PubMed Health⌕ Search

Biomedical subjects

M Sulc

Publications and source records attributed to M Sulc.

At least 19 recordsLinked to original sources
PubMed2006

Monoclonal antibody FsC-47 against carp sperm creatine kinase.

The enzyme creatine kinase (CK) plays a key role in energy homeostasis of cells with high and fluctuating energy requirements. As for spermatozoa, the activity of phosphocreatine shuttle, which directs energy from the mitochondria to sites of ATP consumption, is dependent on individual species. High activities of CK are observed in spermatozoa of nonvertebrate, fish, and birds, contrary to the low-level CK activity in mammalian spermatozoa. A new monoclonal antibody (MAb) to carp sperm creatine kinase was prepared. This antibody is applicable to large-scale immunochemical techniques. In this study, it was applied to the study of carp sperm motility, and the evaluation of the influence of CK on the quality and fertilization ability of carp spermatozoa.

Animals↗
PubMed2004

The histological findings in the gastroesophageal junction of fetuses.

The development of the esophageal and gastric mucosa in the gastroesophageal junction was studied in 61 fetuses of 13-41 weeks of the gestational age. During the 13th-15th week, the esophageal multilayered epithelium was covered by a continuous layer of columnar mucous ciliated cells which were present only focally till the 25th week and disappeared later. Before the 15th week, the gastric mucosa was formed by pits only. The glands started as proliferating tubules in the basal parts of the pits in the 15th week. Further, they differentiated into oxyntic glands. The mucosa of the corpus was fully developed in the 27th week. The cardiac mucosa was absent in all the 10 fetuses examined between the 27th and 41st week of gestation. This supports the view that the gastric cardiac mucosa is not a physiological structure but that it results from glandular metaplasia of the distal esophageal mucosa due to gastroesophageal reflux.

Esophagogastric Junction↗
PubMed2004

Rabbit liver microsomal system: study of interaction with two model N-nitrosamines and their metabolism.

Rabbit liver microsomes of control (non-treated) or animals induced either by ethanol (EtOH) or phenobarbital (PB) were incubated with N-nitrosodimethylamine (NDMA) or N-nitrosomethylaniline (NMA). Difference spectroscopy showed that NMA is bound to the substrate-binding site of cytochrome P-450 (CYP) isoforms as heme ligand in control and EtOH pre-treated microsomes. On the other hand, PB-induced microsomes exhibit with NMA substrate type of spectra. NDMA does not provide any type of binding spectra with used microsomal systems. Oxidative bio-activation of N-nitrosamines by the microsomal CYP isoforms was measured as formaldehyde formation. Analysis of reaction kinetics in control microsomes revealed, for both substrates, two values of Michaelis-Menten constant (K(m)) for, K(m) values of 0.03 and 0.13 mmol/l for NDMA, and 0.30 and 0.82 mmol/l for NMA. Induction of animals with EtOH resulted in a decrease in the K(m) value for both substrates. In contrast, PB treatment caused an elevation of K(m) value for NDMA. Based on these data, we conclude that EtOH-inducible microsomal CYP isoforms (mainly CYP2E1) are responsible for binding and N-demethylation metabolism of both studied N-nitrosamines in rabbit liver microsomal system. The role of the other CYP isoforms involved in the metabolism of mentioned N-nitrosamines is discussed.

Animals↗
PubMed2004

Evaluation of comparative cytochrome P450 2B4 model by photoaffinity labeling.

A homology model of rabbit CYP 2B4 was constructed on the basis of the crystallographic structure of truncated mammalian CYP 2C5/3 and bacterial soluble CYPs. To validate the CYP 2B4 homology model photoaffinity labeling was employed. Three probes (I-III) containing a photo-labile azido-group and an amino-group on opposite ends of the molecule were designed for photoaffinity labeling of the CYP 2B4 in increasing distance from the heme iron. Spectroscopic data proved probes I (the shortest) and II (a middle sized) to be coordinated with the heme iron via their amino-groups in the enzyme active center while the probe III (the longest) was not bound in this way. This binding orientation of probes I and II is in accordance with the model predicting ion-pairing of the negatively charged side chain of CYP 2B4 Asp 105 and a positively charged nitrogen located in an appropriate position in structures of probes I and II, only. The lack of heme binding of the probe III is clear from its docking into the CYP 2B4 model since no Asp 105 ion-pairing is possible. The target of photoactivated probe II, Arg 197, in a distance of about 16.5 A from the heme iron, exactly matches the position of that amino acid residue, predicted from the CYP 2B4 homology model. Moreover, using this technique, a substrate access channel has been identified. To assess the predicted substrate-binding pocket, an interaction of a specific CYP 2B4 substrate, diamantane, was examined. In "silico" docking revealed strong binding of diamantane in an orientation allowing experimentally observed C4-hydroxylation. Our homology model of CYP 2B4 is thus consistent with experimental metabolic and photoaffinity labeling data.

