CLINICALCHEMISTRY, Vol. 34, No. 3, 1988 595 limit for creatine, i.e., for men 4 mgfL, and for wom... more CLINICALCHEMISTRY, Vol. 34, No. 3, 1988 595 limit for creatine, i.e., for men 4 mgfL, and for women 7 mg/ L. As expected, samples with a higher creatinine concentration require less creatine for this interference to be manifested. Evidently creatine interference has no substantive impact on the clinical utility of the Kodak Ektachem single-slide method, because any flagged value is automatically diluted as a part of the routine protocol. Indeed, a “Substrate Depletion” flag should alert one of a possible creatine abnormality and the associated clinical implications, e.g., rhabdomyolysis or other disorders involving destruction or wasting of muscle mass and associated renal failure.
Apoptosis is a gene-directed physiological and programmed process of cell deletion aimed at the r... more Apoptosis is a gene-directed physiological and programmed process of cell deletion aimed at the regulation of tissue and organ development. It affects different cell types and is triggered by a variety of stimuli all inducing closely comparable structural changes. Despite the deeply different morphology and metabolism of the cell models and the various inducers and their initial effects, a convergence seems to take place in a common metabolic pathway that, in most cases, involves the activation of a Ca2+ dependent endonuclease. A growing body of data is now available on the molecular events that lead to DNA damage. DNA cleavage in nucleosomic or oligonucleosomic fragments is related to the appearance of unusual and very characteristic ultrastructural changes. The nucleus is especially affected, and shows chromatin rearrangements consisting of cup-shaped marginations, sharply separated from diffuse chromatin areas. Nuclear fragmentation subsequently appears, finally followed by the formation of numerous micronuclei. Cytoplasmic damage appears at a very late stage and the process takes place despite good preservation of plasma membrane and cytoplasm.
Osteoarthritis (OA) is one of the most common degenerative joint diseases which causes chronic di... more Osteoarthritis (OA) is one of the most common degenerative joint diseases which causes chronic disability in older populations (1). OA and crystal arthropathy frequently coexist, particularly in the knee. This combination, characterized by crystal accumulations of calcium pyrophosphate dihydrate (CCPD), is called chondrocalcinosis (2). The aim of this work was to investigate and compare the articular surface, the layered structure of cartilage and the chondrocyte behaviour in three different conditions: control, OA and chondrocalcinosis. Cartilages of femoral condyle have been evaluated by means of optical, transmission and environmental scanning electron microscopy with EDAX EDS system. In OA and CCPD deposition disease a collagen network disorganization appears, and crystals, in the latter condition, appear particularly stored in the degenerated area. Cartilage stratifications display a clear thickness reduction of superficial and middle layers, with a calcified tissue increase in the specimens of pathologic groups. Numerous chondrocytes in the articular surface of OA and chondrocalcinosis samples reveal necrotic features, while in the middle zone cells show morphological pattern suggestive of chondroptosis (3). In conclusion, cell behaviour knowledge appears to have a key role to understand cartilage disorders and to investigate their morpho-functional mechanisms.
Apoptosis is usually characterized by profound morphological nuclear changes. Chromatin undergoes... more Apoptosis is usually characterized by profound morphological nuclear changes. Chromatin undergoes a progressive condensation that eventually involves all the nucleus. At earlier stages chromatin appears as divided in compact and diffuse areas, while the nuclear pores disappear from the nuclear envelope that surrounds the compact areas, and cluster around diffuse chromatin. Here we have performed a morphometric study on the different chromatin areas of freeze-fractured apoptotic cell nuclei in order to investigate its morphometric and functional organization. We have found large portions of inactive chromatin aggregations corresponding to the dense cap-shaped patches, while domains of nucleosomic fibres have been identified in the diffuse chromatin areas. The correlation of the nucleosomic fibre/diffuse chromatin domain with the nuclear pore clusters is demonstrated, and its implications with a possible residual nuclear activity are discussed.
