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Biomedical subjects

L Valvassori

Publications and source records attributed to L Valvassori.

At least 19 recordsLinked to original sources
PubMed2001

Expression profile of epidermal differentiation complex genes in normal and anal cancer cells.

Anal cancer originates from a peculiar histological region and provides a useful model for investigating alterations in proliferation and/or differentiation of neoplastic keratinocytes. Epidermal differentiation complex (EDC) genes, which form one of the major gene clusters in the human genome, are involved in the terminal differentiation of epithelial cells and in many instances have been implicated in epithelial tumours. We constructed a DNA macroarray capable of characterising the expression profiles of the entire EDC gene complex in normal mucosa and anal cancer biopsies of seven unrelated patients. Brain tissue and cultured keratinocytes were used as controls. All anal cancer samples showed expression profiles in which none of the EDC genes was silent, as evaluated by phosphor-imager analysis. Variance analysis showed significantly lower expression of SPRR2 with respect to SPRR1 or SPRR3, and significantly higher expression of S100A8 than of other S100A subfamily members. At hierarchical clustering analysis, the four basaloid anal cancer cases conglomerated in the top five positions. The macroarray method used by us provides the first demonstration of the expression profile of the EDC gene family in anal cancer, and is capable of producing significant information on the subgrouping of epithelial tumours such as anal cancer.

Adult↗
PubMed2000

Expression analysis and mutational screening of the epithelium-specific ets gene-1 (ESE-1) in patients with squamous anal cancer.

To investigate whether ESE-1 gene abnormalities are involved in alterations of epithelial cell differentiation in squamous anal cancer ESE-1 expression and structure were screened in six patients by reverse transcriptase-polymerase chain reaction (RT-PCR) and automated sequence analysis. The complete cDNA of isoform ESE-1b was always expressed and correctly spliced, with single nucleotide polymorphism being observed in two cases. Presence of ESE-1b point mutations was excluded. Expression of SPRR2A and ENDOA/CK8, two epithelium-specific ESE-1 target genes, were revealed by RT-PCR in all cases. This first report of expression of ESE-1, and of SPRR2A and ENDOA/CK8 (both related to terminal differentiation in different types of epithelia lining) in anal cancer excludes the hypothesis that these genes influenced carcinogenesis in our patients. Despite selecting of patients without clinical evidence of HPV infection, PCR consistently revealed HPV-16 DNA, highlighting the importance of HPV infection in anal cancer.

Adult↗
PubMed1998

Endovascular treatment with GDCs: results in 100 patients.

BACKGROUND: In this paper we review the clinical and morphological results of intracranial aneurysms treated with Guglielmi Detachable Coils. METHODS: We report our experience in 100 patients with intracranial aneurysms treated with GDC. Since February 1993 we have treated 70 females and 30 males, with a mean age of 57 years old, for a total of 118 intracranial aneurysms. Sixty-five patients had a recent history of ruptured aneurysm, 10 suffered from a previous subarachnoid hemorrhage and 25 patients had never bled. In the choice of treatment for subarachnoid aneurysm, in accordance with our neurosurgeons, we have not applied a protocol, rather we have followed guidelines in relation to: age, neurological clinical conditions, systemic disease and location of aneurysm. Morphological aspect of immediate aneurysm occlusion was: 60% more or less complete occlusion, 30% loose packing with 10% failures. RESULTS AND CONCLUSIONS: The clinical outcome at follow-up (1 month-3 years) was: 72 patients without neurological deficits, 19 patients improved pre-existing neurological deficits, 3 patients worsened for procedural complications; 6 patients died (1 patient unrelated).

Embolization, Therapeutic↗
PubMed1995

[Relapsing epistaxis: embolization as treatment of choice].

Epistaxis is a very common disease. Fortunately it occurs most commonly in the anterior septal network of blood vessel and is therefore readily controlled with simple local measures. Severe posterior epistaxis is less frequent but is still a common and much more serious clinical problem and usually requires hospitalization. The classic treatment of these epistaxis is combined anterior-posterior nasal packing. Occasionally, however, this treatment does not control bleeding. The most popular alternative for these patient is arterial ligation. Initially only carotid ligation was performed. Later further advances in surgical technique and instrumentation, permitted internal maxillary and etmoid artery ligation to be carried out. However often arterial ligation cannot be easily performed in some ent departments and furthermore, surgical failure rate is not exceptionally high if one consider the numerous hypsilateral-contralateral arterial anastomoses present in the etmoid-nasal region. Fifteen patients with recurring nasal bleeding were treated with embolization between 1991 and 1993. Ten of them suffered of essential epistaxis while the other five had chronic local and/or systemic diseases (hereditary haemorrhagic teleangectasia and angiomas). Analysis of the results show a good control of bleeding in the first group of patients (90% after one embolization) and a satisfactory control in patients with haemorrhagic teleangectasia. In conclusion, owing to its efficacy, speed and safety therapeutic embolization with PVA particles may be considered treatment of choice in recurrent persistent epistaxis.

