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A Esen

Publications and source records attributed to A Esen.

At least 37 records · Page 2Linked to original sources
PubMed1992

Dual radioisotopic study: a technique for the evaluation of vasculogenic impotence.

Arterial and venous systems are the main points for the evaluation of vasculogenic impotence. To evaluate both of these systems in the same study we propose a dual radioisotopic study in which 99mtechnetium (99mTc) and 133xenon (133Xe) were used. The changes in 99mTc and 133Xe radioactivities administered intravenously and intracavernously, respectively, were monitored before and after intracavernous papaverine injection. These changes were determined as time activity curves, which were generated from the region of interest over the penis. A 99mTc penogram index derived from the 99mTc time activity curve was significantly different in the control and arteriogenic impotence groups (131.67 +/- 74.6 versus 62.94 +/- 51.6, p less than 0.01). A meaningful correlation between 99mTc penogram index results and duplex ultrasonographic findings were observed (r = 0.905). 133Xe penogram index, derived from the 133Xe washout curve was significantly different in the control and venogenic impotence groups (-25.65 +/- 24.9 versus -56.09 +/- 13.4, p less than 0.01). Also, a meaningful correlation was obtained between pharmacocavernosometry and 133Xe penogram index results of venogenic impotent patients (r = 0.86). These findings suggest that the dual radioisotopic study will be a useful technique in the evaluation of the entire vascular system of the penis, since it is a noninvasive method.

Adult↗
PubMed1992

Purification and Partial Characterization of Maize (Zea mays L.) beta-Glucosidase.

Maize (Zea mays L.) beta-glucosidase (beta-d-glucoside glucohydrolase, EC 3.2.1.21) was extracted from the coleoptiles of 5- to 6-day-old maize seedlings with 50 millimolar sodium acetate, pH 5.0. The pH of the extract was adjusted to 4.6, and most of the contaminating proteins were cryoprecipitated at 0 degrees C for 24 hours. The pH 4.6 supernatant from cryoprecipitation was further fractionated by chromatography on an Accell CM column using a 4.8 to 6.8 pH gradient of 50 millimolar sodium acetate, which yielded the enzyme in two homogeneous, chromatographically different fractions. Purified enzyme was characterized with respect to subunit molecular weight, isoelectric point, amino acid composition, NH(2)-terminal amino acid sequence, pH and temperature optima, thermostability, and activity and stability in the presence of selected reducing agents, metal ions, and alkylating agents. The purified enzyme has an estimated subunit molecular mass of 60 kilodaltons, isoelectric point at pH 5.2, and pH and temperature optima at 5.8 and 50 degrees C, respectively. The amino acid composition data indicate that the enzyme is rich in Glx and Asx, the sum of which approaches 25%. The sequence of the first 20 amino acids in the N-terminal region was H(2)N-Ser-Ala-Arg-Val-Gly-Ser-Gln-Asn-Gly-Val-Gln-Met-Leu-Ser-Pro-(Ser?) -Glu-Ile-Pro-Gln, and it shows no significant similarity to other proteins with known sequence. The enzyme is extremely stable at 0 to 4 degrees C up to 1 year but loses activity completely at and above 55 degrees C in 10 minutes. Likewise, the enzyme is stable in the presence of or after treatment with 500 millimolar 2-mercaptoethanol, and it is totally inactivated at 2000 millimolar 2-mercaptoethanol. Such metal ions as Hg(2+) and Ag(+) reversibly inhibit the enzyme at micromolar concentrations, and inhibition could be completely overcome by adding 2-mercaptoethanol at molar excess of the inhibitory metal ion. The alkylating agents iodoacetic acid and iodoacetamide irreversibly inactivate the enzyme and such inactivation is accelerated in the presence of urea.

Journal Article↗
PubMed1991

Dynamic cavernosography in the evaluation of impotence.

