Biomedical subjects

G Biagini

Publications and source records attributed to G Biagini.

At least 91 records · Page 5Linked to original sources

PubMed1995

Changes in glucocorticoid receptor immunoreactivity after adrenalectomy and corticosterone treatment in the rat testis.

The distribution of glucocorticoid receptor (GR) in the rat testis was investigated by means of immunocytochemistry (IR) and computer-assisted image analysis. A monoclonal antibody against rat liver GR showed the presence of GR IR selectively in the nuclei of interstitial and tubular cells. The semiquantitative microdensitometry of GR IR revealed that 77% of the specific staining was localized in the tubular compartment of rat testis. After adrenalectomy, GR IR was greatly reduced both in interstitial and tubular cells, roughly at the same degree. Corticosterone treatment (50 mg/kg, for 5 d) of adrenalectomized animals yielded a recovery of nuclear immunopositivity without changing the cellular distribution of GR, as observed in control rats. Nevertheless, the high dose of corticosterone administered produced a significant (p < 0.01) decrease of GR IR with respect to control rats. These results provide evidence for a prevalent nuclear binding of GR in the tubular compartment in basal conditions. On the other hand, adrenalectomy or repeated corticosterone treatment seem to affect GR similarly in all positive cells without changing significantly the proportion of GR IR in the different testicular compartments. This uneven distribution of GR IR suggests that tubular cells can be a major target of corticosterone when affecting directly testicular functions in the rat.

Adrenalectomy↗

PubMed1995

Modulation of expression of p53 and cell proliferation in locally advanced cervical carcinoma after neoadjuvant combination chemotherapy.

OBJECTIVE: In the present study, we investigated changes of p53 expression and the cell proliferation index detected with MIB 1 in tumors before and after neoadjuvant combination chemotherapy with respect to the outcome of the disease. Our aim was to define more appropriately the significance of chemotherapy in locally advanced cervical carcinoma. MATERIALS AND METHODS: Our study included 17 women with locally advanced squamous cervical carcinoma who had been admitted to the Institute of Gynecology and Obstetrics Ancona University, between January 1990 and December 1994. The patients received neoadjuvant combination chemotherapy consisting of three cycles of cisplatin (80 mg/m2) and bleomycin (30 mg/m2). After chemotherapy, radical surgery was performed. Bioptic specimens were obtained from cervical tumors before and after chemotherapy and processed for immunohistochemical staining with a monoclonal antibody against p53 and with the monoclonal antibody MIB 1. RESULTS: Thirteen patients (76.5%) showed a clinical response (4 complete and 9 partial), while of the remaining 4 cases (23.5%) 3 had no change and 1 showed progression after neoadjuvant combination chemotherapy. A significant relationship was observed between the overexpression of p53 and the sensitivity to chemotherapy; responder patients showed a higher frequency of p53 positive cells than non-responders (P = 0.03). No significant relationship with MIB 1 index was observed. Both expression of p53 protein (P < 0.001) and reaction with MIB 1 (P = 0.003) significantly decreased after chemotherapy. The decrease in expression of p53 protein and staining with antibody MIB 1 was particularly evident in patients who responded to chemotherapy. DISCUSSION: In tumors, p53 protein and index of proliferating cells as determined with MIB 1 showed a significant modulation after treatment, suggesting an association with sensitivity to chemotherapy. However, the limited number of our series of patients does not permit a statement on the clinical implication of expression of p53 and cell proliferation in patients undergoing neoadjuvant combination chemotherapy for locally advanced cervical carcinoma.

Adult↗

PubMed1995

Location of 72-kd metalloproteinase (type IV collagenase) in untreated prostatic adenocarcinoma.

