Biomedical subjects

J Marek

Publications and source records attributed to J Marek.

At least 37 records · Page 2Linked to original sources

PubMed2002

The relationship between serum levels of insulin-like growth factor-I and its binding proteins and microvascular function in acromegalic patients.

The system of insulin-like growth factor-I (IGF-I) and its binding proteins is thought to be involved in the pathogenesis of vascular damage under different pathological circumstances. The results of various studies are rather controversial. This study considers the relationship between the activity of this system and the function of microcirculation in acromegalic patients. Thirteen patients with hormonally active acromegaly and 15 healthy controls were included in the study. The growth hormone, free IGF-I, IGF-I, IGF binding protein (IGFBP) -1, -2, -3 and -6 serum levels and parameters of lipid metabolism were determined. The function of microcirculation was determined by laser Doppler fluxmetry and the intima media thickness of the common carotid artery was measured by ultrasound. We noted significant reduction in postocclusive reactive hyperaemia (PORH(max)) (P < 0.01), in thermal hyperaemia (TH(max)) (P < 0.05) and in the velocity of reaction in both tests in the group of acromegalic patients. A significant negative correlation between free IGF-I serum levels and maximal perfusion during thermal hyperaemia TH(max) (P < 0.02) was found in the control group. Statistically significant positive correlation between free IGF-I serum levels and the time to maximal perfusion in postocclusive reactive hyperaemia PORH(max) (P < 0.05) was found in the group with hormonally active acromegaly. Moreover, a positive relationship between IGFBP-1 serum levels and serum levels of total (P < 0.01) and low density lipoprotein (LDL) (P < 0.05) cholesterol was found in the group of patients with acromegaly. We conclude that the function of microcirculation is impaired in patients with acromegaly and that free IGF-I serum levels may affect the microvascular function as measured by laser Doppler fluxmetry. In addition, we found a significant relationship between the serum levels of IGFBP-1 and those of total and LDL cholesterol in the group of patients with hormonally active acromegaly.

Acromegaly↗

PubMed2002

Effects of stress on serum prolactin levels in patients with systemic lupus erythematosus.

The results of a study of effects of stress on serum prolactin (PRL) levels in patients with SLE reveal statistically significant differences in serum PRL level readings in samples taken over a short period of time, thus corroborating the need to take into account PRL stress induction during sample withdrawals and to interpret the values obtained, especially where moderate idiopathic hyperprolactinemia was detected. To eliminate any external stress factors, it is advisable to take PRL samples repeatedly and in perfectly resting patients.

Adult↗

PubMed2002

Reduced microvascular perfusion and reactivity in adult GH deficient patients is restored by GH replacement.

BACKGROUND: An increased cardiovascular risk and mortality in hypopituitary patients receiving conventional hormonal treatment without GH replacement have been shown in several studies. Various atherogenic risk factors including endothelial dysfunction - an early event in the atherogenesis - are more expressed in adults with GH-deficiency (GHD). Changes in microcirculation and vascular reactivity could represent an early marker of developing vascular changes. OBJECTIVE: To evaluate the microcirculation and vascular reactivity in a GHD state before and during GH replacement. SUBJECTS, METHODS AND DESIGN: Thirteen adult patients (ten men, mean age 40+/-9 years) with severe GHD were studied. The skin microvascular perfusion and reactivity were measured by laser-Doppler flowmetry on the forearm. Two dynamic tests for vascular perfusion and reactivity were used - postocclusive reactive hyperemia (PORH) and thermal hyperemia (TH) at 44 degrees C. Measurements were performed before and after 6 and 12 months on GH replacement with a dose of GH that normalized IGF-I serum levels. The parameters of tissue perfusion and vascular reactivity measured in GHD were compared with values during GH treatment and with the results of the control group. RESULTS: Peak flow during TH in GHD patients was significantly reduced before GH treatment when compared with healthy subjects (means+/-s.e.m., 68+/-6.6 vs 111+/-8.3 perfusion units (PU), P<0.001) and normalized on GH treatment (109+/-12.7 PU). The velocity of perfusion increase during TH before treatment was significantly reduced in GHD as well (0.84+/-0.07 vs 1.53+/-0.19 PU/s, P<0.03) and normalized on GH treatment (1.38+/-0.24 PU/s). The PORH was also significantly reduced in GHD compared with controls (PORH(max) 414+/-63 vs 528+/-58%, P<0.05) and during GH treatment was restored to values not different from controls (642+/-86%, P=NS). CONCLUSIONS: Skin microcirculation and vascular reactivity measured by laser-Doppler flowmetry is significantly reduced in GHD adults and is restored during GH replacement therapy. Reduced tissue perfusion and reactivity probably reflect the endothelial dysfunction in the GHD state. Reduced nitric oxide production and bioavailability and also other factors like increased sympathetic activity and reduced conversion of thyroxine to triiodothyronine in the GHD state can contribute to changes in microcirculation. Restoration of vascular reactivity by GH replacement might have favorable clinical consequences on the increased vascular morbidity of GHD patients. Reduced skin microvascular perfusion and reactivity in GHD probably contribute to the impaired thermoregulation - a clinical symptom of GHD.

