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Biomedical subjects

J Spacek

Publications and source records attributed to J Spacek.

At least 19 recordsLinked to original sources
PubMed1996

Ovine pericardium: a new material for duraplasty.

The authors report on their 2 1/2-year clinical experience using a dural substitute, ovine pericardium, stabilized with 0.3% glutaraldehyde, flat freeze-dried, and sterilized with gamma-irradiation. Packaging of the ovine pericardium in double-plastic transparent bags allows simple storage in operating rooms and the opportunity for the surgeon to choose an ideal graft according to its shape, size, and plasticity. The ovine pericardia were examined histologically and by transmission and scanning electron microscopy in their native, freeze-dried, and irradiated forms. The final product is composed solely of pericardium fibrosum interwoven with artificially formed extracellular microcavities that serve as natural pores for the ingrowth of host tissue. The surfaces of the grafts appear smooth on the inner and rough on the outer sides. Sixteen grafts were examined macroscopically at autopsy and four of these were also examined histologically to illustrate their successful healing with no adhesion to the underlying brain. As a new dural substitute, ovine pericardium proved to be superior to bovine and allogeneic pericardia because of its workability, flexibility, and reduced thickness. In a study of 120 grafts, all but one healed without complications.

Adolescent↗
PubMed1994

Cytoplasmic inclusions in neocortical astrocytes associated with arteriopathic encephalopathy and dementia.

We describe what we believe to be the fifth case of a degenerative condition of the brain characterized by unusual intracytoplasmic inclusions in neocortical astrocytes, and we review four previous reports of what appears to be the same condition. Whereas these previous cases were characterized by prolonged clinical mental and psychomotor retardation, our case describes a rapid onset in a previously fit and mentally able patient in whom the astrocytic inclusions showed a close association with fibrohyaline vascular degeneration and changes resembling those of Alzheimer's disease. The inclusions, which were most frequent in the second to fourth layers of the frontal, temporal, and occipital cortices but absent from subcortical regions, consisted of large, irregular hyaline bodies surrounding the nucleus and extending into the proximal parts of cell processes. Ultrastructurally they consisted of free ribosomes in a granular and filamentous matrix. They were not bound by a membrane. Lipofuscin granules were associated with them. It is suggested that the inclusions might result from a disturbance of protein metabolism in protoplasmic astrocytes, but their true significance is unknown.

Astrocytes↗
PubMed1994

[Adnexal torsion in childhood].

During the 7-year period (1987-1993) the authors treated nine girls on account of torsion of the adnexa. In six girls torsion of primarily unaltered adnexa occurred, in one girl torsion of an ovary enlarged by a cyst and in two torsion of the ovary affected with a benign tumour, a coetaneous teratoma. In seven instances the organ affected with ischaemic necrosis had to be resected. In two girls detorsion of the ovary was performed, according to a sonographic control examination, however, in one the affected ovary atrophied. In the discussion the authors deal with the diagnosis of torsion of the adnexa and the method of treatment. The authors consider ultrasonic examination of organs of the abdominal cavity and retroperitoneum a very suitable method in all cases of abdominal pain in childhood, as this method can greatly contribute to the diagnosis of acute abdominal and gynaecological attacks. During surgery they recommend to preserve adnexa with a doubtful vitality because there is certain hope that they will be saved. During the postoperative period they recommend the long-term follow up of girls clinically and by ultrasonographic checks. If pathological changes are detected on the preserved adnexa, they recommend early re-operation and elimination of the risk factor (cysts etc.). The operation should be supplemented by prophylactic fixation of the preserved adnexa if this fixation was not done already during the primary operation.

Adnexal Diseases↗
PubMed1994

Anatrecon: a user guide to software package for computer-aided three-dimensional reconstructions.

"Anatrecon" is an original Czech software package. It enables one to make easy three-dimensional reconstructions from serial sections of cells and tissues. It offers very acceptable information on the three-dimensional structure and especially on mutual relationships of biological objects in such cases when other methodical approaches, e.g., scanning electron microscopy or laser scanning confocal light microscopy, cannot be applied. The program runs on a standard IBM compatible personal computer supplemented with a digitizing tablet. The author describes the program in detail and presents examples of reconstructions of dendritic spine and nucleus of nerve cell.

Computer User Training↗
PubMed1993

Long-term results in hairy cell leukemia treated by splenectomy.

Splenectomy as a therapeutic modality has been evaluated in a group of 24 consecutive patients. Before and after splenectomy only supportive therapy was applied with the exception of two patients in whom corticosteroids were administered because of vasculitis. Radiation therapy was applied in one patient because of massive retroperitoneal lymphadenopathy. One patient received Leukeran shortly before the fatal outcome because his response to splenectomy was poor. Out of 24 patients 14 patients died. The median survival for the partial responders and non-responders was 6 months only. Patients with a complete response did not reach median survival yet and 8 of them (33% of the whole group) have been alive for more than 9 years, one patient for more than 20 years. Two distinct groups of patients with respect to the outcome of splenectomy can be distinguished: The first group is characterized by a rapid fatal outcome mostly within two years after splenectomy, the second group has a more favorable course with a plateau and only occasional deaths after the fourth year.

