Biomedical subjects

M Kos

Publications and source records attributed to M Kos.

At least 19 recordsLinked to original sources

PubMed2003

The influence of locally implanted high doses of gentamicin on hearing and renal function of newborns treated for acute hematogenous osteomyelitis.

BACKGROUND: [corrected] Osteomyelitis and arthritis still present a serious diagnostic and therapeutic problem. Difficulties arise in particular in the treatment of acute hematogenic osteomyelitis (AHO) in newborns where mega-doses of gentamicin are administered locally for about 3 weeks. Gentamicin possesses strong oto- and nephrotoxicity and the occurrence of these adverse effects depends on the duration of treatment and the serum drug concentration. OBJECTIVE: Aim of the study was to evaluate the influence of local gentamicin application on auditory and kidney functions. MATERIAL AND METHODS: Twenty newborns (14 boys and 6 girls) with AHO were treated at the Department of Pediatric Surgery, Marciniak Hospital, Wroclaw, Poland, by local implantation of miniseptopal or gentamicin sponge. Serum urea, creatinine, antibiotic concentrations and NAG activity/g creatinine ratio in urine were estimated before and 1, 4, 8, 16 days after the operation and compared to values in the control group. Brainstem-evoked auditory potentials (BAEP) were examined before, during the first 3 weeks, and 6-11 months after gentamicin implantation. RESULTS: Mean gentamicin serum concentrations were: 0.67 +/- 0.98 mg/l on the 1st day, 0.16 +/- 0.37 mg/l on the 4th day, 0.03 +/- 0.09 mg/l on the 8th day, 0.01 +/- 0.03 mg/l on the 16th day after operation and did not exceed the upper limit of the therapeutic range. N-acetyl-beta-D-glucosaminidase (NAG)/g creatinine in urine ratios were satisfactory: 77.91 +/- 36.22 UI/g before the operation, 146.51 +/- 82.27 UI/g on the 4th, 162 +/- 111 UI/g on the 8th, 168 +/- 59.83 UI/g on the 16th day after operation and were statistically significantly (p < 0.05) higher than values in the control group. Serum urea and creatinine levels were in the normal range in all groups. Initial BAEP were well in the normal range in 15 of 16 children before treatment and in 14 of 16 children after treatment. CONCLUSIONS: Locally applied gentamicin as miniseptopal or sponge in newborns produces gentamicin concentrations close to the minimal therapeutic serum concentration which are present over a prolonged period. The raised NAG values in urine and normal serum urea and creatinine levels during treatment with gentamicin without concomitant clinical symptoms of renal failure suggest subclinical destruction of the renal tubules. Lack of change in BAEPs shows that there is no impairment of auditory function.

Acetylglucosaminidase↗

PubMed2002

Human estrogen receptor-alpha: regulation by synthesis, modification and degradation.

This review aims to evaluate the impact that human estrogen receptor-alpha (ER-alpha) synthesis, modification and degradation has on estrogen-dependant physiological and pathological processes within the body. Estrogen signaling is transduced through estrogen receptors, which act as ligand-inducible transcription factors. The significance of different isoforms of ER-alpha that lack structural features of full-length ER-alpha are discussed. The influence of differential promoter usage on the amount and isoform of ER-alpha within individual cell types is also reviewed. Moreover, the potential role of phosphorylation, ubiquitination and acetylation in the function and dynamic turnover of ER-alpha is presented.

Acetylation↗

PubMed2002

Midfacial fractures in children.