Adult↗

PubMed2002

[Complex plasty of the atrioventricular valve in defects with a functional single ventricle--surgical technic and midterm results].

Congenital heart diseases with a functionally single ventricle can be surgically treated using total cavopulmonary connection. Regurgitation of atrioventricular valves represents one of risk factors for death and unfavourable long-term result after this operation. During 1996-2001 total cavopulmonary connection with a complex plastic repair of atrioventricular valves was performed in 8 patients at the age from 1.4 to 13.3 years (median 7.8 years). All patients had very complex congenital heart diseases with severe malformation of atrioventricular valves. All but one had pulmonary stenosis or atresia. Six patients had common atrioventricular orifice, 5 patients had bilateral superior caval veins and 4 patients had dextrocardia or mesocardia. In 6 (75%) patients one or two palliative operations had been performed earlier. Before surgery all patients were cyanotic with severe hypoxemia and polyglobulia. All patients had regurgitant atrioventricular valves. The surgery was performed from the midline sternotomy approach, in extracorporeal circulation and moderate hypothermia. The surgery consisted in excision of the atrial septum, construction of a direct connection of all superior and inferior caval veins with the pulmonary artery, transsection of the pulmonary trunk and complex plastic repair of atrioventricular valves. The inferior caval vein was derived to the pulmonary artery using an intraatrial lateral tunnel in 3 patients and using an external conduit from a Goretex vascular prosthesis in 5 patients. In 5 patients a fenestration in tunnel or conduit permitting decompression of the systemic venous return was done. Individualized plastic repair of atrioventricular valves consisted in the suture of the central portions of both common leaflets. Four patients required also commissuroplasty of one to four commissures and two patients required annuloplasty. All patients survived the early postoperative period. In the majority of them complications occurred: hypoxemia in 3, pleural effusions in 3, low cardiac output in 2 and bleeding in 1 patient. In two patients reintervention for severe hypoxemia was necessary. Postoperative echocardiographic examination proved good result in all patients. In 6 (75%) patients the grade of regurgitation of atrioventricular valves decreased immediately after the repair, in the two remaining patients the degree of regurgitation decreased during the follow up. One patient with the most severe residual regurgitation which progressed during the follow up died 2.5 years later under the signs of congestive heart failure after spontaneous closure of fenestration. The 7 (87.5%) living patients remain in good clinical condition in NYHA class I or II. Our experience proved that it is possible to perform total cavopulmonary connection with low mortality and good midterm results even in patients with hemodynamically significant regurgitation of atrioventricular valves. Persistent severe or progressive regurgitation, however, requires surgical reintervention.

Adolescent↗

PubMed2002

Ghrelin -- a new endogenous growth hormone secretagogue.