Dynamic cavernosography before and after papaverine injection into the corpus cavernosum of 6 sexually normal volunteers and 44 impotent patients was performed with digital subtracting angiography technique. The average infusion rates in 26 patients with venous leakage were 325.5 ml/min for induction of erection and 161 ml/min for maintenance. The results for the remaining 18 impotent patients without venous leakage were 128.8 ml/min for induction and 56.9 ml/min for induction and 58.3 ml/min for maintenance. After papaverine injection the average infusion rates decreased to 131 ml/min (induction) and 59 ml/min (maintenance) in patients with venous leakage, 38.4 ml/min and 14.6 ml/min in the impotent patients without venous leakage and 35 ml/min and 14.1 ml/min in the control group, respectively. It was also noticed that in the control group filling of the superficial and deep veins may occur during the flaccid phase which disappeared with induced erection. Therefore we suggest intracavernous papaverine injection with dynamic cavernosography. The digital subtracting technique eliminates unnecessary images, providing a more accurate diagnosis of venous incompetence.

Adult↗
PubMed1991

Detection of beta-glucosidase activity on sodium dodecyl sulphate-polyacrylamide gels.

Maize beta-glucosidase (beta-D-glucoside glucohydrolase, EC 3.2.1.21) was incubated in the presence of SDS concentrations varying from 0.025 to 3.2% at two different pHs (5 and 8), electrophoresed through 10% SDS-polyacrylamide gels, and stained for activity. The zymogram patterns of SDS-treated samples were similar to those of untreated (control) samples. The same samples were also analyzed by native PAGE and IEF, yielding similar patterns for controls and for SDS-treated samples. However, zymogram patterns were severely distorted on IEF gels when SDS concentration of the sample medium was at or above 1.6%. These results suggest that the beta-glucosidase monomer (a 60 kD polypeptide) is either catalytically active or it re-forms dimers upon the removal of SDS during equilibration washes, since the in vivo form of the functional enzyme is thought to be a dimer. The activity of maize beta-glucosidase on SDS-gels after SDS-PAGE does not seem to be limited to this enzyme alone, because beta-glucosidases from other sources (e.g., almond, Trichoderma, and Penicillium) were also active on SDS-gels. Enzyme activity in the presence of SDS or after SDS treatment may be more common than one would expect on the basis of the conventional biochemical dictum that ionic detergents denature and inactivate enzymes. Enzyme activity in the presence of SDS and development of zymograms on SDS-gels offer new approaches to studies of enzyme structure and activity.

Electrophoresis, Polyacrylamide Gel↗
PubMed1990

An immunodominant site of gamma-zein1 is in the region of tandem hexapeptide repeats.

The immunochemical data from studies with polyclonal antisera to gamma-zein1, the 27 kD component of the maize prolamin, indicated that the region containing 8 tandem repeats of the sequence PPPVHL is an immunodominant site. In one case, the entire antibody repertoire of an antiserum recognized epitope(s) within this region. Three 17-mer oligopeptides corresponding to the predicted antigenic epitopes of gamma-zein1 were synthesized and reacted with three different anti-gamma-zein1 sera in order to map antigenic sites in the intact protein. These antisera yielded positive reactions with a 17-mer peptide (peptide 37), which was not in a hydrophilic maximum but derived from the repeat region. The same antisera gave little or no reaction with other peptides (peptides 38 and 39), both of which were in a hydrophilic maximum. In addition, an antiserum to peptide 37 reacted strongly with both the homologous antigen and the intact gamma-zein1. Peptide 37 also blocked the binding of antisera to gamma-zein1 in competition assays. Subsequently, the shorter 6-mer (peptide 82) and 12-mer (peptide 80) versions of peptide 37 were synthesized, and both reacted with anti-peptide 37 serum and also with each of the three anti-gamma-zein1 sera. In these reactions and in competition assays, the reactivity and the blocking ability increased in proportion to the length of the peptide. Based on these data, it was concluded that the repeat region of gamma-zein1 is the site of one or more continuous immunodominant epitopes. The data also suggest that the repeat region is exposed on the surface of the folded protein and probably occur as a mobile, random coil.

Amino Acid Sequence↗
PubMed1990

Maize genotypes classified as null at the glu locus have beta-glucosidase activity and immunoreactive protein.

