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Biomedical subjects

E Rizzi

Publications and source records attributed to E Rizzi.

At least 19 recordsLinked to original sources
PubMed1998

[Core biopsy in the preoperative diagnosis of breast carcinoma].

BACKGROUND: In spite of the widespread use of cytological smears for the diagnosis of breast cancer lesions, many surgeons are still reluctant to accept the cytological report as the only criterion for performing definitive surgery. Modern surgical strategy requires a preoperative planning of the surgical treatment which is possible with the use of core biopsy (CB) or FNB (fine needle biopsy) for the diagnosis of tissue specimens. METHODS: The authors report their five-year experience with this technique and evaluate its diagnostic usefulness and substitution of interoperative biopsy. The histological examination of 92 palpable breast lesions, clinically and mammographically detected, was performed with CB, and diagnosis was confirmed with the surgical sample in 80 cases. RESULTS: A definitive histological diagnosis was obtained with CB in 90% of cases. Only nine cases required confirmation with frozen section diagnosis at the time of definitive surgery. The sensibility of CB was 93%, specificity and predictive value of a positive result were 100%, and diagnostic efficiency was 95%. CONCLUSIONS: This study confirms the usefulness of the systematic use of CB for accurate preoperative diagnosis of breast cancer, and the simplicity, safety and accuracy of this method also make ultrasound-guided CB applicable to non-palpable lesions.

Adult↗
PubMed1996

The transcriptional activator Opaque-2 controls the expression of a cytosolic form of pyruvate orthophosphate dikinase-1 in maize endosperms.

The maize Opaque-2 (O2) protein is a transcription factor of the basic/leucine-zipper class, involved in the regulation of endosperm proteins including the 22kDa alpha-zein storage proteins and b32 protein. In this study we have focussed our attention on the relationship between O2 and the cyPPDK1 gene, which encodes a cytoplasmic pyruvate orthophosphate dikinase (PPDK) isoform. The results of this study showed that PPDK activity is detectable in wild-type maize endosperms, while in o2 mutant endosperms, the levels of PPDK protein, mRNA and enzymatic activity are reduced, indicating that O2 is involved in the regulation of cyPPDK1 in this tissue. By employing transient expression experiments in tobacco mesophyll protoplasts, we have demonstrated that the O2 protein can activate expression of a chloramphenicol acetyl transferase reporter gene placed under the control of the cyPPDK1 promoter. An in vitro binding assay and DNaseI footprint analysis demonstrated that a specific sequence in the cyPPDK1 promoter can be recognized and protected by maize O2 protein. The regulation by the O2 locus of cyPPDK1 reported here, and control of alpha-zein synthesis by O2 suggest that the O2 protein may play a more general role in maize endosperm development than previously thought.

Base Sequence↗
PubMed1996

Early events of liver regeneration in rats: a multiparametric analysis.

5-Bromodeoxyuridine (BrdU), a synthetic analogue of thymidine, has been utilized in vivo to detect the proliferation which occurs in the liver after two-thirds surgical hepatectomy. Immunocytochemical detection of BrdU incorporation has been carried out at both the morphological and flow cytometrical level, while structural changes of regenerating liver have been investigated, using Mallory-Azan-stained paraffin sections, by means of an image analyser. The results obtained show that in vivo DNA synthesis progression throughout S phase follows a pattern similar to that previously described in vitro in both 3T3 fibroblasts and Friend erythroleukemia cells and also demonstrate a precise correlation between morphological patterns of BrdU incorporating cells and their lobular distribution. Moreover, the activation of at least two proliferation waves can be detected from 18 to 34 h after hepatectomy: the former, starting from adjacent regions of contiguous lobules, apparently induces an irregular increase of lobular dimension; the latter, involving both inner and peripheral lobular domains, seems to be correlated with the appearance of nodule-like structures at the lobule periphery. In view of these results the role of the hepatic acinus and the hypothesis of a streaming of parenchymal cells during liver regeneration have been discussed.

Animals↗
PubMed1996

Synovial fluid levels of proinflammatory interleukins and their inter-relationships in elderly vs younger onset rheumatoid arthritis.

Elderly-onset rheumatoid arthritis (EORA) is thought to be different from younger-onset disease (YORA) for many reasons, including a more elevated acute phase response and a more abrupt onset; both events are mainly regulated by pro-inflammatory interleukins (ILs), in particular, IL-1, IL-6 and IL-8. To compare the synovial fluid (SF) levels of these ILs, and their relationship to local inflammation as well as the acute phase response, erythrocyte sedimentation rate (ESR) and serum C-reactive protein (CRP) in the two RA subsets, we determined white blood cell (WBC) number, total protein (TP), IL-1beta, IL-6 and IL-8 concentrations in the SF of 50 patients, 15 with EORA and 35 with YORA. Both ESR and CRP were higher in EORA than in YORA. IL-6 was higher in SF of EORA (2111.37 +/- 1425.03 pg/mL) than YORA (1077.53 +/- 757.62 pg/mL, p = 0.002), while no difference was observed for SF IL-1beta and IL-8. There was a weak correlation between SF IL-6 and IL-1beta in EORA, whereas SF ILs and CRP and/or ESR did not show any correlation in both groups. Our study indicates that in EORA, as in other diseases occurring in the elderly, there are elevated levels of IL-6. Higher SF levels of IL-6 may be, at least in part, responsible for the different behavior of EORA with respect to YORA.

