Mismatch repair status predicts survival after adjuvant treatment in stage II colon cancer patients.

BACKGROUND AND OBJECTIVES: Stage II colon cancer is primarily a surgical disease. Only a still not well-defined subset of patients may benefit from postoperative adjuvant chemotherapy. The relationship between adjuvant chemotherapy and survival after relapse is furthermore still not definitely explored in this group of patients. A number of reports suggest some association between defective mismatch repair (dMMR) and colorectal cancer stage II prognosis, but due to contradictory results from existing studies, the exact predictive role is still not fully understood. METHODS: Retrospective multicenter study including 451 stage II colon cancer patients. The proficiency or deficiency of mismatch repair was tested using immunohistochemistry and analyzed in relationship to two survival outcomes: overall survival (OS) and postrelapse survival. RESULTS: Patients with dMMR (20.4%) derived no OS benefit from adjuvant chemotherapy (hazard ratio [HR], 1.05; 95% confidence interval [CI], 0.47-2.38; P = .897). Patients with proficient mismatch repair (pMMR) tumors receiving adjuvant chemotherapy had the significantly better OS in comparison to those not receiving chemotherapy (HR, 0.54; 95% CI, 0.35-0.82; P = .004). This relationship remained significant in multivariable analysis (HR, 0.42; 95% CI, 0.22-0.78; P = .007). Patients with pMMR relapsing after adjuvant treatment lived significantly longer than those relapsing without previous adjuvant treatment (HR, 0.55; 95% CI, 0.32-0.96; P = .033) and this result remained significant in the multivariable model (HR, 0.49; 95% CI, 0.26-0.93; P = .030). CONCLUSION: In stage II CC patients, adjuvant chemotherapy improves therapeutic outcomes only in patients with pMMR tumors. Survival after relapse in patients having received adjuvant chemotherapy is significantly longer for patients with pMMR. No survival benefit from adjuvant chemotherapy was seen among patients with dMMR tumors.

Genetic variability of pig and human rotavirus group A isolates from Slovakia.

The aim of this work was the genetic typing of RVA isolates originating from pigs and human patients in Slovakia. Seventy-eight rectal swabs from domestic pigs and 30 stool samples from humans were collected. The whole VP7 (G genotypes), VP6 (I genotypes) and partial VP4 (P genotypes) ORFs were amplified by RT-PCR. Genetic variability was higher amongst porcine sequences, where four G genotypes (G3, G4, G5, G11), two P genotypes (P[6], P[13]) and one I5 genotype were detected. Human RVA strains were represented by two G genotypes (G1, G3), two I genotypes (I1, I2), and one P genotype (P[8]). Genetic analysis did not show a relationship between Slovakian porcine and human RVA strains, but phylogenetic grouping of some Slovakian porcine sequences with Hungarian human sequences in both G and P genotypes was observed.

Changes in placental angiogenesis and their correlation with foetal intrauterine restriction.

TYPE OF STUDY: Summary review. SETTING: Department of Gynaecology and Obstetrics, 1st Faculty of Medicine, Charles University and Hospital Na Bulovce, Prague; Department of Physiology, Faculty of Science, Charles University, Prague; Department of Children and Adolescent Medicine, 1st Faculty of Medicine, Charles University in Prague and General Teaching Hospital, Prague. INTRODUCTION: Intrauterine growth restriction (IUGR) is one of the most common problems in obstetrics. Its incidence is ranging between 3-10%, according to the type of study population and chosen criteria. The cutoff value mainly used for defining the IUGR is weight below the 10th percentile for gestational age. The minority of authors defines the cutoff value under the 5th or 3rd percentile. Any pathological interference with normal vascular development of placenta may have a critical impact on foetal growth and development. Ischaemia is the most common cause of IUGR in normally well-supplied placenta. IUGR is then a consequence of insufficient extension, branching, and dilatation of capillary loops during the formation of terminal villi. METHODS: This paper is a review focused on up-to-date-known data concerning changes in placental angiogenesis and their impact on IUGR development. CONCLUSION: The aim of this review is to summarize the knowledge concerning the mechanisms of development of the vascular supply to the placenta under physiological conditions and in conditions that result in IUGR.

