PubMed Health⌕ Search

Biomedical subjects

M Borowski

Publications and source records attributed to M Borowski.

At least 19 recordsLinked to original sources
PubMed2004

Association of T-786C eNOS gene polymorphism with increased susceptibility to acute chest syndrome in females with sickle cell disease.

Acute chest syndrome (ACS) is a life-threatening complication of sickle cell disease (SCD). A retrospective study was performed to evaluate the role of endothelial nitric oxide synthase (eNOS) gene polymorphisms (E298D and T-786C) in African-American SCD patients. The D298 allele showed no association; the C-786 allele showed a statistically significant association (P = 0.0061) in female ACS cases. Multiple logistic regression analysis showed that relative risk of ACS was 8.695 (P = 0.0076, 95% confidence interval 1.761-42.920) for female carriers of C-786. eNOS T-786C is a gender-specific genetic modifier that is associated with increased susceptibility to ACS in female SCD patients.

Acute Disease↗
PubMed2001

A study of transferability of atomic background on EXAFS spectra of simple gaseous compounds of As.

From EXAFS spectra of As and As2O3 vapors and arsine gas AsH3 the ab initio calculated structural signal is removed. The remainders comprise small absorption edges due to shake-up channels involving electrons from 3d or 3p subshell. With enhanced resolution, the edges reveal a fine splitting and a varying contribution of resonance channels, due to individual molecular energy-level structure of the samples. On the resolution level appropriate for routine EXAFS analysis the remainders coincide, representing a unique and transferable atomic absorption background for the range of As valence states spanned by the samples.

Journal Article↗
PubMed2001

Atomic background and EXAFS of gaseous hydrides of Ge, As, Se and Br.

K edge absorption spectra of elements from Ge to Br in gaseous hydrides were measured at the BM 29 station of ESRF with noise level as low as 2x10(-5), so far achievable only on noble gases. The dominant feature of the spectra is the atomic background similar to that of Kr and comparable to it in the quality of detail. Onto the background, a smooth weak EXAFS signal due to the hydrogen neighbors is superposed. For the very simple molecules such as these, its contribution can be calculated ab initio, with exact treatment of the effect of molecular vibrations, so that no best-fit adjustment to the experimental data is necessary. In comparison to the main constituent of the atomic background, i.e. the shake-up absorption edges, the EXAFS signal is of minor importance in HBr with a single H neighbor, but of the same order of magnitude in GeH4.

Journal Article↗
PubMed2001

Liquid Rb micrometric droplets confined in paraffin wax: an X-ray absorption spectroscopy study.

We have performed high-quality X-ray absorption measurements on crystalline (c-Rb) and liquid (l-Rb) Rubidium in the range from 15 K to 320 K. Performing a consistent analysis that takes into account the contribution of the medium range structure, we observe that the l-Rb spectrum is compatible with pair correlation function g(r) previously determined by neutron diffraction experiments. Due to the micrometric size of the liquid droplets we were able to observe a slight undercooling down to 290 K. We were also able to study the details of the very strong multielectron excitations channels in terms of resonances, edges and shake-off features at proper theoretical energy values.

Journal Article↗
PubMed2001

XAS investigation of Al2O3-coated nano-composite ZrO2.

In order to complement the structural characterisation by high resolution electron microscopy and perturbed angular correlation spectroscopy (PAC) of Al2O3 coated nano-composite ZrO2, XAFS spectra have been acquired and analysed. The electron micrographs showed fringes of a well ordered lattice and well defined crystal faces of the as-produced powder whereas the PAC spectra indicated a strongly distorted short range order. On the basis of the XAFS data, a structural model for the ZrO2 core of the nano-composite ZrO2/Al2O3 with a well ordered Zr lattice and a sevenfold, strongly distorted nearest neighbour oxygen shell is proposed. A smooth temperature dependence without an indication for a phase transformation up to a temperature of 700K has been revealed.

Journal Article↗
PubMed2001

K- and L-edge XAFS determination of the local structure of aqueous Nd(III) and Eu(III).