CLINICALCHEMISTRY, Vol. 34, No. 3, 1988 595 limit for creatine, i.e., for men 4 mgfL, and for wom... more CLINICALCHEMISTRY, Vol. 34, No. 3, 1988 595 limit for creatine, i.e., for men 4 mgfL, and for women 7 mg/ L. As expected, samples with a higher creatinine concentration require less creatine for this interference to be manifested. Evidently creatine interference has no substantive impact on the clinical utility of the Kodak Ektachem single-slide method, because any flagged value is automatically diluted as a part of the routine protocol. Indeed, a “Substrate Depletion” flag should alert one of a possible creatine abnormality and the associated clinical implications, e.g., rhabdomyolysis or other disorders involving destruction or wasting of muscle mass and associated renal failure.
Apoptosis is a gene-directed physiological and programmed process of cell deletion aimed at the r... more Apoptosis is a gene-directed physiological and programmed process of cell deletion aimed at the regulation of tissue and organ development. It affects different cell types and is triggered by a variety of stimuli all inducing closely comparable structural changes. Despite the deeply different morphology and metabolism of the cell models and the various inducers and their initial effects, a convergence seems to take place in a common metabolic pathway that, in most cases, involves the activation of a Ca2+ dependent endonuclease. A growing body of data is now available on the molecular events that lead to DNA damage. DNA cleavage in nucleosomic or oligonucleosomic fragments is related to the appearance of unusual and very characteristic ultrastructural changes. The nucleus is especially affected, and shows chromatin rearrangements consisting of cup-shaped marginations, sharply separated from diffuse chromatin areas. Nuclear fragmentation subsequently appears, finally followed by the formation of numerous micronuclei. Cytoplasmic damage appears at a very late stage and the process takes place despite good preservation of plasma membrane and cytoplasm.
Osteoarthritis (OA) is one of the most common degenerative joint diseases which causes chronic di... more Osteoarthritis (OA) is one of the most common degenerative joint diseases which causes chronic disability in older populations (1). OA and crystal arthropathy frequently coexist, particularly in the knee. This combination, characterized by crystal accumulations of calcium pyrophosphate dihydrate (CCPD), is called chondrocalcinosis (2). The aim of this work was to investigate and compare the articular surface, the layered structure of cartilage and the chondrocyte behaviour in three different conditions: control, OA and chondrocalcinosis. Cartilages of femoral condyle have been evaluated by means of optical, transmission and environmental scanning electron microscopy with EDAX EDS system. In OA and CCPD deposition disease a collagen network disorganization appears, and crystals, in the latter condition, appear particularly stored in the degenerated area. Cartilage stratifications display a clear thickness reduction of superficial and middle layers, with a calcified tissue increase in the specimens of pathologic groups. Numerous chondrocytes in the articular surface of OA and chondrocalcinosis samples reveal necrotic features, while in the middle zone cells show morphological pattern suggestive of chondroptosis (3). In conclusion, cell behaviour knowledge appears to have a key role to understand cartilage disorders and to investigate their morpho-functional mechanisms.
Apoptosis is usually characterized by profound morphological nuclear changes. Chromatin undergoes... more Apoptosis is usually characterized by profound morphological nuclear changes. Chromatin undergoes a progressive condensation that eventually involves all the nucleus. At earlier stages chromatin appears as divided in compact and diffuse areas, while the nuclear pores disappear from the nuclear envelope that surrounds the compact areas, and cluster around diffuse chromatin. Here we have performed a morphometric study on the different chromatin areas of freeze-fractured apoptotic cell nuclei in order to investigate its morphometric and functional organization. We have found large portions of inactive chromatin aggregations corresponding to the dense cap-shaped patches, while domains of nucleosomic fibres have been identified in the diffuse chromatin areas. The correlation of the nucleosomic fibre/diffuse chromatin domain with the nuclear pore clusters is demonstrated, and its implications with a possible residual nuclear activity are discussed.
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Papers by Pietro Gobbi