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Biomedical subjects

M Portigliatti Barbos

Publications and source records attributed to M Portigliatti Barbos.

At least 19 recordsLinked to original sources
PubMed1996

Recurrent secondary hyperparathyroidism due to parathyroid carcinoma: usefulness of Ki-67 immunostaining in the diagnosis of a malignant parathyroid tumor.

Parathyroid carcinoma is a very rare disease occurring in less than 2-3% of all the cases showing clinical features of primary hyperparathyroidism. Several histological markers have been used for distinguishing between benign and malignant tumors of the parathyroid glands. However, most of these markers are not easily applicable and clinical prognosis cannot be predicted by histopathological criteria alone. A recent study has drawn attention to the role of the cell cycle associated antigen Ki-67 detected by MIB-1 monoclonal immunocytochemistry in parathyroid tumors: in fact, Ki-67 seems to be a valuable marker of malignancy in such tumors since it permits an easy detection of proliferating and dividing cells. Here we report in detail a case of severe recurrent hyperparathyroidism in a 51-year-old female patient undergoing regular hemodialysis treatment. In the surgical specimens of the parathyroid glands, the tumor proliferative fraction of 56, expressed as the number of Ki-67-positive nuclei per thousand cells, and the mean mitosis count of 0.5, expressed as the percentage of the total amount of Ki-67 positive nuclei, support the diagnosis of parathyroid carcinoma despite the scanty amount of microscopical signs considered characteristic of malignancy, i.e. extensive thick fibrous bands or prominent nucleoli. To our knowledge this paper is the first clinical report that supports the diagnostic role of the cell cycle associated antigen Ki-67 in parathyroid carcinoma in a case of secondary hyperparathyroidism in a patient undergoing hemodialysis.

Female↗
PubMed1992

Middle and long-term results of flexion osteotomy for avascular necrosis of the femoral head.

The authors present the results of 19 flexion osteotomies performed in cases of avascular necrosis of the femoral head and followed up after an average of 8 1/2 years. Significant clinical improvement was achieved in 85% of the patients. The radiographic picture is not quite as positive, but only 26% of the patients developed severe degenerative arthritis. The authors therefore consider this technique to be a valid alternative to immediate prosthetic replacement in selected patients.

Adult↗
PubMed1991

Clinical, histological, and chemical characterization of ectopic calcification in dialyzed and non-dialyzed patients.

In a review of 11 cases of ectopic calcification (5 of which in dialyzed patients and one in a paraplegic), the authors attempt to characterize this disorder in all its various forms using histological, clinical, and chemical methods. In dialyzed patients, two contributing factors were identified: hyperphosphatemia (plus hypercalcemia) and secondary hyperparathyroidism. In hyperphosphatemic patients the calcifications are multiple, paraarticular, labile, and have a fluid-viscous consistency. In secondary hyperparathyroidism, in addition to the above metastatic calcification there is dystrophic calcification typically localized in the anterior muscles of the hip and thigh. The ectopic calcification of the non-dialyzed patients is true ossification. The precise moment of the onset of the lesion is not always discernable, but its evolution points to primary or secondary local irritation as the trigger. Ossification is the predominant phenomenon in the paraplegic as well, while the triggering mechanism is still unknown.

Adult↗
PubMed1991

Reaction of bone to methacrylate: interface remodelling.

Histologic findings of the bone-cement junction are presented for 10 implants in rabbits and 12 human specimens. Nondecalcified sections were made, employing embedding techniques that conserve the cement. Different time periods from operation were considered. The histological approach considers mainly the distribution of the osseous elements, with a description of the sites of new and old bone, of resorptive lacunae and of fibrous tissue. Fluorescent sequential labelling of bone tissue allowed a dynamic evaluation of the viability of bone after insertion of the cement. Histologic features may be summarized as follows: In the initial phase after PMMA implantation a zone of necrosis is present around the cement. In a second phase there is very active bone formation and remodelling in the tissue adjacent to the cement, with fibrous tissue formation. Long-term adaptive bone remodelling leads to extensive resorption of cortical bone and new bone formation producing a shell around the cement with new trabeculae radiating towards the cortex.

Animals↗
PubMed1990

Primary oxalosis mimicking hyperparathyroidism diagnosed after long-term hemodialysis.

Primary oxalosis is a rare inborn error of oxalate metabolism. Most cases are discovered in children, but occasionally symptoms begin later in life. Since early deaths in the past were from renal failure, prolonged survival obtained with chronic dialysis allows oxalosis to develop. This paper presents a 38-year-old man with an atypical history of type-I primary hyperoxaluria, not diagnosed until after 5 years of dialysis. Bone biopsy was performed because the biochemical and radiologic features did not seem consistent with a putative diagnosis of secondary hyperparathyroidism. This case emphasizes the clinical heterogeneity of this disorder, and the need for its considerations in the spectrum of dialysis-related bone diseases. It also stresses that bone oxalosis may mimic hyperparathyroidism, especially radiologically. Differential diagnosis is therefore mandatory.

