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Biomedical subjects

J Marek

Publications and source records attributed to J Marek.

At least 55 records · Page 3Linked to original sources
PubMed2001

[Pars plana vitrectomy in treatment of ocular toxocariasis complications--case report].

Ocular toxocariasis in adults may cause serious diagnostic and therapeutic problems. We describe a case of a 54-year-old farmer who developed peripheral granuloma with dense connective tissue strands joined to the disc. The diagnosis was confirmed by high ELISA titers in the serum and vitreous body. We performed pars plana vitrectomy with epiretinal membrane removal and laser photocoagulation of the inferior retina, obtaining improvement of visual acuity. After a few weeks the patient returned with central retinal detachment and macular hole. After the second vitrectomy with use of silicon oil we obtained reattachment of the retina but without functional improvement.

Animals↗
PubMed2000

[Radiosurgical treatment of hypophyseal adenomas with the gamma knife: results in a group of 163 patients during a 5-year period].

BACKGROUND: Gamma knife radiosurgery of pituitary adenomas is considered to be very perspective. It can be a very useful complement of traditional microsurgery, pharmacotherapy or fractionated radiotherapy which are seldom a sufficient treatment on their own. The modern radiosurgery does not offer the experience representative enough in this indication. We can offer results of medium long follow-up for tumor growth and hormonal hypersecretion of pituitary adenomas in a relatively large series of patients. METHODS AND RESULTS: We have analyzed a group of 163 patients with pituitary adenoma treated with gamma knife during 5 years and followed 12-60 months, median 24 months after irradiation. An antiproliferative effect has been achieved in 1-2 years using the minimal dose to the margin 16-35 Gy, median 20 Gy in all our patients who were controlled by MRI (n = 126 patients). One half of these adenomas evidently decreased their size. Our effective antiproliferative dose was safe for the surrounding structures. The hormonal normalization has been achieved at 50.4% from 133 hypersecreting adenomas (39/91 = 43% of acromegalics, 11/13 = 85% of patients with Cushing's disease, 2/9 = 22% of patients with Nelson's syndrome, 11/18 = 61% of prolactinomas). The median latency was 12 months. The minimal dose to the margin was 10-45 Gy, median 35 Gy. Rare side effects were provoked only by increasing the dose to influence the hypersecretion-the development of partial hypopituitarism in 3.1% of patients, the panhypopituitarism in 0.6% of patient and there was 1 hemianopic visual field defect (0.6%). CONCLUSIONS: Radiosurgery by gamma knife has a similar value for pituitary adenomas as microsurgery has with different distribution of advantages and drawbacks. This makes it suitable for the combined treatment where pharmacotherapy has its place under special conditions. Fractionated radiotherapy has now a marginal importance.

Adenoma↗
PubMed2000

Crystal structure of the haloalkane dehalogenase from Sphingomonas paucimobilis UT26.

The haloalkane dehalogenase from Sphingomonas paucimobilis UT26 (LinB) is the enzyme involved in the degradation of the important environmental pollutant gamma-hexachlorocyclohexane. The enzyme hydrolyzes a broad range of halogenated cyclic and aliphatic compounds. Here, we present the 1.58 A crystal structure of LinB and the 2.0 A structure of LinB with 1,3-propanediol, a product of debromination of 1,3-dibromopropane, in the active site of the enzyme. The enzyme belongs to the alpha/beta hydrolase family and contains a catalytic triad (Asp108, His272, and Glu132) in the lipase-like topological arrangement previously proposed from mutagenesis experiments. The LinB structure was compared with the structures of haloalkane dehalogenase from Xanthobacter autotrophicus GJ10 and from Rhodococcus sp. and the structural features involved in the adaptation toward xenobiotic substrates were identified. The arrangement and composition of the alpha-helices in the cap domain results in the differences in the size and shape of the active-site cavity and the entrance tunnel. This is the major determinant of the substrate specificity of this haloalkane dehalogenase.

Binding Sites↗
PubMed2000

[Combined therapy of acromegaly with a combination of lanreotide and terguride].

BACKGROUND: The aim of the treatment of acromegaly is to normalise the hormonal activity. Besides the surgical and radiation treatment, medical therapy can be used. The project was set to determine the value of combined therapy with lanreotide and terguride in patients with active acromegaly. METHODS AND RESULTS: Nine patients previously treated with lanreotide for at least one year without normalisation of hormonal activity were included in the study. Terguride was added to lanreotide for one month. The combined treatment brought about reduction of growth hormone (GH) levels, however, with marginal significance only. GH-BP, IGF-I and IGFBP-3 serum levels were not changed significantly. Considering the individual cases, the combined treatment resulted in normalisation of GH levels in one patient and that of IGF-I in another one. Substantial decrease of GH levels (> 50%) was found in three patients and that of IGF-I (> 20%) in another one patient. CONCLUSIONS: The combined treatment of acromegaly appears to be more effective than monotherapy with lanreotide only in a subset of acromegalic patients.

