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Biomedical subjects

K Mazanec

Publications and source records attributed to K Mazanec.

At least 19 recordsLinked to original sources
PubMed2001

Structure and surface of TiNi human implants.

The surface and the "bulk" structure of TiNi implants were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoemission spectroscopy (XPS), and scanning Auger microprobe analysis (AES). TiNi implants were compared with otherwise identically prepared non-implanted specimens, and sputter-cleaned and reoxidized samples. Non-implanted and implanted samples had essentially the same surface topography and microstructure. Ti, O, and C were the dominant elements detected on the surface. Trace amounts (approximately 1 at%) of Ni and Ca, N, Si, B, and S were also detected. Ti was present as TiO2 on the surface, while nickel was present in metallic form. A significant difference in Ni peak intensity was observed when retrieved or non-implanted control samples (a very low nickel content) were compared with sputter-cleaned and reoxidized samples (well-detected nickel). It is evident that the method of passivation is crucial for nickel loosening. No major changes occurred in the TiNi samples bulk structure or in the surface oxide during the implantation periods investigated.

Biocompatible Materials↗
PubMed1992

Systemic amyloidosis of beta 2 microglobulin type.

A patient receiving haemodialysis for 15 years developed systemic amyloidosis of beta 2 microglobulin type. Noticeable deposits of amyloid were present in the myocardium, intervertebral discs, joint cartilages and tendons. Less conspicuous amounts were present in blood vessel walls in the lungs, liver, adrenal glands and brain, and within the stroma of the prostate, testis and kidney, often with foci of calcification.

Amyloidosis↗
PubMed1992

[Amyloid in articular cartilage--a new type of amyloid?].

Hip and knee joints from 48 randomly selected autopsies have been investigated for amyloid deposits by means of conventional histology and immunohistology. 45 of 48 hip joints (93.75%) and 28 of 32 knee joints (87.5%) contained amyloid deposits. Amyloid has been found in a thin layer along the surface as well as infissures of the cartilage and around chondrocytes with increasing intensity towards the articular surface. Amyloid characteristically showed apple green birefringence in polarized light after staining with alkaline Congo red and pretreatment with potassium permanganate did not change intensity of reaction in most cases. None of the usual constituents of amyloid could be demonstrated by immunohistological methods. P-component (when present) kept the distribution of the amyloid material. It is possible that articular cartilage amyloid represents a new class of amyloid but its identity is to be proved by chemical analysis.

Adult↗
PubMed1992

[Beta 2-microglobulin amyloidosis].

A 35-year-old man who had been treated by hemodialysis for 15 years suffered from systemic amyloidosis. It was identified as a beta 2-microglobulin type according to immunohistochemistry. Extensive amyloid deposits were found in myocardium, cartilages of intervertebral discs and in carpal tunnel ligament. Less conspicuous deposits comprised blood vessels of lungs, liver, suprarenal glands, brain, and stroma of prostate gland, testicles, kidney, often combined with calcified foci.

Adult↗
PubMed1989

[The significance of carcinoma in situ in testicular biopsies].

The paper summarizes the latest knowledge of carcinoma in situ in testicular tissue. It discusses their morphological, cytogenetic and histochemical characteristic including diagnosis. It stresses the necessity of correct fixation of bioptic samples of the testes. It deals with the malignant character of the cells of carcinoma in situ and reported data supporting their invasive potencial. Further the paper shows the incidence of this finding in at-risk groups as well as clinical and pathological correlations.

Biopsy↗
PubMed1989

Carcinoma in situ in testicular biopsies.

Carcinoma in situ of the testis is an abnormality of the seminiferous epithelium characterized by aneuploid cells with clear cytoplasm located along the tubular basement membrane or in the lumina of tubules. Morphological, cytogenetic, and histochemical features of this anomaly are presented. An adequate fixation of testicular tissue samples is necessary for correct diagnosis. The fact that approximately 50% of carcinoma in situ may develop into malignant germ cell tumours of the testis in 5 years and the investigations of the testicular tissue adjacent to these tumours support the malignant nature and invasive potential of testicular carcinoma in situ. The incidence of carcinoma in situ in persons at risk is reviewed.

Biopsy↗
PubMed1989

Is isochromosome i(12p) present in gonadal precancerous tissue?

The development of frequent gonadal tumors in some syndromes of abnormal sexual differentiation is often preceded by carcinoma in situ. To detect possible early changes in chromosome number and/or structure associated with the carcinoma in situ, gonadal tissue was studied in one patient with the complete form of testicular feminization syndrome, two patients with the incomplete form of this syndrome, and one patient with Swyer's syndrome. In all patients aneuploidy with a bimodal distribution of chromosome numbers with the peaks at diploid and near-tetraploid values was shown. The possible specific chromosomal marker of gonadal tumors, isochromosome i(12p), has not been found. Its absence suggests that this marker might be associated with more advanced stages of long-term cancer development or it could be confined only to a subgroup of testicular tumors, as was proposed earlier. The hypothesis that the major source of hypotetraploid or near-triploid cells often found in many gonadal tumors might be endoreduplications with their subsequent chromosome loss is supported.

Adolescent↗
PubMed1989

[Histopathology of gonads in syndromes of abnormal sexual differentiation].

Gonads were studied from 11 phenotypical women with syndromes of abnormal sexual differentiation. The group comprised 4 cases of complete and 3 cases of uncomplete testicular feminization one masculine pseudohermaphrodite with mosaic 45,XO/46,XY and 3 cases of Swyer syndrome. Sertoli-cells-only tubules with some nodes of so called "tubular adenomas" were the prevailing finding. One classical seminoma and two carcinomas in situ were registered in dysgenetic gonads.

Disorders of Sex Development↗
PubMed1989

[Congenital neuroblastomas].

A group of 2,576 autopsies of children of the age of 0 to 15 years (made between 1978 and 1987) comprised 14 congenital (neonatal) tumours (among 93 tumorous lesions). Teratomas were the most frequent congenital tumours followed by neuroblastomas (4 and 3 cases). Neuroblastomas grew from cervical and thoracoabdominal sympathicus and from the right adrenal medulla. The most frequent and most extent hematogenic dissemination concerned liver, microscopical examination found dissemination in various organs as well as a lymphatic spread to regional lymph nodes (in 2 cases). One case was characterized by an exclusive continual destructive growth in retroperitoneum and posterior mediastinum with 2 macroscopical secondaries in skeleton. Pathognomic differentiated structures were always found by light microscopy. Differential diagnosis of round cell tumours of infancy was discussed with a concise exposure of symptomatology and autoptic findings of neuroblastomas according to congenital cases from literature.

Adolescent↗
PubMed1986

[Rhabdomyoma of the vagina].

Three cases of benign vaginal rhabdomyoma were examined by light and electron microscopy. Frequency, localization, genesis, nomenclature, and differential diagnosis of the rare tumour were discussed.

Adult↗
PubMed1986

[Aneurysmal bone cyst of a rib].

Aneurysmatic bone cyst is rare in ribs; only 37 cases were found in literature up to 1984. In a group of 21 children suffering from aneurysmatic bone cyst only one 13 year-old girl had the lesion in sternal part of the 2nd rib.

Adolescent↗