Biomedical subjects
Publications and source records attributed to I Gustavsson.
High loads of human papillomavirus (HPV) 16 and HPV 18/45 increase the risk of developing invasive cervical carcinoma, revealing higher risk in percentiles of highest viral loads for HPV 16 (odds ratio (OR) 58.7, 95% confidence interval (CI) 21.9-151.4) compared to HPV 18/45 (OR 3.3, 95% CI 1.5-7.2). Thus, HPV load is a type-dependent risk marker for invasive carcinoma.
The head area of bull spermatozoa was measured after viability and acrosome staining using trypan blue and Giemsa stains, followed by X- and Y-chromosome-specific fluorescence in situ hybridisation (FISH). The former staining made possible the categorisation of cells according to morphology and membrane integrity, whereas the latter allowed distinction of spermatozoa bearing X- and Y-chromosomes. Individual spermatozoa could be followed during the consecutive steps of staining, measurement and FISH. Using a high-resolution digital imaging system and measurement software, the head area of more than 3000 cells of five bulls was determined precisely. In all bulls, morphologically normal, viable cells with intact acrosomes were significantly smaller than dead cells with damaged acrosomes. No significant difference in the head area between X- and Y-chromosome-bearing viable, acrosome-intact spermatozoa was found in individual bulls. However, significant between-bull differences were detected in all cell categories.
In order to identify X- and Y-bearing spermatozoa in water buffalo by fluorescence in situ hybridization (FISH), some available probes of closely related species were examined. An X- and Y-specific probe set, made from flow sorted yak chromosomes, labelled in somatic metaphases of water buffalo the whole X and Y, respectively, except their centromere regions. A cattle Y-chromosome repeat sequence (BC1.2) showed strong signal on the telomere region of the buffalo Y-chromosome, demonstrating the evolutionary conservation of this locus in water buffalo. In hybridization experiments with spermatozoa from five buffaloes, the yak X-Y paint set demonstrated clear signals in more than 92% (46.8% X and 45.8% Y) of the cells. Using the cattle Y-chromosome specific BC1.2 probe, clear hybridization signal was detected in more than 48% of the cells. Statistical analysis showed that there was no significant difference between bulls or from the expected 50 : 50 ratio of X- and Y-bearing cells. The probes presented here are reliable to assess separation of X- and Y-bearing spermatozoa.
The viability and sex of bovine spermatozoa were simultaneously evaluated. After viability and acrosome staining with trypan blue/Giemsa, only live spermatozoa became decondensed by a modified papain-dithiothreitol method. Owing to this specific effect, live sperm heads were easily distinguished by their enlarged size and dark violet colour from small, light blue dead sperm heads. In the same sperm sample, X- and Y-chromosome-bearing sperm were distinguished by their fluorescent signal, using fluorescence in situ hybridization (FISH) with an XY paint set and 4,6-diamino-2-phenylindole counterstaining. The combined staining provides a method for morphological and viability evaluation before FISH and permits identification of the proportions of X- and Y-chromosome-containing live spermatozoa in a semen sample. However, only 25% of the undecondensed dead sperm express signals allowing detection of the sex of the chromosome. The method may be an effective tool in evaluating sex-oriented semen samples.
Three hundred and twenty-two (264 males and 58 females), randomly sampled Grey Alpine cattle individuals from Northeastern Italy, were investigated cytogenetically by both conventional chromosome staining and R-banding. Two hundred and eighty-one (87%) individuals had a normal karyotype and 41 (13%) carried chromosomal aberrations such as (a) rob(1;29) in two individuals, (b) rob(26;29) in 36 individuals, (c) XX/XY-chimerism in two individuals, and (d) an abnormally long chromosome in one individual. All these aberrations except (d) have been described before. GBG-, RBG-, CBA-banding and sequential GBG/CBA- and RBG/CBA-banding techniques revealed that the abnormally long chromosome was the result of a reciprocal translocation between chromosomes 1 (q21-->qter) and 5 (q11-->q33), as confirmed also by chromosome painting with human chromosome 3 and 12 probes. The dam of the carrier bull carried the same translocation, while the grandam showed a normal karyotype. Since the sire of the dam was not available for study, no conclusion about the origin of the chromosome translocation could be drawn. The carrier bull was eliminated because of poor fertility. The dam had three other calves, which all were chromosomally normal. On average the dam had to be served 2.5 times (breed average was 1.2) to be in calf.
