PubMed Health⌕ Search

Biomedical subjects

M Stefanini

Publications and source records attributed to M Stefanini.

At least 19 recordsLinked to original sources
PubMed1992

Identification of the eleventh complementation group of UV-sensitive excision repair-defective rodent mutants.

The drug-sensitive mutant UVS1, isolated from the Chinese hamster cell line CHO9, was previously found to complement the UV sensitivity of the excision repair-defective rodent mutants representative of groups 1 to 8 (Hata et al., Cancer Res., 51: 195-198, 1991; M. Numata et al., personal communication). Recently two new complementation groups of UV-sensitive CHO mutants, e.g., groups 9 and 10, have been identified (Stefanini et al., Cancer Res., 51: 3965-3971, 1991). In this paper we demonstrate that the repair defect in UVS1 cells is genetically different from those present in the mutants CHO7PV and CHO4PV, representing groups 9 and 10, respectively. Therefore, UVS1 represents a new complementation group of UV-sensitive rodent cell lines, the eleventh group.

Animals↗
PubMed1992

Immunosuppressive molecules produced by Sertoli cells cultured in vitro: biological effects on lymphocytes.

In the present study we have analyzed the proteins secreted in vitro by murine Sertoli cells to identify immunosuppressive factors. Our data show that Sertoli cells secrete molecules capable to inhibit proliferation of lymphocytes activated in vitro. Cytophluorimetric analysis indicates that treated cells are arrested in the G1 phase of cell cycle. The inhibitory activity is specific for both B or T lymphocytes but not for other non-lymphoid cells and is associated to proteins, heat and freeze stable, with Mr of more than 30 kDa. Lymphocytes treated with Sertoli immunosuppressive proteins drastically reduce the secretion of interleukin-2.

Animals↗
PubMed1992

Development and cytodifferentiation of peritubular myoid cells in the rat testis.

The cytodifferentiation of peritubular myoid cells was studied in developing rats from fetal day 18 through approachment of puberty. The parameters taken into consideration were 1) the presence of desmin, a component of intermediate filaments in contractile cells; 2) the expression of alkaline phosphatase, a cell surface enzyme present in no other cell type of the seminiferous tubule; 3) the expression of the smooth muscle specific isoform of alpha-actin, a marker of terminal differentiation in smooth muscle cells; 4) cell proliferation rate, evaluated in radioautography as labeling index after incorporation of 3H-thymidine in short-term organ culture; and 5) cytoarchitectural changes detected with scanning electron microscopy. By means of immunofluorescence and cytochemistry it was observed that the three markers are expressed early during life, long before the onset of the first spermatogenic wave; in particular desmin is already present in fetal samples and alkaline phosphatase activity appears a few days after birth, whereas alpha-smooth muscle isoactin is first detected around birth. As for myoid cell replication, the high prenatal labeling index was found to drop soon after birth and to further slow down during the first month of postnatal life, suggesting that myoid cell proliferation is not a major factor in peritubular expansion. SEM examination of developing peritubulum has shown that, when approaching puberty, the myoid cell undergoes a dramatic change in cytoarchitecture, consisting in extreme flattening and cytoplasmic expansion resulting in an apparent increase in peritubular surface.

Actins↗
PubMed1992

Different rate of chromosome breakage in human fibroblast strains after storage in liquid nitrogen.

Cytogenetic investigation was carried out on fibroblasts stored in liquid nitrogen during a period of 7-99 months. Cell strains were from 9 individuals, 2 of whom were affected by xeroderma pigmentosum group C (XPC), and 2 XPC heterozygotes. In cell samples from 3 normal subjects and from 1 patient, high frequencies of abnormal mitoses were observed at the first passage after thawing, which returned to normal values after a few subcultures. The most frequent lesions were chromosome gaps and breaks. The cells damaged the most were those from one XP patient. These findings indicate that cells from some individuals are hypersensitive to clastogenic factors acting during freezing and thawing procedures. This sensitivity could be related to the genetic constitution, although the XP homozygous condition is not an essential or sufficient factor.

Adolescent↗
PubMed1992

DNA repair investigations in nine Italian patients affected by trichothiodystrophy.

Trichothiodystrophy (TTD) is a rare autosomal recessive disorder characterized by brittle hair, mental and growth retardation, peculiar face, ichthyosis, and in 20% of the reported cases photosensitivity. Cellular photosensitivity due to the same genetic defect present in xeroderma pigmentosum group D (XP-D) has been described in several patients. Nine patients with clinical symptoms diagnostic for TTD have been identified in Italy to date. We report the results of DNA repair investigations performed in cultured fibroblasts from these patients and 8 TTD parents. Survival, DNA repair synthesis and RNA synthesis following UV irradiation were all normal in the 8 TTD heterozygous cell strains. Among the 9 TTD-affected individuals, normal cellular UV sensitivity was observed in the 2 patients without signs of clinical photosensitivity. In contrast, the other 7 TTD cell strains showed a notable reduction in UV-induced DNA repair synthesis (UDS) levels, ranging between 40% and 5-15% of normal values. Complementation analysis indicated that in the repair-deficient TTD cell strains the genetic defect is the same as that present in XP-D cells. The biochemical heterogeneity of the XP-D defect in TTD patients characterized by different degrees of defective UDS results in different patterns of response to the killing effect of UV light in non-proliferating cells.

