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Biomedical subjects

M Dvorak

Publications and source records attributed to M Dvorak.

At least 19 recordsLinked to original sources
PubMed2005

Transcription factor c-Myb is involved in the regulation of the epithelial-mesenchymal transition in the avian neural crest.

Multipotential neural crest cells (NCCs) originate by an epithelial-mesenchymal transition (EMT) during vertebrate embryogenesis. We show for the first time that the key hematopoietic factor c-Myb is synthesized in early chick embryos including the neural tissue and participates in the regulation of the trunk NCCs. A reduction of endogenous c-Myb protein both in tissue explants in vitro and in embryos in ovo, prevented the formation of migratory NCCs. A moderate over-expression of c-myb in naive intermediate neural plates triggered the EMT and NCC migration probably through cooperation with BMP4 signaling because (i) BMP4 activated c-myb expression, (ii) elevated c-Myb caused accumulation of transcripts of the BMP4 target genes msx1 and slug, and (iii) the reduction of c-Myb prevented the BMP4-induced formation of NCCs. The data show that in chicken embryos, the c-myb gene is expressed prior to the onset of hematopoiesis and participates in the formation and migration of the trunk neural crest.

Animals↗
PubMed2005

20-year experience with operations for popliteal artery aneurysm.

At the 2nd Department of Surgery, St. Anne's University hospital Brno, a total of 76 operations for popliteal artery aneurysm were performed in 67 patients in the last 20 years, in period 1985-2004. 63 operations were elective and 13 urgent. For reconstruction, autologous saphenous vein was used in 53 cases, vascular prosthesis in 15 cases, and a cryopreserved vein allograft in 3 cases. In 5 cases, amputation for advanced lower limb ischaemia was performed without arterial reconstruction. Elective operation is indicated in all patients with popliteal artery aneurysm, and it is associated with a relatively low risk for the patient. In fact, it is a preventive operation. In the acute stage, there is a higher risk of complications and (potential) amputation (Fig. 1, Ref. 8).

Abortion, Legal↗
PubMed2004

20-year experience in operations for subclavian steal syndrome.

The aim of this article is to summarize our experience in operations for subclavian steal syndrome. We recommend anaesthesia with preservation of patient's consciousness and mobility, and we prefer transposition of arteries to prosthesis implantation. The main characteristic of this approaches is an attempt to increase safety of operation. A feasible procedure is suggested also in the case of reconstruction occlusion: the axillo-axillary bypass. (Fig. 6, Ref. 3.)

Female↗
PubMed2003

Histamine induced responses are attenuated by a cannabinoid receptor agonist in human skin.

OBJECTIVE AND DESIGN: In the present study we examined the effects of the cannabinoid receptor agonist HU210 on histamine-evoked somatosensory and vascular responses in humans. SUBJECTS: Two sets of experiments were performed, in which twelve (Study 1, iontophoresis) and six participants (Study 2, microdialysis) were recruited. TREATMENT: HU210 was administered peripherally by skin patch (50 mM) or dermal microdialysis (5 mM), whereas histamine was applied by iontophoresis (50 microAmps) or dermal microdialysis (5 microM). METHODS: Skin blood flow was monitored by laser Doppler, widespread flare reaction was evaluated planimetrically, extravasation of plasma proteins was measured in the dialysate and perceived itch was recorded using a visual analogue scale. Data were evaluated by analysis of variance. RESULTS: Experimentally induced itch was significantly reduced by peripheral administration of HU210 (p < 0.05). Additionally, skin blood flow and neurogenic mediated flare responses were attenuated (p < 0.003 and p < 0.03, respectively), whereas protein extravasation due to histamine was enhanced by co-administration of HU210, as investigated by dermal microdialysis. CONCLUSIONS: In humans peripheral administration of a cannabinoid receptor agonist attenuates histamine-induced itch. The observation that protein extravasation was not decreased demonstrates that the alleviation of itch is not due to an anti-histaminergic property of HU210. The reduced neurogenic flare reaction indicates an attenuated antidromic nerve fibre activation and neuropeptide release.

Administration, Topical↗
PubMed2003

Patient with percutaneous endoscopic gastrostomy.