Bad and Bid - potential background players in preneoplastic to neoplastic shift in human endometrium.

The most common malignancies of the female genital tract are endometrial carcinomas, whose are generally proceeded by hyperplasia. The maintenance of tissue homeostasis is to great extent governed by apoptosis, whose defects can lead to the preneoplastic and/or cancerous changes. Endometrial apoptosis involves among others three groups of proteins of the Bcl-2 family. First group contains anti-apoptotic proteins (e. g. Bcl-2, Bcl-xL). The other two groups belong to the pro-apoptotic proteins with three (e. g. Bax, Bak) or one (e. g. Bad, Bid) so-called BH domains. Bad and Bid trigger the oligomerization of Bak and Bax protein, which permeabilize the outer mitochondrial wall. Unlike Bid, Bad cannot directly trigger apoptosis. Instead, Bad lowers the threshold at which apoptosis is induced, by binding anti-apoptotic Bcl-2 proteins. However, their mutual counterbalance or synergism in the human endometrium has not been reported yet.In this study, the levels of Bid and Bad were measured using SDS-PAGE and Western blotting with specific antibodies, with the aim to analyse expression of Bid and Bad proteins in normal (NE), hyperplastic (HE) and cancerous (CE) endometrium. We demonstrated that Bid expression in CE reached only 47% and 50% of this observed in NE and HE. Conversely, Bad expression in HE reached only 40% and 36% of this observed in NE and CE, respectively. We detected no significant changes of Bid expression between HE and NE, and levels of Bad protein were not different between CE and NE.Trend of Bid and Bad protein expression is clearly opposite in HE and CE. We hypothesise that disrupted apoptotic program in CE seems to be reduced further by lowering levels of direct apoptotic trigger protein Bid. We suggest that the adenocarcinoma tissue of human endometrium thus tries to strengthen its apoptotic effort by lowering the apoptotic threshold via higher Bad levels.

The guidelines for clinical practice for carriers of germline mutations in hereditary breast, ovarian, prostate, and pancreatic cancer predisposition genes BRCA1, BRCA2, PALB2, ATM, and CHEK2 (4.2024).

The Guidelines for Clinical Practice for carriers of pathogenic variants in clinically relevant cancer predisposition genes define the steps of primary and secondary prevention that should be provided to these individuals at high risk of developing hereditary cancer in the Czech Republic. The drafting of the guidelines was organized by the Oncogenetics Working Group of the Society for Medical Genetics and Genomics of J. E. Purkyne Czech Medical Society (SLG CLS JEP) in cooperation with the representatives of oncology and oncogynecology. The guidelines are based on the current recommendations of the National Comprehensive Cancer Network (NCCN), European Society of Medical Oncology (ESMO) and take into account the capacity of the Czech healthcare system.

[Results of gamma-knife radiosurgery treatment for intracranial metastases of renal-cell cancer and prognostic factors influencing on the survival (joint study of three Eastern European Centers)].

Gamma-Knife radiosurgery treatment for intracranial metastases of renal-cell cancer results are presented. Treatments were made in 3 Eastern European Centers: in Prague, Moscow and St. Petersburg from 2000 to 2011. 312 patients were treated. Median survival was 8 months (1-91 months). Follow up data were collected for 210 patients. Neurologic state worsening had place at 12% patients, but only 4% of deterioration cases are connected to GKRS. Causes of the rest cases are related to new metastases. Neurologic improvement was found at 29% of patients. Post-RS MRI data were available for 188 patients. Volume enlargement was observed at 10% of cases, but only 5% caused by continued growth. New metastases appeared at 53% of patients. Actuarial analysis didn't detect statistically significant differences in survival for such parameters as patient age, volume and number of metastases. Favorable prognostic factors (p < 0.05) were found to be Karnofsky state equal or more than 70, controlled primary tumor and absence of extracranial metastases, as well as marginal dose for largest metastasis more than 20 Gy. Now RS is one of the basic method of the discussed pathology treatment, that demonstrates high efficacy in relation to the tumor growth and the patient Quality of Life. It is noteworthy that the length of survival is determined by the depth of the complex treatment of primary disease and success of such treatment.