Cells, Cultured↗
PubMed1992

Voltage-gated calcium channels in rat Sertoli cells.

We have studied Ca2+ voltage-gated channels of immature rat Sertoli cells by measuring intracellular Ca2+ concentration and its variation following administration of various agents in fura-2-loaded, confluent monolayers in culture. Our findings indicate that the basal Ca2+ intracellular level is about 100 nM, a value that falls within the range found in most eukaryotic cells. The intracellular Ca2+ level is rapidly increased by fetal bovine serum through release of intracellularly stored Ca2+ and opening of membrane cation channels. Substantial Ca2+ influx in rat Sertoli cells seems to be mediated by voltage-gated cation channels, which are sensitive to nifedipine, nicardipine, and omega-conotoxin. To investigate whether FSH, which controls several morphological and biochemical events of prepubertal Sertoli cells, modified Ca2+ influx in this cell type, we analyzed the cell response to acute FSH administration. The results show that, although not influencing the basal concentration of Ca2+, FSH decreases intracellular calcium influx induced by membrane depolarization. Similar data were also obtained by adding dibutyryl cAMP to the external medium and by increasing endogenous cAMP.

Animals↗
PubMed1992

Distribution of beta 1 integrin subunit in rat seminiferous epithelium.

We have studied the presence and distribution of beta 1 integrins in the seminiferous epithelium of prepubertal and adult rats. Our immunofluorescence data show that in the adult the antibody recognizes specific areas localized around the heads of elongating and maturing spermatids and above spermatogonia at stages I-VII. The following were found to be negative: a) areas adjacent to spermatogonia at stages IX-XIV and adjacent to spermatocytes and to round spermatids; b) spermiated spermatozoa. In the prepubertal rat, positive tubules are first apparent around Day 17 of age. Immunofluorescence and immunoprecipitation studies show that Sertoli cell monolayers from 3-wk-old rats express beta integrins in vitro.

Animals↗
PubMed1992

Immune defects in families and patients with xeroderma pigmentosum and trichothiodystrophy.

Xeroderma pigmentosum (XP) is a rare autosomal recessive disease characterized by photosensitivity, a high incidence of cancer in sun-exposed portions of the skin and a reduced capacity to repair the u.v.-induced DNA damage. One of the XP mutations (XP-D) has also been identified in patients affected by trichothiodystrophy (TTD), a rare autosomal recessive disease characterized by brittle hair, mental and physical retardation, peculiar face and ichthyosis. However, in these patients there is no evidence of increased skin tumour incidence. Since an impairment of cell-mediated immunity has been proposed as a co-factor in the cancer proneness of XP patients, we investigated the involvement of immune defect(s) in five XP patients, five TTD patients, their parents, and 24 TTD relatives. We evaluated the phenotype of circulating lymphocytes, natural killer (NK) cell lytic activity, target cell binding of NK cells at single cell level and the effect of interferons (IFN) alpha and beta on NK cell activity. The relative proportion of CD3+ and CD4+ circulating lymphocytes was reduced in XP but not in TTD patients. NK cell lytic activity was decreased in XP patients and their mothers, but their fathers showed normal lytic activity. NK activity varied among TTD families: four out of five patients and their relatives presented low NK cell activity, and one family was normal. In TTD family members, NK activity increased after incubation with IFN-alpha or IFN-beta, but never reached normal values. In contrast, in XP patients and their mothers, the defect was almost completely corrected after in vitro incubation with IFN-alpha or IFN-beta. Our study indicates impaired NK lytic activity in the majority of TTD and XP patients and that this defect is present also in members of their families. In addition, XP patients present a low number of circulating T cells. These multiple abnormalities, together with DNA repair defects, could be related to the increased cancer risk in XP patients.

Abnormalities, Multiple↗
PubMed1992

[Clinical and cellular studies in a patient with Cockayne syndrome].

Hypersensitivity to the lethal effect of ultraviolet light (UV) and other DNA-damaging agents has been observed in cells from patients affected by Cockayne syndrome, suggesting that this syndrome is deficient in the capability to repair damage in cellular DNA. We report a case showing the main clinical features of Cockayne syndrome in which the clinical and cellular photosensitivity described as typical for Cockayne syndrome is not present. These cytological results suggest that there is considerable clinical and cellular heterogeneity in Cockayne syndrome and that cellular sensitivity to UV might not be as essential for the diagnosis of Cockayne syndrome as previously thought.