Ghrelin is a new endogenous peptide, discovered in 1999 by Kojima et al., as the result of a search for an endogenous ligand for an orphan receptor of known structure and function. Ghrelin is composed of 28 amino acids and is produced mostly by cells of the stomach, hypothalamus, and hypophysis, but it has also been detected in other tissues. Its discovery is related to the development of a new hypothesis regarding the regulation of growth hormone secretion. It is an antagonist of somatostatin. Ghrelin activates the release of growth hormone from the somatotrophic cells of the hypophysis. It participates in the regulation of energy homeostasis, increases food intake, decreases energy output and exerts a lipogenetic effect. Its metabolic effects do not depend on the GH/IGF-I system, but are mediated by the NPY/Y1 and AGRP receptor system. Ghrelin influences the secretion and motility of the gastrointestinal tract, especially the stomach. The presence of ghrelin and its receptors has also been demonstrated in many other tissues. Its function in these tissues has not yet been studied, thus providing many possibilities for further research.

Animals↗

PubMed2002

[Intraumbilical therapy of fetal supraventricular tachycardia].

The supraventricular tachycardia represents the life threatening disease, which may cause severe heart failure or even during foetal life. The authors present case report of the foetus aged 23 weeks of gestation in whom the supraventricular tachycardia was resistant to standard transplacental treatment by using digoxin and sotalol. The successful rhythm conversion was achieved by intracordal infusion of amiodarone. Further uncomplicated course of pregnancy reached term and healthy boy was subsequently born without having additional psychomotoric complications.

Adult↗

PubMed2002

[Effect of various doses of biosynthetic growth hormone on levels of IGF-I binding protein 3 (IGFBP-3) in patients with hypopituitarism and growth hormone deficiency].

OBJECTIVES: To study the effect of different doses of hGH (biosynthetic human growth hormone--Humatrope) administration on the profile of IGFBP-3 in hypopituitary patients with GHD and to find out the extent of production of IGFBP-3 proteases, which results in the elevated biological IGF-I activity. STUDY DESIGN: Ten patients (after 1. collection) were randomized according to the dose of hGH, administered within three months, into group I: 3 micrograms/kg/day and group II: 6 micrograms/kg/day. After 2. collection the doses of hGH were in both groups duplicated and administered another three months (3. collection). METHODS: RIA's were used to analyse GH, IGF-I, total IGFBP-3 and fIGF-I. The profile of IGFBP-3 forms was studied by electrophoresis with western immunoblotting. RESULTS: Anabolic effect of administered hGH was demonstrated by significant increase of IGF-I and total IGFBP-3 in both groups of patients. It was evident that this increase is associated with the raise of proteolytic fragment of IGFBP-3 (29 kD). CONCLUSION: The increased doses of hGH change the profile of IGFBP-3 in the sense of increasing concentrations of IGFBP-3 (29 kD). As proteolytic clipping of intact IGFBP-3 is associated with the raise of fIGF-I levels in individual patients it is possible to consider 29 kD IGFBP-3 as the marker of the therapy of hGH in our study. However, the increasing tendency to fIGF-I production after 2-fold higher administration of hGH in majority of patients in the trial is not in average significant so it means that the doses of hGH administered to each individual should be optimalized.

Adult↗

PubMed2001

Resynchronization pacing is a useful adjunct to the management of acute heart failure after surgery for congenital heart defects.