The aim of the study was to investigate the location of the expression of 72-kd metalloproteinase (MMP-2) in relation to the distribution of type IV collagen in untreated prostatic adenocarcinoma (PAc). Twenty formalin-fixed, paraffin-embedded PAc cases, in which high grade prostatic intraepithelial neoplasia (PINhigh) was occasionally present, were immunohistochemically examined. Type IV collagen immunoreactivity showed the presence of a basement membrane (BM) at the epithelial-stromal junction. In cribriform and solid/trabecular PAc, the staining was focally disrupted. In acinar PAc, the BM immunostained by anti-type IV collagen was observed around the individual acini, with occasional thinning and fragmentation. Immunostaining for MMP-2 was heterogeneous in intensity and location. Cribriform and solid/trabecular PAc showed weak cytoplasmic immunostaining for MMP-2; both moderately and intensely stained cells were seen in the cell layer adjacent to the stroma; intense immunostaining was shown by small clusters of neoplastic cells or single neoplastic cells located in the stroma which also showed thinning and fragmentation of BM staining. In acinar PAc, weak cytoplasmic immunostaining for MMP-2 was seen throughout most areas of the tumours, whereas moderately and intensely stained cells were observed less frequently than in cribriform and solid/trabecular adenocarcinoma. Intense immunostaining of single or small clusters of neoplastic cells located in the stroma was rarely observed and, as for cribriform and solid/trabecular PAc, mainly located towards the periphery of the tumour nodules. BM stained by anti-type IV collagen was preserved in normal prostate and in PIN, some thinning being present in the latter. The pattern and intensity of immunoreactivity for MMP-2 in PIN was similar to that of cribriform and solid/trabecular PAc, whereas normal ducts and acini showed weak immunostaining in most of the secretory cells and moderate to strong immunoreactivity in scattered basal cells. Thus, MMP-2 appeared basically expressed in cells which lie in direct contact with the stroma. This underlined the importance of evaluating the MMP-2 location in relation to basement membrane degradation and tumour invasion.

Adenocarcinoma↗

PubMed1995

Temporal changes in sulphated glycoprotein-2 (clusterin) and ornithine decarboxylase mRNA levels in the rat testis after ethane-dimethane sulphonate-induced degeneration of Leydig cells.

Short- (3-24 h) and long-term (4-50 days) changes in sulphated glycoprotein-2 (SGP-2) and ornithine decarboxylase (ODC) mRNA levels in the adult rat testis were studied following a single dose of ethane-dimethane sulphonate (EDS), to destroy the Leydig cells. Distribution patterns of SGP-2 and ODC labelling were consistent with prevailing expression of the two transcripts in Sertoli cells and germ cells, respectively. This pattern did not show appreciable changes following EDS administration. No labelling of SGP-2 mRNA was noted in the interstitium of control and EDS-treated rats. This finding indicates that Leydig cell death induced by EDS is not associated with increased SGP-2 mRNA levels, a phenomenon related to apoptotic cell death in many tissues. Semi-quantitative densitometric analysis of the preparations demonstrated differential changes in SGP-2 and ODC mRNA levels in the tubular compartment following EDS treatment. At 6, but not at 3 and 12, h following EDS administration, SGP-2 mRNA levels showed a significant increase, possibly secondary to a direct effect of the alkylating agent on Sertoli cells. A significant decrease in ODC mRNA levels was observed from day 7 to day 28, matching degenerative changes in the seminiferous epithelium. In contrast, a decrease in SGP-2 transcript levels was observed from days 21-35 after treatment. In conclusion, our findings demonstrate that SGP-2 mRNA, a putative marker of apoptosis, is not altered in the testicular interstitium during EDS-induced degeneration of Leydig cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

The human umbilical vein in normal, hypertensive and diabetic pregnancies: immunomorphological and ultrastructural evidence.

Mother-fetus exchanges at the placental level are found to be altered in women affected by hypertensive or diabetic pregnancies following the onset of microenvironmental, circulatory, trophic or tissue disorders. Our aim was therefore to assess the alterations occurring within the umbilical cord, particularly its venous endothelial component and underlying smooth muscle layer, using transmission (TEM) and scanning electron microscopy (SEM) and immunohistochemical analyses. Immunohistochemical data appear to support the ultrastructural evidence for an activated state of these vascular structures, in both conditions (hypertension and diabetes). Furthermore, mainly during diabetic pregnancies, extracellular matrix molecules such as tenascin and fibronectin also quantitatively increase at the vein wall level. The umbilical cord seems to be a structure capable of responding actively to abnormal microenvironmental conditions which seriously threaten the health of the fetus and also the mother herself.

Cell Adhesion Molecules↗

PubMed1995

Umbilical veins in dichorionic twins. A morpho-functional assessment.

