Differential diagnosis of various forms of primary aldosteronism

The blood pressure was investigated in the common left carotid artery (LC), in the left atrium (LA), in the pulmonary artery (PA) and in the right atrium (RA). After adrenaline injection the blood pressure rised rapid and simulatneously in all four regions. After vasopressin injection the blood pressures rised sequence in LC, in LA and PA. The blood pressure in RA in this time was unchanged. These results indicate that primary causes of the lung oedema after adrenaline or vasopressin are different.     

Simultaneous detecting of C3 phenotypes and C3 cleavage by immunofixation]

The C3 phenotypes and C3 cleavage were simultaneously detected using cellulose acetate electrophoris followed by immunofixation and desitometry. Compared to crossed-immunoelectro-phoresis, this method has some advantages in resolution between different bands and was much more rapid, less expensive and more sensitive.     

Differential cleavage of oligonucleotides containing the benzene-derived adduct, 1,N6-benzetheno-dA, by the major human AP endonuclease HAP1 and Escherichia coli exonuclease III and endonuclease IV

We report here that the newly synthesized DNA adduct, 1,N6-benzetheno-dA (pBQ-dA), in defined oligonucleotides [Chenna and Singer, Chem. Res. Toxicol., 8, 865-874], is a substrate for the major human AP endonuclease, HAP1, and the Escherichia coli AP endonucleases, exonuclease III and endonuclease IV. The mechanism of cleavage is identical to that reported previously for 3,N4-benzetheno-dC (pBQ-dC) and leads to a phosphodiester bond cleavage 5' to the adduct. There are, however, significant differences in the rate of cleavage of this adduct by these enzymes. The two bacterial AP endonucleases are both much more efficient than the human repair enzyme. In addition, using two random oligodeoxynucleotide sequences containing a single pBQ-dA, exonuclease III and endonuclease IV are similarly active, while HAP1 shows a distinct sequence preference of approximately 10-fold in efficiency of cleavage. The repair of this adduct by the three recombinant enzymes is further confirmed by using both active site mutant HAP1 proteins and by E.coli mutant strains lacking exonuclease III and/ or endonuclease IV. This sequence-dependent repair of pBQ-dA by HAP1 may play an important role in modulating benzene-induced carcinogenesis.     

Control of mucin molecular forms expression by salivary protease: differences with caries

1. A protease activity capable of degradation of the high mol. wt salivary mucus glycoprotein to a low mol. wt glycoprotein form was identified in human submandibular gland secretion. 2. The protease exhibited optimum activity at pH 7.0-7.4, and gave on SDS-PAGE under reducing conditions two major protein bands of 48 and 53 kDa. The enzyme showed susceptibility to PMSF, alpha 1antitrypsin, and egg white and soybean inhibitors, a characteristic typical to serine proteases. 3. The activity of the protease towards the high mol. wt mucus glycoprotein was found to be 3.8-fold higher in submandibular gland secretion of caries-resistant individuals than that of caries-susceptible. Furthermore, the enzyme from both groups displayed greater activity against the mucus glycoprotein of caries-resistant subjects. 4. Since the low mol. wt salivary mucus glycoprotein form is more efficient in bacterial clearance than the high mol. wt mucin, the enhanced expression of this indigenous salivary protease activity towards mucin may be the determining factor in the resistance to caries.     

Intracellular redistribution of truncated La protein produced by poliovirus 3Cpro-mediated cleavage

The La autoantigen (also known as SS-B), a cellular RNA binding protein, may shuttle between the nucleus and cytoplasm, but it is mainly located in the nucleus. La protein is redistributed to the cytoplasm after poliovirus infection. An in vitro translation study demonstrated that La protein stimulated the internal initiation of poliovirus translation. In the present study, a part of the La protein was shown to be cleaved in poliovirus-infected HeLa cells, and this cleavage appeared to be mediated by poliovirus-specific protease 3C (3Cpro). Truncated La protein (dl-La) was produced in vitro from recombinant La protein by cleavage with purified 3Cpro at only one Gln358-Gly359 peptide bond in the 408-amino-acid (aa) sequence of La protein. The dl-La expressed in L cells was detected in the cytoplasm. However, green fluorescence protein linked to the C-terminal 50-aa sequence of La protein was localized in the nucleus, suggesting that this C-terminal region contributes to the steady-state nuclear localization of the intact La protein in uninfected cells. The dl-La retained the enhancing activity of translation initiation driven by poliovirus RNA in rabbit reticulocyte lysates. These results suggest that La protein is cleaved by 3Cpro in the course of poliovirus infection and that the dl-La is redistributed to the cytoplasm. dl-La, as well as La protein, may play a role in stimulating the internal initiation of poliovirus translation in the cytoplasm.     