Amino Acid Sequence↗
PubMed2002

[Metanephric adenoma. 11 case reports and detection of collagen spherules in one tumor].

Eleven cases of metanephric adenoma are reported. The tumors were selected out of 6500 tumorous and pseudotumorous lesions of the kidney in our registry. Female to male ratio was 1:1.2. The average age of the patients was 48.3 years, with a range of 13-79 years. The mean size of the tumors was 7.2 cm. The tumors were spherical in shape, whitish to yellowish in colour. Histologically, they were arranged in a mainly tubular pattern with short pseudopapillae. The tumorous cells were deeply eosinophilic to basophilic with predominantly round nuclei. Psammomatous bodies were numerous. Immunohistochemically, they reacted positively with antibodies against cytokeratins, vimentin, and WT1. Ultrastructurally, the cytoplasm contained mitochondria, RER, and ribosomes. A collagenous spherulosis, identical with those in salivary gland and mammary tumors, was revealed in one case. The spherules were located mainly inside tubular structures. Ultrastructurally, they were composed of basement membrane-like material, which was surrounded by epithelial cells. Follow-up all of our patients was negative (if known) for 10 months to 4 years.

Adenoma↗
PubMed2002

Intestinal necrosis following Calcium Resonium-sorbitol administration in a premature uraemic infant.

Sodium polystyrene sulphonate (Resonium A) in sorbitol given as an enema or orally to treat hyperkalaemia has been described to induce intestinal necrosis in uraemic patients. We report a case of a premature infant with acute renal insufficiency who developed focal transmural necrosis and perforation of the small intestine after 10 days of administration of calcium polystyrene sulphonatum (Calcium Resonium) in sorbitol by enema and by nasogastric tube. On histological examination of the resected part of the small intestine, numerous strongly basophilic angular crystals of resonium were found in the lumen, in the necrotic wall, as well as in the organized exudate on the peritoneal surface. The crystals showed a strong direct Schiff positivity without preoxidation. They were also stained using PAS, Giemsa, Ziehl-Neelsen, Schmorl, and Gram method. In contrast, the crystals were Congo red and Alcian blue (pH 2.5) negative and non-birefringent. The direct Schiff positivity without preoxidation is virtually pathognomonic for resin crystals in routinely processed tissues. The same crystals were observed in the lumen of the small intestine and in peritoneal adhesions at autopsy. Thus our case provides additional evidence that Resonium A/Calcium Resonium in sorbitol administered as an enema or orally can lead to intestinal necrosis in uraemic patients.

Diuretics, Osmotic↗
PubMed2001

alpha-Naphthoflavone acts as activator and reversible or irreversible inhibitor of rabbit microsomal CYP3A6.

This report describes the effect of alpha-naphthoflavone (alpha-NF), a known substrate, inhibitor and activator of several cytochromes P450 (CYP), on rabbit CYP3A6. Hepatic microsomes of rabbit pretreated with rifampicine (RIF), enriched with CYP3A6, as well as purified CYP3A6 reconstituted with isolated NADPH:CYP reductase were used as enzymatic systems in this study. The data from difference spectroscopy experiments showed that alpha-NF does yield a type I binding spectrum. This compound is oxidized by microsomal CYP3A6 into two metabolites (5,6-epoxide and trans-7,8-dihydrodiol). While alpha-NF is a substrate of CYP3A6, it also acts as an enzyme modulator. Under the conditions used, stimulation of 17beta-estradiol 2-hydroxylation by alpha-NF was observed. In contrast, this compound reversibly inhibited N-demethylation of erythromycin and tamoxifen, competitively with respect to these substrates, having the K(i) values of 51.5 and 18.0 microM, respectively. Moreover, alpha-NF was found to be an effective inactivator of progesterone and testosterone 6beta-hydroxylation catalyzed by CYP3A6 in RIF-microsomes. In addition, time- and concentration-dependent inactivation of human CYP3A4-mediated 6beta-hydroxylation of testosterone by alpha-NF, was determined. The inactivation of CYP3A6 followed pseudo-first-order kinetics and was dependent on both NADPH and alpha-NF. The concentrations required for half-maximal inactivation (K(i)) were 80.1 and 108.5 microM and the times required for half of the enzyme to be inactivated were 10.0 and 11.9 min for 6beta-hydroxylation of progesterone and testosterone, respectively. The loss of the enzyme activity was not recovered following dialysis, while 90% of the ability to form a reduced CO complex remained. This indicates the binding of alpha-NF to a CYP apoprotein molecule rather than to a heme moiety. Protection from inactivation was seen in the presence of all tested CYP3A substrates. Progesterone and testosterone protected CYP3A6 against inactivation competitively with respect to inactivator, erythromycin non-competitively and 17beta-estradiol showed a mixed type of protection. Here, we described for the first time that alpha-NF is capable of irreversible inhibition of microsomal rabbit CYP3A6 and human CYP3A4. The obtained results strongly suggest that the CYP3A active center contains at least two and probably three distinct binding sites for substrates.

