Biomedical subjects

L De Palma

Publications and source records attributed to L De Palma.

At least 19 recordsLinked to original sources

PubMed1992

The ultrastructure of peripheral neurofibroma: the role of mast cells and their interaction with perineurial cells.

The authors analyze the ultrastructure of mast cells and perineurial cells when both are present in neurofibroma of the nerve sheath. Samples of pathologic tissue taken from three patients with neurofibroma of a peripheral nerve sheath were analyzed by light and transmission electron microscopy. The observations document the characteristics of the tumor cells (Schwann cells and perineurial cells) as well as the presence of numerous mast cells, typically in close contact with the perineurial cells and never with the Schwann cells. Many electron-dense vesicles were found between the cells; these vesicles are created when the cell membrane of the mast cell buds, and then they come into contact with the adjacent perineurial cell. Endocytosis vesicles are often present in the cytoplasm of perineurial cells. Analysis of these observations led the authors to assume the existence of a metabolic interaction between the two cell type in contact with each other and an active role of the mast cells in the evolution of the tumor. The following two theories are plausible: either the mast cells actively stimulate tumor growth, or they alter the phenotype of the tumor cell. These findings could have interesting clinical applications. The use of treatment protocols which inhibit mast cell activity could, in theory, stop either the proliferation of the neurofibroma or its malignant transformation.

Cell Division↗

PubMed1991

["Slow" fractures of the metatarsi].

On the basis of clinical observation and reports in the literature, the authors discuss the etiology, pathogenesis, and clinical and radiographic aspects of "slow" fractures, with particular reference to those involving the metatarsal. The different etiologic and pathogenetic theories agree upon one point: the concentration of the stresses as a prelude to areas of osteoclastic resorption which lead to microfractures and thus to "slow" fractures. Many factors are responsible for this concentration, and they may very even according to the site of the lesion. In the foot there are many conditions which can potentially explain the pathogenesis of "slow" metatarsal fractures. Overload of the middle metatarsals is one of the most common causes. The overloaded and fractured metatarsal may then become insufficient and in turn, by the same mechanism, cause fracture of the adjacent metatarsals.

Adolescent↗

PubMed1991

[The metatarsophalangeal articulation and the transverse metatarsal ligament: anatomical observations].

The authors conducted a macroscopic anatomical study of the metatarsophalangeal joints of the middle toes in order to add to our knowledge of the anatomy and physiology of this structure. Anatomical observations reveal the foot's lack of transverse ligamentous formations (as the sagittal bundle in the hand) connecting the extensor tendon to the glenoid plate. Consequently, the containment of the extensor tendon above the metatarsophalangeal joint is considerably less stable in the foot than in the hand, since it is entrusted to the posterior portion of the interossei muscles and the deep and superficial retinacula (all formations which run in a prevalently oblique direction). Hyperextension of the metatarsophalangeal joint causes the posterior portion of the interossei muscles, bound to the extensor tendon, to slide proximally, straightening the fibers and loosening the structures that stabilize the extensor tendon. The tendon can then easily shift in a lateral direction with respect to the rotation axis of the metatarsophalangeal joint, acquiring a valgus action. Even though the metatarsophalangeal joint is equipped with strong collateral ligaments, the valgus action of the extensor tendon eventually overcomes the resistance of both these and the weaker connections to the plantar aponeurosis of the foot and the extensor tendons. In conclusion, the lack of structures to provide passive stabilization of the extensor tendon in the metatarsophalangeal joints of the toes makes the foot particularly susceptible to multiple-toe deformity.

Humans↗

PubMed1991

[Morton's disease: optic and electron microscopy observations].

