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Biomedical subjects

A Franchi

Publications and source records attributed to A Franchi.

At least 163 records · Page 9Linked to original sources
PubMed1978

The role of serum albumin in the uptake of fatty acids by cultured cardiac cells from chick embryo.

Fatty acids enter the cultured cardiac cells from chicken embryo through two mechanisms, one involving a saturable process, the other resembling passive diffusion. Studies of the saturable component, at fixed concentrations of palmitate or of oleate and at increasing concentrations of albumin, show that this protein increases the rate of palmitate uptake with a maximum at palmitate/albumin molar ratios between 7 and 10 while it decreases the rate of oleate uptake under all conditions. Albumin cannot be replaced by other serum proteins; its effect is specific to saturated fatty acids, can be mimicked by the detergent Tween 40 and involves the binding of the fatty acid to the protein, prior to its delivery to the cell. Both with labelled saturated and unsaturated fatty acids the presence of albumin lowers the proportion of unesterified fatty acids and enhances the proportion of esterified fatty acids recovered in the cardiac cell after uptake. A similar effect of albumin was also found with hepatocytes and permanent cell lines. A specific role for serum albumin is presented, which assumes a 'dispersing' effect of this protein towards dimers (or higher aggregates) of saturated fatty acids and the entry of fatty acids into the cell as monomers.

Animals↗
PubMed1977

[Experimental studies on the role of suture materials in the healing of anastomoses of the colon. Mechanical and histological study].

The relation between suture material and consolidation and healing in operations on the colon was investigated by using silk and catgut in one group of disinfected stray dogs subjected to right or left hemicolectomy and resection of the transverse portion, and a synthetic reabsorbable material (polyglycolic acid) in another. The following parameters were assessed following removal of the segment containing the anastomosis after various periods of time: resistance to biomechanical tests, stenosis of the lumen, extent and duration of inflammation and regeneration at the edge. Reabsorbable material was associated with less overall inflammation and healing was more rapid. Consolidation of the suture was not significantly different in the two groups.

Animals↗
PubMed1977

Incorporation of a fatty acid containing a photosensitive group into lipids of cultured cardiac cells from chick embryo.

Radioactive 12-(4-azido-2-nitrophenoxy)-stearic acid (NAP-stearate) was synthetized; it behaves as a competitive inhibitor of long-chain fatty acids for the entry into cultured cardiac cells from chick embryo. After uptake, [3H] NAP-stearate was incorporated by an energy-dependent process into neutral and polar lipids. Photoactivation as a function of time leads to a covalent labelling of the cells: up to 31 per cent of the radioactivity was recovered in the 105 000 g cell pellet, mainly in proteins. These experiments show that fatty acids containing photosensitive groups would potentially allow to localize the proteins involved in the binding and/or in the transport of fatty acids.

Animals↗
PubMedDate not supplied

c-myc gene is transcribed at high rate in G0-arrested fibroblasts and is post-transcriptionally regulated in response to growth factors.

There is increasing evidence that at least some of the cellular homologues to retroviral oncogenes (c-onc or proto-oncogenes) are directly linked to the control of cell growth (for a review see ref. 1). Among these, c-myc, the cellular homologue to the avian myelocytomatosis virus (MC29) oncogene, has been shown to express high levels of mRNA during early G0/G1 phase after mitogenic stimulation of T lymphocytes by concanavalin A or of fibroblasts by platelet-derived growth factor (PDGF) or serum. An attractive model proposed for this regulation is that the c-myc gene is strongly repressed in cells arrested in the G0 phase of the cell cycle by a growth factor-sensitive repressor. We have investigated an alternative model of post-transcriptional regulation. This latter model leads to two testable predictions. First, that c-myc mRNA should be unusually unstable, which we have confirmed. And second, that there would be a high level of constitutive expression, a situation opposite to that implied by the repressor model. Here we report that c-myc gene is indeed transcribed at a high rate in G0-arrested chinese hamster lung fibroblasts, although the level of mature c-myc mRNA is barely detectable. The early and dramatic increase in c-myc mRNA levels when these resting cells are stimulated by growth factors is not accompanied by any appreciable change in the transcription rate of c-myc gene. Taken together these findings support a model of post-transcriptional regulation of c-myc expression at the level of mRNA degradation.

Animals↗
PubMedDate not supplied

Cyclooxygenase-2 pathway correlates with VEGF expression in head and neck cancer. Implications for tumor angiogenesis and metastasis.