Adult↗
PubMed1993

Presence and characteristics of circulating megakaryocyte progenitor cells in human fetal blood.

The in vitro growth of early (burst-forming unit-megakaryocyte [BFU-meg]) and late (colony-forming unit-megakaryocyte [CFU-meg]) megakaryocyte progenitors was investigated in midtrimester human fetal blood and compared with adult bone marrow. Most of the experiments were performed in a serum-free fibrin-clot assay, using purified hematopoietic progenitor (CD34+) cells. High BFU-meg and CFU-meg levels were found in human fetal blood, with a clear prevalence of BFU-meg (BFU-meg:CFU-meg ratio, 2.5:1), at variance with adult bone marrow, in which mature CFU-meg predominate (BFU-meg:CFU-meg ratio, 0.6:1). Fetal and adult megakaryocyte progenitors had a similar phenotypic profile for the expression of CD34, HLA-DR, and glycoprotein-complex IIB-IIIA. However, fetal BFU-meg were larger in size (number of megakaryocytic elements per colony) than adult BFU-meg, but were usually composed by only one or two foci of development. On the other hand, fetal and adult CFU-meg were similar in both morphology and size. Fetal megakaryocyte progenitors appeared earlier in culture and had an increased proliferative activity as demonstrated by the higher number of megakaryocyte progenitors in S phase with respect to adult CFU-meg and BFU-meg. Finally, fetal megakaryocyte progenitors displayed a higher sensitivity to stimulatory cytokines, in particular recombinant interleukin-3, than adult megakaryocyte progenitors, whereas they were inhibited by purified transforming growth factor-beta 1 in a similar fashion to adult megakaryocyte progenitors.

Adult↗
PubMed1989

Nonpulmonary thoracic biopsy.

The aim of the present paper is to distinguish between thoracic pulmonary needle biopsy--which can be carried out under fluoroscopic guidance--and thoracic extrapulmonary needle biopsy, which requires a more accurate type of guidance, such as CT. Among the 500 thoracic punctures performed during the last 5 years, we considered only 90 biopsies of mediastinal (N = 58) or thoracic wall (N = 32) masses. We have thus excluded all parenchymal lesions of the lungs. For extrapulmonary thoracic masses, CT was the method of choice for biopsy guidance which provided diagnostic evidence of small-diameter mediastinal lesions that permitted analysis of the relationship to vascular structures and performance of extrapleural needle insertion, using larger-gauge needles to ensure accurate needle placement within the lesion. In both mediastinal and thoracic wall lesions an overall accuracy rate of 84% was obtained. In no case was thoracic drainage required for treatment of the moderate degree of pneumothorax that occurred in 1% of our patient population.

Biopsy, Needle↗
PubMed1989

Differential activity of saporin 6 on normal and leukemic hemopoietic cells.

The antiproliferative effect of saporin 6 (SO6), a ribosome-inactivating protein (RIP) purified from the seeds of Saponaria officinalis has been tested on three leukemic cell lines (K562, U937, and HL60), human normal bone marrow, and peripheral blood hemopoietic progenitor cells from normal subjects. In leukemic cell lines, SO6 appeared much more effective against erythrocytic than against monocytic and promyelocytic leukemic cells, as shown by protein synthesis assays carried out after up to 72 h of culture. Among the normal hemopoietic progenitor cells, erythroid burst-forming units were the most affected, with results similar to those observed in the erythroid leukemic cell line, both in treated and in pretreated cultures, with strong damage after 24 h of exposure to SO6. On the other hand, granulocyte-macrophage colony-forming units (CFU-GM) from bone marrow were significantly more affected than the myeloid leukemic cell lines after permanent treatment with the inhibitor, the damage being significantly lower after an exposure of 24 h. CFU-GM from peripheral blood and megakaryocyte CFU showed an intermediate sensitivity after 24 h of exposure to SO6, similar to that of the other normal precursors after permanent treatment with the drug.

Bone Marrow Cells↗
PubMed1988

[Magnetic resonance of the thoracic aorta].

Various pathological conditions of the thoracic aorta were studied by MR Imaging in 31 patients: 23 were aneurysms (branching and non-branching), 2 arterio-venous fistulae, 2 aortic prostheses, 2 Marfan's syndromes, 1 coronary sinus aneurysm, and 1 isthmic stenosis. MRI studies were always performed on patients who had been examined by other imaging procedures. A comparative study was carried out on the results of MRI, angiography, computerized tomography, and ultrasounds. The possibility of propedeutic protocol was explored. Our experience, in accordance with the literature on the subject, indicates MRI as the procedure of choice in the study of aneurysms of the thoracic aorta. The advantages offered by MRI--the high natural contrast between circulating blood and the supporting structures, the possibility of obtaining multiplanar images as well as data on intraluminal, parietal, and extraparietal conditions--make it a highly competitive procedure if compared to either CT or angiography. While awaiting further evidence, the use of a propedeutic protocol in non-aneurysmatic diseases is still not advisable, due to insufficient patient population, and to the lack of a consistent literature on the subject.