The acute hemodynamic effect of atrioventricular (AV) and inter/intraventricular (IV) resynchronization accomplished by temporary pacing using multiple epicardial pacing wires was evaluated in 20 children (aged 3.4 months to 14.0 years) after surgery for congenital heart defects fulfilling the following criteria: (1) presence of AV and/or IV conduction delay, and (2) need for inotropic support. AV resynchronization (n = 13) was achieved by AV delay optimization during atrial synchronous right ventricular outflow tract pacing. IV resynchronization (n = 14) was accomplished by atrial synchronous pacing from the right ventricular lateral wall in 7 patients with right bundle branch block and normal AV conduction and by atrial synchronous multisite ventricular pacing in another 7 patients with previously performed AV resynchronization. Compared with baseline values, AV resynchronization resulted in an increase in arterial systolic, mean, and pulse pressures by 7.2 +/- 8.3% (p <0.01), 8.6 +/- 8.1% (p <0.005), and 6.9 +/- 13.5% (p = NS), respectively. IV resynchronization used either alone or added to previously performed AV resynchronization led to a pressure increase of 7.0 +/- 4.7%, 5.9 +/- 4.7%, and 9.4 +/- 7.8%, respectively (p <0.001 for all). The combined effect of AV and IV resynchronization resulted in a systolic, mean, and pulse pressure increase of 10.2 +/- 5.0% (range 4.0 to 19.1), 8.6 +/- 5.4% (range 0.8 to 14.8), and 15.2 +/- 8.5% (range 6.1 to 33.3), respectively (p <0.001 for all). The increase in systolic arterial pressure after IV resynchronization was positively correlated with the initial QRS duration (r = 0.62, p <0.05) and extent of QRS shortening (r = 0.66, p <0.05). In conclusion, resynchronization pacing led to a significant increase in arterial blood pressure and was a useful adjunct to the treatment of acute postoperative heart failure in patients with AV and/or IV conduction delay.

Adolescent↗

PubMed2001

Effect of pH and loading manner on the start-up period of peat biofilter degrading xylene and toluene mixture.

Laboratory-scale biofilters packed with a mixture of peat, bark and wood were used for xylene and toluene removal from waste air. Two kinds of peat, which differed in the resulting pH of the leachate, were chosen for degradation of the pollutants by a mixed culture. Using peat with the lower pH value, the feasibility of single and multiple pollutant loading during the start-up period and augmentation with Pseudomonas putida strains were characterized. The lower pH value of the bed resulted in higher efficiency of toluene degradation from the mixture of pollutants. At higher pH values better degradation of both pollutants was achieved. Regarding the manner of loading during the start-up period, the best results were obtained using toluene as a single pollutant in the initial phase of operation. Pseudomonas strains demonstrated a high ability to degrade both pollutants; more efficient degradation for xylene than for toluene was observed at high loading rates.

Air Pollutants↗

PubMed2001

Preparation, physicochemical properties and biological activity of copper(II) complexes with 6-(2-chlorobenzylamino)purine (HL1) or 6-(3-chlorobenzylamino)purine (HL2). The single-crystal X-ray structure of.

Copper(II) complexes of 6-(2-chlorobenzylamino)purine (HL1) and 6-(3-chlorobenzylamino)purine (HL2), respectively, were prepared. Depending on the pH of the medium and the molar ratio of reactants the following mononuclear (trigonal-bipyramidal) and dinuclear (octahedral, trigonal-bipyramidal or tetrahedral) complexes were isolated: [Cu2(mu-HL1)2(mu-Cl2)2(HL1)2Cl2] (1a,b), [Cu2(mu-Cl)2(mu-L1)2(H2O)2] (2a), [Cu2(mu-Cl)2(mu-L2)2(H2O)2] (2b), [Cu(H+L2)2Cl3]Cl.H2O (3a,b), [Cu2(mu-Cl)2(HL1)2Cl2] (4a), and [Cu2(mu-Cl)2(HL2)2Cl2] (4b). The compounds were characterized by elemental analyses, electronic, infrared and mass (FAB+, ES+) spectral data, magnetic susceptibility temperature dependence measurements and molar conductivity data. An X-ray single-crystal structural analysis of [Cu(H+L2)2Cl3]Cl.2H2O (3b) showed that the Cu2+ ion is penta-coordinated by three chloride ions and by two H+L2 ligands. Thus, the Cu2+ ion adopts a distorted trigonal bipyramidal coordination geometry with the protonated H+L2 ligands coordinated in trans apical positions, while the three chloride ions are situated in an equatorial plane. The cytotoxic activity of the complexes was determined by a calcein AM assay. Mouse melanoma cell line B16-FO, human malignant melanoma cell line G361, human osteogenic sarcoma cell line HOS and human breast adenocarcinoma cell line MCF7 were used. IC50 values, the drug concentrations lethal to 50% of the tumor cells, were estimated. One of the important mechanisms responsible for the cytotoxicity of cytokinin-derived compounds, the inhibition of cyclin-dependent kinases by the studied complexes, was also determined.

