PB in the HAPE group is a consequence of lower Sao2 due to impairment of gas exchange.

Acute Disease↗

[Prognostic value of Doppler flow measurement of the middle cerebral artery for morbidity of premature infants with null or negative flow in umbilical arteries].

We analysed 78 fetuses with absent or reverse endiastolic flow velocities (AREDFV) of the umbilical arteries with respect to fetal acidosis, resistance index of the middle cerebral artery (MCA) and abnormal neurological evaluations. A control group was matched for gestational age and normal umbilical artery flow velocity waveforms. Fetuses with AREDFV showed an increased incidence of fetal acidosis. The number of fetuses with abnormal neurological signs was significantly increased compared to the control group. Most of these fetuses (86%) showed abnormal blood flow velocity waveforms of the middle cerebral arteries called "brain-sparing effect". The combination of premature delivery in the 30th week of gestation, severe idiopathic respiratory distress syndrome, and a resistance index under the 10th percentile in the middle cerebral arteries seems to be a risk factor of the early neurological morbidity in fetus with AREDFV.

Blood Flow Velocity↗

Yeast spindle pole body duplication gene MPS1 encodes an essential dual specificity protein kinase.

The MPS1 gene has been previously identified by a mutant allele that shows defects in spindle pole body (SPB) duplication and cell cycle control. The SPB is the centrosome-equivalent organelle in the yeast Saccharomyces cerevisiae, and it nucleates all the microtubules in the cell. We report the isolation of the MPS1 gene, which encodes an essential protein kinase homolog. The MPS1 open reading frame has been fused to those that encode the LexA protein or the GST protein and both of these constructs function in yeast. The fusion proteins have been affinity-purified from yeast extracts and the GST chimeric protein has been found to be a phosphoprotein. Both proteins have been used to demonstrate intrinsic in vitro protein kinase activity of Mps1p against exogenous substrates and itself (autophosphorylation). A mutation predicted to abolish kinase function not only eliminates in vitro protein kinase activity, but also behaves like a null mutation in vivo, suggesting that kinase activity contributes to the essential function of the protein. Phosphoamino acid analysis of substrates phosphorylated by Mps1p indicates that this kinase can phosphorylate serine, threonine and tyrosine residues, identifying Mps1p as a dual specificity protein kinase.

Amino Acid Sequence↗

One of the two common mutations causing factor XI deficiency in Ashkenazi Jews (type II) is also prevalent in Iraqi Jews, who represent the ancient gene pool of Jews.

In recent years four mutations causing factor XI deficiency have been identified in Jews of Ashkenazi (European) origin. Two of them, type II (a nonsense mutation) and type III (a missense mutation), were found to prevail among 125 unrelated Ashkenazi Jews with severe factor XI deficiency. A finding of type II mutation in four unrelated Iraqi-Jewish families raised the possibility that this mutation is also common in Iraqi Jews, who represent the ancient gene pool of the Jews. A molecular-based analysis performed in 1,040 consecutively hospitalized patients disclosed the following results: Among 531 Ashkenazi-Jewish patients, the type II allele frequency was 0.0217 and among 509 Iraqi-Jewish patients, 0.0167 (P = .50). The type III allele frequency in the Ashkenazi-Jewish patients was 0.0254, whereas none of 502 Iraqi-Jewish patients examined had this mutation. These data suggest that the type II mutation was present in Jews already 2.5 millenia ago. The data also indicate that the estimated risk for severe factor XI deficiency in Ashkenazi Jews (due to either genotype) is 0.22% and in Iraqi Jews, 0.03%, and that the estimated risk of heterozygosity in Ashkenazi Jews is 9.0% and in Iraqi Jews, 3.3%. As patients with severe factor XI deficiency are prone to bleeding after injury and patients with partial deficiency may have similar bleeding complications when an additional hemostatic derangement is present, the observed high frequencies should be borne in mind when surgery is planned for individuals belonging to these populations.

Aged↗

Recombinant CD4-IgE, a novel hybrid molecule, inducing basophils to respond to human immunodeficiency virus (HIV) and HIV-infected target cells.

Basophils and mast cells, as the main effector cells in IgE-mediated type I hypersensitivity, are involved in the elimination of parasites and, according to recent findings, may also play an important role in the defense against bacterial and viral infections. Using a genetic engineering approach we wanted to redirect this potent IgE-mediated defense system against intruding human immune deficiency virus. We constructed a recombinant CD4-IgE molecule, consisting of the two N-terminal domains of CD4 and the CH2-4 domains of the IgE heavy chain, thus providing the IgE with specificity for the gp120 of human immunodeficiency virus (HIV). The binding properties of hybrid CD4-IgE to the high-affinity receptor for IgE (Fc epsilon RI) on basophils as well as to the low-affinity receptor (Fc epsilon RII or CD23) for IgE on lymphoid cells were found to be similar to those of native IgE. At the same time, the CD4 domains of the recombinant molecule retained the gp120 binding specificity with an affinity similar to that of the native CD4. By functional tests, we demonstrated that CD4-IgE armed basophils can be triggered by free HIV and by HIV-infected cells to release their mediators. We further show that HIV-triggered basophils lead to a decreased replication of HIV in susceptible T cells. We, therefore, conclude that the type I hypersensitivity effector cells can be engaged in the elimination of HIV-infected cells, at least in vitro. Because of the strong binding of the CD4-IgE construct to the Fc epsilon RI, we assume that CD4-IgE has a short t1/2 in serum, but may similarly to IgE exhibit prolonged resident time on basophils and mast cells, which are located close to mucosal surfaces or in the connective tissue. Thus CD4-IgE could play an important role in the elimination of HIV also in vivo.

Basophils↗

Antibacterial activity of three dental liners.

PURPOSE: The purpose of the present study was to assess the antibacterial activity of the following three dental liners: Vitrebond (3M, St Paul, MN), Dycal (LD Caulk, Dentsply International, Milford, DE), and Life (Kerr, Romulus, MI). MATERIALS AND METHODS: The test was based on a modification of the agar diffusion test in which samples were placed on agar plates previously inoculated with Streptococcus mutans and were removed after predetermined time periods. The material's effect on bacterial growth was evaluated. RESULTS: Results show that Vitrebond has a strong antibacterial effect that was evident after 1 minute of direct contact with the inoculated bacteria. It was significantly more effective (P<.0001) than Dycal or Life. CONCLUSIONS: This method allows for the evaluation of the antibacterial effect of dental materials.

Analysis of Variance↗