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Biomedical subjects

M Polak

Publications and source records attributed to M Polak.

At least 37 records · Page 2Linked to original sources
PubMed2004

Preliminary results of monitoring research on zearalenone presence in blood of women with neoplastic lesions in reproductive system.

The aim of the monitoring of zearalenone presence in the blood plasma of women with neoplastic lesions in the reproductive tract was to asses whether the phytosteride is noted in the patients blood and whether the correlation exists between its presence and the incidence of particular neoplasm. The presence of zearalenone or its metabolite--alpha-zearalenole, was noted in 13.51% of the examined women. In 60% of the patients with the confirmed presence of the xenobiotic it was noted in the lowest concentrations. These patients had neoplastic lesions of Carcinoma corpus uteri type.

Estrogens, Non-Steroidal↗
PubMed2004

Modification of zearalenone structure in model and natural conditions.

Zearalenone is a mycotoxin widely occurring in cereals and animal feed, and it is associated with hyperestrogenism and other reprodutive disorders in animals. A new method of detoxication of feedstuffs involves alkaline hydrolysis of toxic macrolactone (1) (as well as model compounds (2a, 2b)). The method caused modification of zearalenone structure under mild conditions and the toxin underwent irreversible hydrolysis with high efficiency.

Animal Feed↗
PubMed2004

Metabolic profile of pigs fed feed containing zearalenone destructor.

Zearalenone (ZEA) is a member of macrocyclic lactons family. It is a toxin--phytosteride produced by fungi of Fusarium ssp. genus. Zearalenone contaminates food and animal feeding stuffs and its destruction is difficult. It requires application of particular compounds that would bind zearalenone in the feed or feeding stuff or in the gastrointestinal tract and decrease its bio-accessibility. It should also fulfil all the safety requirements regarding the plant supplements and animals that are fed with this feed. The aim of the study was to estimate if the feed supplemented with different doses of zearalenone and zearalenone destructor causes changes of the metabolic profile in gilts. The results obtained show that applied destructor did not cause negative haematological and biochemical changes in the blood of the gilts examined. It can be suggested that it is a safe feed supplement pigs in prevention of zearalenone micotoxicosis.

Animal Feed↗
PubMed2003

TNF polymorphisms are associated with toxic but not with aGVHD complications in the recipients of allogeneic sibling haematopoietic stem cell transplantation.

NcoI polymorphism within the promoter/enhancer region of TNFalpha and the first intron of TNFbeta encoding gene was analysed in 70 patients with haematological malignancies transplanted from HLA-identical sibling donors. The control group was composed of 130 healthy individuals. We showed that patients heterozygous for one or both TNF genes suffered more frequently from severe (grades III-IV) toxic complications than those carrying the other TNF genotypes (TNFA(*)1,2: 9/10 vs 30/60, P<0.05; TNFB(*)1,2: 20/26 vs 19/44, P<0.01; TNFA(*)1,2 TNFB(*)1,2: 9/9 vs 30/61, P<0.005). Conversely, patients having TNFB(*)2,2 less frequently presented with severe toxic lesions (17/39 vs 22/31, P<0.05). Additional analyses showed that TNFA(*)1,2, independent of the TNFB genotype composition, influenced the manifestation of grades III-IV toxic lesions, while TNFB(*)2,2 and TNFA(*)1,1 in combined association played a protective role. Logistic regression analysis confirmed the association of recipient TNFA(*)1,2 genotype with severe toxic complications, in addition to aggressive myeloablative conditioning regimen and female to male transplantation. No relation was found between TNF polymorphic features and aGvHD incidence by either uni- or multivariable analyses.

Adolescent↗
PubMed2003

Severe insulin resistance contrasting with mild anthropometric changes in the adipose tissue of HIV-infected children with lipohypertrophy.