INTRODUCTION: Since 1980, when percutaneous endoscopic gastrostomy was described and performed for the first time, the number of patients with this way of nutrition has been growing. At present, however, these patients are treated not only in intensive care units, but also in follow-up care institutions or in home care. AIM: We want to explain the problems of nutrition via endoscopic gastrostomy to those physicians who take long-term care of these patients. METHODS: In our department we introduced percutaneous endoscopic gastrostomy in 1994. A total of 78 PEGs were performed. In all cases the pull technique was used. A condition for percutaneous endoscopic gastrostomy insertion was an unaffected gastrointestinal tract from the stomach in aboral direction. The most frequent indications were: necessity of long-term enteral nutrition in patients during artificial ventilation, neurological patients with lost swallowing reflex, and patients with a tumor in the ENT area with preserved patency for the endoscope. RESULTS: In all cases, the intervention itself was without major complications and no death occurred relating to the intervention. Subsequently, mainly local complications such as decubitus ulcers or maceration around the tube and its accidental removal by a restless patient were noticed. CONCLUSION: In cases of more than 6-week inability to ingest food per os with otherwise unaffected gastrointestinal tract, it is appropriate to consider the nutrition via PEG. Using this method, it is possible to ensure an adequate access for enteral nutrition for a longer time without risk of complications associated with the nasoenteric tube, with minimum trouble to the patient. (Fig. 1, Ref. 9.).

Enteral Nutrition↗
PubMed2003

Results of therapy of lower extremity ischemic disease by angiosurgery and radiointervention (PTA) methods.

The aim of our work is to evaluate the results of therapy of lower extremity ischemic disease (LEID) in patients treated at 2nd Department of Surgery, St. Anne's Teaching Hospital, Brno, in 2000. According to the therapeutic approach, the patients were divided into two groups: 1. reconstructive angiosurgeries (95 patients), 2. PTA (42 interventions in 36 patients). The short-term follow-up (18 months) has given the following results: in the group of surgical interventions--the patency was 87.37%, in the PTA group it was 83.33%. There was a marked difference between the patency of PTA reconstructions in the region of pelvic arteries (100%) and that in the femoropopliteal region (58.83%). We have found out that in the solution of LEID, angiosurgeries and radiointerventions are equivalent methods and that they complement each other. (Tab. 2, Fig. 3, Ref. 10.).

Adult↗
PubMed2001

[Assessment of functional capability of liver parenchyma using indocyanine green before liver resection].

During the period from 1997 to 2000, the total of 129 liver operations were performed at the 2nd Surgical Department of the Masaryk's University in Brno. Malignant tumours were present in 91 cases. In-hospital mortality in patients operated on for malignant liver tumours was 2.1%. No case of death was caused by liver insufficiency. Examination of liver function by use of indocyanine green (ICG) enabling the determination of the extent of possible resection, contributes to the lowering of postoperative morbidity and mortality. The rate of indocyanine green retention up to 6% does not limit the extent of resection, the retention rate up to 15% allows bisegmentectomy or a minor surgery, the retention rate up to 20% allows segmentectomy at the most, and the retention rate up to 30% enables superficial excisions only.

Hepatectomy↗
PubMed2001

Recognition and management of atlanto-occipital dislocation: improving survival from an often fatal condition.

OBJECTIVE: To provide an overview of atlanto-occipital dislocation and associated occipital condyle fracturcs so as to alert physicians to this rare injury and potentially improve patient outcome. The pertinent anatomy, mechanism of injury, clinical and radiologic evaluation and the management of these rare injuries are discussed in an attempt to alert physicians to this type of injury and to improve outcome. DATA SOURCES: The data were obtained from a MEDLINE search of the English literature from 1966 to 1999 and the experience of 4 spine surgeons at a quaternary care acute spinal cord injury unit. STUDY SELECTION: Detailed anatomic and epidemiologically sound radiology studies were identified and analyzed. Only small retrospective studies or case series were available in the literature. DATA EXTRACTION: Valid anatomic, biomechanical and radiologic evaluation was extracted from studies. Clinical data came from limited studies and expert opinion. DATA SYNTHESIS: Early diagnosis is essential and is facilitated by a detailed clinical examination and strict adherence to an imaging algorithm that includes CT and MRI scanning. When the dislocation is identified, timely gentle reduction and prompt stabilization throuigh nonoperative or operative means is found to optimize patient outcome. CONCLUSIONS: Atlanto-occipital dislocation should be suspected in any patient involved in a high speed motor vehicle or pedestrian collision. Once suspected, proper imaging and appropriate management of these once fatal injuries can improve survival and neurologic outcome.

Atlanto-Occipital Joint↗
PubMed2000

Ruptured abdominal aortic aneurysm--outcomes in the last ten years.