Asymptotic dynamics of coined quantum walks on percolation graphs.

Quantum walks obey unitary dynamics: they form closed quantum systems. The system becomes open if the walk suffers from imperfections represented as missing links on the underlying basic graph structure, described by dynamical percolation. Openness of the system's dynamics creates decoherence, leading to strong mixing. We present a method to analytically solve the asymptotic dynamics of coined, percolated quantum walks for a general graph structure. For the case of a circle and a linear graph we derive the explicit form of the asymptotic states. We find that a rich variety of asymptotic evolutions occur: not only the fully mixed state, but other stationary states; stable periodic and quasiperiodic oscillations can emerge, depending on the coin operator, the initial state, and the topology of the underlying graph.

[Disturbances of hemostasis in sepsis]. / Poruchy hemostázy u sepse.

Immune system and hemostasis are closely bound together. When one of these systems is activated, another is set in motion too. This is especially noticeable in polytraumas, inflammation, shocks etc. The most important activator of immune system and hemostasis is sepsis. In sepsis there is a vigorous stimulation of immune response because of a liberation of a lot of cytokines and proinflammatory molecules. This may lead to an extrem picture of systemic inflammatory response syndrome. In systemic inflammatory response syndrome a downregulation of thrombomodulin and endothelial protein C receptor on the surface of intact endothel may be detected and there is an upregulation of release of the tissue-type plasminogen activator with a switch to plasminogen activator inhibitor 1 release. There is lowering of activated protein C and fibrinolytic activation followed by fibrinolytic inhibition in septic patients. Consequently we can see consumption of coagulation factors, inhibitors (antithrombin, protein C, and tissue factor pathway inhibitor), microangiopatic hemolysis and thrombocytopenia with a picture of disseminated intravascular coagulation in these patients. The diagnosis of disseminated intravascular coagulation is not uniforme in the literature. Expression of tissue factor on monocytes and endothelium may aggravate this "circulus vitiosus" with serious microcirculatory failure in sense of MOF/MODS (mutliorgan failure/multiorgan dysfunction syndrome). The first steps in the therapy of sepsis represent the treatment of cause of sepsis, vigorous hydratation and maintenance of circulation and pulmonary function, glycemic control etc, the prevention and blocking of the undesirable activation of hemostasis and inflammation being equally important. The treatment with minidoses of heparin was implemented in the past and the question, if this therapy is indicated is not answered yet. The clinical studies of the suitability of the treatment with natural inhibitors of hemostasis (antithrombin, recombinant human activated PC or drotrecogin α activated, rhTFPI) were evaluated in the past and are still under way recently. The unequivocal contribution of these therapies was not proven and recombinant human activated PC was even pulled from the worldvide market.

Conplastic strains for identification of retrograde effects of mitochondrial dna variation on cardiometabolic traits in the spontaneously hypertensive rat.

Mitochondrial retrograde signaling is a pathway of communication from mitochondria to the nucleus. Recently, natural mitochondrial genome (mtDNA) polymorphisms (haplogroups) received increasing attention in the pathophysiology of human common diseases. However, retrograde effects of mtDNA variants on such traits are difficult to study in humans. The conplastic strains represent key animal models to elucidate regulatory roles of mtDNA haplogroups on defined nuclear genome background. To analyze the relationship between mtDNA variants and cardiometabolic traits, we derived a set of rat conplastic strains (SHR-mtBN, SHR-mtF344 and SHR-mtLEW), harboring all major mtDNA haplotypes present in common inbred strains on the nuclear background of the spontaneously hypertensive rat (SHR). The BN, F344 and LEW mtDNA differ from the SHR in multiple amino acid substitutions in protein coding genes and also in variants of tRNA and rRNA genes. Different mtDNA haplotypes were found to predispose to various sets of cardiometabolic phenotypes which provided evidence for significant retrograde effects of mtDNA in the SHR. In the future, these animals could be used to decipher individual biochemical components involved in the retrograde signaling.