Acromegaly↗
PubMed2000

[Multihormonal and multifunctional hypophyseal adenoma and the acromegaly syndrome].

Woman 75-year-old treated 30 years for syndrome of acromegaly refused pituitary surgery and irradiation. Five years and nine months before death she had a colon carcinoma successfully removed. Multinodular hyperfunctional goitre was treated with carbimazole. For six last years of life corticosteroids were given as a replacement therapy. Her cause of death was the heart failure due to acromegalic heart disease. In autopsy a large intrasellar and extrasellar pituitary adenoma without rests of nonneoplastic tissue was found. Nevertheless the target peripheral endocrine glands except ovaries, were not atrophic. A multinodular goitre and diffuse adrenocortical hyperplasia were revealed. Histology, and immunohistochemistry demonstrated that mot neoplastic cells were producing GH and ACTH, dispersly Prl, scattered cells were positive for beta-subunit of FSH, LH, TSH. Electron microscopy proved most of the cells to be densely granulated. We classify the adenoma according to the newly proposed WHO pituitary tumours classification (1) as plurihormonal, hyperfunctional, extrasellar, typical adenoma from densely granulated cells. We conclude that in plurihormonal adenomas with dominant (in the case referred acromegalic) symptomatology the additional hormonal production should be monitored as a possible source of important complications.

Acromegaly↗
PubMed2000

Stereospecific formation of alpha-hydroxycarboxylato oxo peroxo complexes of vanadium(V). Crystal structure of (NBu4)2[V2O2(O2)2(L-lact)2] x 2H2O and (NBu4)2[V2O2(O2)2(D-lact)(L-lact)] x 2H2O.

An overview of structurally characterized alpha-hydroxycarboxylatodioxo- and alpha-hydroxycarboxylatooxoperoxovanadates(V) is presented and the geometric parameters of the V2O2 bridging core are discussed. The first case of a stereospecific formation of oxoperoxovanadates(V) is reported: The crystal structures of the isomeric compounds (NBu4)2[V2O2(O2)2(L-lact)2] x 2H2O and (NBu4)2[V2O2(O2)2(D-lact)(L-lact)] x 2H2O (lact = C3H4O3(2-), the anion of the lactic acid) differ mainly in the arrangement of the V2O2 core and in mutual orientation of the V=O bonds. The complexes with achiral ligands adopt the same structural type as the complexes formed from a racemic mixture of a chiral ligand, while the structure obtained using an enantiopure L,L-hydroxycarboxylate is different.

Crystallography, X-Ray↗
PubMed2000

Prevalence of the sleep apnea syndrome in acromegaly population.

The prevalence of sleep apnea syndrome (SAS) in acromegaly is high. Consequences of SAS are serious and are associated with increased morbidity and mortality. The aim of this study was to assess the relative frequency and predictive factors for SAS in a group of patients with acromegaly (n=55). The presence of SAS was evaluated using the Polymesam device. Hormonal and clinical examination consisted of assessment of growth hormone, insulin-like growth factor I plasma levels, body mass index (BMI), neck circumference, age, sex, treatment modes of acromegaly and ear, nose and throat (ENT) examination. The relative frequency of SAS in our group of patients with acromegaly was 75%. Independent predictors of SAS were: increased activity of acromegaly, higher age and neck circumference. No association between SAS and BMI and ENT findings was observed. The role of gender was controversial.

Acromegaly↗
PubMed2000

Increase of adhesion molecules, fibrinogen, type-1 plasminogen activator inhibitor and orosomucoid in growth hormone (GH) deficient adults and their modulation by recombinant human GH replacement.