BACKGROUND: The HIV-associated lipodystrophic syndrome (HIV-LDS) combines redistribution of fat mass with insulin resistance and hyperlipidemia. We have previously reported that HIV-LDS prevails in children in a comparable pattern as in adults. The metabolic activity itself of the lipodystrophic adipose tissue in HIV infection has been poorly studied. AIM AND METHODS: To assess in situ the insulin sensitivity of the lipohypertrophic subcutaneous abdominal adipose tissue using the microdialysis technique in HIV-infected children. Insulin sensitivity, assessed by the inhibition of glycerol release, was measured in the abdominal subcutaneous adipose tissue during a standard oral glucose tolerance test (OGTT) in six HIV-infected children under multi-therapy with abdominal lipohypertrophy (supra-iliac skinfold thickness >97th percentile) (HIV/LH+), in six obese children (obese group) and in eight HIV-infected children without lipodystrophy (HIV/LH-). RESULTS: Glucose tolerance was normal in all subjects. Mean insulin areas under the curve (IAUC) were significantly higher in the obese and HIV/LH+ groups than in HIV/LH- (8769+/-5429, 8161+/-4552 and 3618+/-2222 mU min l(-1), respectively; P=0.04 for the three groups comparison by the Kruskal-Wallis test), reflecting insulin resistance in the two former groups independent of a significant difference in percentage fat mass (37.2+/-4.7, 22.8+/-10.9 and 20.7+/-7.1%, respectively; P= 0.006). The crude inhibition of glycerol release, expressed as the relative change in dialysate glycerol concentration between baseline and 120 min, was not statistically different between the three groups (14% in obese, -38+/-14% in HIV/LH+ and -51+/-17% in HIV/LH- groups; P=0.3). The inhibition of glycerol release with respect to the circulating insulin level (expressed by IAUC) was similar in HIV/LH+ and obese groups (-6+/-5 x 10(-3) and -7+/-5 x 10(-3) l mU(-1) min(-1), respectively, P=0.4 for two-groups comparison by the U-Mann-Whitney test) and four-fold less than in the HIV/LH- group (-24+/-25 x 10(-3) l mU(-1) min(-1); P=0.02). CONCLUSION: These data argue in favor of insulin resistance in the adipose tissue of lipohypertrophies associated with HIV infection.

Adipose Tissue↗
PubMed2003

Heritability of resistance against ectoparasitism in the Drosophila-Macrocheles system.

Ectoparasites are abundant in natural communities, can have pronounced deleterious fitness consequences to their host and are important vectors of transmissible parasitic disease. Yet very few studies have estimated the magnitude of heritable genetic variation underlying resistance against ectoparasitism, which significantly limits our ability to predict the evolution of this ecologically important character. The present paper reports results of artificial selection for increased resistance in Drosophila nigrospiracula against ectoparasitic, haematophagous mites, Macrocheles subbadius. In this system, which occurs naturally in the Sonoran Desert of North America, ectoparasitism significantly damages the expression of host fitness traits, including longevity, fecundity and male mating success. In the present study, resistance, which was modelled as a threshold trait, responded significantly to selection applied on either sex. Realized heritability, calculated as a mean across four replicates, was estimated to be 0.152 +/- 0.014 (SE). The heritability estimate from selection on males did not differ from that on females, but both estimates differed significantly from zero. This documented presence of additive genetic variation for resistance, coupled with knowledge of the fitness consequences of ectoparasitism, indicates that the host population possesses significant evolutionary potential. Selection was applied on the pre-attachment phase, thereby targeting behavioural forms of defence. This study therefore establishes parallels between insects and other animals in their ability to protect themselves and evolve behavioural defences against ectoparasites.

Animals↗
PubMed2003

Influence of zearalenone on reproductive system cell proliferation in gilts.

Zearalenone (ZEA) is a macrocyclic lactone, estrogenic, diet-depending and fusaric micotoxin, which is produced on many kinds of cereals and feeds in the favourable conditions of humidity and temperature. The structure of ZEA is similar to the structure of estrogens and it enables binding to the estrogenic receptors. The stimulation of protein synthesis in the cells of the reproductive system, which causes intensification of cell proliferation, is one of the effects of ZEA actions. Oedema and vulva reddening are the clinical, external signs of ZEA intoxication in pigs. The aim of this study was to designate the degree of reproductive cell proliferation after low doses of ZEA were applied per os in sexually immature gilts with simultaneous monitoring of zearalenone and alpha-zearalenol levels in peripheral blood. The following were observed in the gilts examined fluctuations of zearalenone and alpha-zearalenol levels in blood, which were connected with entero-hepatic circulation and also numerous histopathological changes in ovarian follicle structure. These changes were present in the reproductive system of sexually immature gilts with a big contribution of PCNA-positive cells. The studies show that zearalenone application in sexually immature gilts caused ovarian follicle atresia and apoptoso-like changes in granule cells. Intensified cell proliferation, which was expressed with the growth of PCNA index, was observed in uterus and oviduct.

