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Biomedical subjects

J Krawczyk

Publications and source records attributed to J Krawczyk.

At least 19 recordsLinked to original sources
PubMed2002

Diffuse X-ray scattering and reverse Monte Carlo simulation of the short-range order in ytterbium iodine phthalocyanine [YbPc(2)]I(2).

Iodine-doped ytterbium phthalocyanine, C(64)H(32)N(16)YbI(2), [YbPc(2)]I(2) (YPI), presents an example of a disordered modulated crystal structure of the intergrowth type. The short-range order in YPI has been studied at ambient temperature by the diffuse X-ray scattering technique. Both Yb and I atoms are disordered. In a unit cell of the average structure, the Yb atoms occupy two positions, 1/2, 1/2, 1/4 or 1/2, 1/2, 3/4, with occupancy 0.5. In the neighbouring unit cells in the (001) plane there is, however, a strong tendency towards an alternating distribution of ytterbium in positions shifted by Delta z = 1/2. The crystal structure of YPI consists of one-dimensional columnar stacks of [YbPc(2)(2/3+)](n) and of linear iodine chains [I(3)(-)](n). The modulation is commensurate since the period c(I) of iodine chains [I(3)(-)](n) in the [001] direction is equal to one-half of the period c of the [YbPc(2)(2/3+)](n) stacks. In the crystal structure, each stack of [YbPc(2)(2/3+)](n) may occur in two settings shifted by c/2 and each iodine chain in three settings shifted along [001] by one-third of the period c(I). The short-range order of iodine chains distributed over three settings results in a complicated pattern. Iodine chains of the same setting tend to form ribbons perpendicular to <100> and running along [001].

Journal Article↗
PubMed2001

[The treatment of cerebral abscesses in children--the clinical experiences of neurosurgical clinic of PMMH in Lodz].

In our study we made attempt to assess which clinical criteria are essential for choosing optimal treatment for children suffering from cerebral abscesses. We observed the clinical results obtained at our Department from treatment of infections of the central nervous system (CNS) in children and analysed them with respect to applied therapy and clinical conditions. Between 1990 to 2000, 45 children aged 3 days to 15 years (mean 1.34 years, standard deviation 3.23 years) with infections of the CNS were treated at our Department. Within this group, 26 patients were diagnosed with cerebral abscesses, 1 with epidural empyema, 3 with subdural empyema and 15 with pyocephalus. 42 patients were operated. In 3 patients a conservative treatment was introduced at the moment when the abscesses were in the initial stage of organisation; in each case after a complete cycle of antibiotic therapy a regression of lesion was noted. The most frequently performed--in 19 patients--surgical procedure was the radical excision of the abscess by craniotomy. In 2 cases a re-operation was necessary. The highest rate of re-operations was noted in the group of children treated by external drainage; within this group of 18 patients only one 3-month-old girl did not require an additional surgical intervention. Neuroendoscopic techniques were used in 7 patients with compound hydrocephalus. Out of 45 treated children, 3 died from encephalitis, the primary reason being the infection of the ventriculo-peritoneal shunt. All children were assessed according to the Glasgow Outcome Scale and the results were significantly worse in those under 3 years in age. We suggest that in children above 3 years of age with mature abscesses of the central nervous system an operative evacuation of the abscesses by craniotomy should be performed.

Adolescent↗
PubMed2001

[Veno-occlusive disease--an important complication in hematopoietic cells transplantation].

Hemopoietic stem cell transplantation is frequently used in clinical practice. However, many severe complications limit its usage. One of the most important is veno-occlusive disease of the liver (VOD). The key pathophysiologic event is a damage to epithelium during chemotherapy. Gradual development of intrahepatic portal hypertension leads to clinical manifestations (jaundice, liver enlargement, ascites). Many risk factors has been identified (pre-transplant liver disturbance, chemotherapy and conditioning, drugs). The diagnosis is based on clinical criteria and exclusion of other diseases. Laboratory, haemodynamic, ultrasound studies and histopathology are very important in diagnosis. In pharmacological prophylaxis heparin is widely used. Therapy requires strict fluid and electrolyte balance. Some patients can benefit from transjugular intrahepatic portosystemic shunt (TIPS) or liver transplantation. Defibrotide gives more hope for patients but further investigations are needed.

Anticoagulants↗
PubMed1997

Krabbe disease: an ultrastructural study of globoid cells and reactive astrocytes at the brain and optic nerves.

We report here a detailed ultrastructural study of a brain biopsy along with post-mortem brain and optic nerve specimens from a case of Krabbe disease, a relatively rare leukodystrophy caused by a mutation in the gene for galactocerebrosidase (GALC) mapped to the 14q31 region of chromosome 14. GALC is responsible for lysosomal hydrolysis of several galactolipids including galactosylceramide, a major sphingolipids of the white matter of the central nervous system, galactosylsphingosine (psychosine) and galactosyldigluceride. The main neuropathological features such as accumulation of globoid cells, loss of myelin and marked gliosis were observed in the white matter. The monocytic origin of globoid cells was confirmed by CD-68 and ferritin-positivity and periodic acid Schiff (PAS) positivity. Ultrastructural study of the globoid cells showed the accumulation of tubular crystalloids, which are highly specific for this disease. The differences with Gaucher's disease and the pathomechanism of neuropathological damage are discussed.