Increased lipid peroxidation and abnormal fatty acid profiles in seminal and blood plasma of normozoospermic males from infertile couples.

BACKGROUND: Reactive oxygen species (ROS) are essential for sperm function. However, excessive ROS production can impair sperm function and might be a factor contributing to male infertility. METHODS: We investigated the levels of arachidonic acid (AA) and docosahexaenoic acid (DHA) as well as lipid peroxidation, as represented by thiobarbituric acid reactive species (TBARS), in blood and seminal plasma of 38 normozoospermic males from infertile couples (NSI-males), compared with that of 17 fertile volunteers (FV-males). RESULTS: TBARS levels in blood and seminal plasma were higher in NSI-males than in FV-males (P < 0.0002, P < 0.0003, respectively), as were AA levels (P < 0.0003, P < 0.00004, respectively). On the contrary, the blood and seminal plasma levels of DHA were lower in NSI-males than in FV-males (P < 0.02 and P < 0.05, respectively). The AA/DHA ratios in blood and seminal plasma were higher in NSI-males than in FV-males (P < 0.003, P < 0.0007, respectively). Significant correlations between seminal and blood plasma levels of TBARS (P < 0.0001, r = 0.548), AA (P < 0.0001, r = 0.571) and DHA (P < 0.0001, r = 0.506) were found. CONCLUSIONS: Our data provide new insight into lipid metabolism in male infertility and indicate that systemic oxidative stress resulting in increased lipid peroxidation and an altered fatty acid profile may be, at least in part, responsible for infertility even in normozoospermic males.

CYP1B1 gene polymorphism modifies pancreatic cancer risk but not survival.

UNLABELLED: Pancreatic cancer represents one of the biggest problems of current oncology. The risk factors of pancreatic cancer development, as well as factors affecting survival are poorly understood. Since biotransformation enzymes modify detoxification of carcinogens, we supposed, that arelationship between their polymorphism and the risk of pancreatic cancer development and eventually its clinical outcome may exist.
Associations of so far not studied cytochrome P450 1B1 (CYP1B1) polymorphisms with pancreatic cancer risk were investigated by case-control study. Atotal of 754 participants were recruited during study period. All patients were followed to determine their treatment and overall survival.
Carriers of rare genotype Val/Val in codon 432 of CYP1B1 (rs1056836) were under significantly lower risk of pancreatic cancer than wild type carriers (p=0.035). Carriers of heterozygous genotype (p=0.033) and rare allele Val (p=0.015) were also under lower risk than wild type carriers. When histology-verified patients were analyzed separately, even more significant associations were found (p=0.016, p=0.009, p=0.003, respectively). On the contrary, CYP1B1 polymorphism in codon 453 (rs1800440) did not significantly associate with pancreatic cancer risk. Median survival of patients with rare homozygous genotype Val/Val in CYP1B1-codon 432 was longer but not significantly different from those with wild-type homozygotes. The same was true for CYP1B1-codon 453 wild-type homozygotes in comparison with Ser/Ser rare homozygotes.
CYP1B1 polymorphism in codon 432 seems to modify the risk of pancreatic cancer development and should be further studied. KEYWORDS: Pancreatic cancer, CYP1B1, polymorphism, risk, survival.

Population-based study of BRCA1/2 mutations: family history based criteria identify minority of mutation carriers.

