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Biomedical subjects

M Masek

Publications and source records attributed to M Masek.

16 recordsLinked to original sources
PubMed2006

[Injury of the scapholunate interosseal ligament--scapholunate dissociation].

Scapholunate interosseal ligament tears manifested with pain, a popping, weakness of the wrist, or limited wrist motion, are probably the most frequent cause of carpal instability. Insufficiency of the injured scapholunate ligament results in pathologic scaphoid and lunate position with wrist kinematics changes that cause irreversible degenerative arthrotic changes. The timely diagnosis combined with proper treatment is required for successful therapy and carpal collapse prevention.

Carpal Bones↗
PubMed2006

[Surgical treatment method of calcaneal intraarticular fractures].

Open repositioning and internal fixation of intraarticular calcaneal fractures has become a standard surgical method, however, concerns over its feared complications, including, in particular, secondary wound healing followed by osteomyelitis, continue fo be discussed. The aim of this study is to inform the surgical public about the surgical method. From February 2004 to September 2005, 26 intraarticular calcaneal fractures in 22 patients were operated using open repositioning and internal cast fixation. In four cases, the fracture was bilateral. The patients were indicated for the procedure based on the Sanders CT classification. The procedure included extensive L-shaped lateral approach (Seattle), anaemization, minimization of soft tissue disruption, and was followed by spongioplasty. In isolated dislocated sustentacular fractures, osteosynthesis through a medial approach was completed, using screws. Post-operatively, the extremity was not fixated and early rehabilitation was initiated. In majority of the operated patients, the skin cover healed per primam. In 3 patients, the wound healed per secundam intentionem. Complete fracture healing was x-ray confirmed in all patients. No signs of the osteosynthetic material release or of pronounced signs of subtalar arthrosis or of a foot arch collapse were present. No deep defects or other serious postoperative complications were recorded. The follow-up period lasted for 6-22 months and goes on. The patients followed for over a year period have no symptoms, they fully wightbear the operated extremity and they have returned to their original professions. Open repositioning and internal stable cast fixation is recommended as a standard treatment method in these fractures.

Adult↗
PubMed2005

[Partial denervation of the wrist by excision of the interosseous nerves from the dorsal approach].

PURPOSE OF THE STUDY: The aim of the study was to optimize, on the basis of an anatomical study, the technique of partial denervation of the wrist in terms of safety for preserving motor innervation of the quadrate pronator muscle, and to include this technique in the range of reconstruction operations for the treatment of degenerative carpal diseases. MATERIAL AND METHODS: The technique of partial denervation of the wrist, using excision of the sensitive branches of the dorsal and volar interosseous nerves, carried out by one-stage surgery from the dorsal approach is presented in a group of 28 patients. The partial denervation was always performed in addition to reconstructive surgery on the proximal carpals and the distal radioulnar joint. On the basis of an anatomical study involving 40 cadaverous upper extremities, the authors determined the location for resection of the sensitive branch of the volar interosseous nerve that is not associated with the risk of damaged motor innervation of the quadrate pronator muscle. RESULTS: A reliable identification of the motor branches of the volar interosseous nerve was achieved when an approximately 2-cm incision in the interosseous membrane was made 1 cm distal to the passing anterior branch of the interosseous artery that was clearly seen in the operating field. This corresponded to an incision in the skin, leading in the proximal direction at a length of about 7 cm, made 2 cm proximal to the distal radio-ulnar joint. DISCUSSION: The identification of motor branches is often difficult and therefore the authors recommend resection of the sensitive branch of the volar interosseous nerve to be performed in a safe zone that was determined by a large number of anatomical dissections. Partial denervation carried out according to the principles of a physiological procedure does not pose a burden for the patient and can markedly enhance the effect of reconstructive surgery. CONCLUSION: Partial denervation of the wrist performed from the dorsal approach is a simple procedure easy to combine with other reconstructive operations on the wrist.

Adolescent↗
PubMed2005

[A case of strangulation ilieus of the ascending colon].

Authors present case of strangulation ileus of ascendent colon as a quite rare reason of bowel obstruction. Patient's clinical status has been affected by his social background. And they document importance of proper anamnesis and clinical examination in era of modern investigation methods that may be misinterpreted and entice surgeon from early operative intervention.

Colon, Ascending↗
PubMed2002

The pathology of hibernating myocardium.

Myocardial hibernation represents a protective mechanism of muscle preservation in the setting of atherosclerotic coronary artery disease. Long-standing myocardial hypoperfusion leads to diminished myocardial contractility that reverses with improved blood flow after revascularization. The morphologic changes in both animal models and humans are described.

