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Biomedical subjects

R Szabo

Publications and source records attributed to R Szabo.

17 recordsLinked to original sources
PubMed2006

Matriptase inhibition by hepatocyte growth factor activator inhibitor-1 is essential for placental development.

Hepatocyte growth factor activator inhibitor-1 (HAI-1) is a Kunitz-type transmembrane serine protease inhibitor that forms inhibitor complexes with several trypsin-like serine proteases and is required for mouse placental development and embryo survival. Here we show that the essential function of HAI-1 in placentation and all other embryonic processes is to restrict the activity of the type II transmembrane serine protease, matriptase. Enzymatic gene trapping of matriptase combined with HAI-1 immunohistochemistry revealed that matriptase is co-expressed with HAI-1 in both extraembryonic and embryonic tissues. As early as embryonic day 8.5, matriptase and HAI-1 were expressed in a population of chorionic trophoblasts. Ablation of HAI-1 disrupted the epithelial integrity of this cell population, causing disorganized laminin deposition and altered expression of E-cadherin and beta-catenin. This led to a complete loss of undifferentiated chorionic trophoblasts after embryonic day 9.5 and prevented the formation of the placental labyrinth. Genetic ablation of matriptase activity in HAI-1-deficient embryos, however, restored the integrity of chorionic trophoblasts and enabled placental labyrinth formation and development to term. Furthermore, matriptase/HAI-1 double-deficient mice were phenotypically indistinguishable from matriptase single-deficient littermates.

Animals↗
PubMed2001

Cla4 protein kinase is essential for filament formation and invasive growth of Yarrowia lipolytica.

The non-conventional yeast Yarrowia lipolytica is a suitable model for the study of yeast dimorphism. In order to identify genes that may be involved in the regulation of this process, random mutagenesis was performed. This led to the isolation of monomorphic mutants that had lost the ability to grow in a hyphal form both in liquid and on solid medium. Filamentation was restored to one of the mutants by transformation with a fragment of Y. lipolytica genomic DNA containing a single 2766-bp ORF. The predicted protein has a molecular weight of 99.6 kDa and is highly homologous to the protein kinases Cla4 of Candida albicans and Saccharomyces cerevisiae, which are members of the p21-activated kinase (PAK) family. Analysis of the putative protein sequence identified conserved C-terminal catalytic, and internal Cdc42p-binding regions, as well as a pleckstrin homology domain typical of PAK kinases. The results indicate that CLA4 is a single-copy gene located on the chromosome V of Y. lipolytica. Deletion of CLA4 is not lethal, but completely eliminates the ability to form filaments and to invade agar. A strain lacking a functional CLA4 gene exhibits an aberrant distribution of chitin in the cell wall, indicating a possible role for the Cla4 protein kinase in the maintenance of cell polarity in Y. lipolytica.

Amino Acid Sequence↗
PubMed2000

The respiratory complex I in yeast: isolation of a gene NUO51 coding for the nucleotide-binding subunit of NADH:ubiquinone oxidoreductase from the obligately aerobic yeast Yarrowia lipolytica.

We have isolated a gene NUO51 coding for a homologue of the nucleotide-binding subunit of mitochondrial respiratory chain linked NADH:ubiquinone oxidoreductase from the obligately aerobic yeast Yarrowia lipolytica. DNA sequencing revealed a 1464 bp open reading frame encoding a protein with predicted molar mass of about 53.7 kDa. The sequence is highly conserved with its counterparts from filamentous fungi and represents the first yeast homologue of the NADH-binding subunit (51 kDa) of the respiratory complex 1. In addition, PFGE and Southern hybridization analysis indicate that NUO51 is a single copy gene in the genome of Y. lipolytica. The expression of NUO51 by Northern blot analysis was also examined.

Amino Acid Sequence↗
PubMed1999

Dimorphism in Yarrowia lipolytica: filament formation is suppressed by nitrogen starvation and inhibition of respiration.