The authors performed an optic and electron-microscope investigation above the common digital nerve of the foot, whose fragments had been surgically removed from patients suffering from "Morton metatarsalgia" (neuroma). Histological sections were taken from pre-stenotic swelling in patients with clinical symptoms persisting for one year; perineural thickening without evidence of fibroblastic proliferation could be demonstrated, together with an intraneural deposition of an amorphous substance. In other patients suffering from Morton's disease for a longer time, a more pronounced epineural thickening in the pre-stenotic zone could be shown, with partial replacement of nerve fibers by amorphous substance. In the same patients endoneural fibrositis was seen at the level of the stenosis. Electron-microscopy in patients after one year showed an increase in collagenous endoneural fibers and microfibrils. These histopathological findings suggest a compressive mechanism in the pathogenesis of the damage to the common interdigital nerve in Morton's disease, caused by the extrinsic anatomical structures surrounding the nerve. The so-called "neuroma" can be identified with the pre-stenotic swelling.

Adult↗

PubMed1990

Morphological changes in growth-plate cartilage in osteogenesis imperfecta.

We obtained specimens of growth-plate cartilage from four patients with osteogenesis imperfecta. Light microscopy showed structural changes in the tissue and morphological changes in chondrocytes and matrix, particularly in the hypertrophic zone. There were changes in the process of calcification in the primary mineralisation zone of the cartilage. We also found histochemical changes in the matrix glycosaminoglycans (GAGs) in the zones where physiological mineralisation was disturbed and where the trabeculae were interrupted and poorly mineralised. In addition to the known molecular defects in collagen, changes in GAGs and non-collagenous proteins are important factors in the pathogenesis of the disease.

Growth Plate↗

PubMed1990

[Osteoid osteoma of the foot].

We relate about our direct clinical experience on 8 cases of osteoid osteoma localized in the bones of the foot. Some atypical appearances, clinical and roentgenographic, of the osteoid osteoma in this bony district may sometimes cause problems in diagnosis and localization, which are exposed and discussed in this paper. Particularly, we underline the importance of bone scan in the detection of the lesion.

Calcaneus↗

PubMed1990

[The foot in rheumatoid arthritis].

Because of its high incidence of rheumatoid arthritis, the foot is probably the best place to study this pathology. Timely diagnosis is very important considering the high risk of disability. On the basis of both other studies and first-hand observations, the particular clinical and radiographic characteristics of rheumatoid arthritis of the foot are analyzed, differentiating it from the same disease in other joints. The research and comparison of these particular aspects helped with the overall clinical evaluation of early-diagnosed rheumatoid arthritis, that is before the development of reabsorption phenomena, bone damage, deformities, and ankylosis of the joints of the foot.

Ankylosis↗

PubMed1990

[Neurogenic deformities of the foot due to congenital malformations of the lumbosacral spine. Their clinical and therapeutic characteristics].

The authors illustrate the different types of nervous disorders of the foot caused by congenital deformations of the lumbosacral spine. They classify these clinical forms according to the level of the neurological lesions, although emphasizing that more complex neurological damage may cause very atypical deformities that are difficult to classify. Today the treatment of nervous disorders of the foot caused by congenital deformations of the lumbosacral spine seems almost promising when compared to neurological and urological problems which have therapeutic priority. Possible methods of surgical correction, as well as indications that differ according to the age of the patient and the type and extent of the deformity, are discussed. These deformities of the foot evolve very quickly; treatment must be timely or reduction is difficult. Furthermore, their peculiar tendency to relapse necessitates periodic comprehensive follow-up exams and regular maintenance therapy (orthetic and physiatric). Special care must be taken before and during treatment to prevent trophic skin lesions. For this reason, solutions other than casts (external fixation, for example) may be preferable for the maintenance of the correction. The treatment of these deformities, whether conservative or surgical, should aim primarily to achieve adequate plantar support for future aided or autonomous ambulation.

Foot↗

PubMed1990

[Apert's syndrome: the clinico-radiographic picture].

Apert's syndrome is a rare malformation (dysostosis), probably of a hereditary nature. It is characterised by craniostenosis, caused by synostosis of the coronal sutures, and by bilateral and symmetrical membranous syndactyly of the hands and feet, to which metacarpal, metatarsal and phalangeal synostoses are associated. Less frequent are dysplastic modifications in other osteo-articular regions and malformations of the viscerae. The authors expose and discuss the etiopathogenetic, clinical and radiographic aspects of this syndrome, in relation to three clinical cases which came to their observation.

