Biomedical subjects

V Svoboda

Publications and source records attributed to V Svoboda.

At least 19 recordsLinked to original sources

PubMed2002

[Recurrent dislocation of the patella--arthroscopic therapy].

PURPOSE OF THE STUDY: The authors present results of the surgical treatment of the recurring patella dislocation. They use the surgical technique of medial percutaneous raphe by absorbable PDS suture and lateral release with arthroscopis assistance. MATERIAL: The operation was performed for recurring dislocation in 19 cases in 16 patients. Three patients underwent a surgery on both knees. The average age of patients was 22 years (range, 14-29 years). The average period after the surgery was 22 months (range, 12-45 months). Minimal number of dislocations prior to operation was 3, maximal more than 20. METHOD: The surgical technique consists in medial raphe by percutaneously inserted absorbable PDS suture with arthroscopic assistance and in performing a lateral release in the "closed manner" under the check of the arthroscope. After-care consists in the application of a rigid orthesis which is starting from the first postoperative day removed for physiotherapy by CPM. After two weeks a hinged orthesis is used with a gradual increase of the range of motion. After 6 weeks the patient starts full weightbearing without any fixation. The authors evaluated the results of the operation after Bentley. They also followed the duration of turniquet of the operated on limb, the duration of hospitalization and the period necessary for the achievement of the full range of motion. Radiograph was used for the determination of the shape of patella after Baumgartl and Wiberg, the angle of the femoral sulcus, the height of patella after the Insall-Salvati index and lateral shift of patella. Arthroscopic examination focused on the evaluation of the patellar and femoral chondromalacy and its classification after Outerbridge. Clinically, Q angle was measured, the axis of the limb, anxiosity test was made and the presence of crepitation was checked. RESULTS: Ninety per cent of the patients evaluated the condition after the surgery as very good or good, twice as poor. In one patient there occurred one recurrence of dislocation after the surgery. In the second patient after the surgery pain aggravated in connection with a severe degenerative damage of the femoropatellar joint. Neither avascular necrosis of the patella nor any more extensive bleeding was encountered. There was no infectious complication in the group of patients. Chondral lesion was recorded in 80% of patients. The degree of the damage increased with the number of dislocations. A frequent complication was a recurring knee effusion with the necessity of its evacuation. The relation between the number of dislocations and the final outcome of the surgery was proved. No patient with the number of dislocations 10 and more was evaluated as excellent. DISCUSSION: AS release and medial raphe is a surgical technique which brings very good and good results in a high number of patients. Independently performed raphe or release do not have comparable good results in the therapy of recurring dislocation. The authors' results do not differ from data in specialised literature. CONCLUSION: Arthroscopically performed lateral release and medial raphe by percutaneously inserted suture and with AS assistance has a number of unquestionable benefits. The performance is associated with only minimum complications. It reduces the duration of hospitalization, immobilization of the limb, duration of physiotherapy as well as the total duration of the incapacity to work. The cosmetic result is good. It is possible to operate on also on young patients prior to the final ossification in the area of the tibial tubercle. A prerequisite of a good result is an accurate performance of the operation and subsequent physical therapy. Contraindications include marked degenerative changes in the femoropatellar joint, instability of the knee, patella dislocation in TKR. Q angle exceeding 30 degrees and valgus deformity of the limb exceeding 15 degrees. A high number of dislocations and the resulting more severe damage to the cartilage reduce the potential for achieving excellent results.

Adolescent↗

PubMed2001

Comparison of methods employing gas chromatography retention data to determine vapour pressures at 298 K.

Validity of five models suggested for expressing the relationship between vapour pressures and GC retention times measured on a non-polar capillary column were tested on a common set of compounds [five homologous series of the type H-(CH2)n-Y, where Y denotes Cl, Br, CHO, OCOCH3 and COOCH3, and n varies from 6 to 14]. Standard methods of statistical analysis, as well as vapour pressure values obtained independently from direct vapour pressure measurements were used as validity criteria. For the 40-compound data set examined, the methods provided vapour pressures agreeing within 9.2-24.7% (average absolute percent error) with direct experimental data.

Air Pressure↗

PubMed2001

Quantification of late complications after radiation therapy.