Maize beta-glucosidase (beta-D-glucoside glucohydrolase; EC 3.2.1.21) was extracted from coleoptiles of 15 maize genotypes (3 normals, 10 nulls, and 2 hybrids) in two fractions, the soluble and the insoluble. The enzyme activity was measured spectrophotometrically in the soluble fraction and also studied on zymograms after native gel electrophoresis and isoelectric focusing. The enzyme was purified from a normal genotype by anion-exchange chromatography and preparative electrophoresis. Antisera were raised in four rabbits, and the soluble and the insoluble extracts of each genotype were analyzed for a cross-reacting material by ELISA and immunoblotting. The results showed that extracts from both the normal and the null genotypes had beta-glucosidase activity, and the activity measured spectrophotometrically was 2- to 10-fold higher in normals than in nulls. Zymograms of the null genotypes were devoid of distinct bands that were present in those of normals and hybrids from crosses between normals and nulls. Zymograms of both the normal and the null genotypes had a diffuse, smeared zone of activity at the cathodic end of native gels. A cross-reacting antigen was present in extracts of both genotypes when assayed by ELISA and a 60-kD polypeptide (beta-glucosidase monomer) was detected by four different monospecific beta-glucosidase antisera on Western blots by immunostaining. Moreover, six of seven null genotypes had a larger amount of their 60-kD polypeptide in the insoluble fraction than in the soluble fraction. These data show that both the null and the normal genotypes have similar amounts of the enzyme protein, but the enzyme occurs mostly as insoluble or poorly soluble polymers in nulls, and the monogenic inheritance reported for the null alleles of the glu locus is likely to be for a factor encoded by another locus which affects directly or indirectly the solubility of the enzyme by increasing its polymerization into large quaternary structures.

Alleles↗
PubMed1989

A blocking agent and a blocking step are not needed in ELISA, immunostaining dot-blots and western blots.

The effect of blocking and non-blocking was compared in ELISA, immunostaining dot-blots and western blots using phosphate-buffered saline with and without the addition of Tween 20 for washes and dilutions. The results indicated that when Tween 20 was included in phosphate-buffered saline, a blocking agent and a blocking step were not required in immunoassays. Moreover, the use of protein-based blocking agents was found to somewhat lower the reactivity between the antibody and the antigen, possibly due to steric hindrance.

Animals↗
PubMed1989

Histopathological changes in adult cryptorchid testes.

The histological specimens of 73 patients who presented with undescended testes after puberty were re-evaluated. None of the specimens revealed carcinoma in situ but in the specimens of 5 patients severe atypia was detected. None of the patients, including 5 with severe atypia, has shown any evidence of invasive testicular tumour during follow-up.

Adolescent↗
PubMed1986

Separation of alcohol-soluble proteins (zeins) from maize into three fractions by differential solubility.

The prolamin of maize (Zea mays L.), zein, was extracted from endosperm meal with 60% (v/v) 2-propanol/1% (v/v) 2-mercaptoethanol either directly or subsequent to extraction with 90% (v/v) 2-propanol. The zein extracted with 90% 2-propanol was essentially made up of 20 to 24 kilodalton polypeptides (alpha-zein) while that extractable with 60% 2-propanol/1% 2-mercaptoethanol contained, in addition to alpha-zein, 17 to 18 kilodalton methionine-rich polypeptides and a 27 kilodalton proline-rich polypeptide. While zein was separated into three fractions by differential solubility in 90% 2-propanol and 30% 2-propanol/30 millimolar sodium acetate (pH 6) using two different fractionation protocols. Each of the three solubility fractions (SF1, SF2, and SF3) had a unique polypeptide composition. Based on results obtained from two inbreds, K55 and W64A, the SF1 constituted 75 to 80% of the total zein and included as major components 20 to 24 kilodalton polypeptides and a minor 10 kilodalton polypeptide. The SF2 made up 10 to 15% of the total zein and included exclusively 17 to 18 kD methionine-rich polypeptides. A 27 kilodalton proline-rich component constituted the SF3 and contributed 5 to 10% to total zein.

Journal Article↗
PubMed1986

Primary structure of a proline-rich zein and its cDNA.

