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Biomedical subjects

R Kozma

Publications and source records attributed to R Kozma.

27 records · Page 2Linked to original sources
PubMed1990

Novel human brain cDNA encoding a 34,000 Mr protein n-chimaerin, related to both the regulatory domain of protein kinase C and BCR, the product of the breakpoint cluster region gene.

A novel human brain complementary DNA sequence encodes n-chimaerin, a 34,000 Mr protein. A single cysteine-rich sequence CX2CX13CX2CX7CX7C in the N-terminal half of n-chimaerin shares almost 50% identity with corresponding sequences in the C1 regulatory domain of protein kinase C. The C-terminal half of n-chimaerin has 42% identity with the C-terminal region (amino acid residues 1050 to 1225) of BCR, the product of the breakpoint cluster region gene involved in Philadelphia (Ph') chromosome translocation. n-Chimaerin mRNA (2.2 x 10(3) base-pairs) is specifically expressed in the brain, with the highest amounts being in the hippocampus and cerebral cortex. The mRNA has a neuronal distribution and is expressed in neuroblastoma cells, but not in C6 glioma or primary astrocyte cultures. The similarity of two separate regions of n-chimaerin to domains of protein kinase C and BCR has intriguing implications with respect to its evolutionary origins, its function in the brain and potential phorbol-ester-binding properties.

Amino Acid Sequence↗
PubMed1988

Analysis of peripheral maternal blood samples for the presence of placenta-derived cells using Y-specific probes and McAb H315.

Using flow cytometry, a small number of cellular elements expressing on their surface an antigen (H315) produced by placental trophoblast have been observed in the peripheral blood of pregnant women. This is in agreement with previous observations (Covone et al., 1984a,b) and recent results documenting the presence of a small number of H315-positive cells in the peripheral circulation of pregnant women (Pool et al., 1987; Caligaris-Cappio and Camaschella, personal communication). When DNA extracts, prepared from H315-positive cells sorted from maternal samples were tested by Southern transfer using Y-specific probes (Y190 or Y411), a Y-specific band could not be detected in any sample analysed, irrespective of the sex of the fetus. In control samples from healthy male donors, a Y-specific band could be detected with as few as 800 46,XY cells without interference from contaminating 46,XX cells. H315-positive cellular elements, sorted by flow cytometry from the maternal peripheral blood, were also examined in interphase using Y-specific probes (Y190 and Y431) and an in situ biotin-avidin fluorescent hybridization technique. The great majority of the sorted H315-positive cellular elements did not show a fluorescent Y body, even in samples from mothers who later delivered a male infant. While previous investigations had failed to demonstrate the in vitro uptake of H315 antigen onto the surface of leucocytes from healthy males incubated in maternal sera, the present studies demonstrate that cells from male donors could adsorb this antigen following incubation in extracts prepared from retroplacental blood. These findings thus suggest that the majority of H315-positive nucleated cells previously detected by flow cytometry in the peripheral circulation of pregnant women are maternal cells which have adsorbed H315 antigen in vivo, either in soluble form or as small cell membrane fragments.

Adult↗
PubMed1988

Fluorescence in situ hybridization and Y ring chromosome.

Investigations by fluorescence in situ hybridization and a Y-specific probe (Y190) of a male patient with a Y ring chromosome, 46,X,r(Y) showed four bright fluorescent spots within the ring. Thus, using this technique, it is possible to suggest that the ring originates from the duplication of the short arms of the Y chromosome.

Adult↗
PubMed1988

In situ fluorescence hybridization of Y translocations: cytogenetic analysis using probes Y190 and Y431.

Two moderately repetitive DNA probes (Y190 and Y431) and a fluorescent in situ hybridization technique, using a biotin, avidin, anti-avidin system, were employed to investigate a group of patients with Y chromosome abnormalities. In normal male subjects, a bright fluorescent spot could be detected in cells in interphase and on the short arm of the Y chromosome in metaphase spreads. Translocations of DNA fragments of the short arm of the Y chromosome to autosomes 10, 13 and 15 were observed in five patients. In a 45,XX male subject the translocation involved one of the X chromosomes. With this in situ hybridization procedure, bright fluorescent spots were also noticed in uncultured amniotic cells and chorionic cellular elements from male fetuses, thus allowing a rapid and reproducible approach to prenatal fetal sexing.

Humans↗
PubMed1987

Detection of trophoblast-like cells in maternal blood using specific monoclonal antibodies.

Mouse monoclonal antibodies reacting against membrane antigens expressed on syncytiotrophoblast (McAb H315), villous cytotrophoblast (McAb 18B/A5) and placental-type alkaline phosphatase-producing cells (McAb H317) were used in conjunction with flow cytometry to detect placental cells in the maternal circulation. H315 and H317-positive cells were found in uterine veins and peripheral blood of pregnant women, while cells reacting with McAb 18B/A5 were either absent or present in very low numbers.

Antibodies, Monoclonal↗
PubMed1986

Detection of syncytiotrophoblast in maternal peripheral and uterine veins using a monoclonal antibody and flow cytometry.

Using a monoclonal antibody (H315) and cytofluorimetry, the presence of deported syncytiotrophoblast was investigated in blood samples collected from peripheral and uterine veins at the time of elective Caesarean sections. In all 10 women studied, a higher incidence of H315-positive syncytiotrophoblast cells was detected in the uterine samples than in peripheral blood, thus confirming that in normal pregnancies a large number of cells are shed from the placenta and gain access into the maternal circulation at the time of delivery.

Antibodies, Monoclonal↗
PubMed1983

20-hydroxyecdysone stimulates tissue-specific yolk-protein gene transcription in both male and female Drosophila.

The yolk polypeptides of Drosophila are normally synthesized in the fat body and ovarian follicle cells of adult females. In response to 20-hydroxyecdysone males synthesize yolk polypeptides. The actual level of yolk polypeptides synthesized in males is not always a direct reflection of the YP-transcripts present. Initially YP-transcripts are efficiently translated into polypeptides whereas later they are not and the YP-transcripts can have a half-life of less than 8 h in males. We suggest that the expression of the genes coding for the yolk polypeptides in males may be regulated at transcriptional and translational levels. Treatment of females with 20-hydroxyecdysone leads to a transient increase in YP-transcript accumulation, but the response is difficult to assess in whole flies due to the high variability in transcript levels during normal development. Analysing the response to 20-hydroxyecdysone at the level of specific tissues shows that transcript accumulation is dramatically increased in body walls (fat-body cells, epidermis and oenocytes) of both males and females. Gut, Malpighian tubules, testis and ovaries are not affected. Treatment of females with 20-hydroxyecdysone followed by measuring YP-transcript accumulation over the next 24 h in ovaries and body walls separately, confirms that only body walls respond to the hormone. There is an increase in yolk-polypeptide synthesis during the period of increased YP-transcript accumulation in females. We conclude that the response of the YP-genes to 20-hydroxyecdysone is tissue-, but not sex-specific.

Animals↗