Animals↗

PubMed2001

Recurrent ACTH-independent Cushing's syndrome in multiple pregnancies and its treatment with metyrapone.

A 17-year-old primigravid woman presented with Cushing's syndrome. Typical clinical symptoms and signs developed at the beginning of pregnancy. By week 17 of gestation, plasma cortisol diurnal rhythm was absent and there was a paradoxical increase in plasma cortisol after a 1-mg dexamethasone overnight suppression test. Basal urinary free cortisol was 10 times above the upper limit (in pregnancy) and ACTH levels were suppressed. The diagnosis of ACTH--independent Cushing's syndrome was established. MRI scans revealed normal adrenal and pituitary glands. To control hypercortisolism, the patient was treated with metyrapone. At 34 weeks of gestation, the patient developed preeclampsia and underwent caesarean section. A female infant weighing 1070 g was delivered. No apparent metyrapone-induced teratogenic effects were observed. Cushing's syndrome in the patient resolved within three weeks of delivery. No corticosteroid replacement therapy either for child or mother was needed. Eight months after delivery the patient became pregnant again and rapidly developed Cushing's syndrome with typical clinical symptoms and signs and laboratory results (urinary free cortisol 6464 nmol/24 h). This second pregnancy was unwanted and terminated by artificial abortion that was followed by rapid resolution of hypercortisolism. A third pregnancy, 12 months after delivery was also accompanied by the rapid development of hypercortisolism which recovered after artificial termination. The mechanisms by which pregnancy-induced Cushing's syndrome occurred in this patient are unclear. Aberrant responsiveness or hyperresponsiveness of adrenocortical cells to a non-ACTH and non-CRH substance produced in excess in pregnancy should be considered. Metyrapone suppression of hypercortisolism currently represents the best treatment for these rare cases.

Abortion, Therapeutic↗

PubMed2001

The changes of IGF binding proteins after rhGH administration to patients totally dependent on parenteral nutrition.

The objective was to study the effect of recombinant human growth hormone (rhGH) administration to patients with chronic malnutrition maintained on total parenteral nutrition (TPN) on the levels of insulin-like growth factor-I (IGF-I) and IGF binding proteins (IGFBPs) during a double-blind trial. After 1 week of TPN the patients were randomized into group I (placebo) or group II (rhGH). Samples were collected on the first day (start of the TPN) to measure basal values, the seventh day to study the effect of TPN and the 10th, 14th and 21st days to evaluate the rhGH effect. Basal laboratory evaluation, nutritional status and glucose tolerance were assessed using standard laboratory techniques. Radioimmunoassays were used to analyse IGF-I, free IGF-I (fIGF-I) and IGFBP1-3. Electrophoresis with Western ligand blotting and Western immunoblotting was applied to find the pattern of IGFBPs. TPN had no effect on the circulating IGF-I concentration and the pattern of IGFBPs present in the studied groups of patients. The rhGH administration led to significant increases of IGF-I, total IGFBP-3, glycosylated IGFBP-3 (39, 42 kDa) and the 29 kDa fragment of IGFBP-3 and the decrease of IGFBP-2 during the trial (P<0.05). The mean levels of IGFBP-1, fIGF-I and the parameters of nutritional status in group II during the trial were not significantly influenced by rhGH. However, it has been found that IGFBP-1 and fIGF-I levels were correlated with the levels of the weekly nitrogen balance of each patient in group II at the end of the trial. In spite of the significant changes of IGF-I, IGFBP-2, total IGFBP-3 and IGFBP-3 (29 kDa proteolytic fragment) after rhGH administration to patients with malnutrition, maintained on parenteral nutrition, the increase of nitrogen balance was seen only in patients who decreased their IGFBP-1 and increased bioavailable IGF-I as reflected by measurement of fIGF-I. The levels of IGFBP-1 may provide a useful marker of IGF-I bioavailability in monitoring the efficiency of the rhGH therapy in malnourished patients.