Adult↗
PubMed1987

Human T-lymphocyte-derived megakaryocyte colony-stimulating activity.

Conditioned medium from a T-lymphoblastic cell line (Mo) contains a number of well-characterized hemopoietins. In this paper we demonstrate that Mo cells also release a factor(s) able to stimulate the growth and the differentiation of megakaryocytic progenitors into large-size pure megakaryocytic colonies in plasma clot cultures. Comparison with other sources of human-active hemopoietins shows that Mo-conditioned medium performs better than others, especially for the megakaryocytic lineage. The factor(s) shows strong similarities with human Meg-CSF obtained from a thrombocytopenic patient's plasma, and is distinguishable from the other hemopoietins present in the medium.

Bone Marrow Cells↗
PubMed1986

Human myeloid precursor cells do not possess or produce procoagulant activity (PCA).

The procoagulant cellular activity (PCA) of human myeloid precursor cells was evaluated after fractionation of normal bone marrow cells over a discontinuous albumin density gradient. No PCA was documented in any of the six freshly isolated fractions (F1-F6); significant amounts of PCA were instead produced, after a 4-h endotoxin preincubation, in fractions F1 and F2, which, unlike the other fractions, contained up to 5% monocyte-macrophages. After removal of the latter by plastic adherence, the PCA was abolished. This study shows that PCA can be produced only by monocyte-macrophages upon endotoxin activation, while myeloid precursor cells, at all stages of differentiation, are incapable of PCA. The PCA demonstrated in some human acute myeloid leukemias, other than that of the monoblastic subgroup, appears therefore to be related to the neoplastic transformation rather than to a maturation arrest or to a toxemic stimulation.

Blood Coagulation Factors↗
PubMed1984

Megakaryocytopoiesis in bone marrow-derived stromal-hemopoietic cells co-cultures: action of Tamm-Horsfall glycoprotein.

Murine bone marrow cells are cultured in agar in the presence of marrow-derived fibroblasts and pokeweed-stimulated spleen conditioned medium. Granulo-monocytic colonies and a few megakaryocytic and mixed colonies are induced. The addition of Tamm-Horsfall glycoprotein - a human glycoprotein produced in the kidneys - increases the number of colonies and stimulates megakaryocytopoiesis. The glycoprotein does not have colony-stimulating activity nor does it induce megakaryocytopoiesis in monolayer cultures. Its major glycopeptide retains the ability to increase the number of colonies, but not to induce megakaryocytopoiesis. Cell-cell interactions occurring in the hemopoietic microenvironment and the effect of glucides are discussed.

Acetylcholinesterase↗
PubMed1981

Ph1-negative T lymphocytic colonies in agar cultures of peripheral blood in chronic myeloid leukemia.

T lymphocytic colony formation by peripheral lymphocytes separated by discontinuous albumin gradient centrifugation was evaluated in 8 patients with Philadelphia (Ph1)-positive chronic myeloid leukemia (CML). Colonies were obtained using a liquid-on-agar culture system recently introduced (PHA overlayer-leukocyte feeder layer assay) which has been shown to be simple and reliable. The pattern of colony growth in CML and in normal controls was similar, the peak ranging from the 4th to the 6th day. Also the morphological aspects of colonies did not differ in the two groups. Cells recovered from CML lymphocytic colonies were shown to belong to T cell lineage, as they are able to form spontaneous E-rosettes and to respond to mitogenic stimulation in vitro. In contrast, cells recovered from all other cultured fractions failed to display these properties. Cytogenetic analysis showed that T colony cells were Ph1-negative whereas the chromosome anomaly was found in nonlymphoid colonies of the same patients, thus suggesting a nonclonal origin of T lymphocytes in CML.

Agar↗
PubMed1980

[Growth in vitro of human bone marrow after freezing in liquid nitrogen: analysis of a case].

Human marrow is frozen according to the Schafer's technique; CFU-C proliferation and differentiation is then evaluated in relation to the time of storage in liquid nitrogen and to the time of in vitro culture in agar system according to the Pike and Robinson's technique. The highest plating efficiency is observed at the twelfth day of culture while in fresh cell suspension the growth peaks at the eighth day.

Bone Marrow Cells↗
PubMed1978

Cell separation, cell differential and granulocyte colony frequency in polycythemia vera.

In seven patients with polycythemia vera, the agar colony growth of bone marrow total nucleated cell suspensions and of the cell fractions obtained with an albumin discontinuous density gradient were studied. In one patient, the density distribution of colony-forming units in culture (CFUc) before and after alkylating treatment was evaluated and cell differentials on smears obtained from each density fraction were determined. A high percentage of low density CFUc compared with the total CFUc population and with that in the normal control subjects in the same density fractions was observed.

Bone Marrow↗