Pregnancy in the interstitial portion of the oviduct following in vitro fertilization-embryo transfer (IVF-ET)
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Adult↗
Biomedical subjects
A Kalogeropoulos
Publications and source records attributed to A Kalogeropoulos.
Coexistence of spermatozoa morphological abnormalities in the semen of subfertile men with varicocele.
Spermatozoal morphology in semen specimens from 107 subfertile men with varicocele, aged from 18 to 50 years, were evaluated from Papanicolaou-stained smears, in order to investigate: (a) the frequency of abnormalities in the neck and tail of spermatozoa with an abnormal head; and (b) the ability of prediction of the morphology of one sperm part when the morphology of another is known. It was found that: (1) Morphological abnormalities in the neck are significantly more frequent (p less than 0.01) in spermatozoa with an abnormal head than in spermatozoa with a normal head. (2) Morphological abnormalities in the tail and cytoplasmic droplet are also more frequent, although not significantly, in spermatozoa with an abnormal head. (3) The proportional reduction in error (PRE) was low in all cases. Our results show that spermatozoa with abnormal heads present morphological abnormalities of their other parts more often than spermatozoa with normal heads. However, no prediction can be made on the nature of the morphology of a part of a spermatozoon on the basis of knowledge of the morphology of another of its parts.
Acrosome↗
Hybrid DNA tracts may start at different sites during meiotic recombination in gene b2 of Ascobolus.
The initiation of hybrid DNA in the b2 spore colour gene was investigated by the analysis of non-Mendelian segregation asci in the progeny of crosses involving several allelic b2 mutations. These analyses showed that, instead of the unique initiation region of hybrid DNA in b2, assumed previously by Paquette and Rossignol (1978), there are multiple sites for hybrid DNA starting. They produce major and minor fractions of hybrid DNA. The major fraction starts upstream of the left end of the gene, propagates rightwards and can cover its entire length. The minor fractions do not span the left b2 end. One of them is detected within the left half of the gene, the others within its right half.
Journal Article↗
Serum levels of the oncofetal antigens CA-125, CA 19-9 and CA 15-3 in patients with endometriosis.
The levels of the oncofetal antigens CA-125, CA 19-9 and CA 15-3 were measured in serum samples taken from 8 women, aged 21 to 37 yr, before treatment, during the last fifteen days of a 6-month administration of danazol and finally three months after treatment withdrawal. The purpose of the study was to investigate: i) whether endometriosis belongs to the pathologic conditions which induce a concomitant increase in the values of CA-125, CA 19-9 and CA 15-3, and ii) the effect of danazol on the levels of these antigens. Our results indicate that before danazol treatment, three women showed pathologic levels of all three antigens, one of CA 19-9 and CA 15-3, one of CA 19-9 alone, and two of CA 15-3 alone. Administration of the drug significantly reduced the levels of CA-125 (p less than 0.001) and CA 19-9 (p less than 0.05) and to a lesser degree the levels of CA 15-3. Three months after danazol treatment discontinuation, the levels of these three antigens remained significantly lower (p less than 0.05) than the respective pretreatment values. Our findings substantiate the view that endometriosis must be classified with the pathologic conditions which induce a rise in the levels of all three antigens, and that ovarian function mainly influences the levels of CA-125 and CA 19-9.
Adult↗
Coexistence of spermatozoa morphological abnormalities in the semen of potentially fertile men.
Spermatozoal morphology in semen specimens from 114 potentially fertile men, aged from 20 to 40 years, was evaluated from Papanicolaou stained smears, in order to investigate: (a) the frequency of abnormalities in the neck and tail of spermatozoa with an abnormal or normal head, and (b) the ability of prediction of the morphology of one sperm part when the morphology of another is known. It was found that: (1) Morphological abnormalities in the neck are significantly higher (p less than 0.001) in spermatozoa with an abnormal head than in spermatozoa with a normal head. (2) Morphological abnormalities in the tail and cytoplasmic droplet are also higher, although not significant, in spermatozoa with an abnormal head. (3) The proportional reduction in error (PRE) was low in all cases. Our results show that spermatozoa with abnormal heads more often present morphological abnormalities of their other parts than spermatozoa with normal heads. However, no prediction can be made on the nature of the morphology of a part of a spermatozoon on the basis of knowledge of the morphology of another of its parts.