Adult↗

PubMed2001

Purification, crystallization and preliminary X-ray analysis of a maize cytokinin glucoside specific beta-glucosidase.

Zm-p60.1, a cytokinin glucoside specific beta-glucosidase from maize, is a key enzyme involved in plant development and growth. It has been overexpressed in soluble form from Escherichia coli with a His tag at its N-terminus. The recombinant protein has been purified and crystallized at room temperature using PEG 4000 as the main precipitant. At least three crystal forms have been observed from very similar growth conditions. A flash-annealed monoclinic crystal diffracted to high resolution (beyond 2 A) with space group P2(1) and unit-cell parameters a = 55.66, b = 110.72, c = 72.94 A, beta = 92.10 degrees. The asymmetric unit is estimated and confirmed by molecular-replacement solution to contain one Zm-p60.1 dimer, giving a crystal volume per protein mass (V(M)) of 1.89 A(3) Da(-1) and a solvent content of 35%.

Crystallization↗

PubMed2001

Craniofacial abnormalities and their relevance for sleep apnoea syndrome aetiopathogenesis in acromegaly.

OBJECTIVE: To explain the effect of craniofacial relations on the development of the sleep apnoea syndrome (SAS) in acromegaly, and to elucidate how the activity of acromegaly affects the severity of SAS. DESIGN: Prospective observational study. METHODS: Cephalometry and sleep ventilation measurements were performed in 26 acromegalic men and in 96 men with SAS. RESULTS: SAS was found in 20 acromegalic men. Compared with non-acromegalic men with SAS, patients with acromegaly and SAS were found to have: enlargement of almost all linear dimensions; increased angle indicating mandibular protrusion; increased difference between maxillary and mandibular protrusion; articular angle decrease; soft palate lengthening; and pharyngeal airway space (PAS) enlargement in the palatal and uvular-tip planes. A comparison of acromegalic men with and without SAS revealed no significant difference in the craniofacial skeleton, although there was a narrowing of the minimal PAS (MinPAS) and of PAS in the uvular-tip plane in patients with SAS. SAS was more frequent in the patients with active acromegaly. MinPAS in the patients with active acromegaly was narrower than in those without disease activity. CONCLUSION: Skeletal abnormalities in acromegalic men with SAS were different from those in SAS patients without acromegaly. Upper airway narrowing due to changes in pharyngeal soft tissues takes a more relevant share in the development of SAS in acromegalic men than skeletal anomalies.

Acromegaly↗

PubMed2001

[Laparoscopic therapy of symptomatic splenic implants in the minor pelvis].

OBJECTIVE: The radical laparoscopic treatment of the aforementioned pathology has made it possible to eliminate recurrent pelvic pain of the 24 years old patient. SUBJECT: Case report. METHODS AND RESULTS: 24 year old, nulligravid patient, had primary laparoscopy in 1998 because of chronic pelvic pain. Histology has confirmed both, the infiltrative endometriosis and the pelvic splenosis. While the endometriosis has been radically excised, splenic implants have been, in accordance with the current opinions in the literature, left in situ. Only their biopsy has been done. Due to recurrent pelvic pain after 15 months and the growth of the splenical implants, the second look laparoscopy was performed with the radical excision of these foci. CONCLUSION: The patient, 4 months after the intervention is asymptomatic. At variance with most of the literature, we assume that the pelvic splenosis in contrast to the abdominal is in many cases symptomatic. It causes especially pelvic pain and dyspareunia in connection with the contingent implant growth. In such cases the radical excision is indicated, where the laparoscopy is the chosen method. Authors are discussing the differentiational diagnosis of this syndrome especially concerning endometriosis, peritoneal carcinomatosis, accessory spleen and the manifestation of the lymphoma.

Adult↗

PubMed2001

Insights into the functional architecture of the catalytic center of a maize beta-glucosidase Zm-p60.1.