The purpose of the study was to present a modern classification and discuss the treatment of midfacial fractures in children. From the beginning of 1 January 1998 to 31 October 2000, 147 children were treated for different craniofacial fractures. Among them 28 patients (19 %) had extensive midfacial fractures complicated by impaired vision and/or CNS dysfunction and were treated surgically. The fractures were divided into: zygomatico-orbital (1 pt) and zygomatico-orbito-maxillary (5 pts), isolated orbital wall fractures (14 pts) and naso-orbital dislocations (2 pts), upper facial portion dislocations (2 pts) and fronto-naso-orbital (2 pts) or cranio-orbital fractures (2 pts). Clinical examination revealed mainly dysfunction of facial morphology and aesthetics (enophthalmos, telecanthus), CSF leakage, impairment of vision and restricted eyeball movements. Ophthalmological, neurological and radiological (Waters view, CT, NMR) examinations were performed in all cases. The treatment consisted of bone repositioning, reconstruction with autologous bone grafts and three-dimensional stabilisation using titanium plates. Twenty-three pts were operated on before and 5 pts after 7th day after trauma. The restoration of normal facial morphology was achieved in 26 patients. In 2 cases it was impossible because of the destruction of soft tissue and an extremely extensive bony trauma. Better reposition of bony fragments, prompt healing and better final results were achieved in patients operated before day 7 after trauma. Achieving good results in midfacial fractures requires prompt and adequate treatment and a multidisciplinary (paediatric, maxillofacial, plastic surgeons, neurosurgeon, ophthalmologist) team.

Bone Plates↗

PubMed2002

Perspectives of clinical application of bone morphogenetic proteins in children.

UNLABELLED: The purpose of the study was to modify the method of Bone Morphogenetic Protein (BMP) extraction from bovine bones, estimate the osteoinductive potential of the extracted protein fractions in relation to the degree of protein purity and to test collagen formed in porous discs as a carrier. It was required before BMP application in reconstructive surgery in children. MATERIAL AND METHOD: BMP preparation from bovine bones was conducted according to a modification of Luyten's method. Three fractions of different degree of purity - demineralised bone matrix "M", extract "E", and fraction after hydroxyapatite column "HP" - were tested for their osteoinductive potential. They were implanted on a collagen carrier into the right rat femoral muscle pouch. Controls were implanted in the same way in the left muscle pouch. The discs were removed after 3 and 6 weeks and tested for alkaline phosphatase activity, a marker of new bone formation. RESULTS: Out of the 10 animals used for testing the osteoinductive potential of matrix fraction, 7 results were positive and 3 negative. In the case of the extract fraction, the analysis was conducted for 3 weeks on 9 rats and 6 weeks on 13 rats. Six and 11 positive results were obtained, respectively. In the HP group 5 animals were observed for 3 weeks (3 positive, 2 negative) and 10 animals for 6 weeks (7 positive, 3 negative). In the case of the extract, the differences in alkaline phosphatase activity after 6 weeks were statistically significant (p <or= 0.05) compared to controls. In the other groups, a positive tendency was observed, but it was not statistically significant. CONCLUSIONS: Purified BMP has osteoinductive abilities causing ectopic new bone formation. From all obtained BMP fractions the extract had the highest osteoinductive potential and seems to be an optimal fraction for further clinical use. These results offer hope for a prompt clinical application of nonantigenic, xenogenic BMP, especially in three-dimensional bone reconstruction, for the treatment of non-united fractures or fractures with delayed union, to fill either bone cysts or other defects.

Alkaline Phosphatase↗

PubMed2002

Down but not out? A novel protein isoform of the estrogen receptor alpha is expressed in the estrogen receptor alpha knockout mouse.

The mouse knockout of the estrogen receptor alpha (ERalpha) gene, known as alphaERKO, has been extensively used for several years to study the role and function of ERalpha. Residual estradiol binding capacity in uterine tissue of 5-10% raised doubts if this knockout is a genuine null mutation of ERalpha. Although alternatively spliced ERalpha mRNA variants in the alphaERKO mouse were reported previously, the corresponding protein isoforms have not been detected to date. Here we show that a variant ERalpha protein, 61 kDa in size, is expressed in the uterine tissue of alphaERKO mice as a result of an alternative splicing. The transactivation capability of this protein is cell dependent and can be as high as 75% of the wild type ERalpha.

3T3 Cells↗

PubMed2001

Tissue-specific expression of human ERalpha and ERbeta in the male.