The short-range coordination of Nd(III) and Eu(III) ions in aqueous solutions has been investigated by means of K-edge x-ray absorption spectroscopy. Experimental data are presented which demonstrate that an accurate determination of the Nd(III) and Eu(III) hydration structural parameters can be obtained from the analysis of the K-edge spectra. It is shown that the large widths of the core hole states do not appreciably reduce the potential structural information of the K-edge EXAFS data. In addition the available k-range of the K-edge spectra is much wider compared to that of the L3-edge which is affected by the presence of double-electron excitations in a more severe fashion.

Journal Article↗
PubMed2001

Investigation of undercooled liquid metals using XAFS, temperature scans and diffraction.

Novel techniques and the experimental station for experiments on condensed matter under extreme conditions that have been developed at the BM29 beamline of the European Synchrotron Radiation Facility (ESRF) are described. The experimental setup includes facilities to collect high-quality extended X-ray absorption fine structure (EXAFS) spectra, to perform controlled temperature scans while monitoring the sample absorption for the direct detection of phase transitions, and to collect high-resolution energy-scanning X-ray diffraction (ESXD) data, with recent enhancements through the installation of a two-channel collimator detector system. Facilities for X-ray absorption temperature scans, introduced five years ago, are now exploited for a wide variety of purposes. A method for the measurement of the nucleation rate in undercooled liquids has been proposed recently. All these advances in the experimental setup and techniques, combined with a simple but rigorous X-ray absorption fine structure (XAFS) data analysis scheme for disordered matter, have contributed to make feasible challenging experiments on undercooled liquid matter that were not even conceivable only a few years ago. An example of the application of these methods to undercooled liquid indium (In) is presented.

Journal Article↗
PubMed2000

Infusion of alpha-galactosidase A reduces tissue globotriaosylceramide storage in patients with Fabry disease.

Fabry disease is a lysosomal storage disorder caused by a deficiency of the lysosomal enzyme alpha-galactosidase A (alpha-gal A). This enzymatic defect results in the accumulation of the glycosphingolipid globotriaosylceramide (Gb(3); also referred to as ceramidetrihexoside) throughout the body. To investigate the effects of purified alpha-gal A, 10 patients with Fabry disease received a single i.v. infusion of one of five escalating dose levels of the enzyme. The objectives of this study were: (i) to evaluate the safety of administered alpha-gal A, (ii) to assess the pharmacokinetics of i.v.-administered alpha-gal A in plasma and liver, and (iii) to determine the effect of this replacement enzyme on hepatic, urine sediment and plasma concentrations of Gb(3). alpha-Gal A infusions were well tolerated in all patients. Immunohistochemical staining of liver tissue approximately 2 days after enzyme infusion identified alpha-gal A in several cell types, including sinusoidal endothelial cells, Kupffer cells, and hepatocytes, suggesting diffuse uptake via the mannose 6-phosphate receptor. The tissue half-life in the liver was greater than 24 hr. After the single dose of alpha-gal A, nine of the 10 patients had significantly reduced Gb(3) levels both in the liver and shed renal tubular epithelial cells in the urine sediment. These data demonstrate that single infusions of alpha-gal A prepared from transfected human fibroblasts are both safe and biochemically active in patients with Fabry disease. The degree of substrate reduction seen in the study is potentially clinically significant in view of the fact that Gb(3) burden in Fabry patients increases gradually over decades. Taken together, these results suggest that enzyme replacement is likely to be an effective therapy for patients with this metabolic disorder.

Adult↗
PubMed1996

[The effect of co-existing diseases with cholelithiasis on the course and results of laparoscopic cholecystectomy].

Six hundred laparoscopic cholecystectomies have been performed in patients with cholelithiasis. Co-existing chronic diseases have been noted in 28% of the operated patients. All these diseases have been known to increase operative risk in classic (open) cholecystectomy (hypertension, coronary disease, cardiac arrhythmias, diabetes mellitus, bronchial asthma). Statistical analysis of the body temperature following laparoscopic cholecystectomy, morbidity and duration of the postoperative hospitalization has revealed that there has been no significant increase in operative risk for laparoscopic cholecystectomy in these patients.

Adolescent↗
PubMed1994

Purification and characterization of multiple forms of the pineapple-stem-derived cysteine proteinases ananain and comosain.

