Biomedical subjects

G Zúccaro

Publications and source records attributed to G Zúccaro.

4 recordsLinked to original sources

PubMed1987

Bacterial adhesion to cerebrospinal fluid shunts.

Bacterial adherence to cerebrospinal fluid (CSF) shunts was analyzed in vivo and in vitro. Scanning electron micrographs (SEM's) of catheters removed from pediatric patients with shunts infected by Staphylococcus aureus or Klebsiella pneumoniae revealed numerous bacterial cells and microcolonies, leukocytes, and erythrocytes attached to the CSF catheters' inner walls, as well as the existence of surface irregularities, such as fissures, rugosities, and holes. Permeability analyses and SEM's demonstrated that catheters develop physical alterations over the period of implantation. Different bacterial strains presented a different in vitro adherence to CSF shunts, suggesting that this attachment may be affected by specific properties of the outer structures of each strain. The attachment of microbial pathogens to CSF shunts seems to contribute to the persistence of bacterial cells within a catheter and the onset of recurrent shunt infection. This study demonstrated that some bacteria can remain attached within shunts in vitro despite a CSF flow at rates up to 200 times higher than those normally demonstrated in vivo. Furthermore, surface irregularities found throughout this study may help to anchor and hide bacterial microcolonies. Based on these findings, it seems advisable to remove an infected shunt and to replace it with a new one after proper antimicrobial therapy, in order to prevent recurrent infections.

Bacterial Adhesion↗

PubMed1985

Primary rhabdomyosarcoma of brain and cerebellum. Report of four cases in infants: an immunohistochemical study.

Tumors of the central nervous system (CNS) composed of pure mesenchymal derivatives with both embryonal and mature striated muscle cells devoid of neuroblastic elements should be considered rhabdomyosarcomas. Some 13 cases have been reported, and here we study four additional cases in infancy under 3 years of age which represent 0.82% of 483 intracranial tumors studied by us at the Children's Hospital in the last 12 years. Two cases were localized in the temporal lobes, and two were in the cerebellar vermis. All of them were typical embryonal rhabdomyosarcomas at various stages of differentiation including undifferentiated mesenchymal cells, embryonal cells, and rhabdomyoblasts. Tumor cells achieved a higher degree of differentiation in the cerebellum, as shown by readily detectable immature muscle fibers which were consistently absent in tumors involving the brain. Myoglobin [peroxidase-antiperoxidase (PAP) technique] was positive throughout in rhabdomyoblasts and in immature muscle cells, whereas glial fibrillary acidic protein was negative in all four tumors. In spite of the well differentiated appearance of the cerebellar tumors, their behavior was highly malignant with extensive infiltration of brainstem leptomeninges in one case, and all patients survived for only a short time after surgery. These tumors may be observed in the midline structures of the posterior fossa and in the brain, but we suspect their true incidence might be higher if immunohistochemical techniques were applied.

Brain Neoplasms↗

PubMed1981

Microscopic studies in shunts for hydrocephalus.

Valve-regulated systems, used for the treatment of hydrocephalus, were studied with the scanning electron microscope. The study was performed on unused systems of shunt replaced after different pathologies and on systems removed due to cerebrospinal fluid infection. Defects in the material, such as holes and protrusions, were systematically found in new systems. Aged shunts (1--8 years of implantation) as well as those removed in cases of cerebrospinal fluid infections showed important changes in the structure of the material too; it was also found that biological material, such as fibrin, red blood cells and bacteria, were able to adhere to the walls of the catheter tubing. These results indicate that the scanning electron microscope could be a complementary tool to be used in research, diagnosis, and quality control of silicone rubber prosthesis.

Cerebral Ventricles↗

PubMed1981

Spinal tumors and hydrocephalus.

Spinal tumors associated with hydrocephalus is a rare condition. The clinical, radiological and pathological features of 6 such cases are reported and correlated with those already published. Hyperproteinorrhachia and arachnoiditis, with basal or cortical blockage of the cerebrospinal fluid pathways have been consistently found and the subsequent hydrocephalus seems to be unrelated to the level, location or the pathology of the spinal lesion.

Cerebrospinal Fluid Shunts↗