Biomedical subjects

D Pavicić

Publications and source records attributed to D Pavicić.

6 recordsLinked to original sources

PubMed2005

Intense-laser-field ionization of the hydrogen molecular ions H2+ and D2+ at critical internuclear distances.

Fragmentation of H2+ and D2+ in ion beams has been studied with short intense laser pulses (100 fs, I=5x10(13)-1x10(15) W/cm2) and by a high-resolution two-dimensional velocity imaging technique. In the Coulomb explosion channel, at intensities just above the threshold for this process, we observe a clear structure in the kinetic energy spectra not previously found or predicted. The peaks can be attributed to single vibrational levels. We interpret this observation as a dissociative allocation of the electron to a proton followed by enhanced ionization at a well-defined "critical" overstretched internuclear distance. When using longer pulses we observe three separate Coulomb explosion velocity groups corresponding to critical distances of about 8, 11, and 15 a.u.

Journal Article↗

PubMed2000

Maternal neonatal outcome in quadruplet and quintuplet versus triplet gestations.

OBJECTIVE: Examination and comparison of the natural histories of triplet versus quadruplet and quintuplet gestations. STUDY DESIGN: A retrospective study of sixty-four multifetal pregnancies (fifty-two sets of triplets, nine sets of quadruplets and three sets of quintuplets) cared for during past 12 years in our department. Quintuplets and quadruplets were compared with triplet pregnancies according to gestational age, birthweight, pregnancy complications and perinatal outcome. Student's t-test, Fisher exact test and chi2 test were used for statistical analysis, considering P value of <0.05 as statistically significant. RESULTS: Although mean gestational age at delivery between triplets and higher order gestations was not significantly different, birthweight of quadruplets and quintuplets was significantly lower. Pregnancy complications, including intrauterine growth retardation, were equally distributed between the groups. Early neonatal and perinatal mortality were significantly higher in quadruplets and quintuplets than in triplets. Surprisingly, survival of growth retarded fetuses was better than survival of their eutrophic counterparts. The spontaneous loss rate was 11.5% for entire triplet gestation and 16.7% for quadru- and quintuplet pregnancies. CONCLUSIONS: As the spontaneous loss rate of triplets and higher order pregnancies observed in our study is quite similar to pregnancy loss rate caused by multifetal pregnancy reduction, conservative management of multifetal pregnancies in specialised tertiary centers seems to be a prudent solution.

Birth Weight↗

PubMed1999

The expression and role of insulin-like growth factor II in malignant hemangiopericytomas.

Hemangiopericytoma is a rare soft tissue tumor originating from contractile pericapillary pericytes. To address the issue of molecular genetic events that participate in genesis and progression of hemangiopericytoma we analyzed insulin-like growth factor (IGF) II and IGF I receptor in 29 tumors collected from a human tumor bank network. Seven of these tumors were associated with severe hypoglycemia; six were retroperitoneal and one was located in the leg. Of 22 tumors tested 12 (54.5%) exhibited IGF II mRNA, while almost 90% (17 of 19) of hemangiopericytomas exhibited IGF I receptor mRNA. Sera from some patients whose tumors expressed IGF II mRNA contained elevated levels of IGF II. Removal of the tumor eliminated most of the IGF II immunoreactivity from the sera. The potential role of IGF II as a growth-promoting factor was examined on three malignant primary hemangiopericytoma cell cultures. Extracellular addition of IGF II significantly enhanced cell proliferation in a dose-dependent manner. Antisense oligodeoxynucleotides that specifically inhibit IGF II mRNA, at a concentration of 40 or 80 micrograms/ml, inhibited the growth of hemangiopericytoma cells significantly, by 40%. Simultaneous administration of antisense deoxyoligonucleotides to both IGF II and IGF I receptor inhibited tumor cell proliferation by even 80%. Our data suggest that tumor cells produce IGF II, and that this in turn stimulates their proliferation by autocrine mechanisms.

Adolescent↗

PubMed1993

PCR amplification of DNA from stained cytological smears.

DNA from archival Papanicolaou stained smears was successfully amplified using the polymerase chain reaction (PCR) to see if it could be used for retrospective genome studies such as detection of the presence of human papilloma virus (HPV) and changes in p53 gene expression. DNA was isolated and purified by treatment with proteinase K, phenol/chloroform, and isoamyl alcohol. Segments of the human beta actin and TGF beta 1 gene were amplified by PCR. Of all stains used in the preparation of Papanicolaou smears, only eosin was detectable as a greenish band in ethidium bromide treated DNA gels under ultraviolet illumination.

Actins↗

PubMedDate not supplied

Concomitant point mutation of tumor suppressor gene p53 and oncogene c-N-ras in malignant neuroendocrine pancreatic tumor.

Activation by point mutation of ras family genes as well as point mutations of the p53 tumor suppressor gene are found in many tumors. Here we describe a rare case of malignant neuroendocrine pancreatic tumor with multiple metastases in different organs showing strong positivity for synaptophysin, glucagon-like peptide 1, pan-cytokeratin, moderate positivity for chromogranin, Phe-5 and calcitonin and weak positivity for vasointestinal peptide. We found a point mutation at codon 61 of the c-N-ras oncogene, and point mutations in the p53 tumor suppressor gene in the primary tumor as well as in its metastases in liver. The mutation in the c-N-ras gene was a cytosine to adenine transversion, resulting in the amino-acid lysine. Allele specific hybridization showed that the mutation involved one of two c-N-ras alleles as the oligonucleotide for the normal codon also hybridized to amplified tumor DNA. Concomitant mutation of the p53 tumor suppressor gene at codons 248 and 249 was found. The mutation in codon 248 was a cytosine to guanine transversion resulting in the amino-acid glycine. The mutation in codon 249 was a third base, G- > T, transversion leading to a change from arginine to serine. This is the first time that concomitant point mutations in c-N-ras and p53 have been found in a neuroendocrine pancreatic tumor. Based upon these and our previous results, we concluded that these genetic changes may play a role in the development of this particular pancreatic tumor.

Biomarkers, Tumor↗

PubMedDate not supplied

[Occupational asthma].

The definition of occupational asthma is described. Causative agents which may be responsible for the development of occupational asthma are listed. Among factors responsible for the development of occupational asthma, immunological and nonimmunological mechanisms are specially described. The clinical characteristics of the disease, diagnostic methods, differential diagnosis, prognosis and prevention of occupational asthma are described. Procedures for determining exposure, occupations in which most frequently occupational asthma can develop, as well as preventive measures are reported.

Asthma↗