Animals↗
PubMed2002

Efficacy of Humalog injections before an afternoon meal and their acceptance by children and adolescents with type 1 diabetes.

AIMS: To evaluate the acceptability and efficacy of an injection of insulin lispro, before an afternoon meal. METHODS: The subjects, 43 patients with Type 1 diabetes, 16 boys and 27 girls, aged 12.4 +/- 2.4 years, were randomly assigned to the treatment (n = 20) or the untreated control group (n = 23). The treatment was an injection of insulin lispro immediately before the afternoon meal. The control group had no injection. The treatment and the control group consumed identical types of meals for 2 months. The mean before-dinner blood glucose was measured during the last 2 weeks of the study. RESULTS: Injection of insulin lispro resulted in a significant reduction in the before-dinner blood glucose compared with the untreated control group (10.4 +/- 3.8 mmol/l vs. 14.7 +/- 3.9 mmol/l, respectively). The number of days on which the blood glucose was > 10 mmol/l was reduced by half in the insulin lispro group. The difference in HbA1c between baseline and endpoint differed slightly but significantly between the two groups, in boys. Treated patients ate the meal less frequently (11.4 +/- 3.0 times per 15 days) than the control patients (14.4 +/- 0.6 times per 15 days) and injected themselves with insulin 8.9 +/- 3.6 times per 15 days. The HbA1c increased significantly with the number of meals taken without injection. There was no statistically significant difference in the frequency of hypoglycaemia or changes in weight between the two groups. CONCLUSIONS: We conclude that an injection of insulin lispro before the afternoon meal can effectively lower the before-dinner blood glucose, and in boys also lowers the HbA1c. Patients were satisfied with the lower blood glucose before dinner, and did not find the insulin lispro injection difficult. However, compliance with the protocol procedures decreased during a subsequent 6-month period.

Blood Glucose↗
PubMed2002

Genotype-phenotype relationships in Berardinelli-Seip congenital lipodystrophy.

Generalised lipodystrophy of the Berardinelli-Seip type (BSCL) is a rare autosomal recessive human disorder with severe adverse metabolic consequences. A gene on chromosome 9 (BSCL1) has recently been identified, predominantly in African-American families. More recently, mutations in a previously undescribed gene of unknown function (BSCL2) on chromosome 11, termed seipin, have been found to be responsible for this disorder in a number of European and Middle Eastern families. We have studied the genotype/phenotype relationships in 70 affected subjects from 44 apparently unrelated pedigrees of diverse ethnic origin. In all subjects, hepatic dysfunction, hyperlipidaemia, diabetes mellitus, and hypertrophic cardiomyopathy were significant contributors to morbidity with no clear differences in their prevalence between subjects with BSCL1 or BSCL2 and those with evidence against cosegregation with either chromosome 9 or 11 (designated BSCLX). BSCL2 appears to be a more severe disorder than BSCL1 with a higher incidence of premature death and a lower prevalence of partial and/or delayed onset of lipodystrophy. Notably, subjects with BSCL2 had a significantly higher prevalence of intellectual impairment than those with BSCL1 or BSCLX (p<0.0001, OR 17.0, CI 3.6 to 79.0). The higher prevalence of intellectual impairment and the increased risk of premature death in BSCL2 compared to BSCL1 emphasise the importance of molecular diagnosis of this syndrome and have clear implications for genetic counselling.

Adolescent↗
PubMed2001

DNA-cation interactions: The major and minor grooves are flexible ionophores.

Several crystallographic, solution-state and theoretical studies carried out this past year provide new support for the sequence-specific nature of monovalent and divalent cation coordination within the DNA major and minor grooves. Correlations observed between groove width and cation coordination indicate that the grooves are flexible and respond to cation binding.

Binding Sites↗