Adult↗
PubMed1990

Mineralometry of the lumbar spine and histomorphometry of the iliac crest: preliminary results of a comparison of several parameters in the same individual.

Twelve patients affected with various bone pathologies (osteoporosis, renal osteodystrophy, osteogenesis imperfecta, hyperparathyroidism) were submitted to mineralometry of the lumbar spine with double photonic ray and transiliac biopsy for histomorphometry. A comparison of the values obtained for the mineralometric and histomorphometric parameters--despite the small number of cases--revealed a correlation between bone mineral content of the lumbar spine and trabecular and cortical bone volume of the iliac crest. The correlation is even more significant for the sum of these last two parameters. It may be concluded that: 1) both the methods have predictive values for an evaluation of osteopenia; 2) the measurement of cortical and subcortical bone volume increases the significance of the histomorphometric finding (which is usually limited to the trabecular bone volume); 3) there is a correlation between histomorphometry (iliac crest bone volume) and mineralometry (lumbar spine with double photonic ray) in the same individual.

Absorptiometry, Photon↗
PubMed1989

Orientation of collagen in human tibial and fibular shaft and possible correlation with mechanical properties.

The pattern of collagen orientation in two human tibiae and fibulae was studied. Serial 100 microns plane parallel cross-sections at 1 cm intervals at the same level in tibia and fibula were cut using an annular blade saw. Distribution of transversely oriented collagen was mapped using circularly polarized light and an image analyzing computer. In both the tibia and fibula the pattern of collagen orientation is characteristic, which may be related to the distribution of the bending forces normally operative in these bones.

Biomechanical Phenomena↗
PubMed1987

Micro-biomechanics vs macro-biomechanics in cortical bone. A micromechanical investigation of femurs deformed by bending.

Previous studies have shown that longitudinal and transverse lamellae in compact bone signal the presence of tensile and compressive forces, respectively. On this basis an investigation has been carried out to ascertain the distribution of lamellae in femoral shafts that have been deformed by bending. To do this, a series of undecalcified plane-parallel sections 100 microns thick were prepared, and the proportion of transversely oriented collagen and crystallites in the lamellae was measured, using circularly polarized light as an illuminating source and a Quantimet 720 image-analyzing computer. It has been concluded that the distribution of the two types of lamellae is in accordance with the need to compensate for the deformity produced by the bending of the bones, and that an obvious relationship exists between the macroscopic features of the femurs and their modified microscopic structures.

Biomechanical Phenomena↗
PubMed1987

Distribution of lamellae in human femoral shafts deformed by bending with inferences on mechanical properties.

On the basis of previous investigations indicating that the distribution of osteonic and interstitial lamellae in a normal femur depends on its mechanical properties, a procedure has been devised to provide information on the distribution of lamellae in human femora diaphyses deformed by bending. To achieve this, exactly plane parallel cross sections, 100 micron thick, were prepared from the portion of maximum bending, using an annular blade microtome. An index of the distribution of longitudinal lamellae (whose fiber bundles and crystallites have a longitudinal course and withstand loading by tension) and transverse lamellae (whose fiber bundles and crystallites have a transverse course and withstand loading by compression) was determined using circularly polarized light as illuminating source and a Quantimet 720 image analyzing computer. The results show that, even in a pathologically deformed bone, both the microscopic structure of sections at the level of osteonic and interstitial lamellae, and their macroscopic shape may be governed by the distribution of the forces active in bone.

Biomechanical Phenomena↗
PubMed1985

Observations on the replacement of loose prostheses.

Revision surgery for loosening of the components in total hip prostheses is still a problem and not only from the purely technical aspects. According to our experience, the use of cement is contraindicated, at least in Schneider grades 2 and 3 of aseptic loosening, because of the biological damage it can cause to the bone grafts used in such cases. The stability of non-cemented reimplants is dependant on good biological anchorage through endosteal osteogenesis. The cardinal points of technique are: complete removal of all cement, necrotic bone, and interposed fibrous membrane; the use of autoplastic bone grafts in the form of chips to replace the lost "bone stock"; the use of prostheses designed for optimum load distribution (long stem, large acetabulum). In the case of ruptured stems, diaphyseal osteotomy is necessary for complete removal of the cement and prosthesis; this can be stabilised by using a Lord prosthesis with a long stem.

Aged↗
PubMed1985

Osteochondritis dissecans of the femoral condyles. A histological study with pre-operative fluorescent bone labelling and microradiography.

A review of the literature in osteochondritis dissecans of the femoral condyles reveals that the aetiopathology is still unclear and that relatively few histopathological studies have been carried out. The authors describe a method of study based on microradiography and on preoperative fluorescent labelling of the osteogenetic area followed by examination of the bone remodelling under ultraviolet light microscopy. The results in 12 adult cases are reported in relation to a topographical scheme which divides the lesions into four separate zones.

Adult↗
PubMed1984

Collagen orientation in compact bone: I. A new method for the determination of the proportion of collagen parallel to the plane of compact bone sections.

