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Biomedical subjects

J Malec

Publications and source records attributed to J Malec.

At least 19 recordsLinked to original sources
PubMed2006

[Clinical appearance and outcome of zone 1 retinopathy of prematurity (ROP)].

The goal of this clinical trial was to evaluate outcomes of the treatment of retinopathy of prematurity (ROP) located in zone 1 (Zone 1 ROP). This disease has a specific clinical appearance and poor prognosis. Usually it is difficult to identify particular stages of ROP and to indicate treatment while following progression of the disease. In the group of zone 1 ROP it is necessary to separate transient forms (TF), in which vascularizations reach edges of zone 2, from very posterior forms (VPR), in which vascularizations and pathological changes are present only in zone 1. There were 24 eyes with zone 1 ROP (15 children) treated with combination of transcleral laser photocoagulation and cryotherapy during the years 2000 till 2005 in our series. Five eyes suffered from VPR, 19 eyes from TF. Average follow -up was 24 months. We found better outcomes in eyes with TF treated in pre-threshold stage of ROP (10 eyes) than in threshold stage of ROP (9 eyes). All 5 eyes with VPR developed unfavourable ROP stage IV or V. Zone 1 ROP becomes diagnostic and therapeutic challenge considering growing incidence of surviving of newborns with low or very low birth weight. Treatment initiation during prethreshold stage of ROP as it is supported by ETROP study (Early treatment of ROP) seems to be promising.

Cryotherapy↗
PubMed2005

[Use of ruthenuim 106 in retinoblastoma treatment].

The Charles University Teaching Hospital in Prague - Motol started to treat patients with retinoblastoma by means of brachytherapy after obtaining the permission to use closed source of ionizing radiation in the beginning of the year 2003. The applicator containing ruthenium (106Ru) emitting mostly the beta radiation was chosen. Half-life is 369 days and the nominal activity of the source is 21.1 MBq. The applicator is placed in place for one to several days according to the prominence of the tumor and actual activity of the source. Duration of the application is calculated with a special program. In the year 2003, three patients with retinoblastoma were treated. In one case bilateral involvement was determined, and the brachytherapy was used for treatment of both eyes. The next patient was treated twice; one treatment followed the other with different localization of the applicator because of too large basis of the tumor. In 2003, altogether the brachytherapy was used for treatment of retinoblastoma five times. In all cases, the combined treatment (chemoreduction, teletherapy, transpupillary thermotherapy, or cryotherapy) was performed. One eyeball was enucleated because of severe post-radiation retinopathy, the second one for persisting tractional retinal detachment. In remaining cases no serious complications or progression of the malignancy were observed.

Brachytherapy↗
PubMed2004

[Hemi-hangback recession (retroposition) of extraocular muscles].

In a small clinical study the author evaluates the efficiency of the hemi-hangback recession (retroposition) procedure. This surgical procedure, which weakens extraocular muscles, proceeds from the hangback recession (retroposition) technique (hanging the muscle on a resorbable suture), which combines with the traditional recession. Hemi-hangback recession procedure is suitable in cases when a recession of more than 7 mm is needed. It is experimentally and clinically as well demonstrated in extra large recessions, that a shift towards the original insertion of the muscle occurs. The combination of the classical and hangback recession has its advantages in specific indications. More convenient surgical access and a reduction of the objectionable shift of the muscle backwards are main advantages of this procedure. The surgical procedure is described in this article and results in the group of patients from the Children's and Adult's Department of Ophthalmology at the Faculty Hospital in Motol, Prague, Czech republic. The hemi-hang-back muscles recession is indicated in third and sixth nerve palsies, restrictive forms of strabismus and complicated or successive forms of strabismus.

Adult↗
PubMed2003

[Hang-back retroposition as a variation in oculomotor muscle weakness].

In a clinical study the authors evaluate efficiency of the operation on oculomotoric muscles by the hang-back retroposition method. A total of 70 children have been operated on, 52 of the patients suffering from esotropia and 18 from exotropia. The mean preoperation deviation in esotropia was 30 +/- 12 pdpt, the postoperation deviation was in the range of 6 +/- 7 pdpt. In the exotropia cases the preoperation deviation improved from original 76.9%, in the exotropia group being 77.8%. The overall success rate of the hang-back retroposition in all these patients was 77.1%. Ina group of children operated on by a traditional retroposition there was an overall success rate 78.7% (77.6% in esotropia and 82.4% in exotropia cases). Hang-back retroposition has been equally effective as the traditional retroposition of oculomotoric muscles. Its main advantages include visibility of the operation field, minimum risk of perforation of sclera and a fair time factor of the intervention. The authors discuss the development, indications, further advantages but also possible disadvantages or limitations of this acknowledged surgical procedure in strabology.