The two major susceptibility genes, BRCA1 and BRCA2, are involved in hereditary breast and ovarian cancer syndrome. Early detection of mutation carriers has crucial clinical importance, as it allows identification of women who may benefit from intensive clinical follow-up or prophylactic surgery. Generally accepted inclusion criteria for BRCA1/2 mutation testing are based either upon family history of breast or ovarian cancer or young age at cancer diagnosis. In order to analyze the impact of BRCA1/2 mutations on breast cancer development in the Czech population and to confront the clinical and histopathological data of mutation carriers with current criteria for mutation testing we examined the frequency of mutations in unselected breast cancer cases. Mutational analysis of BRCA1/2 genes performed in 679 unselected female breast cancer patients included all recurrent deleterious alterations previously identified in the Prague area and truncating mutations in the whole exon 11 of BRCA1. Within analyzed gene sequences more than 80% of mutations were identified previously in high-risk patients. A total of 16 breast cancer patients (2.4%) carried a mutation. BRCA1 mutations were identified in 14 (2.1%) whereas BRCA2 in 2 (0.3%) women. Family history of ovarian cancer was a strong predictor of a BRCA1/2 mutation (OR = 8.3; p = 0.01), however, family history of breast cancer was not indicative of carrier status. A significant association between medullary breast cancer and mutation status was observed. Current criteria for BRCA1/2 mutation testing would distinguish only 6 out of 16 (37.5%) carriers identified in our study. Ten breast cancer patients with confirmed BRCA1/2 germ-line mutation exhibited no clinical characteristics that would predict their carrier status. Therefore, we believe that the testing for BRCA1/2 mutations in the Czech Republic may not be restricted only to high-risk patients. Our results indicate that analysis of locally prevalent BRCA1/2 mutations in all breast cancer patients might extend substantially the percentage of identified mutation carriers.

Detection of Mycobacterium avium subsp. paratuberculosis in Slovakian wildlife.

Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of infectious enteritis called paratuberculosis that has a high economic impact on the worldwide livestock production. A central important question arises: Can wildlife animals serve as a reservoir for transmission of MAP to domestic ruminants? With this in mind, we devised a study to detect MAP in various Slovakian wildlife species found in the areas where paratuberculosis had been documented in domestic ruminants. The samples of parenchymatous organs (intestines, ileocecal valve and mesenteric lymphatic nodes) from 83 wildlife animals representing 13 species, inclu- ding 7 herbivorous, 5 carnivorous and 1 omnivorous species were collected during a four-year period. The clinical and pathological examinations failed to demonstrate any manifestations of paratuberculosis in any of the wildlife samples. The detection of MAP was done by widely used tests, i.e. cultivation and the PCR analysis. The bacterial cultures revealed the growth of Mycobacterium spp. colonies in 58 (70%) of all of the wild animals, but the PCR testing demonstrated paratuberculosis only in one (7.69%) of the roe deer population.

Gradual cold acclimation induces cardioprotection without affecting ß-adrenergic receptor-mediated adenylyl cyclase signaling.

Novel strategies are needed that can stimulate endogenous signaling pathways to protect the heart from myocardial infarction. The present study tested the hypothesis that appropriate regimen of cold acclimation (CA) may provide a promising approach for improving myocardial resistance to ischemia/reperfusion (I/R) injury without negative side effects. We evaluated myocardial I/R injury, mitochondrial swelling, and ß-adrenergic receptor (ß-AR)-adenylyl cyclase-mediated signaling. Male Wistar rats were exposed to CA (8°C, 8 h/day for a week, followed by 4 wk at 8°C for 24 h/day), while the recovery group (CAR) was kept at 24°C for an additional 2 wk. The myocardial infarction induced by coronary occlusion for 20 min followed by 3-h reperfusion was reduced from 56% in controls to 30% and 23% after CA and CAR, respectively. In line, the rate of mitochondrial swelling at 200 µM Ca2+ was decreased in both groups. Acute administration of metoprolol decreased infarction in control group and did not affect the CA-elicited cardiprotection. Accordingly, neither ß1-AR-Gsα-adenylyl cyclase signaling, stimulated with specific ligands, nor p-PKA/PKA ratios were affected after CA or CAR. Importantly, Western blot and immunofluorescence analyses revealed ß2- and ß3-AR protein enrichment in membranes in both experimental groups. We conclude that gradual cold acclimation results in a persisting increase of myocardial resistance to I/R injury without hypertension and hypertrophy. The cardioprotective phenotype is associated with unaltered adenylyl cyclase signaling and increased mitochondrial resistance to Ca2+-overload. The potential role of upregulated ß2/ß3-AR pathways remains to be elucidated.NEW & NOTEWORTHY We present a new model of mild gradual cold acclimation increasing tolerance to myocardial ischemia/reperfusion injury without hypertension and hypertrophy. Cardioprotective phenotype is accompanied by unaltered adenylyl cyclase signaling and increased mitochondrial resistance to Ca2+-overload. The potential role of upregulated ß2/ß3-adrenoreceptor activation is considered. These findings may stimulate the development of novel preventive and therapeutic strategies against myocardial ischemia/reperfusion injury.