Investigations on singleton and twin pregnancies show different functional behaviour on maternal-fetal relationship. In some ways twin pregnancies may be considered at risk and they may develop associated pathologies such as hypertension. The aim of this work was to evaluate the morpho-functional behaviours of umbilical cord veins in twin and singleton gestations to better understand the role of these extra-embryonic tissues in the regulation of pregnancies. The umbilical cords were studied from singleton pregnancies and from dichorionic twin pregnancies. Biochemical and morphological investigations were carried out. A significant decrease in the anisotropy values was observed in endothelial cells from twins compared with singletons. Our ultrastructural data show immaturity features at the vein vessel wall level in twins. Furthermore, immunohistochemical investigations showed a lower degree of expressivity concerning adhesion molecules such as ICAM-1 and ELAM. Morphogenetic extracellular glycoproteins like fibronectin and tenascin seem over-expressed in twin pregnancies. Our morpho-functional data well testify the lower maturation degree of umbilical cord veins in twins with respect to singletons.

Anisotropy↗

PubMed1995

Human skeletal muscle mitochondria in aging: lack of detectable morphological and enzymic defects.

We have investigated structural and functional properties of skeletal muscle mitochondria obtained from biopsies from young and old individuals. The morphometric analysis of muscle sections revealed a tendency to an increase of total area, numerical density and volume density of mitochondria in the aged. The enzymatic activities of NADH-Coenzyme Q reductase, succinate cytochrome c reductase, ubiquinol-cytochrome c reductase exhibited a high variability of specific activities without any correlation with age. Expression of the values as enzyme turnovers reduced the variability but was unable to reveal any age-dependent modification.

Adolescent↗

PubMed1994

Different classes of volume transmission signals exist in the central nervous system and are affected by metabolic signals, temperature gradients and pressure waves.

Volume transmission (VT) is the mode of intercellular communication involving the diffusion of transmitters, via extracellular fluid (ECF) pathways, from nerve cells selectively capable of producing the signal (signal source) to nerve and glial cells selectively capable of recognizing it (signal target). The proposal is now put forward that at least two classes of VT signals can be distinguished: (a) the private-code signals, exemplified by neurotransmitters, which are released by a limited group of nerve cells and recognized, via high affinity G-protein coupled receptors or by cytosolic enzymes such as guanylate cyclase in the case of nitric oxide, by a specific group of cells; and (b) the accessible-code signals, such as the electrical signals that are released by all neuronal cells and decoded by almost every CNS cell. In the present paper, it will be underlined that carbon dioxide, hydrogen ions, temperature gradients and pressure waves may be regulators of wiring transmission and VT.

Animals↗

PubMed1994

Possible mechanisms for the powerful actions of neuropeptides.

In order to understand the mechanisms underlying the powerful actions of neuropeptides, the present article has emphasized the unique ability of neuropeptides to act as VT signals, which via high-affinity G-protein coupled receptors can exert long-lasting actions and control synaptic transmission via receptor-receptor interactions. Also of substantial importance is the ability of neuropeptides to act as a set of signals via the formation of different types of active fragments, which can act as negative-feedback or positive-feedback signals to modulate the response elicited by the parent peptide and to give origin to syndromic responses. Also in the actions of the fragments on the neuronal network, receptor-receptor interactions may play an important role both by modulating the parent peptide receptors and by modulating other types of VT and/or WT receptors. Future work will have to evaluate the role of neuropeptides as transcellular signals and as regulators of neuronal excitabilities after the formation of carbamates, but certainly new important developments are within the horizon of today's research.

Animals↗

PubMed1994

A biochemical-morphological study on microvillus plasma membrane development.

The microvillus plasma membrane of the human placental syncytiotrophoblast at term has been extensively studied, while little is known about the characteristics of its development. The aim of the present work was to compare functional and structural properties of this membrane at early and term gestational age. Ten normal term placentas (40 weeks) and ten placentas at 10 weeks of gestational age were studied. The Na+/K+-ATPase activity is significantly decreased in the syncytiotrophoblast plasma membrane obtained from term placentas as compared to the early ones, with significant variation of maximum velocity (Vmax). The microviscosity, evaluated by the P parameter of DPH and Sn parameters of 5- and 16-NS, is increased in the term placentas compared to the early placentas. This alteration is accompanied by an increased cholesterol to phospholipids ratio in term placentas, while there is a decreased unsaturated to saturated fatty acid ratio. As follows from morphological studies, an increased mean diameter in the E face was observed in the term placenta with respect to the early placenta. The distribution factor DF, which indicates the particle aggregation state, decreased in the E face in the term placenta as compared to the early one. The present biochemical morphological study shows that a deep modification of the membrane is at the basis of the syncytiotrophoblast plasma membrane development.