BACKGROUND: An increasing number of patients survive cancer after having received radiation therapy. Therefore, the occurrence of late normal tissue complications among long-term survivors is of particular concern. METHODS: Sixty-three patients treated by radical surgery and irradiation for rectal carcinoma were subjected to an unconventional sandwich therapy. Preoperative irradiation was given in four fractions of 5 Gy each applied within 2 or 3 days; postoperative irradiation consisted mostly of 15 x 2 Gy (range, 20-40 Gy). A considerable proportion of these patients developed severe late complications (Radiother Oncol 53 (1999) 177). The data allowed a detailed analysis of complication kinetics, leading to a new model which was tested using data from the literature. RESULTS: Data on late complications were obtained for eight different organs with a follow-up of up to 10 years. For the various organs, the percentage of patients being free from late complications, plotted as a function of time after start of radiation therapy, was adequately described by exponential regression. From the fit, the parameter p(a) was obtained, which is the percentage of patients at risk in a given year of developing a complication in a given organ during that year. The rate p(a) remained about constant with time. Following sandwich therapy, the annual incidence of complications in the bladder, ileum, lymphatic and soft tissue, and ureters was about the same (p(a)=10-14%/year), whereas complications in bone or dermis occurred at lower rates (4.7 or 7.5%/year, respectively). DISCUSSION: Numerous data sets collected from published reports were analyzed in the same way. Many of the data sets studied were from patients in a series where there was a high incidence of late effects. Three types of kinetics for the occurrence of late effects after radiotherapy were identified: Type 1, purely exponential kinetics; Type 2, exponential kinetics, the slope of which decreased exponentially with time; Type 3, curves composed of two components, a fast initial decline followed by an exponential decrease. For each kind of kinetics, provided that the dose distribution is not too heterogeneous, the incidence of late effects appears to occur at exponential or approximately exponential kinetics, even many years after treatment. This implies that a random process might be involved in the occurrence of late radiation sequelae. CONCLUSIONS: There might be a lifelong risk of developing late complications, of which patients and clinicians should be aware. It appears worthwhile to try to identify, in follow-up examinations of patients after radiation therapy, what kind of processes might be involved in triggering subclinical residual injury to develop into a clinically manifest late effect.

Adenocarcinoma↗

PubMed1999

Late complications after a combined pre and postoperative (sandwich) radiotherapy for rectal cancer.

BACKGROUND AND PURPOSE: The purpose of this study was to analyse the treatment related side effects, the outcome and the prognostic significance of clinical parameters in two groups of patients with rectal cancer receiving either preoperative or pre and postoperative radiotherapy after radical resection. The authors of this study were not involved in the radiation treatments. PATIENTS AND METHODS: From 1986 to 1990, 63 patients received a combined pre and postoperative (sandwich) radiotherapy. Preoperative irradiation was given in four fractions of 5 Gy each applied within 2 or 3 days. Postoperative irradiation consisted mostly of 15 x 2 Gy (31 patients) but the range was 20-40 Gy. The results were compared with those on 73 patients who only received preoperative radiotherapy in the same time period. The distribution of prognostic factors was not very different between treatment groups. Out of 63 patients in the sandwich group, 22 received concurrent chemotherapy and 18 also received radiotherapy to the liver. Radical surgery usually followed on the day after the last preoperative radiotherapy session. Median follow-up of survivors was 6 years. RESULTS: Local tumour control was 88% after 5 years and 84% after 8 years in the sandwich group, and 90 and 85%, respectively, in the preoperative radiotherapy group. Thus, tumour control was similar for the two radiotherapy regimens applied. However, the percentage of patients suffering from one or more complications after 5 years was 84% in the sandwich and 17% in the preoperative radiotherapy group. The incidence of severe late complications (grade > or = 3) was recorded as a function of time after start of treatment. In the sandwich group the actuarial rates of late complications at 5 years (and the median time to diagnosis) were 53% (27 months) for anorectum, 43% (37 months) for bladder, 28% (51 months) for bone, 19% (36 months) for dermis, 47% (48 months) for ileum, 41% (32 months) for lymphatic and soft tissue, and 44% (53 months) for ureters. CONCLUSIONS: Severe late reactions did not occur within a certain period of time, but continued to appear for at least 10 years after radiotherapy. Sandwich therapy, as given in this series, did not appear to give a greater tumour control than preoperative radiotherapy alone, whereas the rate of complications was drastically enhanced. Thus, the rationale of a sandwich therapy with a long time interval between surgery and postoperative irradiation appears questionable.

Actuarial Analysis↗

PubMed1997

Reduction of subacute lethal radiotoxicity of polonium-210 in rats by chelating agents.