Adult↗
PubMed1992

Dynamics of Golgi impregnation in neurons.

This paper describes the early stages of impregnation by the Golgi rapid method in sections and blocks of brain tissue. Aldehyde-fixed and potassium dichromate-treated sections of cerebral cortex were placed on glass slides and coverslipped. The dichromate solution was then replaced by a silver nitrate solution, and events taking place in the section were monitored and time-lapse recorded until the impregnation was interrupted and the sections subsequently prepared for electron microscopy. The tissue blocks, fixed and chromated in the same way, were placed into a silver nitrate solution for 30 min to 24 h and the progress of impregnation compared with the results obtained in the sections on the glass slides. Two basic modes of impregnation were observed, apparently in direct relation to the process of crystallization of silver chromate: crystals of silver chromate growing directly from the surface of the tissue into the nerve cell via its transected plasma membranes, and microcrystalline precipitate of silver chromate spreading into the nerve cell from nucleation centres dispersed in the tissue. The precipitate grows inside the cell as in a preformed channel until the cell has been filled. If the nucleation begins extracellularly, the precipitate extends into the narrow intercellular gaps. Electron microscopy showed that the crystalline precipitate consisted of multilamellar formations containing dense coalesced granules that did not cross plasma or endocellular membrane boundaries.

Animals↗
PubMed1991

Benign cyst of the paramedian pontine tegmentum.

A benign ovoid cyst, without an epithelial lining, localized in the paramedian pontine tegmentum, was examined by computed tomography (CT) and magnetic resonance imaging (MRI) (25 x 15 x 15 mm) and successfully operated upon. The one-and-a-half syndrome (horizontal gaze palsy to the right and paralysis of adduction of the right eye) and ipsilateral "peripheral" VII nerve palsy dominated the clinical picture. Fenestration, 5 mm in diameter, of the cyst wall through the floor of the IV ventricle was performed and 2.6 ml of clear, colorless fluid was evacuated. Inspection of the cyst, using the operating microscope, revealed a smooth, white, glistening cavity with no evidence of other pathological tissue. Duraplasty was performed with allogenic pericardium. Neurological symptoms improved immediately after surgery. Light and electron microscopy of the cyst wall revealed a fibrillar astroglial network and fragments of ependyma at the ventricular side of the biopsy.

Adolescent↗
PubMed1990

Pulmonary and dermal manifestations of myelosarcoma with delayed onset of acute myeloid leukemia.

An unusual case of illness of a 49 year old woman who suffered from inexpressive skin rash for three years is described. Repeated biopsies did not bring an unequivocal result. Then an illness followed with a short term fever, prolonged cough, and progressing dissemination of tiny focal shadows of infiltration character in both lungs. Simultaneous biopsies of the skin and excised pulmonal tissue revealed histiocytolymphocytic infiltrations of an identical character. Atypical cells which were difficult to classify were present. Dermal and pulmonal infiltrations disappeared after chemotherapy. Eruption occurred again after a year and hasty development of acute myeloid leukemia started. It was a case of prodromal myelosarcoma stage with skin and pulmonal infiltration by quite undifferentiated reticulohistiocytic elements of the myeloid line, which ended as acute myeloid leukemia after 4 years.

Acute Disease↗
PubMed1989

[Repair of the dura mater in children using xenogenic pericardium].

The authors report their five-year experience with the use of xenogenic calf pericardium for plastic operations of the cerebral and spinal dura mater which they introduced into neurosurgical practice in 1983. Of 165 grafts they selected 50 which they used in children for the plastic operation of the dura mater above the posterior cranial fossa, above the convexity of the brain and at the skull base. The xenogenic pericardium proved successful and resolved also the shortage of allogenic collagenous tissues (fascia lata, dura mater) used for plastic operations of the dura mater. Moreover, due to its resistance it achieved priority in some indications and localizations. When used, certain conditions must be met to ensure satisfactory incorporation (suitable size, intradural submersion, careful suture).

Bioprosthesis↗
PubMed1989

Dynamics of the Golgi method: a time-lapse study of the early stages of impregnation in single sections.