In contrast to Saccharomyces cerevisiae, nitrogen starvation inhibited formation of hyphae in liquid cultures of Y. lipolytica, while carbon source did not seem to be important for filament formation. Inhibitors of mitochondrial respiration strongly suppressed the development of hyphae, indicating that energy conversion processes, and thus carbon metabolism, may be involved. pH of the medium also strongly affected the morphology, but only in the presence of a complex nitrogen source, implying that the cells respond to altered nutrition in media with different pH rather than to pH itself. The results suggest that the XPR2 gene encoding Y. lipolytica alkaline extracellular proteinase is involved in the regulation of dimorphism in this species.

Ammonium Sulfate↗
PubMed1990

Increased sensitivity of the rapid hydrophobic grid membrane filter enzyme-labeled antibody procedure for Escherichia coli O157 detection in foods and bovine feces.

Several strains of Escherichia coli O157:H7 artificially inoculated into vegetables and dairy products were recovered on hydrophobic grid membrane filters and enumerated by an enzyme-labeled antibody assay. The mean of the recoveries from 12 fresh vegetables was 108.8%, whereas that from 10 dairy products was 93.2%. Modified tryptic soy broth at 43 degrees C with shaking at 100 rpm provided optimum recovery of the organism from meat, with a sensitivity of less than or equal to 1 CFU/g, which is 10 times more sensitive than direct plating. The method performed equally well with vegetable and dairy products. Tryptic soy broth, however, under the same conditions gave the best results for fecal samples. Of 22 asymptomatic dairy cattle, reported as having positive Brucella titers when assayed with polyclonal antibodies, eight were found to contain E. coli O157 in their feces as demonstrated by the enzyme-labeled antibody assay by using monoclonal antibodies. This finding may explain some of the false-positive Brucella tests.

Animals↗
PubMed1986

Evaluation of the reversed passive latex agglutination (RPLA) test kits for detection of staphylococcal enterotoxins A, B, C, and D in foods.

Four lots of the SET-RPLA kit (Denka Seiken Co. Ltd., Tokyo), a commercial reverse passive latex agglutination test kit for the detection of staphylococcal enterotoxins A, B, C, and D in foods, have been evaluated for their efficacy. The kits showed high specificity and sensitivity with a detection limit of 0.75 ng enterotoxin/g of food. The test is simple, is completed within 24 h, and does not require complicated extraction or concentration procedures nor expensive equipment. In addition, the assay is semiquantitative. However, as in any other immunological system, routine verification of the specificity of the latex reagents against standard enterotoxins and toxin-free food extracts is necessary.

Enterotoxins↗
PubMed1986

The inhibition of flexor tendon adhesions.

In a single blind control study using adult rabbits, the effectiveness of locally applied dextran-70 and 1% hyaluronic acid were evaluated in the control of flexor tendon adhesions after laceration of the profundus tendon in Zone II. Dextran-70 proved effective, whereas application of hyaluronic acid did not.

Animals↗
PubMed1985

Cost of orthopedic injuries sustained in motorcycle accidents.

Fifty-one serial admissions to the orthopedic services at the University of California, Davis, Medical Center, Sacramento, for motorcycle accident trauma with open fractures were reviewed. Fifty-five percent of those tested were alcohol intoxicated at the time of admission. Seventy-five percent carried no insurance of any kind, and for the total group, 72% of the cost of acute hospitalization (+17,704 per patient) was paid by the state of California, with an additional 10% paid by other tax-based sources. Care of motorcycle trauma consumes a substantial portion of public health care funds in California. This could be reduced by legislative action concerning helmet use, licensing, and rigid enforcement of compulsory insurance.

Accidents, Traffic↗
PubMed1984

Hydrocele following internal spermatic vein ligation: a retrospective study and review of the literature.

We reviewed 82 consecutive infertile men with varicoceles and 1 teenage boy with a painful varicocele, all of whom underwent a total of 111 internal spermatic vein ligations (55 unilateral and 28 bilateral) by the suprainguinal approach (Palomo method). Of these patients 3 who underwent unilateral and 3 bilateral internal spermatic vein ligations subsequently suffered a total of 8 hydroceles after an average postoperative interval of 18.2 months. The protein concentration of the hydrocele fluid in the 2 most recent patients was consistent with lymphatic obstruction.