The protective effect of N,N'-di(2-hydroxyethyl)ethylene-diamine-N,N'-biscarbodithioate (HOEtTTC) against the subacute lethal radiotoxicity of polonium-210 was investigated in a survival study and by histopathological and haematological examinations of some organs and tissues in Sprague-Dawley rats. This effect was compared with that of N,N'-diethylamine-N-carbodithioate (diethy dithiocarbamate, DDTC). In the survival study, rats injected in intravenously solely with a lethal amount of 210Po (1.45 MBq kg-1 body mass) died within 14-44 days while 90% of rats treated with HOEtTTC survived for 5 months until sacrificed. When treated with DDTC all rats died within 36-93 days. In the histopathological examination, relevant changes resulting from incorporation of 210Po were found in lymph nodes, thymus and humeral bone marrow. After the treatment with HOEtTTC no pathological changes were observed. In the haematological examination, severe reduction in blood and femoral bone marrow (BM) cell counts was revealed in rats injected with 210Po. This reduction was reversed by treatment with HOEtTTC. Treatment with DDTC led only to partial recovery of blood and BM cell count. In conclusion, under the conditions of the experiment only HOEtTTC was fully effective in reducing subacute lethal radiotoxicity of 210Po.

Animals↗

PubMed1995

The EORTC randomized trial on three fractions per day and misonidazole (trial no. 22811) in advanced head and neck cancer: long-term results and side effects.

From 1981 to 1984, a randomized study was done by the EORTC Radiotherapy Group comparing a fractionation schedule with three fractions per day (multiple fractions per day, MFD), with or without misonidazole, to conventional fractionation. The aim of the study was to obtain improved local and regional control and survival by shortening of the treatment time in the first 2 weeks of irradiation. Three fractions of 1.6 Gy/day (4-h interval) were given during 10 irradiation days to a total of 48 Gy. After 3-4-weeks interval, a boost was given to 67.2 or 72 Gy also in three fractions per day. This schedule was compared to an identical arm with misonidazole 1 g/m2/day and a third arm with conventional fractionation (70 Gy in 35 fractions, 7 weeks or 75 Gy in 44 fractions, 9 weeks). A total number of 523 patients was included in the study. Acute mucositis was much heavier in patients treated with three fractions per day (Van den Bogaert et al. Int. J. Radiat. Oncol. Biol. Phys. 8: 1649-1655, 1982). Early results, communicated in 1986 (Van den Bogaert et al. Int. J. Radiat. Oncol. Biol. Phys. 12: 587-591, 1986) showed no differences in treatment outcome between the three treatment arms. Long-term results and data on late effects are now available. Survival at 5 years was 18% (SE 1.9%) and locoregional control was 27% (SE 2.9%). No statistically significant differences could be observed between the three treatment arms.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗

PubMed1995

The EORTC randomized trial on three fractions per day and misonidazole in advanced head and neck cancer: prognostic factors.

In trial no. 22811 on a randomized comparison of multiple fractions per day (MFD), with or without misonidazole, to conventional fractionation in advanced head and neck cancer, a large number (523) of patients was entered in a short period of time. No differences in treatment results were obtained, but the study created an important database, allowing for detailed evaluation of the most important factors influencing prognosis. In univariate analysis, factors significantly influencing survival and locoregional control were: performance status, histological differentiation, tumor site, tumor and nodal staging, and tumoral and nodal volume. In multivariate analysis, significant factors for survival were nodal involvement, tumor stage, performance status, and tumor site. Significant factors for locoregional control were nodal involvement and total tumor burden. This analysis suggests that total tumor burden (volume) should be included in the interpretation of treatment results in head and neck cancer.

Combined Modality Therapy↗

PubMed1991

The effect of high energy electron irradiation on blood-brain barrier permeability to haloperidol and stobadin in rats.

The heads of rats were irradiated by 4 MeV electrons in doses 90, 180, and 360 Gy. The observed times of deaths ranged 120-600, 60-420, and 150-370 min after 90, 180, and 360 Gy, respectively. A dose dependent decrease of the brain uptake index of haloperidol was observed 1 and 3 h post radiation. On the other hand an increased brain uptake index was found for stobadin after head irradiation with doses of 180 and 360 Gy. Regional cerebral blood flow, blood pressure, and heart rate were not significantly altered in the period following irradiation with 180 Gy. The observed changes in blood-brain barrier (BBB) permeability seem to be the result of the damaged function of morphological structures forming the BBB rather than altered regional blood flow.

Animals↗

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

[The gastrointestinal post-irradiation syndrome].

