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Biomedical subjects

H Walt

Publications and source records attributed to H Walt.

62 records · Page 4Linked to original sources
PubMed1983

Motile spermatid flagella during differentiation.

Flagella of living early human and rat spermatids show slight differences in duration of motion as revealed by phasecontrast microscopy and videotechnique. Wave-like motion of these 9+2-axonema becomes restricted to bending at later stages in the rat, whereas spermatozoa were found immotile in both species. Additional results were obtained from freely swimming spermatids of the rat and from the inner surface of rat seminiferous tubules, rinsed free of spermatozoa prior to scanning electron microscopy. Obviously, spermatids from some kind of flagellated cell layer that could be involved in liberating mature stages and in facilitating spermatozoa to glide more easily along seminiferous tubules.

Animals↗
PubMed1981

Motile components in early rat spermatids.

In early rat spermatids, two distinctly different kinds of movements of cell components were detected by video-analysis. The primary flagellum, a typical 9 + 2 axonema, is capable of inducing wave-like movements in three dimensions, unlike late spermatid forms, which display motility of the now thickened flagellum only by repeated bending of its extreme part. Additionally, at the apical regions of spermatids of the same early stage, cytoplasmic protrusions executed rhythmic movements at a frequency of almost three times per second. The two kinds of motility of the different components in the same type are thought to be involved in normal orientation and transfer of spermatids in the tubulus seminiferous during their differentiation to sperm.

Animals↗
PubMed1978

Inhibition of lactate dehydrogenase in cultured SIRC cells by cigarette smoke.

SIRC cell monolayer cultures were exposed to whole smoke from a mid tar and nicotine level research cigarette (ASFC, 72 puffs), or from a high tar and nicotine level reference cigarette (Kentucky 2RI, 48 puffs) over a period of 65 days. The activity and distribution of lactate dehydrogenase (LDH) in the cells were investigated, and the electrophoretic characteristics of its isozymes studied. Cell morphology was examined by light microscopy and by transmission- and scanning electron microscopy. LDH activity was reduced by exposure to smoke from both cigarette types, the greater inhibitory effect being produced by that of the Kentucky cigarette. In addition, cells exposed to this high tar and nicotine smoke displayed intramitochondrial granules which were larger and more numerous than those found in cells exposed to the mid tar and nicotine smoke, or in the control cells. It is speculated that cation accumulation in the mitochondria may be involved in the observed inhibition of LDH activity.

Cells, Cultured↗
PubMedDate not supplied

Motile components in spermatids as related to transport of spermatids and spermatozoa.

Two distinctly different components of motility were detected in living early spermatids of the rat using phase contrast microscopy and video-analysis: the primary flagellum (a 9 + 2 axonema) executes wave-like motion in three dimensions. At the same time the flagellum displays alternatively in clockwise and counter-clockwise directions partial torsion, whereas shortening and elongation can also be observed. The second component is based on rhythmical movements of the spermatid cytoplasm at identical stages. During differentiation the capacity for motion reduces progressively. For instance, late spermatids are only capable of bending their now thickened flagellum. Spermatozoa were found immotile. Germ cells during differentiation are thought to contribute themselves to their transfer through the germinal epithelium. Reduction of motility in the differentiating flagellum is due to growing accessory structures surrounding the axonema, whereas motility of the cytoplasm is reduced by its resorption. In man, some forms of hypofertility and sterility, such as the immotile-cilia syndrome, might already be caused by imperfect motile components present in spermatids.

Animals↗
PubMedDate not supplied

Mosaicism of dynein in spermatozoa and cilia and fibrous sheath aberrations in an infertile man.

Male patients displaying an immotile or almost immotile sperm population are the object of an interdisciplinary study concerning a ciliary mutant that induces the "Immotile-Cilia Syndrome". Development and function of both sperm flagella and cilia are normally affected because of disturbances of the 9 + 2-arrangement. During this program, clinical, physiological, genetical and ultrastructural investigations were done. The ultrastructure of immotile spermatozoa of an infertile man did not reveal inner and outer dynein arms. Lack of the ATPase dynein which is essential for movement of the 9 + 2-axoneme, is typical for the above syndrome. In addition, symmetry of the fibrous sheath of the spermatozoa was very abnormal. The pneumologist examined normal lung function, where the ultrastructure of the cilia of the nasal mucosa displayed the dynein arms. Analysis of family tree and chromosomes by the geneticist also gave a normal result. As revealed by this infertile patient it seems likely that expression of dynein must not be identical in both germ cells and somatic cells. Such variations are therefore regarded as additional forms of the "Immotile-Cilia syndrome". Asymmetric fibrous sheaths are thought to be a result of immotile spermatid flagella, leading to an abnormal arrangement of the accessory axonemal structures. Normal early spermatid flagella of man and rat show specific movements.

Adenosine Triphosphatases↗
PubMedDate not supplied

Hypercalcemic-type of small cell carcinoma of the ovary: characterization of a new tumor line.

BACKGROUND: The aim of this study was to develop and characterize a mouse xenograft model for the hypercalcemic-type of small cell carcinoma of the ovary (HTSCCO). PATIENTS AND METHODS: Tumor fragments were removed from a patient and cultured in six subsequent generations of nude mice. Histology, comparative genomic hybridization (CGH), electron microscopy and serum calcium levels were investigated. RESULTS: Morphology remained the same from the primary tumor of the patient through the 6th passage in the mouse. Serum calcium levels were significantly higher in the tumor-bearing mice compared to controls. CGH of the HTSCCO did not show evidence of a close relationship to either a germ cell tumor or an epithelial ovarian cancer. CONCLUSION: Some evidence was provided that the HTSCCO is an inhomogeneous tumor that is neither related to a germ cell tumor nor to an epithelial ovarian cancer, but is a distinct tumor entity.

Adult↗