Adolescent↗
PubMed1981

Discrimination between schizophrenic and control subjects by means of plasma dehydroepiandrosterone measurements.

In this study we were able to distinguish 10 schizophrenic subjects from 10 control subjects with 100% accuracy by measuring plasma dehydroepiandrosterone (DHEA) diurnal rhythms and analyzing the data using a linear function equation. Discrimination with this high level of accuracy is in contrast to most studies of altered biological functioning in schizophrenia which have yielded inconsistent results. These findings are regarded as preliminary; further study is necessary to elicit any consistent DHEA disturbance in schizophrenics and to discover the significance for the pathophysiology of the illness. Measurements of plasma cortisol, aldosterone, DHEA-SO4, and testosterone did not provide such a basis for discrimination.

Adult↗
PubMed1976

Selective enrichment of Shigella in the presence of Escherichia coli by use of 4-chloro-2-cyclopentylphenyl beta-D-galactopyranoside.

A procedure involving the use of citrate-buffered lactose broth (pH 6.5) containing an analogue of a beta-galactoside (4-chloro-2-cyclopentylphenyl beta-D-galactopyranoside) has been developed for the enrichment of Shigella in competition with a 100-fold higher population of Escherichia coli. The system makes use of the beta-galactosidase activity of E. coli which hydrolyzes the phenolic derivative of beta-galactoside to galactose and an aglycone moiety (4-chloro-2-cyclopentylphenol) which is toxic to E. coli but is tolerated by Shigella. The procedure is particularly effective in the enrichment of S. sonnei and S. flexneri; S. dynsenteriae and S. boydii are enriched to a lesser extent.

Buffers↗
PubMedDate not supplied

Computed tomography of the normal radioulnar joints.

Computed tomography followed by sectional radiography and photography as performed on eight cadaveric specimens in order to define the anatomy and normal motion of both the proximal and the distal radioulnar articulations. Osseous landmarks were defined that allowed measurement of rotation at the glenohumeral, proximal radioulnar and distal radioulnar joints as well as rotation between humerus and radius and between humerus and ulna. Findings included the absence of independent ulnar rotation and the presence of normal translatory motion at the distal radioulnar articulation that may be misinterpreted as evidence of subluxation of the distal ulna.

Elbow Joint↗
PubMedDate not supplied

Computed tomography of the normal soft tissues of the wrist.

Computed tomography and sectional radiography and photography were performed on eight cadaveric wrist specimens in order to define the soft tissue structures of the normal wrist. Three specific levels were analyzed in detail: the levels of the distal radioulnar joint, of the pisotriquetral joint, and of the hook of the hamate. All soft tissues, with the exception of arteries and veins, were well demonstrated with computed tomography. In particular, the contents of both Guyon's canal and the carpal tunnel could be delineated. The position of the extensor carpi ulnaris tendon and sheath could also be evaluated. Contrast opacification of the flexor tendon sheaths and palmar synovial sacs did not contribute to the analysis. Computed tomography appears to be an important imaging modality in the evaluation of significant clinical problems, including the carpal tunnel and ulnar tunnel syndromes and subluxation of the extensor carpi ulnaris tendon.

Humans↗
PubMedDate not supplied

Localized amyloid tumor of the tongue. A case report and review of the literature.

Amyloid is usually deposited in the tongue, as a part of generalized amyloidosis. Isolated localized amyloidosis of the tongue is relatively rare. We report such a case which presented with glossodynia and glossopyrosis and was thought clinically to represent median rhomboid glossitis. Histologically the amyloid stained positively with Congo-red giving green birefringence under polarized light, was not abolished after permanganate pretreatment and did not react immunohistochemically for amyloid A, beta 2 microglobulin and transthyretin.

Adult↗