Correlation between structural transformation and cleavage of the major head protein of T4 bacteriophage

Human infections associated with Yersinia enterocolitica in Hungary in the years 1969-1974 have been surveyed. During this period the public health laboratory network isolated 1355 strains from 1096 persons. The number of isolates according to sero-groups was: 1343 O3, 6 O9, 2 O1, 2a, 3 and 1 strain for O5, O6, O1O and O15 each. (ii) A total of 2192 serum specimens from patients gave positive agglutination reaction with antigen O3 in 26.8%, with antigen O9 in 3.2%. (iii) Fifty-six per cent of bacteriologically positive persons had enteritis. Other clinical forms (pseudoappendicitis and other abdominal complaints, erythema nodosum, rheumatoid arthritis) were encountered in O 1-2.7%. Symptomless excreters of Y. enterocolitica amounted to 23.1% of all positive persons. (iv) Patients with enteritis and symptomless excreters were rather evenly distributed between 10 and 60 years of age; 1--9-year-old children were affected more frequently (47.7% of all positive persons). Six distribution was, males: females = 1.5 : 1. In seasonal incidence yersiniosis differed from other enteric diseases: it showed a peak in the autumn-winter months. Sporadic cases and family outbreaks were the most frequent; epidemic infections in nurseries were also recorded. (v) Out of 59 animal strains 39 group O3 cultures were isolated from pigs, which may be assumed as the most important reservoir of yersinosis in Hungary.     

Epitope cleavage by Leishmania endopeptidase(s) limits the efficiency of the exogenous pathway of major histocompatibility complex class I-associated antigen presentation

The activation of CD8+ T cell responses is commonplace during infection with a number of nonviral pathogens. Consequently, there has been much interest in the pathways of presentation of such exogenous antigens for major histocompatibility complex class I-restricted recognition. We had previously shown that Leishmania promastigotes transfected with the ovalbumin (OVA) gene could efficiently target OVA to the parasitophorous vacuole (PV), with subsequent recognition by class II-restricted T cells. We now report the results of studies aimed at evaluating the PV as a route of entry into the exogenous class I pathway. Bone marrow-derived macrophages can present soluble OVA (albeit at high concentrations) to the OVA(257-264)-specific T cell hybridoma 13.13. In contrast, infection with OVA-transfected Leishmania promastigotes failed to result in the stimulation of this hybridoma. This appeared unrelated to variables such as antigen concentration, parasite survival, and macrophage activation status. These results prompted an analysis of the effects of promastigotes on class I peptide binding using RMA-S cells and OVA(257-264). Our data indicate that the major surface protease of Leishmania, gp63, inhibits this interaction by virtue of its endopeptidase activity against the OVA(257-264) peptide. The data suggest that this activity, if maintained within the PV, would result in loss of the OVA(257-264) epitope. Although we can therefore draw no conclusions from these studies regarding the efficiency of the PV as a site of entry of antigen into the exogenous class I pathway, we have identified a further means by which parasites may manipulate the immune repertoire of their host.     