Eighty-five cDNA clones for gamma-zein (proline-rich zein) from a cDNA expression library were isolated using specific antibody and cDNA probes. Nucleotide sequences of seven independent clones were determined and found to be identical in regions where they overlapped. The primary structure of the mature protein, determined from the sequence of one near full-length clone, consists of 204 amino acids. It has a molecular weight of 21,824 daltons, about 5 kilodaltons less than that estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The N-terminal one-half of the sequence contained eight essentially identical tandem repeats of the hexapeptide Pro-Pro-Pro-Val-His-Leu and two of the octapeptide Gln-Pro-His-Pro-Cys-Pro-Cys-Gln. The codon specifying the third proline in the hexapeptide repeating units is identical (CCG) in all of the eight repeats. The coding region has a very high G-C content (69.8%). The multiple charge components of gamma-zein detected by isoelectric focusing do not seem to be encoded by members of a multigene family. Moreover, it was found that the codon preference in gamma-zein is, in fact, the base preference in the wobble position. A codon usage value was devised to express this phenomenon.

Journal Article↗
PubMed1985

Screening expression libraries with nonradioactive immunological probes.

An immunological screening method employing protein A-peroxidase which does not require radiolabelled antibodies for detection of Escherichia coli colonies synthesizing foreign proteins in a cDNA expression library is described. The technique is sensitive, simpler and more rapid than the procedures that rely on radiolabelled antibodies and autoradiography.

Gene Expression Regulation↗
PubMed1984

An enzyme-linked immunosorbent assay for zein and other proteins using unconventional solvents for antigen adsorption.

An enzyme-linked immunosorbent assay (ELISA) performed in polystyrene microtiter plates that can detect and quantitate the maize prolamin zein is described. The assay yields positive reactions with as little as 1 ng of antigen and uses solvents not ordinarily employed in ELISA methods. A systematic investigation of zein adsorption to polystyrene in various solvents supports the hypothesis that antigen binding occurs through nonpolar interactions. The method was also used to determine structural relationships among three zein polypeptides differing in size and charge. Additional experiments indicate that a number of soluble proteins are absorbed to polystyrene in the denaturing agent urea and retain immunological reactivity. The retention of antigen reactivity after solubilization in 6-8 M urea suggests that ELISA methods may be applicable to other proteins which are insoluble, or rendered insoluble, in aqueous buffers.

Cross Reactions↗
PubMed1983

A simple and rapid dot-immunobinding assay for zein and other prolamins.

A simple method for the immunochemical assay of zein and other prolamins is described. Alcohol-solubilized zein is spotted onto chromatography paper disks or strips, incubated with antiserum (30-60 min), washed with several changes of Tris-buffered saline (10 min), incubated with protein A-peroxidase (30 min), and washed with several changes of Tris-buffered saline (10 min). the binding of zein-specific antibody is visualized by peroxidase-catalyzed color production from 4-chloro-1-naphthol. The method is simple, inexpensive, and rapid (2 h total time) and has potential application to other insoluble antigens.

Densitometry↗
PubMedDate not supplied

A prospective analysis of sexual functions during pregnancy.

The aim of the study was to evaluate the sexual functions during pregnancy using the Female Sexual Function Index (FSFI) questionnaire. Pregnancies were recorded in a prospective cohort study comprising 40 healthy pregnant women. Pregnant women who had a stable relationship with their partner were enrolled in the study when were first diagnosed to be pregnant. During their antenatal visits, subjects were asked to complete the FSFI questionnaire and other information about their sexual life in each trimester. Each FSFI domain score was calculated and mean scores in each domain were compared according to the trimesters of pregnancy. Data of 37 subjects for the first, 36 for the second and 34 for the third trimesters of pregnancy were eligible for the analysis. The mean age was 25.5+/-4.5 y; mean parity was 0.4+/-0.7 and mean gravity was 1.6+/-0.9. The frequency of intercourse attempts during the last 4 weeks was 8.6+/-3 before pregnancy, and 6.9+/-2.5, 5.4+/-2.6 and 2.5+/-1.4 in the first, second and third trimesters of pregnancy, respectively. In all domains of FSFI, significant decline in domain scores was determined during pregnancy. The comparison of satisfaction and pain domain scores between first and second trimesters showed significant differences. All of the domain scores significantly decreased in the third trimester of pregnancy. Our results showed that sexual functions are significantly decreased during pregnancy and worsen as the pregnancy progresses. Childbearing couples should be given information about the sexual problems and fluctuations in the patterns of sexuality during pregnancy.

Adult↗