OBJECTIVE: GH deficiency (GHD) is usually associated with a higher incidence of cardiovascular disease (CVD). The aim of this study was to establish whether patients with GHD, like those with CVD, show an increase in fibrinogen (FBG), type-1 plasminogen activator inhibitor (PAI-1), acute phase response proteins (APR), and soluble adhesion molecules. The effect of recombinant human GH (rhGH) replacement, on these parameters was also investigated. PATIENTS AND DESIGN: Concentrations of PAI-1 antigen (Ag), adhesion molecules sE-selectin, sP-selectin, and intercellular adhesion molecule-1 (sICAM-1), FBG and levels of APR orosomucoid (ORM), and 'negative APR' transferrin (TRF) were established in 11 panhypopituitary (PHP) patients (eight men and three women, age median 39.0 years, body mass index (BMI) 27. 49 +/- 3.89 kg/m2) before and after 12-month replacement with rhGH. Control values were obtained by examination of 33 healthy age and sex matched subjects (24 men and nine women with BMI 24.16 +/- 1.99 kg/m2). RESULTS: PHP patients had higher concentrations of ORM (0.80 +/- 0.25, vs. 0.61 +/- 0.20 g/l; P = 0.05), FBG (3.22 +/- 0.48, vs. 2.57 +/- 0.47 g/l; P = 0.001), PAI-1 Ag (97.12 +/- 33.23, vs. 44.11 +/- 21.40 microgram/l; P = 0.001), sE-selectin (72.42 +/- 28.35, vs. 42. 80 +/- 12.60 microgram/l; P = 0.004), sP-selectin (221.26 +/- 75.12, vs. 104.79 +/- 26.01 microgram/l; P = 0.001) sICAM-1 (409.75 +/- 137.78, vs. 228.10 +/- 37.54 microgram/l; P = 0.001), and lower levels of TRF (2.14 +/- 0.40, vs. 2.76 +/- 0.39 g/l; P = 0.001) than controls. After 12-month rhGH replacement the patients showed an increase of TRF (2.64 +/- 0.84 g/l, P = 0.037) and decrease of soluble adhesion molecules (sE-selectin 57.98 +/- 27.04 microgram/l, P = 0.01, sP-selectin 121.74 +/- 50.42 microgram/l, P = 0.007; and sICAM-1 279.95 +/- 88.32 microgram/l, P = 0.005), which then, similarly to the ORM (0. 67 +/- 0.12 g/l) and FBG level (2.82 +/- 0.51 g/l), did not statistically differ from the values in the control group. CONCLUSION: rhGH replacement led to modulation of the 'inflammatory response' in panhypopituitary patients. This modulation occurred locally at vascular endothelium level where after rhGH replacement, sE-selectin, sP-selectin and sICAM-1 concentrations decreased, a similar effect as in the systemic inflammatory response, as was also apparent from the changes in acute phase response protein levels.

Adult↗
PubMed2000

Late complications and quality of life after atrial correction of transposition of the great arteries in 12 to 18 year follow-up.

BACKGROUND: Most adolescents and young adults born with transposition of the great arteries and survivors of Mustard operation are alive today and are leading ordinary lives. How far is the quality of their life influenced by residual findings? METHODS: We have analysed the oldest group of 177 children operated on with the Mustard procedure during 1979-1984 from our total experience of 609 corrections of transposition of the great arteries until 1996. In the long-term follow-up 12 to 18 years after Mustard operation the clinical investigation, 24 hours ECG Holter monitoring, 2D and colour flow Doppler echocardiography, radionuclide angiocardiography and exercise testing were performed. RESULTS: Basic sinus rhythm had 61% of 137 survivors, sinus node dysfunction had 51%. All but 4 patients needed no antiarrhythmic therapy. There were 10 sudden deaths. Severe tricuspid valve regurgitation developed in 15.9% of children, and decreased to 6% after intensive medical treatment. The right ventricular systolic dysfunction was found on radionuclide ventriculography in 8% of children after surgery. The left ventricular ejection fraction was subnormal in 10% and left ventricular diastolic function expressed by rapid filling fraction was subnormal in 80% of patients and may cause inability to increase cardiac output at exercise The obstruction of caval veins was found in 9%. There were neurological complications in 13.3% (10% already preoperatively) but severe brain damage was found in 4.4% only. CONCLUSIONS: Exercise tolerance with the maximum oxygen consumption over 30 ml/kg/min in 96% of investigated children suggests the good ability and full efficiency for recreation sports. Most survivors (84%) are reported to lead ordinary lives and function in NYHA class I.

Adolescent↗
PubMed2000

[Removal of inital cataract in high degenerative myopia--selection of surgical technique and planned refractive effect].

Visual function deteriorates additionally in high degenerative myopia in consequence of initial cataract causing increase of refractive index and refractive error. This paper presents indications for removal of initial cataract with posterior chamber lens implantation to improve visual acuity, colour perception, contrast sensitivity and to broaden visual field. Particular conditions of cataract surgery in myopic eye, selection criteria of operative technique and anaesthesia, power and diameter of implant and possible postoperative complications are discussed.

Anesthesia↗
PubMed2000

Cluster buckling as a result of compression-bending balance in lipid bilayer.

A new approach supporting the possibility of cluster buckling during the main phase transition in the lipid bilayer is presented. The elastic energy is calculated via harmonic approximation which yields the potential minimum in the case of buckling cluster, if critical cluster size is achieved. The significance of this event for interbilayer interaction in multilamellar vesicles is discussed.

Elasticity↗
PubMed2000

[The sleep apnea syndrome in hypophyseal disorders with the exception of acromegaly].