Astrocytes↗
PubMed1996

[Radioimmunologic methods for determining cortisol binding globulin-CBG in human serum].

The authors described double antibodies radioimmunoassay of human cortisol binding globulin serum level in support of previous isolated and purified trancortin and anti-transcortin antibodies produced by rabbit immunization. Antigen was iodinated by chloraminet method and purification on Ultragel AcA 54 column. Standard curve had specific Bx/Box100%. Using described method investigation of transcortin globulin serum level is precise and repetitive.

Carrier Proteins↗
PubMed1995

[Chronic inflammation of the gastric mucosa and some immunologic aspects of Helicobacter pylori infection].

UNLABELLED: The aim of the study was to determine what is the correlation between immunological phenomena and pathological changes in chronic gastritis and how it refers to the histology and endoscopy. PATIENTS AND METHODS: 42 patients with dyspepsia underwent following procedure: 1) gastroscopy and antral biopsy of 3 specimens; 2) histology; 3) immunofluorescence of the specimens in purpose to detect bound immunoglobulins using antibodies anti-human IgA + IgG + IgM labelled with rhodamine; 4) serologic test for anti-H.pylori antibodies. The research included 17 females and 25 males (ages 30-86, median 53.4 +/- 15.47). The obtained data were compared referring to mutual correlations and presented according to the kind of pathological changes depending on:--presence or absence of Helicobacter pylori infection;--presence or absence of anti-Helicobacter pylori antibodies;--presence or absence of lymphocytic infiltration;--presence or absence of bound immunoglobulins in gastric mucosa. RESULTS: --We have not observed ulcerations in anti-Helicobacter pylori seronegative group;--intestinal metaplasia and gastric ulcer were more frequent in bound immunoglobulins positive group;--biliary reflux was observed less frequently in lymphocyte infiltration negative group then in the positive one. CONCLUSION: pathological changes in chronic gastritis may depend not only on the presence of Helicobacter pylori infection, but also on the presence and quality of immunological response on its antigens.

Adult↗
PubMed1992

Seventeen years experience with accelerated radiotherapy for carcinoma of the breast.

Between 1973 and 1989, one hundred and three women received accelerated radiotherapy to the breast. Fifteen of them had the treatment after local tumor removal; the rest had primary radiotherapy for inoperable cancer. Eleven patients were irradiated twice a day, 83 three times a day, and nine four times a day. The overall time was five days in 52 courses, 7-15 days in 49 courses, and two patients had a longer regime. Actuarial local tumor control was 34.6% at five, and 24.7% at ten years in the whole group, and 25.5% and 14.6%, respectively, in the patients with macroscopical disease. Crude local control in the latter patients was achieved in 24.4% after a five day course, 28.8% after 7 to 11 days course, and 50% after a time of 12 or more days. Crude local control after total dose of less than 40 Gy was 15.8%, after 40-45 Gy, 31.7%, after 45.1-50 Gy, 33.3%, and after more than 50 Gy, 100% (four patients). Sixty patients were evaluable for late damage at 18 months; twenty three of them developed moderate changes. Six suffered severe late damage such as skin leathering or necrosis: three of them were treated for recurrence after previous radiotherapy. The main factor influencing tumor control was not the overall treatment time, but the total dose.

Adult↗
PubMed1991

The nature of the conductance increase induced by filipin in cholesterol-containing planar lipid bilayers.

The effects of the polyene antibiotic filipin on the conductance and permeability of planar lipid bilayers were investigated under voltage-clamp conditions. The membrane conductance of lipid bilayers containing no cholesterol was not affected by filipin. In the presence of cholesterol containing lipid bilayers, filipin induced a 10(4)-10(5)-fold increase in transmembrane conductance. This conductance increase was dependent on the ionic species present in solution, decreasing in the following order: GCsCl greater than GNaAc greater than GKCl greater than GNaCl greater than CaCl2 greater than GNa2SO4 greater than GBaCl2 greater than GMgCl2. Reversal potential measurements in simple biionic conditions revealed the following relative permeability sequence: PK greater than PCl greater than PNa approximately Pac approximately PBa greater than PCs greater than PMg approximately PCa greater than Psulphate. The filipin-sterol mediated increase in membrane conductance was independent of the membrane potential. The increase in membrane current following a step alteration in membrane potential occurred instantaneously and had no dependence on the previous value of the holding membrane potential. We propose that the filipin-sterol complex forms ion channels in lipid membranes. These channels are found in a single configuration (open state) and select preferentially monovalent cations or anions over divalent ions. Our experimental results are discussed in relation to the effects of other polyene antibiotics on the membrane permeability, and also in relation to experimental problems previously reported with the use of filipin in planar lipid bilayers.