Female↗

PubMed1994

Stimulatory effect on bone formation exerted by a modified chitosan.

A novel modified chitosan carrying covalently linked imidazole groups (average molecular weight 700,000, degree of substitution 0.28, degree of acetylation 0.08) was used to stimulate bone formation in an animal model. Lesions (7 mm diameter) were surgically made in the femoral condyle of sheep and treated with the modified chitosan. Within 40 d after surgery, the neoformed tissue occluded the surgical hole and assumed a trabecular structure in the peripheral area of the lesion, while looking like a mineralization nodule in the central part in association with a fibrous component. In the control, no sign of osteoinduction or reparative process was observed and bone marrow was rich in adipocytes.

Adipocytes↗

PubMed1994

The concept of astrocyte-kinetic drug in the treatment of neurodegenerative diseases: evidence for L-deprenyl-induced activation of reactive astrocytes.

Basic fibroblast growth factor (bFGF) increases neuronal survival and growth in cell cultures and stimulates functional recovery from brain lesion. In addition, bFGF is able to induce glial cell proliferation and differentiation. Recently, L-deprenyl has been shown to potentiate astrocyte reaction to a mechanical lesion and to possess a trophic-like activity in several experimental models. In the present paper, we have therefore investigated if the enhancing effect of L-deprenyl on astrocyte reactivity is accompanied by increased levels of bFGF. The effect of L-deprenyl (0.25 mg/kg/day) on bFGF immunoreactivity (IR) after the insertion of an injection cannula in rat neostriatum have been investigated. It has been found that subchronic L-deprenyl treatment potentiates both the lesion-induced increase of glial fibrillary acidic protein (GFAP) and bFGF IRs (P < 0.01). These data suggest that a possible mechanism for L-deprenyl-induced neuroprotection may be the activation of astrocytes associated with increased secretion of trophic factors that promote neuronal survival and growth. This "astrocyte-kinetic" action of L-deprenyl could represent a new therapeutical approach to increase trophic support of lesioned neurons.

Animals↗

PubMed1994

The use of acellular autologous skeletal muscle grafts in peripheral nerve repair: a morphometrical-morphological study.

Alternative materials for autologous nerve grafts in peripheral nerve surgery have long been investigated. This report describes the use of acellular (freeze-thawed) autologous skeletal muscle grafts (ASMG) to bridge a 2 cm gap in the sciatic nerve of rats. Neurophysiologic and morphometric studies performed 6 weeks after surgical procedure showed for the nine treated Sprague-Dawley rats (Group A) a good axon regeneration rate, although this was lower than that for the control group (Group B), a lower Nerve Conduction Velocity (NCV) and a thinner myelin sheath than in group B (n = 9 Sprague-Dawley rats). In the latter case, complete resection of 2 cm of the sciatic nerve was followed by an immediate coaptation of the proximal and distal ends.

Animals↗

PubMed1994

Characterization of large unilamellar vesicles as models for studies of lipid peroxidation initiated by azocompounds.

The aim of this work was to characterize large unilamellar vesicles (LUVETs) prepared by a hand-driven extrusion device in order to use them for studies of lipid peroxidation and antioxidant activity. Vesicle structure and size were examined by electron microscopy. Lipid and antioxidant content was determined before and after the extrusion procedure. Then LUVETs were subjected to autoxidation initiated by both the lipid-soluble 2,2'-azobis(2,4-dimethylvaleronitrile) and the water-soluble 2,2'-azobis(2-amidinopropane hydrochloride) azocompounds. The results demonstrated that: i) LUVETs prepared with lipid concentrations ranging between 25 and 150 mM were essentially unilamellar and reasonably homogeneous, with an average diameter of 90 nm; ii) the phospholipid, cholesterol and antioxidant amounts retained by filters were about 10-15%; iii) LUVETs were suitable for autoxidation studies initiated by the water-soluble azocompound both in the absence and presence of antioxidants. The lipid-soluble azocompound could be used only at low concentrations and its vesicle content had to be determined since part of the initiator was not incorporated into the lipid bilayer. These data suggest that LUVETs seem to be recommended for studies of lipid peroxidation and antioxidant activity.

Antioxidants↗

PubMed1994

Fibroblast proliferation over dialysis membrane: an experimental model for "tissue" biocompatibility evaluation.

