Biomedical subjects
Publications and source records attributed to E Govoni.
Various methodological approaches that can be used to detect ototoxic effects caused by the administration of various substances are presented, using the Sprague-Dawley rat as an animal model. Electrophysiological data are also presented to show how the model behaves with potentially ototoxic (hyaluronic acid) and initially inert (hydroxy-propyl-methyl-cellulose) substances.
Age-associated changes of the human synovium have been investigated by microarthroscopy, optical and electron microscopy, immunohistochemistry, and cytochemistry. The knee joints of nineteen 15- to 56-year-old subjects, classified as normal by inspection, were carefully examined by microarthroscopy; small synovial tissue biopsy specimens from both the suprapatellar pouch and the medial tibiofemoral gutter were taken. Microarthroscopy showed that the villi were more numerous and the vascular network and cell distribution and profiles less regular in aged individuals. These data were confirmed by scanning electron microscopy, which also showed large areas of the synovial surface devoid of cells and collagen bundles in contact with the joint cavity in aged subjects. Light and transmission electron microscopy confirmed these data and allowed evaluation of the number, distribution, shape, and internal organization of cells as well as the distribution of vessels and the organization of the extracellular matrix in the full thickness of the synovium (down to 2 mm). Particular attention was paid to synovial lining cells, among which three main phenotypes could be recognized: synthetic type (present at all ages and hypertrophied in aged subjects), macrophagelike (increasing with age), and fibroblastlike. Collagen increased with age. Further studies are needed for comprehensive understanding of age-associated changes in the human synovium.
In experimental animal studies, exogenous hyaluronan (HA) has been shown to exert beneficial effects on the healing of tympanic membrane perforation. As any other exogenous substance, HA may prove potentially toxic, by filling the middle ear cavity, to the sensory cells of the organ of Corti. Electrophysiological (ABR) and morphological studies were carried out in the rat to examine the auditory function and the structure of the sensory epithelium. Rats received either HA or hydroxy-propyl-methyl-cellulose by trans-tympanic injection (middle ear cavity was completely filled up) and were compared to untreated, age- and weight-matched rats. In both treated groups ABR revealed transitory, mild conduction hearing loss, in particular for high frequencies, until day 7 postinjection. This loss recovered completely within the 15th day. Morphologically, no significant degenerative/necrotic lesions were observed in the organ of Corti, from both treated groups.
The late cytoplasmic phases of human Cytomegalovirus (HCMV) morphogenesis in cultured fibroblasts have been studied by transmission electron microscopy focusing attention on the relationship between the viral particles and host cell organelles. The results obtained largely reflect changes in cells subjected to sublethal injurious stimuli induced by many viruses as well as different noxious agents. A great increase in the number of Golgi apparatuses and lysosomes was observed, both of them interacting with the viral progeny. HCMV seems to acquire its final envelope from Golgi-derived structures and, less frequently, from the plasma membrane.
Severe prolonged migrainous symptoms and prolonged partial status epilepticus are characteristic features of the MELAS syndrome (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes). Maternal transmission previously found in myoclonus epilepsy and ragged-red fibers (MERRF), another mitochondrial disease, is suggested in this disorder as well.
Human uteri were perfused with Krebs-Ringer bicarbonate-glucose buffer with and without estrogens and progesterone for a period of up to 48 hours to preserve a viable organ, which was responsive to hormones. Flow rates of 12 to 35 ml/minute per artery were fully distributed into the organ, with pressure values ranging from 80 to 120 mm Hg. Arteriovenous gradients of oxygen and carbon dioxide tensions as well as the levels of lactate, lactic dehydrogenase, and creatine kinase released in the perfusate, indicators of tissue ischemia or cell necrosis, showed a good preservation of the organ for up to 48 hours. The light- and electron-microscopic examinations of endometrial and myometrial tissues taken before and during perfusion confirmed this result. The extracorporeal perfusion of uteri with buffer containing estrogens plus progesterone exhibited secretive modifications of the proliferative endometrium, thus suggesting the viability of the organ and its responsiveness to sex steroids.
A case of a mediterranean boy with congenital muscular dystrophy (CMD) and central nervous system (CNS) involvement with mild intellectual impairment and seizures is reported. Muscular dystrophy involved both skeletal and mimic muscles, and histological findings were consistent with a congenital dystrophy. EEG recordings showed generalized and localized paroxysmal activities. CT scan demonstrated low-density periventricular areas. Ophthalmoplegia was also observed. A literature review disclosed that in some western cases of CMD plus CNS involvement, cranial muscles other than mimic muscles may be involved.
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The doctor of today must adopt the 'cellular way of thinking' in the evaluation of diseases. This ultrastructural outlook provides him with much indispensable information that also serves a practical purpose. A diseased cell organelle is at the basis of every clinical sign and any attempt of therapy must be aimed at that specific point of lesion. We intend, in the light of a long experience, to propose to clinicians a new way of thinking in which a precise correlation between symptoms and submicroscopic changes of the cell is considered. Many different examples amply justify this proposal. Electron microscopy can contribute by enabling identification of structural subcellular modifications suitable for the finest differential diagnosis, more and more complete understanding of pathogenic pathways of various diseases, the establishment of guidelines for precise pharmacological interventions at the molecular level.
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The immunohistochemical and ultrastructural findings of 7 primary argyrophilic tumors of the breast are described. Five cases were selected because of a growth pattern reminiscent of a "carcinoid" tumor and 2 were obtained from 70 consecutive common carcinomas. All patients were females (mean age 68.8) and none had clinical evidence of hormonal secretion. On ultrastructural examination dense-core granules were seen in addition to findings more suggestive of a common carcinoma. Immunoperoxidase stainings for ACTH, calcitonin etc. were negative in all tumors. The authors believe that organoid growth pattern, argyrophilia and dense-core neurosecretory-like granules are not sufficient elements to demonstrate the endocrine nature of a breast neoplasm.
The bone marrows of five patients with primary myelofibrosis at different stages of the disease have been studied. In the myelofibrotic bone marrow, associated with "reticulum cells", two other cell types have been identified, namely fibroblast-like and myofibroblast-like reticulum cells, as well as a spectrum of transitional forms. Our findings suggest that reticulum cells may represent a reserve stromal cell pool (i.e. primitive reticulum cells) able to modulate themselves and to transform differently according to functional requirements. Some suggestions regarding the functional significance of fibroblast-like and myofibroblast-like reticulum cells in primary myelofibrosis are suggested.
Uterine osteosarcoma represents an extremely rare pure heterologous sarcoma of the uterus. In the present case osteosarcoma occurred primarily in the uterine cavity of a 56-year-old woman. The tumor was anaplastic and the presence of different proliferative patterns caused differential diagnostic problems with various malignant tumor types. The osteoid features of extracellular matrix were demonstrated by electron microscopy. Clinical and pathological features of previously reported cases of uterine osteosarcoma are critically reviewed.
Two cases of X-linked bulbo-spinal neuronopathy (BSN) of late onset are presented. An extensive review of the literature shows that, in addition to the signs of a chronic degeneration of brainstem and spinal neurons, other clinical features may also be present at the onset of the disease, or develop during its course. Some clinical, electrophysiological and anatomical data support the hypothesis that BSN is not purely a motoneuronopathy but also concerns sensory nerve.
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