Animals↗
PubMed2001

[Oncocytoma of the kidney--morphologic variation in 102 cases].

From the collection of 2500 cases of renal epithelial tumors in our files, 102 renal oncocytomas were analyzed for size, multifocality and a morphologic spectrum of the growth pattern. The size of the tumors ranged from 1.5 to 13 cm in diameter, with a mean of 6.3 cm. Three cases were multifocal, four cases were combined with another primary renal tumor (1x angiomyolipoma, 1x conventional renal carcinoma, 2x papillary renal cell carcinoma). A central fibrosis or a scar was noted in 13 cases, and there was a gross area of hemorrhage in 11 cases. In 4 cases extensive necroses were recognized. Histologically, an alveolar pattern was noted in 70 cases. A tubular pattern was revealed in 31 cases and an unusual tubopapillar ("glomeruloid") pattern was noted in one case. Foci of atypical nuclei were identified in 58 cases. In 4 oncocytomas broad areas of clearance of the oncocytes were found. Psammoma bodies were recognized in 9 tumors and foci of ossification were present in 4 cases. Intracellular and extracellular hyaline globules were noted in two cases. Renal oncocytoma has a variable morphologic spectrum, and its diagnosis should be based on an analysis of structural and cytologic features. Differential diagnosis of renal oncocytomas with various tumors of the kidney which contain granular cytoplasm is discussed. These tumors with granular cytoplasm include conventional renal cell carcinomas, chromophobe cell carcinomas, and rare examples of papillary renal carcinomas.

Adenoma, Oxyphilic↗
PubMed1999

Heterobifunctional photoaffinity probes for cytochrome P450 2B.

Three heterobifunctional photoaffinity probes, N-(p-azidobenzyl)-N-methyl-p-aminobenzylamine (I), N-(p-azidobenzyl)-N-methyl-p-aminophenethylamine (II), and N-(p-azidophenethyl)-N-methyl-p-aminophenethylamine (III), were synthesized and characterized. These probes, containing a photolabile azido-group and an amino-group on opposite sides of the molecule, were designed for photoaffinty labeling of the cytochrome P450 (CYP) 2B active site cavity differing in distance from the heme iron. Spectroscopic studies proved that probes I and II coordinated with the heme iron via their amino-group in the enzyme active center, whereas probe III did not. This result in conjunction with data from kinetic studies suggests probes I and II are appropriate for photoaffinity labeling of the CYP 2B active center. Thus, probe II was used to identify amino acid residues within a distance of the probe length (about 16.5 A) from the heme. Analysis of a Lys-C digest of the probe II-labeled CYP 2B4 revealed a single labeled hexapeptide corresponding to position 192-197 of the CYP 2B4 sequence. Using postsource decay/matrix-assisted laser desorption ionization-time of flight, Arg197 was identified as a probe II target. The location of the labeled site in three-dimensional structures of bacterial CYPs and in CYP 2B homology models is discussed.

Affinity Labels↗
PubMed1999

Atypical lipomatous tumors with smooth muscle differentiation: report of two cases.

Two cases of soft-tissue atypical lipomatous tumors with areas of smooth muscle cell differentiation are presented. The patients were a 72-year-old man (Case 1) and a 62-year-old woman (Case 2); their neoplasms were located in the left inguinal region and on the chest, respectively. The adipocytic component in Case 1 contained cells with nuclear atypism and lipoblasts. Case 2 showed only slight nuclear atypism and lacked any lipoblasts. Smooth muscle fascicles were composed of well-differentiated cells with a few mitoses having none or only a slight atypism. They expressed muscle-specific actin and desmin in both cases. No recurrence was recorded during the follow-up time.