The maize (Zea mays) beta-glucosidase Zm-p60.1 has been implicated in regulation of plant development by the targeted release of free cytokinins from cytokinin-O-glucosides, their inactive storage forms. The crystal structure of the wild-type enzyme was solved at 2.05-A resolution, allowing molecular docking analysis to be conducted. This indicated that the enzyme specificity toward substrates with aryl aglycones is determined by aglycone aromatic system stacking with W373, and interactions with edges of F193, F200, and F461 located opposite W373 in a slot-like aglycone-binding site. These aglycone-active site interactions recently were hypothesized to determine substrate specificity in inactive enzyme substrate complexes of ZM-Glu1, an allozyme of Zm-p60.1. Here, we test this hypothesis by kinetic analysis of F193I/Y/W mutants. The decreased K(m) of all mutants confirmed the involvement of F193 in determining enzyme affinity toward substrates with an aromatic aglycone. It was unexpected that a 30-fold decrease in k(cat) was found in F193I mutant compared with the wild type. Kinetic analysis and computer modeling demonstrated that the F193-aglycone-W373 interaction not only contributes to aglycone recognition as hypothesized previously but also codetermines catalytic rate by fixing the glucosidic bond in an orientation favorable for attack by the catalytic pair, E186 and E401. The catalytic pair, assigned initially by their location in the structure, was confirmed by kinetic analysis of E186D/Q and E401D/Q mutants. It was unexpected that the E401D as well as C205S and C211S mutations dramatically impaired the assembly of a catalysis-competent homodimer, suggesting novel links between the active site structure and dimer formation.

Amino Acid Sequence↗

PubMed2001

[Changes in serum levels of IGF-I and its binding proteins and their relation to microcirculation in obese patients].

The IGF-I system and its binding proteins participate in the pathogenesis of vascular affections under various pathological conditions. The mechanism and mode of its action were however not elucidated in details so far and views on its role are controversial. The objective of the study was to assess the relationship of this system and the blood flow in the microcirculation in obese patients. The authors examined 21 obese patients (BMI 39.7 +/- 7.3 kg/m2) and a group of healthy volunteers. They examined: serum concentrations of total IGF-I, free IGF-I, IGFBP-1,-2,-3, and -6, total cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides as well as the intimomedial thickness of the common carotid arteries and parameters of blood flow in the microcirculation, evaluated by a laser-Doppler examination. In obese patients there were significantly lower serum concentrations of IGF-I and free-IGF I (p < 0.05) as compared with the control group. Comparison of the function of the microcirculation revealed in obese patients, as compared with the control group, a lower percentage increase of perfusion after occlusion (PORH%, p < 0.05) and after heating (TH%, p < 0.05) and a slower onset of thermal hyperaemia (THmax/t, p < 0.05). In the control group serum concentrations of free-IGF-I correlated inversely with the maximum perfusion after heat induced hyperaemia (THmax (r = -0.54, p < 0.02) and the rate of onset of hyperaemia after heating (THmax/t) (r = 0.51, p < 0.02). In the group of obese patients serum concentrations of free-IGF-I correlated inversely with the maximum perfusion after heat induced hyperaemia (THmax) (r = -0.55, p < 0.02), and IGFBP-3 concentrations correlated inversely with maximum hyperaemia after occlusion (PORGmax) (r = -0.57, p < 0.01). The results suggest that the function of the microcirculation in obese subjects is affected. The activity of the IGF-I system and its binding proteins is related to the affected function of the microcirculation and a negative part is played particularly by serum concentrations of free IGF-I. The negative effect of IGFBP-3 on the function of the microcirculation is surprising.

Blood Flow Velocity↗

PubMed2001

[Evaluation of tear film stability by means of laser interferometry].

PURPOSE: The paper presents a new method for evaluation of the tear film stability on the human eye. METHODS: The tear film distribution on the cornea is measured by the lateral shearing interference technique. The eye is kept open during approximately a two-minute recording, when the blinking has to be prevented. Continuous recording and viewing of interferograms enables registration of the changes in disturbances of interference fringes during elapsed time. The changes in fringes are caused by evaporation of tears from the ocular surface and appearance of the breakups. CONCLUSIONS: The noninvasive tear breakup time (NITBUT) can be evaluated by comparing the recorded consecutive interferograms.

Cornea↗