Genotype and haplotype analysis of cell cycle genes in sporadic colorectal cancer in the Czech Republic.

The Czech Republic has one of the highest incidences of colorectal cancer (CRC) in the world. To assess the role of genetic variants on the disease, we genotyped polymorphisms in the TP53 (rs17878362:A(1)>A(2), rs1042522:G>C, rs12947788:C>T, and rs17884306:G>A), CDKN1A (rs1801270:C>A and rs1059234:C>T), and CDKN2A (rs3731249:G>A, rs11515:C>G, and rs3088440:C>T) genes in 614 hospital-based CRC cases and 614 matched controls from the country. Despite the tendency toward differential distribution of variant allele frequencies for some polymorphisms, none was significantly associated with CRC risk. We observed differential distribution of major haplotypes arising from four polymorphisms in the TP53 gene between cases and controls (global P<0.0001). The two most common haplotypes, A(1)GCG and A(2)CCG, were present in 81% of the cases compared to 71% of the controls. In comparison to the most common haplotype (A(1)GCG), the haplotype A(2)CCG was associated with an increased risk (odds ratio [OR], 1.40; 95% confidence interval [CI], 1.07-1.82), while the four other haplotypes A(1)CCG (OR, 0.60; 95% CI, 0.45-0.79), A(2)GCG (OR, 0.53; 95% CI, 0.35-0.81), A(1)GTG (OR, 0.31; 95% CI, 0.15-0.64), and A(1)GCA (OR, 0.19; 95% CI, 0.07-0.51) were associated with a decreased risk. The effect of haplotypes in the TP53 gene was similar in colon (global P<0.0001) and rectal cancers (P=0.006). No association with the disease was observed with haplotypes of the CDKN1A and CDKN2A polymorphisms. The results from this study suggest that prevalent haplotypes within the TP53 gene may modulate CRC risks in the population.

Buoyancy and solar spin-down.

The transition of a cylinder of water with a vertical density gradient between convective and viscous spindown occurs near the point at which the maximum buoyancy force equals the radial pressure gradient that is driving the convection. A similar analysis applied to the sun shows the maximum buoyancy force to be 1500 times the convective force. A rapidly rotating solar interior would not be damped by largescale convection.

Influence of dihydropyrimidine dehydrogenase gene (DPYD) coding sequence variants on the development of fluoropyrimidine-related toxicity in patients with high-grade toxicity and patients with excellent tolerance of fluoropyrimidine-based chemotherapy.