We evaluated the role of COX-2 pathway in 35 head and neck cancers (HNCs) by analyzing COX-2 expression and prostaglandin E2 (PGE2) production in relation to tumor angiogenesis and lymph node metastasis. COX-2 activity was also correlated to vascular endothelial growth factor (VEGF) mRNA and protein expression. COX-2 mRNA and protein expression was higher in tumor samples than in normal mucosa. PGE2 levels were higher in the tumor front zone in comparison with tumor core and normal mucosa (P<.0001). Specimens from patients with lymph node metastasis exhibited higher COX-2 protein expression (P=.0074), PGE2 levels (P=.0011) and microvessel density (P<.0001) than specimens from patients without metastasis. A significant correlation between COX-2 and tumor vascularization (r(s)=0.450, P=.007) as well as between COX-2 and microvessel density with VEGF expression in tumor tissues was found (r(s)=0.450, P=.007; r(s)=0.620, P=.0001, respectively). The induction of COX-2 mRNA and PGE2 synthesis by EGF and Escherichia coli lipopolysaccharide (LPS) in A-431 and SCC-9 cell lines, resulted in an increase in VEGF mRNA and protein production. Indomethacin and celecoxib reversed the EGF- and LPS-dependent COX-2, VEGF, and PGE2 increases. This study suggests a central role of COX-2 pathway in HNC angiogenesis by modulating VEGF production and indicates that COX-2 inhibitors may be useful in HNC treatment.

Aged↗
PubMedDate not supplied

Cerebellar liponeurocytoma: immunohistochemical and ultrastructural study of a case.

The clinical, histopathological, and ultrastructural features of a cerebellar liponeurocytoma are reported. The tumor, a 3-cm mass localized in the right cerebellar hemisphere, was resected from a 61-year-old man clinically presenting with symptoms of intracranial hypertension. The lesion was composed of small, in some areas closely packed, medulloblastoma-like cells with prominent areas of lipidization phenomena. Moreover, mitoses, cellular atypia, and numerous vascular structures were focally observed. Glial and neuronal differentiation was immunohistochemically noted (glial fibrillary acidic protein, synaptophysin, neurofilaments, and neuron-specific enolase positivity). The p53 oncoprotein was detected in the majority of neoplastic cells and a moderate proliferation activity, evaluated by Mib-1 antibody, was focally appreciated. Ultrastructural study did not show evident neuritic processes, synapses, or dense core neuroendocrine granules. This cerebellar tumor previously called lipidized medulloblastoma and recently renamed cerebellar liponeurocytoma is considered an adult neoplasm with excellent prognosis histologically presenting prominent lipidized areas and, at the immunohistochemical and ultrastructural level, both glial and neuronal differentiation. The present study provides the first description of a less differentiated and histologically more aggressive form of this unusual tumor.

Antigens, Nuclear↗
PubMedDate not supplied

Middle ear adenoma is an amphicrine tumor: why call it adenoma?

Middle ear adenoma (MEA) is a rare tumor postulated to take origin from the lining epithelium of the middle ear cavity. The authors report on a case of MEA arising in a 53-year old woman suffering from a sensation of fullness in her left ear, otalgia, and light left-sided hearing loss. Histopathologically, the lesion was composed of cuboidal and polygonal cells displaying a trabecular, tubulo-glandular, and solid pattern of growth. Immunohistochemically, neoplastic cells diffusely stained with anti-vimentin antibodies and were focally positive for chromogranin A, neuron-specific enolase, lysozyme, and cytokeratins AE1/AE3. The majority of tumor cells showed weak and diffuse staining with both anti-PP and anti-ACTH antibodies and intense positivity with anti-glucagon and anti Leu-7 antibodies. Ultrastructural investigation revealed both mucinous-glandular and neuroendocrine differentiation. The authors suggest that the appropriate terminology would be adeno-carcinoid or amphicrine tumor of the middle ear rather than "adenoma," a term that does not reflect its dual nature.

Adenoma↗
PubMedDate not supplied

Submicroscopic and immunohistochemical profile of surface osteosarcomas.

While the analysis of the clinical, radiologic, and histopathologic features of surface osteosarcomas has been the subject of several papers, identification of the phenotypic features of these tumors has so far received little attention. The aim of the present study was to characterize the neoplastic cells of surface osteosarcomas using an ultrastructural and immunohistochemical approach. Glutaraldehyde-fixed, epoxy resin-embedded archival pieces of tissue from 8 surface osteosarcomas (4 parosteal low-grade osteosarcomas, 3 dedifferentiated parosteal osteosarcomas, 1 periosteal osteosarcoma) were investigated using transmission electron microscopy. Sections of formalin-fixed, paraffin-embedded tumor specimens were employed for the immunohistochemical analysis of osteonectin and osteocalcin, two markers of cells of osteoblastic lineage, and sigma-smooth muscle actin and muscle specific actin. By electron microscopy, the tumors were composed of a mixture of neoplastic cells with varied differentiation, i.e., osteoblast-like, fibroblast-like, myofibroblast-like, and chondroblast-like. The latter were particularly abundant in the periosteal osteosarcoma. Osteocalcin expression was detected in the cytoplasm of neoplastic cells in 6 cases (66.6%), while osteonectin was expressed at least focally in all cases. The expression of the noncollagenous bone proteins was higher in low-grade osteosarcomas than in dedifferentiated osteosarcomas. sigma-Smooth muscle actin and muscle-specific actin expression were detected in 4 (44.4%) and 5 (55.5%) cases respectively, and the distribution was similar in both low-grade and dedifferentiated lesions. The results do not confirm previous observations regarding the prevalence of a specific cellular phenotype in surface osteosarcomas. Further, the myofibroblast-like cells that are present in variable numbers in these tumors are probably modified osteoblasts, since they co-express actin, osteonectin, and osteocalcin.