Adaptation, Physiological↗
PubMed2002

[Pelvic pain--appendiceal diseases and laparoscopic treatment].

The authors describe the diagnostic problem of "pelvic pain" by the laparoscopic approach. They draw attention to the high percentage of appendicopathies revealed during laparoscopic revisions on account of this diagnosis. They describe their own laparoscopic procedure, its advantages ad universal application which makes it possible to perform not only laparoscopic appendectomies but also other laparoscopic operation of organs of the pelvis minor as well as cholecystectomies. In the discussion they draw attention to the important number of other findings which usually are not detected during classical operations and where the laparoscopic approach is also important.

Adolescent↗
PubMed2001

[Fournier's gangrene].

Fournier's gangrene, although bearing the eponymous name of J.A. Fournier, was first reported by Baurienne in 1764 and 1883. His description was characterized by an abrupt onset of a rapidly progressive gangrene of the scrotum in otherwise healthy young males with an absence of a specific causative agent. Today, the frontiers of Fournier's gangrene have expanded to include all cases of necrotizing fasciitis of the perineum and external genitalia males and females from all age groups. All the patients were treated with antibiotics, surgical debridement and frequent wound dressings with hypertonis saline, hydrogen peroxide, colostomy and epicystostomy.

Adult↗
PubMed2000

Direct isolation of human central nervous system stem cells.

Stem cells, which are clonogenic cells with self-renewal and multilineage differentiation properties, have the potential to replace or repair damaged tissue. We have directly isolated clonogenic human central nervous system stem cells (hCNS-SC) from fresh human fetal brain tissue, using antibodies to cell surface markers and fluorescence-activated cell sorting. These hCNS-SC are phenotypically 5F3 (CD133)(+), 5E12(+), CD34(-), CD45(-), and CD24(-/lo). Single CD133(+) CD34(-) CD45(-) sorted cells initiated neurosphere cultures, and the progeny of clonogenic cells could differentiate into both neurons and glial cells. Single cells from neurosphere cultures initiated from CD133(+) CD34(-) CD45(-) cells were again replated as single cells and were able to reestablish neurosphere cultures, demonstrating the self-renewal potential of this highly enriched population. Upon transplantation into brains of immunodeficient neonatal mice, the sorted/expanded hCNS-SC showed potent engraftment, proliferation, migration, and neural differentiation.

Animals↗
PubMed2000

Purified hematopoietic stem cell grafts induce tolerance to alloantigens and can mediate positive and negative T cell selection.

Engraftment of allogeneic bone marrow (BM) has been shown to induce tolerance to organs genotypically matched with the BM donor. Immune reconstitution after BM transplantation therefore involves re-establishment of a T cell pool tolerant to antigens present on both donor and host tissues. However, how hematopoietic grafts exert their influence over the regenerating immune system is not completely understood. Prior studies suggest that education of the newly arising T cell pool involves distinct contributions from donor and host stromal elements. Specifically, negative selection is thought to be mediated primarily by donor BM-derived antigen-presenting cells, whereas positive selection is dictated by radio-resistant host-derived thymic stromal cells. In this report we studied the effect of highly purified allogeneic hematopoietic stem cells (HSCs) on organ transplantation tolerance induction and immune reconstitution. In contrast to engraftment of BM that results in near-complete donor T cell chimerism, HSC engraftment results in mixed T cell chimerism. Nonetheless we observed that HSC grafts induce tolerance to donor-matched neonatal heart grafts, and one way the HSC grafts alter host immune responses is via deletion of newly arising donor as well as radiation-resistant host T cells. Furthermore, using an in vivo assay of graft rejection to study positive selection we made the unexpected observation that T cells in chimeric mice rejected grafts only in the context of the donor MHC type. These latter findings conflict with the conventionally held view that radio-resistant host elements primarily dictate positive selection.

Animals↗
PubMed2000

[Acute necrotizing pancreatitis--a constant surgical problem].

The treatment of each patient admitted for the diagnose of acute pancreatitis requires a very individual approach. It is necessary to consider the possibility of severe complications. Currently, there is no specific therapeutic measure to prevent the development of pathogenic processes. In addition to all modes of supportive therapy and surgical sanatation of the local finding, it is necessary to retain the energetic intake by means of parenteral and enteral modes of nutrition provision.

Adult↗
PubMed1999

[Dynamics of the sliding screw].