Acute-Phase Reaction↗
PubMed1996

Value of synovial fluid interleukin-1 beta determination in predicting the outcome of psoriatic monoarthritis.

OBJECTIVE: To investigate the value of synovial fluid analysis in predicting the outcome of psoriatic monoarthritis. METHODS: In synovial fluid from knee joints of 18 patients with psoriatic monoarthritis lasting less than six months, white blood cell count, acid phosphatase, lysozyme, and interleukin (IL)-1 beta were determined. ESR and serum C reactive protein were also measured. To define the outcome, the patients were monitored for at least three years and then subdivided into those with polyarthritis and those without. RESULTS: Among the blood and synovial fluid indices considered, synovial fluid IL-1 beta was the only variable which differed between the patients who developed polyarthritis, within three years and those without polyarthritis after this time, at 20.82(SD 8.79) v 4.19(4.73) pg ml-1, P < 0.0001). A correlation was found between synovial fluid IL-1 beta concentrations and the number of affected joints after three years (r = 0.739, P < 0.0001). CONCLUSIONS: Determination of synovial fluid IL-1 beta at disease onset may be useful in revealing the outcome of psoriatic monoarthritis since, among the variables considered in our study, this was the only one capable of predicting the evolution of monoarticular psoriatic arthritis to polyarthritis.

Adolescent↗
PubMed1995

Immunocytochemical detection of phosphatidylinositol 4,5-bisphosphate localization sites within the nucleus.

Phosphatidylinositol 4,5-bisphosphate (PIP2) is a key element of signal transduction, being the preferential substrate of specific phospholipases that produce second messengers such as inositol trisphosphate (IP3) and diacylglycerol (DG). Because PIP2 has been cytochemically identified by monoclonal antibodies not only in the cytoplasmic membranes but also in the nuclear envelope and within the nucleus, we performed a study by immunoblotting and by confocal and electron microscopic immunocytochemistry to identify the nuclear sites of PIP2 localization and to exclude any cross-reactivity of the antibody with other nuclear molecules. The results confirm the specificity of the immunolabeling and indicate that PIP2 is localized at precise intranuclear sites both in in situ and in isolated nuclei. They also show that a significant amount of the phospholipid is retained by the cytoskeleton and by the inner nuclear matrix in in situ matrix preparations. Moreover the sensitivity of the immunocytochemical reaction is capable of detecting quantitative variations of PIP2 nuclear content induced by agonists that modulate the signal transduction system at the nuclear level.

3T3 Cells↗
PubMed1995

High-resolution FEISEM detection of DNA centromeric probes in HeLa metaphase chromosomes.

HeLa metaphase chromosome spreads were hybridized with centromeric biotinylated DNA probes and detected with gold-conjugated anti-biotin antibodies. Chromosomes were observed by an in-lens field emission scanning electron microscope (FEISEM), which permits detection of biological samples without any coating. DNA probes were well localized in the centromeric region of chromosomes and there was clear discrimination between 10 nm fibers that hybridized to DNA probes and those that did not hybridize. This approach shows that in situ hybridization can be directly visualized at the FEISEM level by evaluating only secondary electron emission, which allows physical localization of the hybridized probe with high resolution so that backscatter detection represents only a control. Because chromosomes maintain the 10-nm fiber organization after in situ hybridization procedures, our data suggest that this fiber represents the lowest order of chromatin arrangement that permits transitory DNA denaturation.

Centromere↗
PubMed1994

High resolution detection of uncoated metaphase chromosomes by means of field emission scanning electron microscopy.

HeLa metaphase chromosomes were examined by means of "in lens" field emission scanning electron microscopy, which permits high resolution detection of uncoated biological samples. By using uncoated chromosomes as a model for comparison we report evidence of how traditional scanning electron microscopy techniques such as metal coating and conductive methods can generate errors in chromosome structure evaluation, since both give rise to morphological artifacts. By comparing the morphology of uncoated chromosomes obtained by two different isolation procedures, such as that utilized in standard cytogenetics and the polyamine method, we have drawn the following conclusions: (a) the standard cytogenetic method gives rise to a chromosome structure consisting of a flattened network of 10 nm fibers, in which higher order chromatin organization is absent. (b) Chromosomes obtained by the polyamine method show both three-dimensional profile and higher level folding of chromatin fibers, supporting the loop chromosome organization previously suggested by scanning electron microscopy observation of hexylene glycol isolated chromosomes.

