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Biomedical subjects

M Marciniak

Publications and source records attributed to M Marciniak.

At least 19 recordsLinked to original sources
PubMed2002

Acromegaly due to GHRH-secreting large bronchial carcinoid. Complete recovery following tumor surgery.

A case of acromegaly, secondary to GHRH secretion by a large bronchial carcinoid is reported. A 61-year-old woman presented with typical symptoms and signs of acromegaly for at least 10 years. She suffered from recurrent pneumonias, but repeated chest X-ray examinations failed to demonstrate the bronchial tumor. The diagnosis was confirmed by elevated GH, IGF-1 and GHRH secretion. We have shown an enlarged pituitary gland without focal lesions together with a cerebral meningioma on MRI and the presence of a bronchial carcinoid tumor. The latter was confirmed by histology carried out after bronchoscopy and tumor excision. We observed partial suppression of GH secretion following short-term oral bromocriptine administration in this patient. Surgical removal of the carcinoid tumor resulted in a complete clinical, hormonal and radiological cure of acromegaly. This case of acromegaly due to ectopic GHRH secretion by bronchial carcinoid differs from others described in the literature by an atypical large tumor size, the suppression of elevated GH secretion by oral bromocriptine and a concomitant meningioma.

Acromegaly↗
PubMed2001

Errors involved in the application of an imperfect peritoneal volume marker.

Peritoneal volume markers have been used in numerous studies on fluid transport in peritoneal dialysis. The basic assumption used was that the macromolecular marker was stable and that the free fraction of a label (usually radiolabel) was negligibly small. In this study are presented theoretical investigations on the errors involved in application of an imperfect volume marker containing free fraction of a label. These investigations were used in assessing the errors in calculation of peritoneal volume time course, V, and fluid absorption rate (estimated by volume marker clearance, kE) using data from 20 clinical dwell studies with 1.36% Dianeal dialysis solution and radioiodinated human serum albumin as a volume marker. It has been shown that with an in vitro measured 125I free fraction of 2.72%, the error of kE estimation was 11%. However, the maximal error in estimation of V was only 0.2%. In conclusion, the performed analysis implies that calculation of the peritoneal volume time course during the dwell (with correction for the volume marker elimination) is very reliable, and the existence of a free fraction of a volume marker label results in a negligibly small error. However, even small free fraction of the label results in a significant overestimation of the fluid absorption rate.

Absorption↗
PubMed2000

Characterization of Titania/Silica Gel by Means of Low-Pressure Nitrogen Adsorption.

Adsorbents synthesized by grafting of titania onto mesoporous silica gel surfaces at different temperatures were studied by means of nitrogen adsorption-desorption and water desorption. The pore size distribution f(R(p)) of titania/silica gel depends on the titania concentration (C(TiO(2))) and the temperature of titania synthesis. Nonuniformity of TiO(2) phase is maximal at a low C(TiO(2)) value (3.2 wt.% anatase deposited at 473 K), and two peaks of the fractal dimension distribution f(D) are observed at such a concentration of titania, but at larger C(TiO(2)) values, only one f(D) peak is seen. More ordered filling of pores and adsorption sites by nitrogen, reflecting in the shape of adsorption energy distributions f(E) at different pressures of adsorbate, is observed for adsorbent with titania (rutile+anatase) grafted on silica gel at a higher temperature (673 K). Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

Highly Dispersed X/SiO(2) and C/X/SiO(2) (X=Alumina, Titania, Alumina/Titania) in the Gas and Liquid Media.

Fumed oxides, such as silica, alumina, titania, and mixed X/silicas (X=Al(2)O(3) (AS), TiO(2) (TS), CVD-TiO(2), Al(2)O(3)/TiO(2) (AST)), pristine or covered by carbon deposits formed due to pyrolysis of cyclohexene, were studied using nitrogen adsorption-desorption, photon correlation spectroscopy particle sizing, and electrophoresis. A significant influence of the nature of surface-active sites and structural features of oxides (individual silica, mixed fumed, or prepared using chemical vapor deposition (CVD)) on the pyrolysis of cyclohexene is observed with respect to the pore size distributions due to differences between primary particles in aggregates and on their outer surfaces in the filling of channels by pyrocarbon, resulting also in a decrease in fractal dimension. Structural characteristics and dependences of the particle size distribution and electrokinetic potential of X/SiO(2) and C/X/SiO(2) on the pH of aqueous suspensions suggest that the carbon deposit covers mainly acidic sites at the X/SiO(2) interfaces and X phase patches possessing catalytic activity in pyrolysis, as the negative charge of particles is reduced by pyrocarbon grafting. Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

Cigarette consumption and sales of nicotine replacement products.