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According to present knowledge there is a germ cell chimerism (XY/XX) in young bulls born in heterosexual twinning due to exchange of primordial germ cells in embryonic life. These germ cells were believed to have been eliminated in the young bull. Two-color fluorescence in situ hybridization (FISH) identification of the sex chromosomes by biotinylated and digoxygenin labeled probes have been used. The material consisted of three bulls born in heterosexual twinning. The results obtained indicated that even mature bulls (more than two years old) demonstrate spermatogonial chimerism. Several authors state that the bulls with blood cell chimerism, originating from dizygous twinning, are characterized by decreased fertility. Changes of the sex ratio of offspring due to proliferation of the female cells have also been proposed. The present observations should give a renewed interest in checking the possibility of survival and differentiation of germ cells from the female partner in the germ cell lines.
Sex steroids influence the growth of mammalian uterine tissues and the proto-oncogenes c-fos and c-jun have been implicated in the cascade of cellular events induced by the cyclic influence of oestrogen and progesterone. To investigate the role of these proto-oncogenes for fibroid growth their mRNA expression was measured in myometrium and fibroids under different hormonal conditions, using a solution hybridization method. Fibroids and myometrium were collected at surgery from premenopausal, postmenopausal and pregnant women as well as women treated with a gonadotrophin releasing hormone agonist (GnRHa; Goserelin). The phase of the menstrual cycle was determined in all the untreated, premenopausal, non-pregnant women. The mRNA expression of c-fos and c-jun in fibroids was significantly lower than in homologous myometrium. No significant differences in c-fos expression were observed in myometrium, or fibroids, due to menstrual cycle phase, GnRHa treatment, pregnancy or the menopause. The c-jun expression in myometrium from pregnant women without fibroid disease was significantly higher than the corresponding control myometrium from premenopausal, non-pregnant women. These results demonstrate a tissue difference in the expression of c-fos and c-jun between myometrium and fibroids.
The expression of insulin-like growth factor-I (IGF-I) was measured at the mRNA and protein level in myometrium and fibroids from women with and without preoperative treatment with a gonadotrophin-releasing hormone (GnRH) agonist for 3 months, from post-menopausal women, from pregnant women and in myometrium from women without fibroid disease. Women with menstrual periods were classified according to the phase of the cycle. In tissues from non-treated premenopausal women, IGF-I mRNA expression was significantly higher in fibroids than in myometrium, with no differences related to phase of the menstrual cycle. In post-menopausal women and in GnRH agonist-treated women responding to treatment, similar mRNA expression was seen in myometrium and fibroids but the concentrations were lower than in untreated premenopausal women. The IGF-I mRNA value in fibroids from pregnant women was higher than in any other group and myometrium from pregnant women exhibited higher mRNA expression than myometrium from non-treated premenopausal women. The IGF-I protein was more abundant in fibroids than in myometrium of non-treated premenopausal and of pregnant women and in both tissues the concentration was significantly higher in the group of pregnant women. The IGF-I protein concentrations in fibroids and myometrium from GnRH agonist-treated and post-menopausal women were similar to those from premenopausal non-treated women. High sex steroid concentrations in pregnant and non-pregnant women of fertile age seem to be associated with a higher expression of IGF-I in fibroids than in myometrium, suggesting that IGF-I contributes to the selective growth advantage of these tumours.
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Double colour fluorescence in situ hybridization with sex chromosome probes was applied on sperm cells of five Swedish Holstein-Friesian bulls. It was demonstrated that cosmids with strong fluorescence signals and scraped chromosomes can successfully be used as markers in this type of study. X and Y segregated as expected according to a 1:1 ratio, and there were no interindividual variations. There was a tendency for there to be more Y- than X-bearing spermatozoa, but this bias was assumed to be due to the markers used. Disomic spermatozoa occurred with a frequency of more than 0.1 % (0.067% XX, 0.029% YY, and 0.029% XY), which is considerably lower than the frequency in humans. Diploid sperm cells occurred with a frequency of 0.05 %.