Alterations in dihydropyrimidine dehydrogenase gene (DPYD) coding for the key enzyme (DPD) of fluoropyrimidines (FPs) catabolism contribute to the development of serious FPs-related toxicity. We performed mutation analysis of DPYD based on cDNA sequencing in 76 predominantly colorectal cancer patients treated by FPs with early development of high (grade 3-4) hematological and/or gastrointestinal toxicity. Six previously described [85T>C (C29R), 496A>G (M166V), 775A>G (K259E), 1601G>A (S534N), 1627A>G (I543V), IVS14+1G>A, 2194G>A (V732I)] and two novel [187A>G (K63E) and 1050 G>A (R357H)] non-synonymous DPYD variants were found in 56/76 (73.7%) high-toxicity patients. Subsequently, these alterations were analyzed in 48 patients with excellent long-term tolerance of FPs and in 243 controls and were detected in 37/48 (77.1%) and 166/243 (68.3%) cases, respectively. Analysis of these alterations as risk factors for development of toxicity in pooled FPs-treated population demonstrated that C29R negatively correlated with overall gastrointestinal toxicity (OR = 0.48; 95%CI 0.23-1.0) and M166V in women protected against overall hematological toxicity and neutropenia (both OR = 0.26; 95%CI 0.07-0.89), whereas IVS14+1G>A (found in five high-toxicity patients only) increased risk of mucositis in overall population (OR = 7.0; 95%CI 1.1-44.53), and thrombocytopenia in women (OR = 10.8; 95%CI 1.24-93.98). Moreover, we identified a strong association of V732I with leucopenia (OR = 8.17; 95%CI 2.44 - 27.31) and neutropenia (OR=2.78; 95% CI 1.03-7.51). Our data enabled characterization of "high risk" haplotypes (carriers of IVS14+1G>A or V732 lacking M166V) representing small (22% female and 11% male patients), population in high risk of serious hematological toxicity development, and in patients with "lower risk" that unlikely develop serious hematological toxicity [carriers of M166V without IVS14+1G>A and V732I in females (32% women), and non-carriers of C29R, M166V, IVS14+1G>A, and V732I in males (46% men)]. Our results indicate that genotyping of several DPYD variants may lead to stratification of patients with respect to the risk of serious hematological toxicity development during FPs treatment.

Short-chain ceramides decrease skin barrier properties.

Stratum corneum ceramides are major determinants of skin barrier function. Although their physiological and pathological role has been widely investigated, to date no structure-activity relationships have been established. In this study, a series of short-chain ceramide analogues with polar head structure identical to ceramide NS, a sphingosine length of 12 carbons and an acyl chain length of 2-12 carbons was synthesized. Their effect on skin permeability was evaluated using porcine skin and two model drugs, theophylline and indomethacin, and compared to that of a physiological ceramide NS. The results showed that the ceramide chain length was crucial for their barrier properties. Ceramides with a 4- to 8-carbon acyl chain were able to increase skin permeability for both drugs up to 10.8 times with maximum effect at a 6-carbon acyl chain. No increase in permeability was found for ceramide analogues with 2- and 12-carbon acyl chains and ceramide NS. The same relationships were obtained for skin concentrations of the model drugs. The relationship between ceramide acyl chain length and its ability to perturb skin barrier showed striking similarity to the behavior of short-chain ceramides in sphingomyelin/phospholipid membranes and confirmed that short-chain ceramides do not act as natural ceramides and their use as experimental tools should be cautious.

[Comparison of reactive oxygen species production in neat semen and washed spermatozoa]. / Porovnání produkce reaktivních kyslíkových cástic v nativním ejakulátu a v suspenzi spermií.

OBJECTIVE: To determine Reactive Oxygen Species (ROS) production in neat semen and spermatozoa suspension using chemiluminescence and to examine correlation between both methods. SUBJECT: Prospective laboratory study. SETTING: Department of Obstetric and Gynecology, University Hospital, Olomouc. METHODS: The study included fertile volunteers (FV, n = 17), men from infertile couples (NM, n = 19) and men with idiopathic infertility (NMI, n = 15). ROS levels were determined by the same method in neat and washed semen samples. RESULTS: The ROS production in neat semen was lower than that in spermatozoa suspension. There was no significant diference in ROS production between volunteers and males from infertile couples. There was a significant correlation between log ROS in neat semen and in spermatozoa suspension in studied groups (FV r = 0.85, p = 1.5 x 10(-5); NM r = 0.76, p < 2 x 10(-4); NMI r = 0.75, p < 1.5 x 10(-3)). CONCLUSIONS: Measurement of ROS in neat semen is simpler, faster and better reflecting the actual level of oxidative stress than the same measurement in spermatozoa suspension. The implementation of this method can complement the algorithm of diagnostics and treatment of male infertility and be helpful in selection of patients for antioxidant or antibiotic treatment.