BACKGROUND: The first nicotine replacement product, Nicorette Gum, was marketed in 1984 as an adjuvant to help smokers quit smoking. In 1992, sales of nicotine patches were begun. Before 1996, nicotine gums and nicotine patches were prescribed by physicians and supplemented with behavioural counselling. Since 1996, nicotine gums and patches became available over the counter. OBJECTIVES: To examine the effect of sales of nicotine replacement products on national cigarette consumption. DESIGN: National time series quarterly cigarette consumption, sales of nicotine gums and patches data between 1976 and 1998 are used to estimate a time series autoregressive moving average intervention model. PARTICIPANTS: National reported statistics. MAIN OUTCOME MEASURES: Per capita cigarette sales. RESULTS: A 10% increase in sales of nicotine replacement products will lead to a 0.04% reduction in cigarette sales. The model indicates that a 0.076% reduction in cigarette consumption is associated with the availability of nicotine patches after 1992. The over the counter dummy variable (after 1996) has a negative sign, but is not significant, perhaps due to only a few quarters of data in the study period. CONCLUSIONS: Nicotine replacement products (nicotine gums and nicotine patches) play a significant role in reducing cigarette consumption, in addition to the negative effect of increasing cigarette price and the overall trend of declining cigarette consumption (as reflected by the time trend variable). The findings of this study suggest that additional efforts for promoting sales of nicotine replacement products will be another effective alternative to discouraging cigarette consumption.

Adolescent↗
PubMed1999

Characterization of Fumed Alumina/Silica/Titania in the Gas Phase and in Aqueous Suspension.

Fumed oxide alumina/silica/titania was studied in comparison with fumed alumina, silica, titania, alumina/silica, and titania/silica by means of XRD, (1)H NMR, IR, optical, dielectric relaxation, and photon correlation spectroscopies, electrophoresis, and quantum chemical methods. The explored Al(2)O(3)/SiO(2)/TiO(2) consists of amorphous alumina ( approximately 22 wt%), amorphous silica ( approximately 28 wt%), and crystalline titania ( approximately 50 wt%, with a blend of anatase (88%) and rutile (12%)) and has a wide assortment of Brønsted and Lewis acid sites, which provide a greater acidity than that of individual fumed alumina, silica, or titania and an acidity close to that of fumed alumina/silica or titania/silica. The changes in the Gibbs free energy (DeltaG) of interfacial water in an aqueous suspension of Al(2)O(3)/SiO(2)/TiO(2) are close to the DeltaG values of the dispersions of pure rutile but markedly lower than those of alumina, anatase, or rutile covered by alumina and silica. The zeta potential of Al(2)O(3)/SiO(2)/TiO(2) (pH of the isoelectric point (IEP) equals approximately 3.3) is akin to that of fumed titania (pH(IEP(TiO2)) approximately 6) at pH > 6, but it significantly differs from the zeta of fumed alumina (pH(IEP(Al2O3)) approximately 9.8) at any pH value as well as those of fumed silica, titania/silica, and alumina/silica at pH < 6. The particle size distribution in the diluted aqueous suspensions of Al(2)O(3)/SiO(2)/TiO(2) studied by means of photon correlation spectroscopy depends relatively slightly on pH in contrast to the titania/silica or alumina/silica dispersions. Theoretical calculations of oxide cluster interaction with water show a high probability of hydrolysis of Al-O-Ti and Si-O-Ti bonds strained at the interface of alumina/titania or silica/titania due to structural differences in the lattices of the corresponding individual oxides. Ab initio calculated chemical shift delta(H) values of H atoms in different hydroxyl groups at the oxide clusters and in bound water molecules are in agreement with the (1)H NMR data and show a significant impact of charged particles (H(3)O(+) or OH(-)) on the average delta(H) values of water droplets with (H(2)O)(n) at n between 2 and 48. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Structure of Chemical Vapor Deposition Titania/Silica Gel.