The present study reports on a biological model based on fibroblast proliferation applied to 3 different types of flat-plate dialysis membrane, in order to ascertain whether the artificial materials currently used in hemodialysis cause in vitro cellular proliferation. The study plan we followed involved plate membrane isolation from non-used dialyzers and used dialyzers, observed through scanning electron microscopy (SEM) both before and after testing with human fibroblasts by means of cell culture. Fibroblast growth was assessed by phase contrast light microscopy examination and cytometric DNA content evaluation. Our investigations proved that the artificial materials we considered interact with fibroblast cultures. Noticeable proliferative response was observed both after contact with unused material and on mediation by the protein layer absorbed on the membrane surface at the end of dialysis sessions. In this last case fibroblast proliferative activity appeared higher than that observed with unused membranes, showing that the soluble molecules entrapped in the protein layer appeared able to exert a biological activity even in vitro tests.

Acrylic Resins↗

PubMed1994

Lack of major mitochondrial bioenergetic changes in cultured skin fibroblasts from aged individuals.

Human skin fibroblasts from young and old donors were cultured in vitro and compared in their mitochondrial morphology and function. A decreased numerical density of mitochondria in the fibroblasts from old individuals was balanced by the increased size of individual mitochondria. The mitochondrial membrane potential, estimated in the intact cells by the difference between the total accumulation ratio of the lipophilic cation tetraphenylphosphonium and the accumulation ratio in presence of uncoupler, was unchanged, as were some mitochondrial enzymatic activities tested in the homogenates. The results point out that the decreased proliferating capacity observed in the fibroblasts from the old subjects was accompanied by a likely decrease of mitochondrial duplication; the decreased energy utilization for cell division balances a possible energetic decline in such way that the steady-state energy status is unchanged.

Aging↗

PubMed1994

[Regeneration of peripheral nerves after interposition of acellular muscle into larger defects].

Peripheral nerve grafting is an established procedure in reconstructive surgery. Nerve grafts, however, are only available to a limited extent and patients are faced with neurologic deficits at the donor areas. Pretreated skeletal muscle has been proposed as an alternative grafting material. In nine adult Sprague-Dawley rats, a 2 cm gap of the sciatic nerve is grafted with a M. gracilis segment which has been pretreated through repeated freezing and thawing. Regeneration is evaluated after six weeks postoperatively. The results are compared to nine conventional nerve grafts. Regeneration was evident in all grafts. Histologically, the muscle grafts revealed a high proportion of connective tissue, a good vascularisation but an inferior degree of myelinisation. Morphometrically, the muscle grafts proved to be inferior according to axon counts and myelinisation. Muscle grafts provide a substrate comparable to peripheral nerves regarding the tubular architecture based on laminin. There are however no viable Schwann cells within these substitutes, which makes them inferior compared to conventional nerve grafts for peripheral nerve repair. These results are discussed with respect to further experiments concerning allogeneic nerve grafting and peripheral nerve preservation.

Animals↗

PubMed1993

Indole-pyruvic acid, a tryptophan ketoanalogue, antagonizes the endocrine but not the behavioral effects of repeated stress in a model of depression.

Increased glucocorticoid secretion is frequent in mood disorders and is normalized by long-term antidepressant therapy. Many antidepressants act by increasing central serotonin transmission. We investigated the effects of a serotonin precursor, indole-pyruvic acid (IPA), in an animal model of depression based on repeated exposure to unpredictable stress. Rats were divided in groups, and IPA (20 mg/kg), the tricyclic antidepressant imipramine (IMI) (5 mg/kg), or vehicle was administered daily during 3 weeks of repeated exposure to various stressors according to the procedure described by Katz et al [Katz RJ, Roth KA, Carroll BJ (1981): Neurosci Biobehav Rev 5:247-251]. After treatment, rats were evaluated for stress-induced exploratory behavior and killed 24 hr later. Serum corticosterone levels and glucocorticoid receptor (GR) immunoreactivity (IR) in the nuclei of neurons located in the hippocampal subregion CA1 were also measured. Rats exposed to repeated stress showed a lower exploratory behavior score (p < 0.01), higher basal corticosterone levels (p < 0.01), and stronger GR IR in the hippocampus (p < 0.05) than control rats. All of these effects were antagonized by IMI treatment. IPA administration did not affect the behavioral response induced by repeated stress (p < 0.01) but normalized serum corticosterone levels. In addition, IPA treatment produced a decrease in GR IR (p < 0.05 versus control group) that was not modified by exposure to repeated stress.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