Adult↗
Two mechanisms for directional gene conversion.
G234 is a large silent deletion located in the middle of gene b2, which controls spore pigmentation in Ascobolus immersus. Its gene conversion directionality was studied in asci, which show evidence of heteroduplex DNA at flanking markers, and was compared to the behavior of closely linked single-base-pair insertions or deletions. We found that with the G234 deletion, the genotype of the donor strand in the heteroduplex is preferentially recovered, irrespective of its G234 or wild-type nature, whereas with single-base-pair insertions or deletions, the direction of conversion favors one genotype, whether it was the donor or the recipient strand. We conclude that there exists two mechanisms for directional gene conversion, the "donor-directed" conversion mechanism being epistatic to the "genotype-directed" one. We discuss these data with regard to models for mismatch repair.
Ascomycota↗
Gene conversion at the gray locus of Sordaria fimicola: fit of the experimental data to a hybrid DNA model of recombination.
A hybrid DNA (hDNA) model of recombination has been algebraically formulated, which allows the prediction of frequencies of postmeiotic segregation and conversion of a given allele and their probability of being associated with a crossing over. The model considered is essentially the "Aviemore model." In contrast to some other interpretations of recombination, it states that gene conversion can only result from the repair of heteroduplex hDNA, with postmeiotic segregation resulting from unrepaired heteroduplexes. The model also postulates that crossing over always occurs distally to the initiation site of the hDNA. Eleven types of conversion and postmeiotic segregation with or without associated crossover were considered. Their theoretical frequencies are given by 11 linear equations with ten variables, four describing heteroduplex repair, four giving the probability of hDNA formation and its topological properties and two giving the probability that crossing over occurs at the left or right of the converting allele. Using the experimental data of Kitani and coworkers on conversion at the six best studied gray alleles of Sordaria fimicola, we found that the model considered fit the data at a P level above or very close (allele h4) to the 5% level of sampling error provided that the hDNA is partly asymmetric. The best fitting solutions are such that the hDNA has an equal probability of being formed on either chromatid or, alternatively, that both DNA strands have the same probability of acting as the invading strand during hDNA formation. The two mismatches corresponding to a given allele are repaired with different efficiencies. Optimal solutions are found if one allows for repair to be more efficient on the asymmetric hDNA than on the symmetric one. In the case of allele g1, our data imply that the direction of repair is nonrandom with respect to the strand on which it occurs.
Alleles↗
Quantitative evaluation of magnetic resonance imaging (MRI) abnormalities in subclinical hepatic encephalopathy.
BACKGROUND/AIMS: Cirrhotic patients often demonstrate high signal intensity on T1-weighted magnetic resonance (MRI) images in basal ganglia with accumulation of manganese being the predominant causing factor. In these patients, electrophysiological tests and especially electroencephalogram (EEG) are considered to be the most sensitive methods in detection of subclinical hepatic encephalopathy. The aim of this study is to correlate MRI findings with biochemical parameters and EEG alterations in cirrhotic patients without clinically overt encephalopathy. METHODOLOGY: Twenty-two cirrhotic patients (16 males and 6 females, mean age of 65.2 +/- 9.5 years), classified according to Child-Pugh score, were submitted to brain MRI, neurological assessment (including psychometric tests and EEG) and complete biochemical testing. None of them had any clinical signs of brain dysfunction. MRI findings were evaluated both qualitatively (normal, mild, moderate and severe) and quantitatively with the ROI method. EEG alterations were also classified as normal, mild, moderate and severe. RESULTS: Statistical analysis revealed a significant linear association between EEG grading and MRI signal intensity (r2=0.248, p=0.035). Among clinical and biochemical parameters, overall Child-Pugh score and albumin levels were identified as significant predictors of the MRI signal intensity (p=0.006 and p=0.021 respectively). CONCLUSIONS: Although further investigation must be performed to confirm the clinical impact of brain MRI in hepatic cirrhosis, our study strongly suggests that MRI alterations are good predictors of liver and brain dysfunction in cirrhotic patients.
Aged↗