Proteolytic cleavage of urokinase-type plasminogen activator by stromelysin-1 (MMP-3)

Matrix metalloproteinase-3 (MMP-3, or stromelysin-1) specifically hydrolyzes the Glu143-Leu144 peptide bond in 45-kDa single-chain urokinase-type plasminogen activator (scu-PA) and in its two-chain (tcu-PA) derivative, yielding a 17-kDa NH2-terminal domain comprising the u-PA receptor (u-PAR) binding site and a 32-kDa COOH-terminal moiety containing the serine proteinase domain of u-PA. The conversion is completely abolished in the presence of the MMP inhibitors EDTA or 1,10-phenanthroline. Biospecific interaction analysis indicates that binding of MMP-3 occurs through the 32-kDa fragment. The 32-kDa fragment derived from scu-PA (scu-PA-32k) has a specific activity of 相似文献   

Hydrogen-induced cleavage fracture of Fe3Al-based intermetallics

Hydrogen-induced fracture of ductile Fe₃Al-based intermetallics was studied through mechanical testing, fracture surface observation, andin situ transmission electron microscopy (TEM) tests of tensile specimens. Mechanical properties of ordinary ductile X-80 pipeline steel (low-alloy steel) were tested and compared with Fe₃Al intermetallics. Elongations of the Fe₃Al alloy decreased from 14 to 10 pct, with increases in the strain rate from 10⁻⁶ to 10⁻³/s. The elongation reduction of Fe₃Al was caused by the hydrogen-induced fracture. There was no elongation reduction when the testing was done in mineral oil. Non-necking occurred near the fracture section, and the fracture surfaces mainly consist of cleavage and partial intergranular morphologies. Elongation near the fracture surface of the Fe₃Al intermetallics was about 14 pct, which is the same as the total elongation. For the pipeline steel, however, an elongation near the fracture cross section was greater than 130 pct, which was much higher than its total elongation of 17 pct.In situ TEM observation on a tensile test sample showed crack propagation accompanied by dislocation plasticity. When the Fe₃Al was precharged cathodically, the crack tip was sharp. Its radius was much less than that obtained without hydrogen charging. The crack propagated along the grain boundary for the charged specimens, but penetrated the grain boundary for the specimen without hydrogen charging. Effects of hydrogen on plastic deformation and grain-boundary cracking are discussed in this article.     

Differential expression of uterine progesterone receptor forms A and B during the menstrual cycle

Recent studies suggest that the progesterone receptor isoforms (PR-A and PR-B) activate genes differentially and that PR-A may act as a repressor of PR-B function. Hence, the absolute and relative expression of the two isoforms will determine the response to progesterone. We have measured their relative expression in the uterus of cycling women who underwent endometrial biopsy. PR isoforms were identified on blots of SDS-PAGE gels by reaction with the AB-52 antibody after immunoprecipitation from endometrial extract. Both isoforms were highest in the peri-ovulatory phase, but levels of PR-A were always higher than those of PR-B. The ratio of PR-A to PR-B changed during the menstrual cycle. Between days 2 and 8, PR-B is almost undetectable and the A:B ratio is >10:1. From days 9 to 13, the ratio is about 5:1, and it is about 2:1 between days 14 and 16. Thereafter, PR-B dwindles rapidly and is virtually undetectable at the end of the cycle. In various hypoestrogenic environments, PR-B expression was reduced. However, exogenous estrogens in the follicular phase in the form of oral contraceptives, enhanced PR-B expression. These data support the possibility that progesterone acts through cycle-specific PR isoforms.     

Dominance is the major genetic basis of heterosis in rice as revealed by QTL analysis using molecular markers

A set of 194 F7 lines derived from a subspecific rice cross showing strong F1 heterosis was backcrossed to the two parents. The materials (388 BC1F7 lines, 194 F8 lines, two parents, F1) were phenotyped for 12 quantitative traits. A total of 37 significant QTLs (LOD > or = 2.0) was detected through 141 RFLP markers in the BC1F7 populations. Twenty-seven (73%) quantitative trait loci (QTLs) were detected in only one of the BC1F7 populations. In 82% of these cases, the heterozygotes were superior to the respective homozygotes. The remaining 10 (27%) QTLs were detected in both BC1F7 populations, and the heterozygote had a phenotype falling between those of the two homozygotes and in no instances were the heterozygotes found to be superior to both homozygotes. These results suggest that dominance complementation is the major genetic basis of heterosis in rice. This conclusion was strengthened by the finding that there was no correlation between most traits and overall genome heterozygosity and that there were some recombinant inbred lines in the F8 population having phenotypic values superior to the F1 for all of the traits evaluated--a result not expected if overdominance was a major contributor to heterosis. Digenic epistasis was not evident.