Previous work has shown that different types of osteons that have different mechanical properties with regard to tension and compression can be identified and studied by polarized light microscopy. This study reports the development of an automated method for the analysis of that proportion of collagen in transverse sections of human femurs that lies parallel with the plane of section. The method is based upon the use of circularly polarized light to detect collagen with a major component lying in the plane of the section, correcting the measurement for bright collagen under these circumstances with a corresponding darkfield measurement to determine the area of bone within each field of the section analyzed. The method has been validated in several different ways. The measured value of bright collagen under circularly polarized light depends upon the section thickness, since a linear relationship was found between section thickness and bright areas for a large number of microscopic fields. Plane parallel sections are therefore recommended for this study. The pattern of distribution of bright areas was the same for different observers and different set detection levels in any one section. The pattern found in adjacent sections from the same region of the shaft was identical.

Adult↗
PubMed1984

Collagen orientation in compact bone: II. Distribution of lamellae in the whole of the human femoral shaft with reference to its mechanical properties.

Starting from a previous personal investigation (Portigliatti Barbos et al., 1983) indicating that the distribution of osteons and interstitial bone in the middle of the femoral shaft is related to their structure, a new procedure has been devised to allow information of the same kind to be gathered from the whole of the femoral diaphysis. Twenty-three exactly plane parallel cross-sections, 100 micron thick, each located 1 cm from the next, were prepared using an annular blade microtome. The distribution of longitudinal lamellae (whose fiber bundles and crystallites have longitudinal course and withstand loading by tension) and transverse lamellae (whose fiber bundles and crystallites have a transverse course and withstand loading by compression) was determined for both osteonic and interstitial bone, using circularly polarized light as the illuminating source and a Quantimet 720 image analyzing computer. The results show that along the femoral shaft the transverse and longitudinal lamellae from osteonic and interstitial bone have a characteristic rotational distribution consistent with the distribution of the bending forces normally operative in bone.

Adult↗
PubMed1984

Mittelmeier's prosthesis: histological and microradiographic study two years after operation.

The writers present the results of the histological and microradiographic study of a femur and acetabulum two years after the implantation of Mittelmeier's prosthesis, the patient having died from an accident. The periprosthetic diaphyseal cortical bone had been fully resorbed, spongy bone had developed in the central portion and subperiosteal elongated lacunae had formed in the antero-medial part. The sclerosis at the calcar and at the apex of the shaft was made up of osteone systems, part of which consisted of newly laid down bone. The periprosthetic osteofibrous layer was separated from the cortical bone by wide inter-trabecular spaces except in the lateral sector where the shaft was supported by cortical bone that had been relatively conserved.

Acetabulum↗
PubMed1984

Histomorphometric study of the dynamics of mineralization in a case of osteomalacia caused by anticonvulsants treated with 25(OH)d3.

The authors describe the experimental method used to make histomorphometric determinations in a case of osteomalacia caused by anticonvulsant drugs treated with 25(OH)D3. This comprised double fluorescent markings repeated at set time intervals after taking biopsy samples from the patient. This combined method of study enabled the effect of the treatment to be monitored throughout its course.

Adult↗
PubMed1983

Distribution of osteonic and interstitial components in the human femoral shaft with reference to structure, calcification and mechanical properties.

This paper analyzes the distribution of osteons and interstitial bone in the femoral compacta according to their structure, degree of calcification and mechanical properties. Three cross sections, 100 microns thick, each located 1 cm from the next, were prepared by grinding from the middle third of a human femoral shaft. Starting from the premise that, in lamellar bone, lamellae whose fiber bundles and crystallites have a longitudinal course withstand loading by tension, whereas those whose fiber bundles and crystallites have a transversal course withstand loading by compression, each osteon and fragment of interstitial bone has been given a number recording the percentage of its surface consisting of lamellae with transversally oriented fiber bundles and crystallites (bright under the polarizing microscope). The degree of calcification of the same structures was determined micro-radiographically. The distribution of both osteons and interstitial bone was assessed using a tungsten grid for reference. The total surface of each bone microstructure, and the percentage of that surface consisting of bright lamellae, were all calculated using a Zeiss Video-plan. Our results confirm the view that the distribution of both osteons and interstitial bone is mainly related to their structure--and hence to their mechanical properties. In addition, bone remodeling seems to be most active in areas capable of supporting tensile stress.

Biomechanical Phenomena↗
PubMed1983

Metallic debris arising from prosthetic abrasion: investigation of biodegradation of the materials and physiopathology of the bone.

The authors investigated the tissue around a failed knee prosthesis which had a metal-on-metal bearing made of chromium-cobalt-molybdenum alloy. Histological examination and the quantitative analysis of metallic particles found in the bone marrow (by fluorescent spectrometry and laser microsound) provided a detailed picture of the quantity, nature and distribution of the wear debris. The type and nature of the tissue response to the presence of the metal particles was determined by fluorescent microscopy and microradiography.

Aged↗