A mixture of ananain (EC 3.4.22.31) and comosain purified from crude pineapple stem extract was found to contain numerous closely related enzyme forms. Chromatographic separation of the major enzyme forms was achieved after treatment of the mixture with thiol-modifying reagents: reversible modification with 2-hydroxyethyl disulphide provided enzyme for kinetic studies, and irreversible alkylation with bromotrifluoroacetone or iodoacetamide gave enzyme for structural analyses by 19F-n.m.r. and electrospray mass spectrometry respectively. Structural and kinetic analyses revealed comosain to be closely related to stem bromelain (EC 3.4.22.32), whereas ananain differed markedly from both comosain and stem bromelain. Nevertheless, differences were seen between comosain and stem bromelain in amino acid composition and kinetic specificity towards the epoxide inhibitor E-64. Differences between five isolatable alternative forms of ananain were characterized by amidolytic activity, thiol stoichiometry and accurate mass determinations. Three of the enzyme forms displayed ananain-like amidolytic activity, whereas the other two forms were inactive. Thiol-stoichiometry determinations revealed that the active enzyme forms contained one free thiol, whereas the inactive forms lacked the reactive thiol required for enzyme activity. M.s. provided direct evidence for oxidation of the active-site thiol to the corresponding sulphinic acid.

Amino Acid Sequence↗
PubMed1994

[Prevention and treatment of chronic pain in oncologic patients].

The rules of three step therapy of chronic pain in terminal malignant has been presented. The need of priority of non narcotic drugs in retard form, oral or enteral administration and individual schedule out-pacing the occurring of pain has been stressed.

Analgesics↗
PubMed1993

[Laparoscopic cholecystectomy in older patients].

Operational risk of laparoscopic cholecystectomy in elderly patients has been retrospectively evaluated in 600 consecutive patients. Statistical correlation between age and risk factors as: biliary duct disease, adhesions, perforation of the gall bladder, necessity of extending of the incision, duration of the procedure, body temperature after LCh, morbidity, conversion rate from LCh to open cholecystectomy, has been tested. Despite of greater technical difficulties in elderly patients morbidity was not increased significantly. LCh in aged patients with cholecystitis is a safe method of choice.

Adolescent↗
PubMed1993

[Laparoscopic cholecystectomy--treatment outcome of 500 patients].

500 patients with symptomatic biliary stones disease have been treated by laparoscopic cholecystectomy (LCh). Contraindications, such as: acute inflammation, earlier laparotomies, common duct stones or obesity were considered as relatives. In cases with duct stones, ERCP with sphincterotomy and evacuation of duct stones was performed before LCh. Small percentage of LCh failures (2.6%) and of postoperative morbidity (3.4%) by undoubted advantages as: lack of postoperative paresis of digestive tract, reduced inability time for professional activity and low risk of postoperative abdominal hernia make this procedure attractive for patients and surgeons.

Adolescent↗
PubMed1990

Cloning and expression of peptide-N4-(N-acetyl-beta-D-glucosaminyl)asparagine amidase F in Escherichia coli.

The peptide-N4-(N-acetyl-beta-D-glucosaminyl) asparagine amidase F (PNGase F) gene from Flavobacterium meningosepticum was cloned into a high copy number Escherichia coli plasmid. Levels of PNGase F activity produced in cultures of the recombinant strain were up to 100-fold higher than those obtained in cultures of F. meningosepticum. The complete PNGase F gene sequence was determined. Comparison of the predicted amino acid sequence of pre-PNGase F to the N-terminal sequence of the native mature enzyme indicates that the protein is synthesized with a 40-amino acid signal sequence that is removed during secretion in F. meningosepticum. The recombinant PNGase F produced in E. coli is a mixture of products comprised predominantly of two proteins with molecular masses of 36.3 and 36.6 kDa. These proteins have a higher apparent molecular mass than the 34.7-kDa native enzyme. N-terminal amino acid sequencing demonstrated that these higher molecular mass products result from cleavage of the pre-PNGase F in E. coli upstream of the native N terminus. The PNGase F gene was engineered to encode a preenzyme that was processed in E. coli to give an N terminus identical to that of the native enzyme. Purified preparations of this form of recombinant PNGase F were shown to be suitable for glycoprotein analyses since they possess no detectable endo-beta-N-acetylglucosaminidase F, exoglycosidase, or protease activity.

Amidohydrolases↗