This paper describes the early stages of impregnation by the Golgi method. Sections of aldehyde-fixed and potassium dichromate-treated cerebral cortex were mounted on glass slides and cover slipped. The dichromate solution was replaced by silver nitrate solution and events in the section were followed and recorded by time lapse microphotography and video recording until stopped by replacement of silver nitrate solution by glycerol. The sections were subsequently prepared for electron microscopy (EM) study. In sections about 2 x 2 mm and 100 microns thick a fine, dark granular precipitate formed at the edges within the first minutes of exposure to silver nitrate and a wave of brownish colouration spread to a depth of about 0.3 mm. After approximately 7 min, shrub-like focal precipitates (nucleation centres) appeared in the sections. From these nucleation centres (but also from the section edges) thread-like 'outgrowths', usually identified as dendrites, spread into somata. Sometimes impregnation began within the soma and spread into dendrites. The rate of impregnation (i.e., of silver chromate deposition within dendrites) was typically 1-7 microns min-1, faster in the earlier stages (up to 3 microns s-1) and very slow after 30 min, by which time many neurons were more or less fully impregnated. The dimensions of the section, the width of an agar frame around the sections, and the frequency with which the silver nitrate in the sections was replenished all affected the extent and time course of the impregnation. By EM the earliest intracellular deposits consisted of tubulolamellar formations which did not cross plasma or endocellular membrane boundaries and which contained irregularly shaped and scattered granules, initially about 10 nm in diameter. The latter progressively enlarged and coalesced as the tubulolamellar formations extended, eventually to fill the cross-sectional area of neuronal processes and cell bodies. These observations shed light on why so few neurons become impregnated with the Golgi method. Impregnation occurred only in those cells a part of which was within a nucleation centre.

Animals↗
PubMed1989

Xenogeneic pericardium as a dural substitute in reconstruction of suboccipital dura mater in children.

A 5-year experience with the glutaraldehyde-stabilized freeze-dried radiation-sterilized calf pericardium used as a dural substitute is reported. The structure of pericardium xenograft is compared with other collagenous materials used for duraplasty (allogeneic fascia lata and dura mater) by light and electron microscopy. The special neurosurgical techniques involved in using pericardium xenografts in the reconstruction of suboccipital dura mater in children are presented in detail.

Animals↗
PubMed1989

[Developmental cysts in the area of the quadrigeminal plate in children].

The authors describe three cases of operated developmental cysts in the area of the laminae quadrigeminae in children. The performed multiple fenestrations or excision of the wall of the cyst and effective communication with the subarachnoid or ventricular system, as well as a plastic operation of the dura mater with collagen tissue from a Tissue bank. By means of light microscopy the walls of two cysts were examined (one arachnoid and one glioependymal), one cyst was examined by electron microscopy (glioependymal). The authors supplemented by their own cases the number of hitherto described cysts in the collicular region to 56.

Arachnoid↗
PubMed1989

Computer-aided three-dimensional reconstructions of biological objects using simple facilities.

An analysis of serial sections is an important method applied in all fields of biology studying objects divided into sections, especially at light and electron microscopy levels. It affords a qualitative and quantitative information on spatial organization of tissues, cells and organelles. This study describes simple and cheap ways of obtaining computer-aided three-dimensional reconstructions of biological objects from serial sections.

Computer Graphics↗
PubMed1989

[Eosinophilic leukemia].

On the example of a patients with eosinophil leukaemia, which at first was manifested as eosinophilia in the peripheral blood stream and bone marrow without involvement of other organs and only after three years acquired the character of malignant growth, the authors draw attention to difficulties in the differential diagnosis of hypereosinophil syndrome. At the same time the authors review briefly views on the origin of eosinophil leukaemia, morphological and cytogenetic findings considered useful as evidence of this rare type of leukaemia.

Adult↗
PubMed1988

Personal microcomputer-aided three-dimensional reconstructions.

A fast, cheap and simple method is described which enables three-dimensional reconstructions to be produced from short series of sections. The reconstruction is formed and displayed either as a full line or hidden line diagram or shaded model. It may be rotated, magnified or reduced, all with the aid of a personal microcomputer, peripherals and software, the total cost of which does not exceed several hundreds of US dollars.

Animals↗
PubMed1987

Ultrastructural pathology of dendritic spines in epitumorous human cerebral cortex.

Ultrastructural changes in the human epitumorous cerebral cortex were examined. A swelling of nerve cell perikarya, dendrites and axon terminals, and an occasional hyperplasia and disarray of microtubules and neurofilaments were observed. Accumulations of lysosomes, tubuloreticular structures and intracytoplasmic or intramitochondrial crystalloid inclusions were also found. Some myelinated axons were degenerated. Astrocytes and their processes were focally swollen. A mild swelling was found also in microgliocytes. Oligodendrocytes occasionally contained accumulations of dense bodies. Special attention was paid to dendritic spines. The spine surface morphology changed distinctly on swollen dendritic segments. The necks of most spines were short and wide, and numerous sessile forms were present in this location. The spine apparatus was often hypertrophied and disorganized. Smoothing out of spines on swollen dendrites is described and a possible functional significance of the observed changes in the symptomatology of brain tumors is hypothesized.

Animals↗