Child, Preschool↗
PubMed2002

[New views on aberrant innervation of oculomotor muscles ].

Aberrant innervations of oculomotor muscles are a special group of clinical entities, the common sign of which is an abnormal innervation of the oculomotor muscles with nerve fibres which originally were not meant for this purpose. The majority of these anomalies develops during the embryonic period of lesions at the level of nuclei of cranial nerves or peripheral fibres. Congenital aberrations affect most frequently n. VI, less frequently n. III and rarely n. IV. Acquired affections are most frequent in n. III. Abnormal innervation connections concern not only oculomotor muscles but also muscles engaged in mastication and those of the upper eyelid. Clinically they are manifested as eyelid and facial synkinesias. Among aberrant innervations which lack an uniform terminology belong according to the more recent classification the following clinical units: Duan's syndrome, synergic divergence, double-elevator palsy, misdirection syndrome, Marcus Gunn phenomenon, some forms of congenital fibrous syndrome, trigemino-abducens synkinesia, pseudohyperfunction of the lower oblique muscle, crocodile tears syndrome, and aberrant affection of n. III. The authors describe the course, possible etiology of these anomalies and demonstrate, based on their own observations, clinical cases which can be explained by these mechanisms.

Abducens Nerve↗
PubMed2001

[Treatment of paralysis of cranial nerve VI: evaluation of the Hummelsheim method of transposition surgery of the oculomotor muscles].

The authors evaluated in a retrospective study the results of surgery in 28 patients with paralysis of the VIth cranial nerve. The standard surgical procedure which was selected as primary achieved orhtophoria in 21 patients. In 7 patients with persisting esotropia and diplopia transposition of the oculomotor nerves according to Hummelshein was indicated. After stabilization of the postoperative finding in all patients parallel position of the eyes and a improved compensatory position of the head was found. Markedly restored motility in abduction was observed only in patient. The method of first choice in treatment of paralysis of the sixth nerve but also of other oculomotor nerves are standard surgical procedures. By retro-position and resection of oculomotor muscles usually a satisfactory state in the primary position is achieved. Transposition operations are rather useful as supplementary operations in previously operated eyes. Indications are persisting diplopia and esotropia. Postoperative results as regards the primary position of the eyes are satisfactory but usually marked improvement of the motility cannot be foreseen.

Abducens Nerve Diseases↗
PubMed2001

[Time factors and instrumental treatment of lacrimal duct obstruction in childhood].

The authors evaluate the effectiveness of probing and rinsing of the lacrimal system in a group of 155 infants and young children (300 eyes) with congenital obstruction of the lacrimal pathways. The mean age during the first treatment was 3.7 months--range 21 days to 24 months. Patency of the lacrimal pathways was achieved in 83.49% of the group. In children treated before the 6th month the passage was restored in 91.30%. The effectiveness of procedures declines with advancing age. In the author's opinion it is best to make the operation between the 4th and 6th month of age. The operation under local anaesthesia ensures in the majority of children a rapid and permanent regression of complaints and a relatively small number of required repeated probings. At a later age the effectiveness of probes or rinsing declines and the solution is rather an indication for intubation of the lacrimal pathways or DCRS. One of the main still open questions for discussion is the optimal age for the operation. The author discusses also views of adverseries of probing and the problem of spontaneous canalization of the lacrimal pathways.

Child, Preschool↗
PubMed1998

[Personal experience with non-contact tonometry in children].

In a comparative study of the tonometer Pulsair 2000 (PA) with Goldmann's applanation tonometry (AT) on 240 eyes of children aged 7-18 years the mean value of intraocular pressure (IOP) was 17.09 torr +/- 4.35 SD when using AT and 16.86 torr +/- 4.56 when using PA. Regression analysis revealed a close correlation between the two methods (r = 0.86) with high statistical significance (p < 0.0005). It was found that PA had a tendency to underestimate the IOP at lower levels and overestimate it at levels above 19 torr. Between 13 and 24 torr, however, the difference between AT and PA on average was not greater than 1 torr. The mean scatter of IOP values during individual measurements was 1.25 torr with AT and 1.5 torr with PA, the difference being at the borderline of statistical significance (p = 0.055). A scatter under 2 torr was recorded in 92.1% eyes using AT and 86.7% when using PA, under 3 torr 98.3% and 94.2% eyes respectively. The analysis revealed moreover that the accuracy of assessment in PA is improved by longer experience of the examining physician, while in AT the relationship was not unequivocal. The authors consider assessment of IOP by means of a non-contact portable tonometer Pulsair 2000 comparable with AT and consider PA suitable for use in children.