Fractures of the upper end of the femur are treated by the authors since August 1993 by the method of a dynamic gliding screws. This method is considered sparing and economical. The operation is implemented as urgent with a screen of antibiotics and anticoagulants in order to reduce postoperative complications. As a matter of routine intensive early rehabilitation is ensured and early return of the patient to his normal environment. Between August 1, 1993 and August 31, 1998 at the authors clinic 259 osteosyntheses were made using a dynamic gliding screw. There were 10 reoperations. In three instances the reason was incorrect surgical technique, in seven instances unsuitable indication of osteosynthesis in an arthrotic joint with impaired nurture in a severely dislocated fracture of the subcapital type. Reoperation was implemented twice by the original technique, eight times by replacement of the hip joint [4, 6]. For successful treatment of patients with fractures of the upper end of the femur it is essential that the department should have an X-ray amplifier, instruments for a dynamic gliding screw, a gamma and reconstruction nail and a hip joint replacement.

Bone Screws↗
PubMed1998

Hematopoietic stem cells and lymphoid progenitors express different Ikaros isoforms, and Ikaros is localized to heterochromatin in immature lymphocytes.

The generation of lymphoid cells in mice depends on the function of the Ikaros protein. Ikaros has been characterized as a lymphoid-restricted, zinc-finger transcription factor that is derived from an alternatively spliced message. Ikaros knockout mice have defects in multiple cell lineages, raising the question of whether the protein regulates multiple committed progenitors and/or multipotent stem cells. To address this issue, we examined Ikaros expression in purified populations of multipotent cells and more committed progenitors. We found that the DNA-binding isoforms of Ikaros were localized in the nucleus of the most primitive hematopoietic stem cell subset. Changes in the RNA splicing pattern of Ikaros occurred at two stages: (i) as long-term self-renewing stem cells differentiated into short-term self-renewing stem cells and (ii) as non-self-renewing multipotent progenitors differentiated into lymphoid-committed progenitors. Unexpectedly, we found Ikaros localized to heterochromatin in Abelson-transformed pre-B lymphocytes by using immunogold electron microscopy. These observations suggest a complex role for Ikaros in lymphoid development.

Animals↗
PubMed1988

6-Hydroxydopamine mediated cardiotoxicity in rabbits.

Weekly injections of the catecholamine depleting agent 6-hydroxydopamine (6-OHDA) were used to denervate rabbit hearts chemically. Analyses of morphology and beta-adrenergic receptor density were made at 1, 2, and 4 weeks. Changes resulting from subacute and chronic inflammatory processes were evident by light microscopy after 1 week. At that time, electron microscopy revealed marked increases in collagen, large myocytic vacuolizations in myocytes, widened gap junctions, and myofibrillar degeneration and dropout. Receptor density was marginally increased at 2 weeks but was decreased (p less than .05) at 4 weeks (maximal [3H]dihydroalprenolol (DHA) binding in fmol/mg: 69.6 +/- 5.4 in controls vs 49.2 +/- 5.1 in 6-OHDA-treated animals). Basal, isoproterenol-stimulated and F- -stimulated adenylate cyclase activities were decreased in the 6-OHDA-treated group at 4 weeks. We conclude that administration of 6-OHDA may cause severe myocardial damage, and that this process may involve loss of some functional components of the cell membrane.

Adenylyl Cyclases↗
PubMed1985

The lymphocyte subpopulations in cyclosporine-treated human heart rejection.

Monoclonal antibodies are being used as specific therapeutic agents for treating organ rejection. This type of treatment requires that the pattern and type of infiltrating cells in the graft during acute rejection be defined. In this study 24 endomyocardial biopsies from cyclosporine-treated human heart allograft recipients were obtained during acute rejection. The biopsies were stained with immunological markers to define the infiltrating cells. The biopsies were divided into three groups; mild, moderate and resolving acute rejection. In all groups T-lymphocytes (marked with the monoclonal Leu-4) were the predominant cells with absence of B-lymphocytes (marked with T015). The results of this study showed that cyclosporine-treated heart transplant recipients have a mixed suppressor/cytotoxic (Leu-2a) and helper/inducer (Leu-3) myocardial infiltrate in contrast to the biopsies of recipients treated with azathioprine, in which suppressor/cytotoxic T-lymphocytes (Leu-2a) were predominant. A clear sequential pattern of changes in the T-cell subpopulations did not emerge, although macrophages became more prevalent with resolving rejection.

Acute Disease↗