Actins↗
PubMed1998

Glassy hyaline globules in granular cell carcinoma, chromophobe cell carcinoma, and oncocytoma of the kidney.

The presence of glassy hyaline globules (GHG) in renal carcinomas has been rarely emphasized in the literature. We studied the frequency of these globules in numerous renal carcinomas, including granular cell, mixed clear cell/granular cell, papillary renal cell, and chromophobe renal cell carcinoma, as well as oncocytomas. GHG are eosinophilic bodies in the hematoxylin-eosin stained sections with a size ranging from 1 to 30 micrometer and strongly positive with the periodic acid-Schiff (PAS) histochemical stain. Ultrastructurally, they are seen as amorphous secretion inside of the cisternae of the rough endoplasmic reticulum. GHG were found in 49 of 64 cases of granular cell and mixed clear cell/granular cell renal carcinomas and in 5 of 33 papillary renal cell carcinomas. No GHG were found in 22 cases of chromophobe cell carcinomas and 26 renal oncocytomas. Our findings suggests that GHG are a characteristic feature of granular cell carcinomas, mixed clear cell/granular cell renal carcinomas, and in a small minority of papillary renal cell carcinomas. In addition, it suggests that the presence of GHG in a renal cell tumor may be of aid for excluding a diagnosis of chromophobe cell carcinoma or oncocytoma.

Adenocarcinoma↗
PubMed1997

Calcifying fibrous pseudotumour of visceral peritoneum.

AIMS: Calcifying fibrous pseudotumour, a recently characterized rare but distinctive lesion, has been reported previously only in soft tissues and in the pleura. We describe four cases of calcifying fibrous pseudotumour which arose in the visceral peritoneum of the small bowel and stomach. METHODS AND RESULTS: In contrast to the calcifying fibrous pseudotumour of soft tissues which generally occurs in children, all four cases in our report occurred in adults. We consider the calcifying fibrous pseudotumour to be a distinctive tissue reaction. CONCLUSIONS: Its characteristic appearance of concentric whorls of lamellated collagen associated with psammoma bodies and other forms of dystrophic calcification is entirely different from all other lesions displaying hyaline collagenous deposits, such as inflammatory pseudotumour, desmoid, hyalinizing granuloma or fibrous plaques of peritoneum.

Adult↗
PubMed1997

[Myofibroblastic proliferative lesions in the paratesticular area].

Myofibroblastic pseudotumorous proliferations have been recognized at a variety of sites. Six cases of paratesticular myofibroblastic lesions with emphasis on the spectrum of morphologic features were described. The microscopic features changed from abundant cellular spindle cell proliferation resembling nodular (pseudosarcomatous) fasciitis to hypocellular and hyalin fibrovascular lesion with extensive dystrophic calcification. The age of the patients ranged from 14 to 77 years. In four cases sarcoma was suspected histologically. Differential diagnosis and histogenesis of the lesion were discussed.

Adolescent↗
PubMed1989

[Epithelioid hemangioendothelioma of the liver].

Epitheloid hemangioendothelioma of the liver was found at autopsy of two women and one man (at the age of 67, 74 and 68). It occurred in multinodular form or as a huge tumours infiltration. In one case secondaries were noticed in a portal lymphnode and in the lung. Histology was characterized by epitheloid and elongated cells with irregular nuclei and sparse cytoplasmic vacuoles. A massive growth of tumour into sinusoid, central and portal veins resulted in a progressive liver atrophy or destruction. Differential diagnosis comprised epithelial tumours, especially cholangiocellular carcinoma, angiosarcoma and non-neoplastic processes (liver fibrosis and venoocclusive disease.

Aged↗
PubMed1988

Gerstmann-Straüssler-Scheinker disease.

In three out of six investigated cases of familially occurring dementia in adult age, the neuropathological examination disclosed Gerstmann-Sträussler-Scheinker disease, morphologically characterized by the presence of amyloid plaques and spongy condition of the brain grey matter. The spongy condition makes this disease related to Creutzfeldt-Jacob disease. The presence of the amyloid plaques signalizes an extreme production of the protein material which accumulates in them and which will be different from the amyloid in the senile plaques in Alzheimer's disease, and probably corresponds with infectious protein substances--prions or protein-like particles (PLP).

Adult↗