Ruptured abdominal aortic aneurysm (AAA) remains to be represent a common and highly lethal problem. We reviewed the records of 92 patients (73 men and 19 women) operated on for ruptured infrarenal AAA within the past 10 years (January 1989 to October 1999) in the 2nd Department of Surgery in Brno, Czech Republic. The mean age was 71 years (range 57 to 92 years). Only 10 patients (10.9%) were known to have an AAA before the rupture. Preoperative systolic blood pressure below 90 mmHg was present in 70 patients (76%) and 15 patients (16.3%) experienced cardiac arrest before surgery. The in-hospital mortality rate was 47.8% (44 patients). Among the total of 92 patients, haemoperitoneum was discovered only in 30 patients (32.6%) with the mortality rate of 40% (12 patients). In 62 patients (67.4%) also hemoperitoneum was present, the mortality rate was 51.6% (32 patients) in these patients. Multiorgan failure due to an irreversible hemorrhagic shock was the main cause of death in 23 patients (25%). Further causes were: heart failure--8 patients (8.7%), pulmonary complications--5 patients (5.4%), renal failure--4 patients (4.3%), bleeding--3 patients (3.3%), and sepsis--1 patient (1.1%). The patient's prognosis depends on early diagnostics and on the quality of peroperative and postoperative care. (Tab. 2, Ref. 8.)

Aged↗
PubMed1998

The influence of surveillance methods on surgical wound infection rates in a tertiary care spinal surgery service.

STUDY DESIGN: A 1-year prospective study of the influence of surveillance methods on the surgical wound infection rates in a tertiary care spinal surgery unit. OBJECTIVES: To assess the effect of postdischarge surveillance, the diagnostic indications for surgery, and the type of procedure on the surgical wound infection rates. SUMMARY OF BACKGROUND DATA: Use of the National Nosocomial Infection Surveillance system for surgical wound infection resulted in infection rates above the published values for procedures performed by the Spinal Surgical Service. A preliminary review failed to find causes for these higher rates, and a study was undertaken to assess the influence of the surveillance methods used. METHODS: Patient information collected by the Spinal Surgical Service and surveillance data obtained by infection control were combined in a relational database. Surveillance after discharge was performed by regularly sending questionnaires to surgeons' offices. The diagnostic indications were assessed by dividing all patients into three groups: Class D (disc disease or spinal stenosis). Class T (spinal trauma within 60 days), and Class M (mostly complex spinal procedures for deformity and instability). Infection rates for the three diagnostic indication classes and for procedures with and without instrumentation were calculated. RESULTS: Postdischarge surveillance significantly increased the infection rates, mostly by detecting superficial infections that did not require readmission. Significant differences were noted between Class T and Class M patients undergoing lumbar posterior segmental instrumentation, despite the fact that they had a similar incidence of risk factors according to the National Nosocomial Infection Surveillance system. The surgical wound infection rates of the National Nosocomial Infection Surveillance system may not be appropriate standards for specialized units with a high incidence of complex clinical problems and complicated surgical procedures. CONCLUSIONS: Postdischarge surveillance, surgical procedure classification methods, and the indications for surgery (e.g., trauma, congenital deformity) influence the surgical wound infection rate. Current adjustments for some of these factors in the National Nosocomial Infection Surveillance system appear to be inadequate when used in a tertiary care facility.

Adolescent↗
PubMed1998

Location of a VIPoma by iodine-123-vasoactive intestinal peptide scintigraphy.

A major problem in patients with small endocrine tumors is the difficulty in localizing the primary tumor site. Many endocrine tumors possess larger amounts of high affinity vasoactive intestinal peptide (VIP) binding sites compared with normal tissue or blood cells. We used radiolabeled VIP to localize the tumor site in a patient with Verner-Morrison syndrome (VMS). Under octreotide therapy, the VIP levels had declined in this patient, but a tumor site could not be detected by conventional techniques or by radiolabeled octreotide. However, using 123I-VIP, the tumor was detectable in the pancreatic tail. Surgical resection of the tumor was followed by complete remission of the VMS. Expression of VIP binding sites in the tumor was confirmed by a radioreceptor assay and showed cross-competition between VIP and octreotide. The identity of the VIP binding site in the tumor was analyzed by Northern blotting and revealed the expression of somatostatin receptor subtype 3, which binds both somatostatin-14 and VIP with higher affinity than octreotide. Iodine-123-VIP scintigraphy would be an effective tracer to identity the tumor site in VMS patients.

Adult↗
PubMed1997

c-Jun involvement in vitamin E succinate induced apoptosis of reticuloendotheliosis virus transformed avian lymphoid cells.