Adolescent↗
PubMed1998

[The Tono-Pen XL--a tonometer suitable for measurement of common and less common conditions associated with intraocular pressure].

In the introduction the authors describe a portable electronic tonometer Tono-pen XL and explain the principle of its function. After this follows a comparative study with Goldmann's applanation tonometry (AT) on 240 eyes in children aged 7 to 18 years. The mean value of the intraocular pressure (IOP) was 17.09 torr +/- 4.35 SD with AT and 16.46 torr +/- 4.04 SD when using the Tono-pen. Regression analysis revealed a very close correlation between the two methods of assessment (r = 0.925) with a high statistical significance (p < 0.0005). The difference as compared with AT values was constant, on average close to -0.68 torr in the whole range from 7 to 35 torr. The authors found also a significantly greater variability of values obtained by means of the Tono-pen (p = 0.0009), the mean scatter of individual values being 1.55 torr as compared with 1.25 torr in AT. However 97.1% of the eyes were within a range of 3 torr. The authors did not find a significant relationship between assessment by means of the Tono-pen and the doctor's experience. The unique advantage of Tono-pen as compared with all other methods of routine tonometry is the relatively accurate assessment of the IOP under irregular conditions of the cornea. It is also possible to take measurements in children where AT cannot be used.

Adolescent↗
PubMed1993

Current perceptions of rehabilitation professionals towards mild traumatic brain injury.

There has been long-standing controversy in the medical literature and increasing interest within the rehabilitation field in mild traumatic brain injury and postconcussion syndrome. The Head Injury Interdisciplinary Special Interest Group of the American Congress of Rehabilitation Medicine conducted an opinion survey to analyze the perceptions of rehabilitation professionals towards patient's with these problems. The survey initially compared response patterns of rehabilitation personnel to two earlier identical surveys made with a group of neurosurgeons and a group of neuropsychologists. As a group, rehabilitation professionals tend to have perceptions of mild traumatic brain injury that are similar to those of neuropsychologists. The survey also included a group of questions developed to analyze specific issues among rehabilitation professionals related to symptomatology, persistence, and treatment. The most salient findings concluded that rehabilitation providers: (1) want a grading system associated with the term to designate injury severity, symptom severity, and level of functional impairment; (2) most frequently use neuropsychologists in assessment and treatment of these patients; (3) report cognitive deficits as the most common symptom, followed by irritability and somatic complaints; (4) when medications are used, most frequently use antidepressants; (5) typically follow these patients anywhere from six to 18 months postinjury; and (6) report that most patients make a complete functional recovery, though there is a substantial proportion (about 25%) who do not. Implications drawn from the survey include that there is a need to better define the term and its associated features and that there is a substantial group of patients who remain at least partially functionally disabled and present a major challenge to the rehabilitation community.

Attitude of Health Personnel↗
PubMed1991

Comparison of the effect of hydroxyurea and methotrexate on DNA fragmentation at various reaction conditions.

Using the changes in DNA breakage as a marker of DNA damage, the direct action of hydroxyurea (HU) and methotrexate (MTX) on DNA was examined. The experimental design was to expose isolated DNA to HU and MTX alone or HU and MTX with accelerators of free radical reaction (H2O2, Fe..) and to determine DNA fragmentation assessed by electrophoresis. The results indicated that HU can damage DNA, but to demonstrate this ability it needs H2O2, Fe.. or prolonged incubation in solution. Unlike HU, MTX with H2O2 was ineffective; MTX with Fe.. at certain degree protected DNA against lesions induced by Fe.. alone. It is concluded that despite several common features of HU- and MTX-induced toxic side-effects in the cells suggesting interference of these drugs with free radical reactions, their direct effect on DNA under oxidizing conditions is quite different at least at the concentrations used by us.

DNA↗
PubMed1989

Enhancement of methotrexate-induced growth inhibition, cell killing and DNA lesions in cultured L5178Y cells by the reduction of DNA repair efficiency.

Acute treatment of L5178Y cells by methotrexate (MTX) caused concentration-dependent post-treatment growth inhibition and cell killing. The effects were potentiated in the presence of caffeine (CAF). At the same experimental conditions the CAF-dependent increase in mature and newly formed DNA lesions was found. The results suggest that even short MTX treatment can cause DNA lesions which are normally, at least partially, repaired. By the reduction of DNA repair efficiency with CAF, these lesions can be expressed what finds its reflection in the enhancement of MTX cytotoxicity.