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Human L-type Ca2+ channel alpha 1C subunit gene (CACNL1A1) maps to the distal region of chromosome 12p13, and is composed of approximately 50 exons spanning over 150 kb of the human genome as estimated by restriction map analysis. However, the structure and the total length of the 3'-end of the gene is not clear because the size of several big introns remains unknown. Here the fiber-FISH technique was used to determine the relative order and size of eight partial genomic DNA clones from the central and 3'-terminal regions of CACNL1A1. The total physical distance of this region, including the size and gap distances between the clones were re-estimated. The results show that the physical order of the tested clones was 5'-g14-5 > g12-2 > g10-8 > g4-5 > g16-7 > g8-3 > g12-5 > g6-20-3'. Their individual sizes vary between 6.7 and 21.9 kb. Clones g6-20 and g12-5, both containing repetitive exon 45/46-like element, were found to be located within 59.1 kb downstream of g8-3 containing earlier identified polyadenylation site, i.e. 229.5 kb away from clone g14-5 (exons 10, 11). The possible implications of this structural complexity is discussed.
The content of estrogen and progesterone receptors (ER, PR) is higher in fibroid tissue than in homologous myometrium, and both receptors seem to be regulated by the levels of circulating sex steroids. Myometrial and fibroid tissues were recovered from women undergoing gynecological operations during different phases of the menstrual cycle and during treatment with an analogue of GnRH (GnRHa). Contents of ER and PR in the tissue cytosol were determined by enzyme immunoassay. The ER levels were significantly higher in fibroid tissue than in homologous myometrium in all the endocrine conditions. During the secretory phase, when luteal progesterone production is prominent, the ER levels in the myometrium and fibroids were lower than during the proliferative phase. During GnRHa treatment, the ER levels in both tissues were similar to those in the proliferative phase but significantly higher than in the secretory phase. The PR levels were also significantly higher in fibroids than in myometrium in all the different endocrine conditions. In both tissues, the PR levels were lower in the secretory phase and during GnRHa treatment, compared with the proliferative phase. Our data suggest that, in these categories of women, both ER and PR are overexpressed in fibroid tissue. Apparently, high progesterone levels down-regulate the ER in both fibroids and myometrium, whereas estrogen mediates the up-regulation of the PR during the proliferative phase. Increased knowledge about the mechanisms by which sex steroids regulate their own receptors in uterine tissues might provide a basis for development of new treatment strategies for women with fibroid disease.
Contrary to extensive banding similarities of the autosomes, there are variations in the morphology as well as banding patterns of the X chromosomes of various species of bovidae family. We used three bovine X chromosome specific cosmid clones for fluorescence in situ hybridization mapping on cattle, goat, sheep, and river buffalo chromosomes to identify homologous regions in the genomes of the four species. The three cosmids (cIOBT 314, 945, and 1489) mapped to well spaced locations on buffalo X, and both arms of cattle X chromosome. However, of the three probes, cosmids cIOBT 314 and 1489 showed no hybridization signal on any of the goat-sheep chromosomes. Incidentally, the two cosmids show correspondence to those regions of the buffalo X chromosome which are proposed to be lost during the structural reshuffle of the latter, leading to sheep/goat X chromosomes. The lack of hybridization signal of the two cosmids in sheep and goat, therefore, indicates that these DNA sequences are most likely absent in the two genomes and probably correspond to the segments lost during evolution of their X chromosomes.
An in vitro assay for measuring and comparing the efficacy of different antimicrobial agents against Chlamydia pneumoniae was developed. Azithromycin, a representative of the new azalide group of antibiotics, and doxycycline were evaluated with respect to their antibacterial effect and capacity for intracellular killing under different experimental conditions. For both study drugs, the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values increased significantly with longer bacterial preincubation time. The effect of different exposure times of antibiotics on the bacteria was also studied.
Three X chromosome-specific bovine cosmids were used for fluorescence in situ hybridization mapping on reindeer (Rangifer tarandus) chromosomes, to test whether such large genomic clones could be used for comparative mapping across distantly related species. All three cosmids showed distinct unique hybridization sites on the reindeer X. Comparative map locations of these cosmids, together with the relative C-banding and genome size data on the X chromosomes of the two species, provide preliminary indications that the short and long arms of bovine X correspond, respectively, to the long and short arms of the reindeer X. The study also demonstrates that cosmid clones can be used successfully for comparative mapping across species that diverged 35 million years ago.