Actins↗
PubMedDate not supplied

Microsatellite instability as biomarker for risk of multiple primary malignancies of the upper aerodigestive tract.

Head and neck cancer (HNC) patients are at high risk of developing second primary tumors of the upper aerodigestive tract and this is a chief cause of death. Genomic instability reflecting the propensity and the susceptibility of the genome to acquire multiple alterations is considered a driving force behind multiple carcinogenesis and the alterations of the length of single repetitive genomic sequences or microsatellite instability (MI), implicating impaired DNA repair mechanisms, and could be a sensitive marker for assessing genomic instability in multiple HNC. To investigate whether a genetic defect(s) involving the mismatch repair system constitutes a risk factor in patients with multiple head and neck cancer, we examined replication errors (RER) at 10 microsatellite loci in 21 primary and 5 second primary cancers in 21 patients with multiple malignancies of the upper aerodigestive tract, in comparison with match-paired primary HNC from patients without multiple malignancies. A RER+ phenotype (alterations at > or =2 loci) was observed at 10 microsatellite alterations on chromosomes 2, 3, 11, 17 in at least one tumor from 15 out of 21 (71.5%) patients with multiple primary cancers but only in 11 tumors from 40 (27.5%) HNC patients with single cancer (P=0.001). A RER+ phenotype was also associated with a positive familial cancer history (P=0.046). Our results suggest that a genetic instability may play an important role in the pathogenesis of multiple primary cancers and that testing for MI in a primary HNC may be useful in detecting patients with high risk for developing multiple malignancies of the upper aerodigestive tract.

Adult↗
PubMedDate not supplied

[Health surveillance program for the prevention of Mycobacterium tuberculosis infection risk among health personnel of the Polyclinic and the University of Modena].

Surveillance programme for the prevention of Mycobacterium tuberculosis risk infection among health care workers at Azienda Policlinico and Università di Modena. Increase in tuberculosis (TB) morbidity and mortality in the last decade even in highly industrialized countries represents a major public health problem. Health care workers (HCWs) are one of the high-risk group for TB infection in the population. Several international guidelines for the prevention and control of TB infection among HCWs have been proposed, also including expensive and not easily applicable interventions. A surveillance programme has been set up at the Servizio di Sorveglianza Sanitaria in the Azienda Policlinico di Modena aimed to the early identification of hospital workers with recently-acquired latent TB infection, B.C.G. vaccination of PPD skin negative subjects working in intermediate-high TB risk workplaces, periodic evaluation of PPD skin conversion rates among personnel of each working area. This programme, whose feasibility depends on the availability of adequate resources, is considered as a tool suitable for the individual risk assessment and should be performed together with technical and structural interventions to carry out an effective primary prevention of TB infection among HCWs.

Humans↗
PubMedDate not supplied

Immunohistochemical and ultrastructural investigation of neural differentiation in Ewing sarcoma/PNET of bone and soft tissues.

The authors evaluated the role of immunohistochemistry and electron microscopy in defining neural differentiation in 28 cases of Ewing sarcoma/PNET. The panel of primary antibodies used included vimentin, MIC-2, NSE, S-100 protein, leu7, neurofilaments, GFAP, and chromogranin A. Cases were considered undifferentiated when neural markers were absent, poorly differentiated if one neural marker was present, and well differentiated if two or more markers were observed. Cases were also evaluated for the presence of cytoplasmic processes, microtubules, and neurosecretory granules as ultrastructural features of neural differentiation: the tumor was classified as well differentiated if two of these features were present; and poorly differentiated if one was evident; all other cases were considered undifferentiated. According to immunohistochemistry, 10 cases (35.7%) were undifferentiated, 12 cases (42.9%) were poorly differentiated, and 6 (21.4%) were well differentiated. According to the ultrastructural analysis, 10 tumors were undifferentiated (35.7%), 14 poorly differentiated (50%), and 4 well differentiated (14.3%). The overall concordance between the two techniques was low (35.7%), and both modalities were concordant in classifying only 1 well-differentiated, 5 poorly differentiated, and 4 undifferentiated tumors. In conclusion, the authors suggest that investigations devoted to test the prognostic significance of neural differentiation in these neoplasms should employ both immunohistochemistry and electron microscopy, separately and in combination, to assess what is the most effective choice for predicting the clinical course.

Adolescent↗