The important role of estrogens in women in physiological and pathological processes is well accepted, but recently it has become evident that estrogens are also important in male physiology, in particular, within bone metabolism and reproduction. Consequently, it is necessary to identify and to characterize the molecular mechanisms of estrogen action in order to evaluate how the pleiotropic effects of estrogens are mediated in a variety of tissues. We have recently shown that human estrogen receptor alpha (ERalpha) mRNA is transcribed from at least six different promoters (1A-1F). Transcription of ERalpha in bone is exclusively dependent on the F-promoter. To study the regulation of ER expression in this tissue, we examined 1 kbp of the F-promoter region of human ERalpha, which is located more than 70 kbp upstream of the transcription start site of the ERalpha gene. Transient transfection experiments demonstrated a basal activity from the F-promoter, which was further increased when ERalpha was cotransfected. We have shown recently that the F-promoter can give rise to at least two ERalpha isoforms in bone. On the contrary, ERbeta expression in primary osteoblasts is extremely low, indicating that this ER isoform plays only a minor role in these cells. In contrast to bone, we have demonstrated that both ERalpha and ERbeta transcripts are readily detected in testis. Here, we report that besides ERalpha, ERbeta transcripts can give rise to two protein isoforms and that this complex situation could have important functional consequences for the signalling of estrogens and their analogs.

Alternative Splicing↗

PubMed2001

Systemic conditions for performance of pharmacoepidemiologic studies in Slovenia.

In Slovenia, the national health insurance system covers almost the whole population. The average patient receives six to seven prescriptions per year with an average value of 15 USD per prescription. This paper presents the systemic conditions necessary for the performance of pharmacoepidemiologic studies. A recent study addressing the use of antiepileptic drugs is an example. The current law on Personal Data Protection, which is compliant with EU Directive 95/46/EC, prevents infringement of personal integrity resulting from inappropriate use of personal data or inappropriate management and use of databases containing personal data. Since July 2000, the Law on Health Care Related Databases has defined the databases and the ways data can be acquired, processed, transferred, and exchanged among persons authorized to perform health care services. When gathering additional data not currently contained in the health care-related databases defined by the law, written consent from participants is required, and study documentation must be submitted for approval to the national Medical Ethics Committee. The main legislation covering clinical and pharmacoepidemiologic research is the Medicinal Products and Medical Devices Act of 1999, together with its by-laws, which is also in accordance with EU Directives.

Bioethics↗

PubMed2001

Immunocytochemical demonstration of visual pigments in the degenerate retinal and pineal photoreceptors of the blind cave salamander (Proteus anguinus).

Visual pigments in the regressed eye and pineal of the depigmented neotenic urodele, the blind cave salamander (Proteus anguinus anguinus), were studied by immunocytochemistry with anti-opsin antibodies. The study included light- and electron-microscopic investigations of both the eye and the pineal organ. A comparison was made with the black pigmented subspecies Proteus anguinus parkelj (black proteus), which has a normal eye structure. In the retina of the black proteus, we found principal rods, red-sensitive cones and a third photoreceptor type, which might represent a blue- or UV-sensitive cone. Photoreceptors in the regressed eye of the blind cave salamanders from the Planina cave contained degenerate outer segments, consisting of a few whorled discs and irregular clumps of membranes. The great majority of these outer segments showed immunolabelling for the red-sensitive cone opsin and only a few of them were found to be positive for rhodopsin. An even more pronounced degeneration was observed in the photoreceptors of the animals derived from the Otovec doline, which are completely devoid of an outer segment, most of them not even possessing an inner segment. Even in some of these highly degenerate cells, the presence of rhodopsin could be detected in the plasma membrane; however, immunoreactions with antibodies recognizing cone visual pigment were negative. In the pineals of all studied animals, the degenerate photoreceptor outer segments were recognized exclusively by the antibody against the red-sensitive cone opsin. The presence of immunopositive visual pigments indicates the possibility of a retained light sensitivity in the blind cave salamander photoreceptors.

Animals↗

PubMed2001

Minireview: genomic organization of the human ERalpha gene promoter region.

The ERalpha gene has been intensively studied for more than a decade. During this long time, multiple promoters used in ERalpha expression have been discovered in several species. Although an already large body of literature describing various aspects of the regulation of ERalpha expression and utilization of different promoters is constantly growing, the inconsistent terminology used by individual authors makes the interpretation and comparison of data very difficult. Furthermore, completion of the human genome project now allows all known human ERalpha promoters to be placed on a physical map. This review describes promoters used in the generation of ERalpha transcripts in human and in other species and suggests a consistent nomenclature. The possible role of multiple promoters in the differential expression of ERalpha in tissues and during development is also discussed.