In the recent years, more attention is paid by radiobiologists to both prevention and therapy of a relatively less studied gastrointestinal postirradiation syndrome (GPS). Moreover, the increase in interest in GPS is motivated with the requirement as to obtain the decrease in action of ionizing radiation on the intestinal mucosa at making radiotherapy of abdominal or pelvic region. The GPS occurs consequently to the affected abdominal region or all the organism with ionizing radiation. Its approximal doses from 10 to 100 Gy (gamma) are critical for the survival of intestinal mucosa, especially that of jejunum and ileum. Under the threshold of a single and total dose from 6 to 10 Gy, the intestinal mucosa may usually regenerate, and the survival depends mainly on the preservation or restoration of hemopoietic activity of blood forming tissues. The main pathogenetic GPS factor resides in the afflication of stem cells of mucosal crypts. The intestinal epithelium stops to be fluently replaced after the irradiation. The motion arrests of epithelial cells from crypts to the apex of villi. The elderly cells undergoes degradation, and after several days the denudation of mucosa occurs with possible distortion of deeper layers of intestinal wall. The intestinal microflora is involved in the pathogenesis both directly and indirectly. Amongst the former events is ranged the invasion of distorted mucosa in compromised both local and systemic immunity. Indirectly, the intestinal microflora is GPS associated by stimulating mitotic activity in crypts, therefore more cells are in the radiosensitive phase. In germ-free animals there is a significant decrease in mitotic activity of crypts, and the migration time of epithelial cells from crypts to the apex villi is twice more prolongated, what induces possible restoration of active center after the irradiation. The GPS also results in disorder of metabolic processes which are conditioned with intestinal mucosa. Its typical manifestation resides in the wash-out of mucus, decreased resorption of nutrients and loss of water and minerals into the intestinal lumen. The GPS-related are another disorders of the organism, those of liver and kidney apparently induced due to the intoxication with catabolic products. The microflora has been stated to be involved in GPS by the experiments on germ-free animals. In the absence of microflora, the survival is greater in duration. After a total pigs irradiation with 10-30 Gy, more than two times survival prolongation occurs. The abdominal irradiation with 12 Gy results to the death of only conventional pigs, whereas those germ-free show a survival.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1991

Morphological study of the effect of abdominal compression on acute intestinal radiation syndrome. I. Local irradiation with 14 Gy.

The effect of abdominal compression on acute intestinal radiation syndrome in rats was studied morphologically using light microscopic and histochemical methods. It was confirmed that the method of abdominal compression introduced by Svoboda et al. does not induce either acute or later changes (until 11 months) of the structure of abdominal cavity organs. The structure of intestinal mucosa of rats exposed to local irradiation of the abdomen with 14 Gy of gamma radiation from a Co60 source with or without abdominal compression was quite different with respect to acute changes. Ischemia of the intestine wall protects stem cells of intestine epithelium and subsequently allows a rapid and pronounced regeneration of radiation injury.

Abdomen↗

PubMed1991

Morphological study of the effect of abdominal compression on acute intestinal radiation syndrome. II. Local irradiation with 30 Gy.

The radioprotective effect of abdominal compression introduced by Svoboda et al. on rats exposed to local irradiation of the abdomen with 30 Gy was studied using light microscopic and histochemical methods. Irradiation combined with abdominal compression does not lead to the development of typical radiation alterations of intestinal mucosa. The protected animals retained normal structure of intestinal and colon mucosa, and unchanged epithelium with typical enzymatic equipment. Local differences in protective effect may be due to various degree of ischemization of intestinal tract.

Abdomen↗

PubMed1990

Irradiation of the head by 60Co opens the blood-brain barrier for drugs in rats.

The passage of 6 model drugs; acetylsalicylic acid, chloramphenicol, ethimizol, carbisocaine, heptacaine, and diazepam, through the blood-brain barrier, was determined in unirradiated control rats and in animals 1, 3, and 7 days after irradiation of the head only with a dose of 25 Gy from a 60Co source. The brain uptake index (BUI), which compares the uptake of the test substance with that of 3H2O 5 s after their injection into the common carotid artery, was significantly increased in comparison with unirradiated controls 7 days after irradiation, for all substances tested except for ethimizol. For acetylsalicylic acid and chloramphenicol it was also significantly increased in the other time intervals. The less lipophilic substances showed a greater relative increase of BUI than the more lipophilic ones.

Animals↗

PubMed1990

Effect of gamma-irradiation on disposition of the local anaesthetic, carbisocaine in rabbits.