Previous studies have shown that treatment of avian reticuloendotheliosis virus-transformed RECC-UTC4-1 (C4-1) lymphoblastoid cells with 10 microg/ml (18.8 microM) of RRR-alpha-tocopheryl succinate (vitamin E succinate, VES) for 3 days induced approximately 50% of the cells to undergo apoptosis. Elevated and prolonged expression of c-jun mRNA and protein was temporally correlated with VES-induced cell death. Data presented in this paper show that the elevated and prolonged expression of c-jun message and protein are not accounted for by enhanced stability, and show the involvement of c-Jun in VES-induced apoptosis in this lymphoblastoid cell type. C4-1 cells infected with a virus carrying a dominant, negatively acting mutant form of c-Jun, supjun-1, exhibited: (i) 71% reduction in VES-induced apoptosis, (ii) a 2.0-2.5-fold decrease in wildtype, endogenous c-Jun expression, and (iii) a 2.4-2.6-fold reduction in AP-1 binding activity. Additionally, cells co-treated with VES plus RRR-alpha-tocopherol, exhibited a 70% reduction in apoptosis, a marked reduction in c-Jun expression and a 1.6-fold reduction in AP-1 binding activity. These studies suggest that c-Jun plays a crucial role in VES-induced apoptosis in C4-1 cells, and add to our understanding of mechanisms of action involved in VES-mediated tumor cell growth inhibition.

Animals↗
PubMed1996

TGF-beta 1 forms functionally normal bone in a segmental sheep tibial diaphyseal defect.

OBJECTIVE: Transforming growth factor-beta 1 (TGF-beta 1) is a polyfunctional regulatory cytokine that has been shown to have roles in extracellular matrix interactions, soft tissue healing, and osteogenesis. This study was undertaken to determine the efficacy of TGF-beta 1 in the formation of functionally normal bone in tibial-diaphyseal defects. METHOD: Seven hundred fifty micrograms of recombinant human TGF-beta 1 was added to a guanidine-extracted demineralised bone matrix (Gu-DBM) carrier and the implants were used to fill a 2.5 cm tibial diaphyseal defect in skeletally mature female sheep. The defects were allowed to heal over a 12-week period. After sacrifice, they were analyzed using four-point bending mechanical testing. RESULTS: Implants with TGF-beta 1 showed complete bony bridging of the defect and stress-strain curves similar to the normal contralateral limb, while implants with the carrier alone failed to bridge the gap. CONCLUSIONS: These results demonstrate the ability of TGF-beta 1 to induce new bone which has structural and functional characteristics similar to normal bone.

Animals↗
PubMed1995

Ankylosed spines are prone to fracture.

Fracture of an ankylosed spine is often overlooked. Because the force that damages an ankylosed spine is frequently slight, patients do not realize they are injured. Doctors can miss the fracture for the same reason and because patients already have a history of back pain. Plain radiographs sometimes fail to demonstrate the fracture site.

Adult↗
PubMed1993

An anatomic, radiographic, and biomechanical assessment of extrapedicular screw fixation in the thoracic spine.

This study performed a thorough review of the pertinent thoracic spine anatomy to determine the appropriate landmarks for extrapedicular screw placement and indentified the anatomic structures at risk; assessed the safety and accuracy of the newly proposed screw insertion technique; determined the stability and strength of this new screw position through biomechanical testing; and analyzed the stability of this extrapedicular screw location with respect to bone mineral density of the vertebra.

Biomechanical Phenomena↗
PubMed1990

Arthroscopic anatomy of the hip.

The arthroscopic anatomy of the hip has been studied using a number of portals. Both distraction and positioning are necessary to allow insertion of instruments, and to allow exposure of the important anatomical structures. The internal anatomy of the hip joint is described in detail based on the arthroscopic view from the different portals. This study helps orient those interested in arthroscopy of the hip.

Arthroscopy↗
PubMed1989

Supercoil-induced Z-DNA formation within 5'-end of chicken myb proto-oncogene.

We have analyzed the recently sequenced and characterized 2.9 kb fragment derived from the 5'-end of chicken myb proto-oncogene with respect to structural perturbations induced by DNA supercoiling. Within the first intron a 50 bp sequence stretch was localized, starting approximately 450 nucleotides downstream from putative ATG initiation codon, which forms a non-B-DNA structure. Fine mapping with structural probes revealed the three adjacent regions with imperfect purine-pyrimidine alternation creating together relatively long Z-forming tract, parts of which may undergo a B-Z DNA transition at different superhelical densities.

Alkylation↗