Animals↗

PubMed2001

ERalpha gene expression in human primary osteoblasts: evidence for the expression of two receptor proteins.

The beneficial influence of E2 in the maintenance of healthy bone is well recognized. However, the way in which the actions of this hormone are mediated is less clearly understood. Western blot analysis of ERalpha in osteoblasts clearly demonstrated that the well characterized 66-kDa ERalpha was only one of the ERalpha isoforms present. Here we describe a 46-kDa isoform of ERalpha, expressed at a level similar to the 66-kDa isoform, that is also present in human primary osteoblasts. This shorter isoform is generated by alternative splicing of an ERalpha gene product, which results in exon 1 being skipped with a start codon in exon 2 used to initiate translation of the protein. Consequently, the transactivation domain AF-1 of this ERalpha isoform is absent. Functional analysis revealed that human (h)ERalpha46 is able to heterodimerize with the full-length ERalpha and also with ERbeta. Further, a DNA-binding complex that corresponds to hERalpha46 is detectable in human osteoblasts. We have shown that hERalpha46 is a strong inhibitor of hERalpha66 when they are coexpressed in the human osteosarcoma cell line SaOs. As a functional consequence, proliferation of the transfected cells is inhibited when increasing amounts of hERalpha46 are cotransfected with hERalpha66. In addition to human bone, the expression of the alternatively spliced ERalpha mRNA variant is also detectable in bone of ERalpha knockout mice. These data suggest that, in osteoblasts, E2 can act in part through an ERalpha isoform that is markedly different from the 66-kDa receptor. The expression of two ERalpha protein isoforms may account, in part, for the differential action that estrogens and estrogen analogs have in different tissues. In particular, the current models of the action of estrogens should be reevaluated to take account of the presence of at least two ERalpha protein isoforms in bone and perhaps in other tissues.

Alternative Splicing↗

PubMed2001

Anencephaly: structural characterization of gangliosides in defined brain regions.

Gangliosides from histopathologically-defined human cerebrum-resembling remnant and cerebellum from 37 and 30 gestational week-old anencephaluses were identified using mass spectrometry and high performance thin layer chromatography combined with immunochemical analysis in comparison to respective normal newborn/fetal and adult brain regions. A novel strategy of nano-electrospray ionization quadrupole time-of-flight tandem MS has been developed for identification of ganglioside components in complex mixtures. By morphoanatomical and histological investigation the anencephalic cerebral remnant was found to be aberrant, while the anencephalic cerebellum was defined as normal. Total ganglioside concentrations in the anencephalic cerebral remnant and the cerebellum were 34% and 13% lower in relation to the age-matched controls. In the cerebral remnant, GD3, GM2 and GT1b were elevated, while GD1a was decreased in the anencephalic cerebral remnant, but enriched in anencephalic cerebellum. GQ1b was reduced in both anencephalic regions. Gg4Cer, GM1b and GD1alpha, members of the alpha-series biosynthetic pathway, and neolacto-series gangliosides were found to be present in anencephalic, as well as in normal, fetal and adult brain tissues, indicating the occurrence of these biosynthetic pathways in human brain. In both cerebral and cerebellar anencephalic tissues, GM1b, GD1alpha, nLM1 and nLD1 were expressed at a higher rate in relation to normal tissue. It can be demonstrated that the anencephalic cerebral remnant, as a primitive brain structure, represents a naturally-occurring model to study the ganglioside involvement in induction of aberrant brain development.

Anencephaly↗

PubMed2001

Congenital gastrointestinal system malformations in a 5-year post mortem series.