The structure of porous silica gel/titania synthesized using chemical vapor deposition (CVD) of titania via repeated reactions of TiCl(4) with the surface and subsequent hydrolysis of residual Ti-Cl bonds at different temperatures was investigated by means of low-temperature nitrogen adsorption-desorption, X-ray diffraction (XRD), IR spectroscopy, and theoretical methods. A globular model of porous solids with corpuscular structure was applied to estimate the porosity parameters of titania/silica gel adsorbents. The utilization of this model is useful, for example, to predict conditions for synthesis of titania/silica with a specified structure. Analysis of pore parameters and fractal dimension suggests that the porosity and fractality of samples decrease with increasing amount of TiO(2) covering the silica gel surface in a nonuniform layer, which represents small particles embedded in pores and larger particles formed at the outer surface of silica globules. Theoretical simulation shows that the Si-O-Ti linkages between the cover and the substrate can be easily hydrolyzed, which is in agreement with the IR data corresponding to the absence of a band at 950 cm(-1) (characteristic of Si-O-Ti bridges) independent of the concentration of CVD-titania. Copyright 1999 Academic Press.

Journal Article↗
PubMed1998

[The assessment of changes of the plate growth in Blount disease by MRI].

The changes within growth plates around the knee in Blount disease have been analyzed with MRI in 4 patients with late onset tibia vara. Extensive changes were found in both tibial and femoral growth plate. General widening of the plate, invagination into metaphysis and high intensity irregularities of the shape were observed. Lateral aspect of both physes was involved to higher degree. Our study supports mechanical etiology of the late onset tibia vara. In our opinion long lasting distraction stress on the lateral aspect of the knee due to the varus deformity might be responsible for the changes observed in MRI.

Adolescent↗
PubMed1998

[Evaluation of peritoneal solute transport parameters in diabetics treated with continuous ambulatory peritoneal dialysis].

Increasing number of diabetics (D) on CAPD induced us to perform detailed kinetic evaluation of these patients. The purpose of the study was to characterize peritoneal solute transport parameters in diabetics and non-diabetics (ND) treated with CAPD and furthermore to assess clinical implications of eventual differences, especially with regard to programming the long-term CAPD in D. Twelve patients (7D and 5ND) on CAPD for 3-55 months were qualified to the investigation. They were clinically stable, with no impairment of ultrafiltration and free of peritonitis for at least 3 months. Four hours dwell studies with 2.0L of 3.86% glucose dialysis fluid were performed and mass transport coefficients (KBD) for glucose, potassium, sodium, total protein, urea and creatinine were calculated. No statistical differences for KBD between D and ND were found. However for every solute the average KBD values were higher in D that in ND. The observed differences do not justify any different treatment modality for D on peritoneal dialysis (PD). However high SD values, resulting from differences of peritoneal solute transport between patients, indicate the necessity of individualization of PD program.

Adult↗
PubMed1996

Transport of lanthanides in milk into suckling rats.

The aim of this paper was to examine the transport of lanthanides in milk of contaminated rats into their sucklings and the retention of lanthanides in the sucklings. The research involved 55 female Wistar rats contaminated in the period of lactation and their offspring (400 infant rats). The study showed that in the period of lactation the transport in milk from the mother to the offspring of the lanthanide radionuclides under examination (144Ce, 147Nd, 152Sm, 155Eu and 160Tb) increased with their mass numbers: CE < Nd < Sm < Eu < Tb, and varied from 0.01% for 144Ce to 17.7% for 160Tb of the administered dose per litter. It was demonstrated that lanthanides were not absorbed from the digestive tract of sucklings because they were not detected beyond its area. Because of its highest concentration in milk 160Tb was chosen for further investigation of the kinetics of transport in individual segments of the digestive tract. The model for determining the function of lanthanide retention in separate parts of the digestive tract of sucklings and the half life of effective accumulation and elimination of 160Tb in the whole organism as well as in individual segments of the digestive tract are presented. Terbium-160 accumulation in sucklings increased whereas its elimination decreased with the age of the infant. No significant differences in 160Tb specific activity in stomach, and small and large intestines were observed in sucklings one to 21 days old. Biological half lives for retention of the contaminated milk were as follow: 0.25 +/- 0.021 per day for the stomach, 0.92 +/- 0.12 per day for the small intestine and 5.03 +/- 0.22 per day for the large intestine. The data obtained can be used in the evaluation of the doses absorbed from 160Tb and from other lanthanide radionuclides that are nonabsorbable from the digestive tract, as well as in estimation of the radiation risk to the offspring of mothers contaminated in the period of lactation.