Acrocephalosyndactylia↗

PubMed1989

[Fibrinolytic activity and adhesive syndromes of the lumbar vertebral canal].

The recent studies, related in medical literature, indicate a reduced activity of fibrinolysis in patients with low back-pain caused by multiple factors (lumbar disc disease, post-laminectomy, post myelography) and suggest a new pathogenetic hypothesis of this disease and new therapeutic implications. The authors conducted a research based on the study of fibrinolysis in patients affected by post-surgical lumbar adhesive syndrome, with the aim of finding, eventually, a relationship between reduced fibrinolytic activity and clinical symptoms. The results are referred and discussed.

Adult↗

PubMed1989

[Radiographic course of inverted osteochondral graft using the Regnauld technic in the surgical treatment of hallux valgus].

The osteocartilaginous bone graft, conceived by Regnauld for surgical treatment of hallux valgus, is to-day widely known and practised. We have preferably employed the so called "inverted graft", while Regnauld, in his recent monography, defines it less satisfactory than the "cork" or "hat" shaped grafts. Therefore, we have observed the radiological evolution of our inverted grafts, to evaluate the possible differences of their "rootage" in comparison to the cork grafts, studied by Valenti in 1976. Some possible causes of the infrequent failures of this grafting are also examined and discussed. We conclude that the osteocartilaginous graft evolution do not show radiological differences referable to the graft morphology and that unfavourable evolution, when is present, concern at first the articular (cartilaginous) side of the graft, being independent of failed rootage or aseptic necrosis of the bony side.

Bone Transplantation↗

PubMed1989

[Osteo-articular involvement in microdrepanocytic anemia].

Drepanocytosis is a hereditary hemoglobinopathy which is particularly common in Blacks; in its homozygote form there is constant general involvement of the osteoarticular system with clearly recognisable clinical and radiographic pictures. Microdrepanocytosis (double heterozygotosis) is instead more difficult to recognise. Based on their observations the authors report several specific aspects of the disease of orthopaedic interest.

Anemia, Sickle Cell↗

PubMed1987

Ultrasound investigation of the posterior fossa in the fetus.

One hundred and thirty normal pregnancies, ranging in gestational age from 15 to 40 weeks, were investigated to evaluate the capability of ultrasound to demonstrate the anatomy of the fetal posterior fossa. The cerebellum, including the cerebellar hemispheres, the superior and inferior vermis, the fourth ventricle, and the cisterna magna could be demonstrated easily. The ultrasound interpretation of the brain structures was verified by the anatomic dissection of the brains of 10 stillborn premature infants. A systematic approach to the prenatal ultrasound examination of the posterior fossa is described.

Cranial Fossa, Posterior↗

PubMed1986

The fetal subarachnoid cisterns: an ultrasound study with report of a case of congenital communicating hydrocephalus.

The intracranial anatomy of 351 normal fetuses, ranging from 15 to 42 weeks' gestational age, was investigated sonographically in an attempt to define the normal sonographic anatomy of the subarachnoid spaces during intrauterine development. The triangular velum, vein of Galen, ambient, interpeduncular, chiasmatic, Sylvian, and supracerebellar cisterns and the cisterna magna were easily recognized in the vast majority of cases as fluid-filled spaces following the contour of the brain. A large fluid layer, overlying the cerebral convexities, was seen in early gestation and subsequently disappeared. Evaluation of the subarachnoid cisterns in a fetus with ventriculomegaly allowed the prenatal diagnosis of communicating hydrocephalus. Knowledge of the normal sonographic anatomy of the subarachnoid spaces is useful both in avoiding misinterpretation of the normal sonogram and in the differential diagnosis of congenital hydrocephalus.

Cisterna Magna↗

PubMed1986