Animals↗
PubMed1989

Hydroxyurea-induced toxic side-effects in animals and an attempt at reducing them with vitamins E and C.

Using the changes in several blood parameters and in the histological picture of the liver as markers of toxicity, the effect of hydroxyurea (HU) in healthy rabbits or mice was examined during two weeks after a single administration of this drug. In rabbits a transient significant decrease in blood erythrocyte count with a gradual increase in their osmotic resistance, a suppression of granulocyte phagocytic capacity, and an elevation of acid phosphatase activity in the serum were found. An increase in the proportion of lymphocytes without detectable lysosomes as tested by supravital staining also appeared. No significant difference was observed in the white cell count and lipoperoxide levels after HU administration. Histological picture of the liver, excised from HU-treated mice, indicated a marked hepatotoxicity of the drug. Some of the toxic effects were reduced in animals supplemented with vitamins E and C.

Acid Phosphatase↗
PubMed1988

Millon Clinical Multiaxial Inventory (MCMI) findings among breast clinic patients after initial evaluation and at 4- or 8-month follow-up.

Twenty-seven patients who subsequently underwent benign biopsy and 41 patients diagnosed to have breast cancer completed the Millon Clinical Multiaxial Inventory (MCMI) after initial examination in a breast problem clinic and again after 4 months or, for CA patients who were completing a course of chemo/radio-therapy, after 8 months. At initial testing, the trend toward fewer moderate-severe disorders among the benign biopsy (BB) group did not reach statistical significance. However, at follow-up, the difference was significant; the BB group showed fewer moderate-severe disorders (7.5%) than the cancer (CA) group (29%). Concordance of two-point peak elevations on scales 1-8, S, C, and P was examined. For the BB group, 56% had the same two high points on both testings, compared to only 27% of the CA group. Test-retest correlations on personality scales were generally lower for the CA group than for the BB group. We concluded that (1) approximately 30% of breast CA patients showed a disruption of psychological adjustment clearly severe enough to merit consideration of a mental health referral; (2) despite the frequency of significant distress, major affective and thought disorders were infrequent among this group; (3) distress associated with breast CA may interfere with the reliable assessment of long-standing personality traits.

Adaptation, Psychological↗
PubMed1988

Inhibition of leucocyte migration by cancer chemotherapeutic agents and its prevention by free radical scavengers and thiols.

The exposure of human blood in vitro to a range of concentrations of adriblastine, hydroxyurea, methotrexate, 5-fluorouracil, 6-mercaptopurine, cytosine arabinoside and nitrogen mustard induced reduction in leucocyte migration rate in all drug dilutions under study. The reduction was dose-dependent. This effect was used to examine the protection of alfa tocopherol, acetylosalicylic acid and thiourea against drug-induced cytotoxicity. It has been found that at the suitable concentration of the protecting agent, a preventive effect of tocopherol against toxicity of all drugs, except nitrogen mustard, can be achieved. Acetylosalicylic acid protected the cells against adriblastine, cytosine arabinoside, hydroxyurea and methotrexate toxicity. Thiourea prevented the toxic effect of adriblastine, fluorouracil, hydroxyurea, methotrexate and nitrogen mustard.

Antineoplastic Agents↗
PubMed1987

Protection of L5178Y cells by vitamin E against acute hydroxyurea toxicity does not change the efficiency of ribonucleotide reductase-mediated hydroxyurea-induced cytotoxic events.

Exposure of L5178Y cells in culture to 0.2 mM hydroxyurea (HU) for up to 48 h induces inhibition of DNA synthesis, killing of about 20% of cells during the first 24 h exposure, gradual progress of cells into the state of unbalanced growth (measured as progressive increase in cell size, DNA protein ratio and acid phosphatase activity) with final death of the majority of cells. These effects were used to compare effectiveness of rapid and late HU cytotoxicity in cells treated with HU in the presence or absence of vitamin E, employed as a protective agent against non-specific toxicity of HU. It has been found that while the presence of vitamin E prevents cell killing induced by HU treatment during first 24 h, its presence does not change the progress of cells into the state of unbalanced growth and final cell killing. It is suggested that the protection exerted by vitamin E against HU-induced side toxicity does not change the effectiveness of ribonucleotide reductase-mediated DNA synthesis inhibition, leading to cell death through the state of unbalanced growth.

Animals↗