Animals↗
PubMed1994

Bombesin plasma levels in patients with benign and malignant breast disease.

Some reports suggest a role for bombesin-like peptides in the pathology of breast tumors. Bombesin and related gastrin-releasing peptides have been shown to influence the inositol phospholipid signalling pathway and stimulate growth of some cells, including some human breast cancer cell lines. We measured the plasma concentration of bombesin in 23 breast cancer patients, 32 patients suffering from benign breast disease and in 21 healthy controls. The bombesin concentration in plasma taken from the thoracodorsal vein, in the vicinity of the tumor in breast cancer patients was higher than that in the peripheral circulation (mean +/- SEM, 91.3 +/- 54.3 vs. 40.9 +/- 27.4 pg/ml; p < 0.05). Bombesin concentrations in the cubital vein in breast cancer patients and in those with benign breast disease (61.7 +/- 49.3 pg/ml) was significantly higher than that in the control group (23.7 +/- 5.06 pg/ml; p < 0.05). Our findings suggest storage or synthesis of bombesin-like peptides within the affected breast and may confirm the role of these peptides in the growth of breast tumors.

Bombesin↗
PubMed1994

Morphometric ultrastructural study of satellite cells of rats during postnatal development (1st and 30th day of life).

Ultrastructural morphometric analysis of satellite cells of the diaphragm from one and 30-day-old rats was performed. The nuclear and cytoplasmic components of the cells were evaluated. The results obtained indicate that the satellite cells of one-day-old female rats are in a state of low activity. In 30-day-old animals, on the contrary, the cells are excited and active. This may be connected with their intensive participation in the process of development of the diaphragm muscle.

Animals↗
PubMed1992

[Castleman tumor].

A case of a mediastinal benign tumor in a 56 year old male is presented. The tumor was detected during a routine chest radiographic examination. The patient was asymptomatic. During thoracotomy two tumors were found. One was localized in the middle mediastinum the other in the posterior mediastinum. Both tumors were removed completely. Basing on the results of the clinical examination, of the laboratory data and the histopathological examination of the resected tumors a diagnosis of Castleman's tumor of the plasma-cell type was made.

Castleman Disease↗
PubMed1990

Murine lymph nodes in response to the local administration of dextran sulphate.

In mice a single injection of 4 mg of Dextran sulphate within a few days produces an enlargement of area draining lymph nodes and activates basophils/mast cells. This activation is manifested by many-fold increase of mast cell number per lymph node, degranulation of mast cells and appearance of young, immature mast cells capable to synthetize new granules. In contrast to the lymph nodes, the Dextran-injected connective tissue mast cells remained unchanged. This suggest that Dextran sulphate directly activates lymph node mast cells, probably by activation of T-cell suppressor or macrophages.

Animals↗
PubMed1989

[Alloplasty of the hip joint and the proximal part of the femoral shaft].

The possibilities of the use of untypical prostheses of the hip in cases with lesion of the proximal femoral end together with a part of the shaft have been presented. A hip prosthesis with the upper part of the femur was implanted in two cases for neoplastic disease, and in one case for pseudoarthrosis of the femur within the intertrochanteric region. Good early clinical and radiological results was obtained and the total range of motion in the implanted joint was 210 degrees. After operation the patients did not complain about pain and they walked with the aid of a cane.

Adult↗