Anions↗
PubMed1991

The influence of some factors on local control of early glottic cancer.

A total of 135 patients with T1N0M0 and T2N0M0 carcinoma of the vocal cord were treated during a 20-year period at St Mary's Hospital in Portsmouth by local radiotherapy. A total of 122 patients were available for local control analysis. The local control of T1 tumours was 80.5%, and for T2, 51.1%, total T1 + T2 local control was 69.7% (P less than 0.001). The only other factor in univariate analysis, which influenced the results was the overall treatment time. In the group of patients treated by an overall time of 45 days or less, the local control was 83.7%. For longer time it was 62% (P less than 0.02). Multivariate analysis confirmed these findings but brought out the importance of vocal cord mobility as the best discriminating factor between local control and failure, followed by overall treatment time.

Adult↗
PubMed1991

Management of soft tissue sarcomas in Portsmouth 1965-1985.

This paper describes the results of combined surgical and radiotherapy management of 118 patients with soft tissue sarcoma referred to the Department of Radiotherapy and Oncology at Portsmouth between 1965 and 1985. After exclusion of paediatric rhabdomysarcomas, tumours of the gastrointestinal tract and patients who were referred for follow-up only, 109 patients were left for retrospective analysis: 23 patients had surgery only, 11 received a course of preoperative radiotherapy, 52 were irradiated postoperatively and 14 had only radiotherapy. A range of doses and fractionations was used. The total 5-year actuarial survival was 39.7%, the disease-free survival was 35.6%. After excluding Kaposi sarcomas, retroperitoneal tumours, patients with distant metastases or those too ill for radical therapy, the respective figures were 55.5% and 49.7%. If we also excluded patients, treated by radiotherapy only, or irradiated with gross postoperative disease, the figures were 62.7% and 57.3% respectively. Five-year actuarial local control in 68 patients irradiated either without surgery, or postoperatively, was 57.2%. In tumours smaller than 5 cm in diameter, 5-year survival was 86.7%, and local control was 93.3%. For large tumours over 10 cm in diameter, the respective values were 22.2% and 50%. The dose of 60 Gy was satisfactory, if the surgical procedure removed all macroscopical disease, but higher doses are recommended when there is clinically apparent residual disease.

Adolescent↗
PubMed1990

[Specificity of cytochrome P-450 forms in the rat liver after inhalation of multicomponent hydrocarbon mixture].

Rats were inhaled with C6-C9 petroleum fraction 12 hrs daily for 9 days. The hydrocarbons and their metabolites gas chromatographic profiles from liver, kidney, brain and blood were investigated by means of head space technique. The observed characteristic profile composed of some hydrocarbons and secondary alcohols does not undergo qualitative changes and internal quantitative proportions remain constant in spite of cytochrome P-450 induction. Only total amount of hydrocarbons and their metabolites was varied. The results suggest that C6-C9 petroleum fraction inhalation does not induce new forms of cytochrome P-450 with different catalytic properties, but at the same time substrate binding site is modified to facilitate biotransformation of hydrocarbons and their metabolites.

Administration, Inhalation↗
PubMed1989

Comparison of the circadian rhythm in cell proliferation in corneal epithelium of male rats studied under normal and hypobaric (hypoxic) conditions.

Groups of 20-45-day-old rats maintained on a light (0600-1800)/dark (1800-0600) regimen with food and water available ad libitum were studied for the effect of hypoxic hypoxia on the circadian rhythm of corneal epithelial mitosis and thymidine incorporation. In experiments conducted during the months of September and November, hypoxic hypoxia was accomplished by the exposure of rats to a simulated altitude of 7500 m in one series of experiments, or to a gaseous mixture of 8% oxygen and 92% nitrogen at sea level atmospheric pressure (760 mmHg) in another series of experiments. Controls were included as well. Statistically significant (P less than 0.05) circadian rhythmicity in the corneal mitotic index was substantiated in the control animals with mesor (M) = 12.4%, amplitude (A) = 9.6% and acrophase (phi) of 0911. In the hypoxic hypoxia situation, the mesor and amplitude were depressed to 8.6 and 5.9%, respectively. In control groups, thymidine incorporation was circadian rhythmic with M = 38.5 and A = 11.3 cpm/microns DNA and acrophase of 2255. In the hypoxic hypoxia situation, the mesor was similar to the controls; whereas the amplitude was suppressed to 6.1% and acrophase was phase advanced by about 7 hr. Changes in the circadian rhythm of corneal mitosis and in thymidine incorporation under hypoxic hypoxia can be explained by programmed-in-time energy requirements during the corneal cell regeneration cycle.

Animals↗