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V Landa

Publications and source records attributed to V Landa.

45 records · Page 3Linked to original sources
PubMed1975

Activity and subcellular localization of proteolytic enzymes of boar and rabbit spermatozoa.

Comparison of the mode and time course of depolymerization of the gelatin by boar and rabbit spermatozoa obtained from the ejaculates and the female reproductive tract revealed that the proteolytic activity of the spermatozoa was not changed during their passage through the female reproductive tract. In all sperm samples the depolymerization started at the level of the equatorial segment, proceeded to the apical part and digested the substrate around the sperm head. The time course of depolymerization was also the same in all samples. Slight differences were caused by degeneration changes affecting the acrosomal region of the sperm head and accelerating the initial course of substrate depolymerization. The results were confirmed by investigating the state of the acrosomes of individual sperm samples using the silver proteinate method. It appeared that samples with greater numbers of spermatozoa with damaged acrosome begin to affect the substrate a few minutes earlier. The disadvantage of the methods used is that the release of the proteolytic enzymes from the sperm head is probably caused by postmortem degeneration changes of the spermatozoa.

Acrosome↗
PubMedDate not supplied

Non-isotopic detection of nucleolar transcription in pre-implantation mouse embryos.

Nucleolar transcription was analysed in permeabilized pre-implantation mouse embryos at the four-cell, eight-cell, morula and early blastocyst stages using confocal microscopy to detect incorporated 5-bromouridine. The results demonstrated that the patterns of nucleolar transcription sites were common for all embryonic stages studied. They consisted most frequently of tightly associated groups of transcription foci similar to those encountered in somatic interphase cells. In addition, the nucleologenesis accompanying each cell cycle apparently gave rise to a different fluorescent pattern, that is to spatially separated fluorescent foci in the cells just after the resumption of rRNA synthesis. An immunoelectron microscopic analysis of the nucleolar transcription was also performed in the eight-cell embryos. A signal, usually consisting of clustered gold particles, was found specifically within nucleolar dense fibrillar components. This result was in agreement with established findings, which identify dense fibrillar component as the major site of nucleolar transcription in somatic cells.

Animals↗
PubMedDate not supplied

[Immune response to influenza vaccination].

The present study investigated the level of immunity of the population against three strains of the influenza virus (A Chile/1/83 -A Philippines/2/82 and B URSS/100/83) before and three months after vaccination, and the immune response to whole virus vaccine as compared with fragmented virus vaccine. A high percentage of the population had titers greater than or equal to 1/10 before vaccination for the Chile (54%) and Philippines (65.7%) strains, while titers against the URSS strain were lower (25.4%). There was a definitive increase in antibody titer in the vaccinated population, although it was lower than expected. The overall response to both vaccines, with protecting titers greater than or equal to 1/40 after vaccination was 65.2% for the Chile strain, 74.6% for the Philippines strain, and 15% for the URSS strain. No differences in the overall immune response were found between the groups vaccinated with whole and fragmented virus.

Adult↗