14C Labelled carbisocaine, a local anaesthetic agent, has been administered intravenously in a dose of 2 mg kg-1 to rabbits 7 days after whole-body 60Co gamma-irradiation with a dose of 5 Gy (1.9 Gy min-1) and to control rabbits. The plasma carbisocaine concentration-time courses were approximated by biexponential equations. The estimated pharmacokinetic parameters obtained when the data were fitted to an open two-compartment model were significantly different for the irradiated group relative to control animals, indicating a radiation-induced slower elimination rate of carbisocaine: AUC: 0.37 vs 0.29% dose min mL-1, CLtot: 109.8 vs 155.4 mL min-1, Vdss: 27.6 vs 33.2 mL kg-1, kel: 0.0259 vs 0.0307 min-1, MRT: 251.7 vs 214.6 min. The total excreted amount of 14C radioactivity in the irradiated group was lower in comparison with controls: 6.5 vs 8.7% in bile and 18.3 vs 23.7% in urine. However, lower carbisocaine concentrations were recorded in the heart, lungs, liver, and kidneys of irradiated rabbits compared with controls.

Anesthetics, Local↗

PubMed1990

Postirradiation changes in small intestine mucosa of piglets selectively decontaminated by peroral antibiotics.

There was performed light microscopic and morphometric comparison of changes in the intestinal mucosa structure after the irradiation of the lower part of body by radiation 60Co in a dose of 12 Gy, observed the third day after irradiation in piglets kept under conventional conditions and the fifth, the fifteenth and the twentieth days after irradiation in piglets kept under the conditions of selective decontamination by peroral antibiotics. The non-irradiated animals kept conventionally as well as under the conditions of decontamination served as controls. The estimation was performed on transverse slices of the cranial part of jejunum and of the caudal part of ileum. The slices were stained by the method hematoxylin-eosin. The drawings prepared with the help of the projective microscope Pictoval were used for measuring on the apparatus for the quantitative analysis of image MOP AM 03. A markedly lower damage of the intestinal mucosa was evidenced in piglets selectively decontaminated by peroral antibiotics. In the studied time intervals after irradiation in a dose of 12 Gy, the epithelial cover of mucosa, the crypt epithelium and the general outline of mucosa are much better maintained. The favourable effect of the selective decontamination on the maintenance and regeneration of the mucosa of jejunum and ileum is confirmed by a range of morphometric parameters.

Administration, Oral↗

PubMed1990

[The role of the whole-body stereotaxic apparatus in directed interventions in humans].

All-body aiming apparatuses in conjunction with computed tomography are a new promise in the diagnostic and therapeutic complex. They make it possible to reach any point inside the body from any point on its surface. The space where the target is found is operated by the arms of the apparatus in three planes normal to each other and by rotating two angles round the longitudinal and transverse axis. Guiding of the apparatus on the target is controlled by the computer programme. Immobilization of the patient is achieved by a vacuum cushion. The apparatus was tested under model conditions and is ready for clinical use.

Brain↗

PubMed1990

Hemoblastoses in mice contaminated with low activities of 239Pu.

Female ICR mice were injected intravenously with low activities of 239Pu (3.0 kBq, 6.0 kBq, 12.3 kBq/kg). In these mice with high spontaneous incidence of hemoblastoses the occurrence of myeloid leukemia, lymphocytic leukemia, lymphosarcoma, reticulum-cell sarcomas and osteosarcoma was studied. Hemoblastoses, on the whole, remained in their numbers radiation-independent, nevertheless, the distribution into specific types changed, with moderate prevalence of myeloid and lymphocytic leukemia and lymphosarcoma. After plutonium injection the mean survival time of mice bearing myeloid and lymphocytic neoplasias was significantly shorter than the survival of mice that died of retothelosarcoma and from other causes. These contamination-dependent differences could not be observed in matched controls. As expected, 239Pu activities used in this experiment induced osteosarcomas. Whereas in leukemogenesis alpha-radiation appeared as a factor promoting and modifying the leukemogenic process, in osteosarcoma the alpha-particles acted rather as an initiator, the effect of which was dependent on the dose to the endosteal progenitor cells.

Animals↗

PubMed1990

Position of whole body stereotactic device among targeted interventions into human organism.

An universal targeting device coupled with computerized tomography is a new promise in the complex of diagnostics and therapy. It allows any point inside the human body to be reached from any spot on its surface. The space containing the target is controlled by moving the arms of the device on three mutually perpendicular planes and by turning at two angles around the longitudinal and transversal axes. The targeting is controlled by computer. The patient is immobilized on a vacuum mattress. This device was tested in model conditions and is now ready for clinical application.

Algorithms↗