The aim of the study was to ascertain the occurrence of the sleep apnoea syndrome (SAS) in patients after pituitary afunctional adenoma operation or in patients with other affection in sella turcica region except acromegaly patients. Eighty-one patients were addressed. Sixteen patients (eight men, eight women) underwent the examination; the rest of them had no interest to be explored. Afunctional pituitary adenoma was diagnosed in twelve patients, afunctional pituitary adenoma and subsequently optic glioma in one patient, craniopharyngioma in one patient, prolactinoma in one patient and undifferentiated cystic pituitary tumour in one patient. Neurological examination was done in all patients (standardized sleep questionnaire was included). SAS was quantified using PolyMESAM. Severity of SAS were set up from the value of M index (M = ODI.delta saturation; ODI--oxygen desaturation index). Mild SAS: 40 < M < 100; middle SAS: 100 < M < 210; severe SAS: M > 210. SAS was diagnosed in 13 patients: mild SAS in three of them (average value of M index: 81.0 +/- 12.7), moderate SAS in seven patients (average value of M index: 129.0 +/- 18.7) and severe SAS in three patients (average value of M index: 790.0 +/- 563.0). Therapy by continuous positive airway pressure (CPAP) was recommended in six patients. Five of them continue in using of CPAP--four patients with good compliance. The occurrence of SAS was 16.05% in measured group, higher than in normal population.

Acromegaly↗
PubMed1999

Regression of acromegalic left ventricular hypertrophy after lanreotide (a slow-release somatostatin analog).

A group of 13 acromegalic patients was treated with lanreotide for 18 months and followed-up echocardiographically; these patients showed significant correlations between the decrease of both growth hormone (GH) and insulin-like growth factor-1 and the decrease of left ventricular mass index. This documents a regression of left ventricular hypertrophy in acromegaly after lanreotide treatment, the degree of which is dependent on the magnitude of the decrease of GH and insulin-like growth factor-1 serum levels.

Acromegaly↗
PubMed1999

Retinal oligodendroglioma.

PURPOSE: To report a case of oligodendroglioma originating from the accessory glia of retina. METHOD: Case report of a 72-year-old woman with a tumor in the temporal fundus of the right eye that was suspected to be choroidal melanoma. Enucleation was declined, but 5 years later, because of tumor growth, pain, and loss of light perception, the globe was enucleated. RESULTS: Histopathologic examination disclosed a neuroepithelial tumor with a structure of oligodendroglioma. Melanoma and metastatic tumor were excluded. CONCLUSIONS: Oligodendrogliomas are rare in the retina but may originate from retinal oligodendrocytes. This case suggests that the differential diagnosis of choroidal melanoma should include the possibility of oligodendroglioma.

Aged↗
PubMed1999

Crystallization and preliminary X-ray diffraction analysis of haloalkane dehalogenase LinB from Sphingomonas paucimobilis UT26.

Haloalkane hydrolytic dehalogenase LinB from Sphingomonas paucimobilis UT26, an enzyme which releases chloride or bromide anion from n-halogenated alkanes and has a broad range of substrate specificity, was crystallized using the hanging-drop vapour-diffusion method at 278 K. The best crystals were obtained by microseeding with a precipitant containing 18-20%(w/v) PEG 6000, 0.2 M calcium acetate and 0.1 M Tris-HCl pH 8.9. The crystals diffract to at least 1.60 A using synchrotron X-ray under cryogenic (100 K) conditions. They belong to the orthorhombic space group P21212 with unit-cell parameters a = 50.29, b = 71.70, c = 72.73 A. The asymmetric unit contains one molecule of the enzyme.

Crystallization↗
PubMed1999

[Sleep apnea syndrome in acromegaly. Treatment and development-- retrospective analysis].

In total 56 subjects with acromegaly (37 men and 19 females) were examined in attempt to find sleep apnoea syndrome (SAS). The examination consisted of clinical examination and of all-night monitoring MESAM4 or polyMESAM. The diagnosis of SAS was established in 76.4% of subjects: 31 men and 11 females, average age 51.8 (SD +/- 9.6) years. The average ODI (oxygen desaturation index--number of oxygen saturation drops per 1 hour of sleep) of SAS patients was 29.2 (+/- 20.7). The therapy of SAS was recommended to 27 patients: sleeping position on the side (3 patients), reduction of the weight (8 patients), change of hypnotic drug (1 patient) and CPAP--continuous positive airway pressure (24 patients). CPAP titration was performed in 18 patients (in one subject the titration was repeated 4 years later). CPAP was titrated within all-night polysomnography in 10 subjects and in 9 subjects using self adjusting CPAP. Primary acceptance of CPAP was 94.4%. The average CPAP pressure was 7.8 (+/- 2.1) mbar. The theoretical duration of CPAP use was 546.6 (+/- 533.7) days. Long term compliance was considered as sufficient (weekly 25 hours or more) in 66.7% of patients. Ten patients underwent important acromegaly therapy or its change during the follow up and the improvement or the disappearance of SAS symptoms occurred in 6 of them.

Acromegaly↗