The aim of this study was to determine the types and frequencies of congenital gastroinstestinal (G-I) tract malformations on post mortem in the period from 1996 to 2000. Autopsy protocols of aborted fetuses, stillborn infants and infants that died within 7 days after delivery were retrieved from the archive and studied. Cases of cleft lip and/or palate, biliary tract, pancreatic and diaphragmal malformations were not included in the study. During the mentioned period, 1251 autopsy was performed with 127 showing some malformation. G-I tract malformation was diagnosed in 37 cases (2.9% and 29.1%, respectively). Most frequent malformations were atresias at the different level of the G-I tract (56.75%), followed by omphalocoele (35.13%) and gastroschisis (8.1%). Of atresias, the most frequent were oesophageal and anorectal (38.1% of atresias, each). A striking male preponderance (2.36:1) in the frequency of G-I malformations was noticed. Isolated G-I malformations were found in 32.4%, different but simultaneous G-I malformations in 5.4% and association with other organ system(s) malformations in 62.2%. Omphalocoele and anorectal atresia were associated with other organ system malformation(s) in 34.8%, each. Other organ systems affected by malformation besides the G-I tract were cardiovascular system (65.21%), urogenital system (also 65.2%), gastrointestinal system with the malformation of another kind or atresia at the different level (17.4%), CNS (17.4%), skeletal system (26.1%) and other organs or systems (30.7%).

Autopsy↗

PubMed2000

Identification of a new isoform of the human estrogen receptor-alpha (hER-alpha) that is encoded by distinct transcripts and that is able to repress hER-alpha activation function 1.

A new isoform of the human estrogen receptor-alpha (hER-alpha) has been identified and characterized. This 46 kDa isoform (hERalpha46) lacks the N-terminal 173 amino acids present in the previously characterized 66 kDa isoform (hERalpha66). hERalpha46 is encoded by a new class of hER-alpha transcript that lacks the first coding exon (exon 1A) of the ER-alpha gene. We demonstrated that these Delta1A hER-alpha transcripts originate from the E and F hER-alpha promoters and are produced by the splicing of exon 1E directly to exon 2. Functional analysis of hERalpha46 showed that, in a cell context sensitive to the transactivation function AF-2, this receptor is an effective ligand-inducible transcription factor. In contrast, hERalpha46 is a powerful inhibitor of hERalpha66 in a cell context where the transactivating function of AF-1 predominates over AF-2. The mechanisms by which the AF-1 dominant-negative action is exerted may involve heterodimeri zation of the two receptor isoforms and/or direct competition for the ER-alpha DNA-binding site. hERalpha66/hERalpha46 ratios change with the cell growth status of the breast carcinoma cell line MCF7, suggesting a role of hERalpha46 in cellular proliferation.

Base Sequence↗

PubMed2000

DNA ploidy analysis and cell proliferation in congenital sacrococcygeal teratomas.

BACKGROUND: Congenital sacrococcygeal teratoma is the most common germ cell tumor in infants and children. It usually is diagnosed at birth, is benign, and consists of fully differentiated mature tissues. Congenital sacrococcygeal teratomas (SCTs) also may contain immature tissues, most commonly of neural origin. The proportion of malignant teratomas increases with advancing age, but the relation between mature and immature SCTs is not well understood. Thus, it is very important to determine proliferative activity, DNA ploidy, and DNA index to predict biologic behavior of these tumors. METHODS: DNA ploidy and cell proliferation were analyzed by flow cytometry, and the expression of proliferating cell nuclear antigen (PCNA) and Ki-67 were analyzed immunohistochemically on paraffin embedded tissue. RESULTS: All the tumors that were surgically treated within 3 months after birth, including immature teratoma, were diploid. Strongly positive PCNA immunostaining was found in both immature teratomas, and weakly positive PCNA was found in nine cases. Weak positivity for Ki-67 was observed in 2 cases, and moderate positivity was observed in 6 cases including immature teratomas. CONCLUSION: The value of flow cytometry in the prediction of biologic behavior of congenital SCT should be analyzed further. Our results suggest that Ki-67 and especially PCNA may reflect the proliferative activity of these tumors.

Cell Division↗

PubMed2000

Tissue-specific expression of multiple mRNA variants of the mouse estrogen receptor alpha gene.