Chromosomes, Human↗
PubMed1993

Bromodeoxyuridine incorporation in corneal epithelium: an immunocytochemical study in rats.

Here we investigate the kinetics of rat corneal epithelium at both single cell and tissue level by means of a BrdU-anti BrdU method. The results obtained have then been compared with those previously obtained by us in rat vocal cord epithelium. In this way two main aspects of BrdU incorporation can be indicated at both light and electron microscopy level. First, we report evidence of a new incorporation pattern corresponding to middle S phase, which is characterized by labelling distribution at the border between interchromatin and heterochromatin at ultrastructural level. Second, by comparing tissue incorporation in rats treated with BrdU at the beginning of light time and at the beginning of dark time, we show an increase of cell proliferation during the last hours of dark time and the first hours of light time. In this way, we demonstrate a different progression of circadian rhythms in peripheral regions of corneal epithelium in comparison with that previously observed in vocal cord epithelium.

Animals↗
PubMed1992

DNA synthesis progression in 3T3 synchronized fibroblasts: a high resolution approach.

In order to investigate at ultrastructural level the mechanism of DNA synthesis progression during the different moments of S-phase a bromodeoxyuridine-anti bromodeoxyuridine (BrdU-anti BrdU) method has been applied to synchronized 3T3 fibroblasts. After 30 min BrdU incorporation, five different labelling patterns can be identified and should be related to early, middle and late S-phase. These patterns are represented mainly by diffuse labelling localized in different nuclear domains and by quite rare cases in which the labelling is limited to isolated clusters of gold particles. After a 5-min pulse with BrdU it is possible to observe isolated clusters of gold particles at each moment of S-phase, which, however, exhibit the same distribution of the five principal labelling patterns observed after 30 min incorporation. In both cases labelling can be detected in the interchromatin regions during early S-phase, at the boundary between interchromatin and heterochromatin during middle S-phase and in the heterochromatin domains during late S-phase. Considering their size, the isolated spots of labelling could be interpreted as single replication units which are subsequently activated throughout the different moments of the S-phase.

3T3 Cells↗
PubMed1991

Characterization and cell cycle kinetics of hepatocytes during rat liver regeneration: in vivo BrdUrd incorporation analysed by flow cytometry and electron microscopy.

The incorporation of bromodeoxyuridine (BrdUrd) into newly synthesized DNA has been analysed during hepatocellular regeneration induced by partial hepatectomy in young rats. The kinetic state of the liver has been studied by flow cytometric analysis of the incorporated BrdUrd, while the fine localization of DNA replication sites through the cell cycle has been investigated at the ultrastructural level by the immunogold technique. Eighteen hours after partial hepatectomy flow cytometry revealed an early S phase distribution which corresponded to a specific staining of the interchromatin domains of the hepatocyte nucleus. Thirty-four hours after hepatectomy, on the other hand, when most cells were in late S, a specific staining of heterochromatin domains was observed. The effect of the BrdUrd technique on nuclear aggregation has also been analysed and discussed. The results demonstrate that specific patterns of DNA replication can be recognized during the cell cycle and that flow cytometry and electron microscopy appear to be complementary in the kinetic study of liver regeneration.

Animals↗
PubMed1991

Cell kinetics of vocal fold epithelium in rats.

In order to investigate the kinetics of vocal fold epithelium a bromodeoxyuridine-anti bromodeoxyuridine method has been applied in vivo at both light and electron microscopy level. This method is able to define the length of both epithelium turnover and cell-cycle in basal elements, as well as the existence of a higher proliferation rate during night time in comparison with day time. Moreover distinct labeling patterns observed in incorporating cells allow us to define the precise localization in S-phase of cycling elements.

Animals↗
PubMed1989

Liver toxicity due to 1,2-dichloropropane in the rat.

The effect of 1,2-dichloropropane on rat liver was studied after short (5 days) and long term (4 weeks) i.p. administration. Animals were injected daily with 10-500 mg/kg body wt 1,2-dichloropropane and biochemical and histological changes of liver were investigated. Treatment was monitored by measuring urinary mercapturic acid excretion. A significant increase of mercapturate excretion was observed at all dose levels, with no further increase during the treatment; at lower doses a return to baseline values occurred within 48 h after the end of treatment. Mercapturate excretion at the end of weeks 2, 3 and 4 of treatment was significantly lower than that observed at the end of week 1. The liver reduced glutathione content was different after single or repeated injections. A dose-dependent decrease of liver reduced glutathione was observed after a single injection and a dose-dependent increase after 4 weeks. The liver biochemical pattern after 4 weeks of treatment (characterized by a decrease of cytochrome P-450 and by an increase of reduced glutathione and glutathione S-transferase activity) suggests a hyperplastic evolution of the liver cells, probably a repair mechanism induced by early depletion of reduced glutathione. Light microscopy confirms that the prevalent alterations are regenerative in type (atypical mitosis and hyperplastic nodules). Areas of focal necrosis are isolated, and trend to disappear after long term treatment.

Acetylcysteine↗