The isolation of five new mouse estrogen receptor alpha mRNA variants (mERalpha A, B, F1, F2 and H) is described. All of these transcripts are generated by alternative splicing and all encode the 66 kDa ERalpha protein that the previously identified mRNA C variant generates. However, these transcripts differ in their 5' untranslated regions. RT-PCR and S1 nuclease protection assays revealed a tissue- and sex-specific expression pattern of all variants. The C and F mRNA variants are the predominantly expressed mERalpha variants in mouse. The expression of mERalpha H mRNA is restricted to liver, although female mice produce around a five fold higher level of this transcript than males. Our results show that the mERalpha gene is a complex genomic unit in mice that exhibits alternative splicing which is regulated in a tissue-specific manner.

5' Untranslated Regions↗

PubMed2000

Neutrophil antigen 5b is carried by a protein, migrating from 70 to 95 kDa, and may be involved in neonatal alloimmune neutropenia.

BACKGROUND: Neutrophil antigen 5b has been described as involved in transfusion reactions and not in neonatal alloimmune neutropenia. CASE REPORT: Anti-5b was found in the serum of a mother of a persistently neutropenic newborn, who had several bacterial infections. The neutropenia responded to treatment with recombinant human granulocyte-colony-stimulating factor. Immunoprecipitation experiments performed with this and three other 5b antisera identified a protein, migrating from 70 to 95 kDa, as carrier of 5b. The observed pattern of migration may point to heavy glycosylation of this protein. RESULTS: Six 5b-negative donors were identified among 54 screened white donors, for a 5b gene frequency of 0.66. CONCLUSION: Alloimmunization to 5b in pregnancy is rare. In the patients with neonatal neutropenia analyzed in the last decade, this was the first case discovered.

Antigens↗

PubMed2000

Analysis of Bcl-2 protein expression in chronic lymphocytic leukemia. A comparison of three semiquantitation techniques.

A number of studies revealed that high expression of the proto-oncogene bcl-2 correlated with poor prognosis or resistance to chemotherapy in some tumors but predicted a favorable clinical course in other neoplasias. In these studies, however, different immunologic techniques for Bcl-2 detection were used, raising the question of whether the methods applied were comparable. Using chronic lymphocytic leukemia (CLL) cells, the aims of our study were as follows: (1) to determine the reproducibility of Bcl-2 semiquantitation by immunocytochemistry, flow cytometry, or immunoblotting; (2) to study the agreement between results obtained by these methods; and (3) to examine the association between Bcl-2 expression in tumor cells of 99 patients with CLL and clinical parameters. We found that determination of Bcl-2 expression by immunocytochemistry was reproducible and the results were comparable with those of flow cytometry and immunoblotting. In the patient collective examined, Bcl-2 expression did not reflect the extent of tumor mass, but higher levels were found more often in patients with progressive disease.

Flow Cytometry↗

PubMed2000

Three-dimensional sonography in prenatal diagnosis: a luxury or a necessity?

Three-dimensional sonography revolutionized ultrasound imaging with its capacity to depict an unlimited number of planes in which the object of interest can be displayed. The addition of numerous modalities of image rendering promotes three-dimensional sonography to the top of the spectrum of diagnostic imaging in obstetrics and gynecology. The aim of this article is to present our experience in 3-D sonography during the second and third trimester of pregnancy and to give a comparative review of literature. 247 patients in gestational age ranging from 12 to 40 weeks of gestation were examined over a three year period. The majority of patients entered the study because fetal anomaly was suspected at two-dimensional sonography. Some patients were sent on to three-dimensional sonography because it was not possible to depict clearly normal fetal anatomy by two dimensional sonography. Out of 170 fetal anomalies three-dimensional sonographic analysis failed in only three cases. In all three anomaly was accompanied with severe oligohydramnios. Main advantages of three-dimensional ultrasound in perinatal medicine and antenatal diagnosis include scanning in the coronal plane, improved assessment of complex anatomic structures, surface analysis of minor defects, volumetric measuring of organs, "plastic" transparent imaging of fetal skeleton, spatial presentation of blood flow arborization and, finally, storage of scanned volumes and images. It is our decided opinion that three-dimensional sonography has gained a valuable place in prenatal diagnosis, becoming a necessity for every modern perinatal unit.

Congenital Abnormalities↗