Adolescent↗
PubMed1991

Blood and bone marrow eosinophilia in malignant tumors. Role and nature of blood and tissue eosinophil colony-stimulating factor(s) in two patients.

Eosinophilia of the blood and bone marrow may be encountered in patients with disseminated malignancies. It is unrelated to the histologic type of the tumor but usually reflects its aggressiveness and prognostic outlook. Its pathogenesis is controversial. The presence of eosinophil colony-stimulating factor(s) in serum and malignant tissue extracts was evaluated in two cases of malignancies accompanied by marked blood and bone marrow eosinophilia. When compared with controls, serum and tumor tissue extracts stimulated the growth of G, M, and Eo colonies in semisolid cultures of human bone marrow. Such stimulating effect was inhibited by the addition of antibodies to granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3. Thus, the colony-stimulating factor(s) play a role in the pathogenesis of the eosinophilia associated with some malignant tumors, and these factors appear to include GM-CSF, interleukin-3, and probably others.

Adenocarcinoma↗
PubMed1991

Novel Chinese hamster ultraviolet-sensitive mutants for excision repair form complementation groups 9 and 10.

In this paper we demonstrate that the mutants CHO7PV and CHO4PV isolated by us from the CHO-K1 prol- cell line represent two new complementation groups of UV-sensitive excision repair-defective rodent mutants. We have classified the mutant CHO7PV as representative of Group 9 and CHO4PV as representative of Group 10. Cellular and biochemical characterization of these mutants indicates that they are moderately sensitive to a broad spectrum of mutagens (UV and mono- and bifunctional alkylating agents), partially unable to perform UV-induced DNA repair synthesis, and partially defective in the incision step of the DNA excision repair pathway and in the removal of the two main lesions caused by UV [cyclobutane pyrimidine dimers and (6-4) photo-products]. In terms of UV survival and incision, CHO4PV is apparently more defective than CHO7PV (40% and 50% of wild-type survival, respectively, and 55% and 75% of wild-type incision), whereas when repair DNA synthesis and lesion removal are compared, CHO7PV seems to be more severely affected (30% of wild-type unscheduled DNA synthesis in CHO7PV and 60% in CHO4PV). This suggests a subtlety in the relation between removal of these specific lesions and overall repair capacity and survival.

Animals↗
PubMed1991

In vitro production of estradiol by ovarian granulosa cells in a case of McCune-Albright syndrome.

A 14-year-old girl presented with classic McCune-Albright syndrome. She underwent the ablation of several cysts during a laparotomy performed on the basis of persistent and intense pelvic pain and recurrent episodes of menometrorrhagia not responsive to pharmacologic therapy. Granulosa cells obtained from an isolated follicle and a cyst were cultured and estradiol (E2) secreted in the culture medium measured. Granulosa cells, obtained from the follicle, produced much higher levels of estradiol compared to those of cells coming both from follicles of equivalent size and preovulatory follicles of normal patients. Secretion of E2 by granulosa cells from the cyst was comparable to that of normal preovulatory follicles. We conclude that in this patient, ovaries are hyperfunctioning in terms of E2 production. This high production of estradiol and the fact that several cysts were found in the ovaries can justify the high levels of estradiol found in the serum of this patient at the moment of the operation.

Adolescent↗
PubMed1991

Chromosome rearrangements in normal fibroblasts from xeroderma pigmentosum homozygotes and heterozygotes.

Chromosome analysis was carried out in cultured fibroblasts from unaffected skin of five unrelated xeroderma pigmentosum (XP) patients and nine family members. Structural chromosome changes were observed in cultures from all examined individuals. Furthermore, in one XPD patient and in one XPC patient and his parents, cytogenetically abnormal clones were detected. Some of these clones were present starting from the primary explant. This cytogenetic pattern is similar to that observed in an XPC patient previously studied by us. The analysis of breakpoint distribution from clonal and non-clonal chromosome rearrangements showed that some breakpoints were more frequent and common to different families or to different family members although definite evidence of preferential involvement of chromosome bands was not obtained. This investigation indicates that there is a consistent tendency toward chromosome instability in XP mutation carriers. The instability could be related to the multiple chromosome anomalies characterizing skin tumors in XP subjects.

Adolescent↗
PubMed1990

An intercellular adhesion protein of rat testis: isolation and preliminary characterization.

By using biochemical and immunochemical approaches, we have isolated a rat spermatocyte surface protein of an apparent molecular weight of 80 kd involved in spermatocyte-Sertoli cell recognition in culture. Preliminary characterization of such a molecule has demonstrated that 1) it is a nonintegral membrane component; 2) it possesses a small amount of N-linked oligosaccharides of the high mannose type; and c) it is a stage-specific molecule, being present only in middle-late pachytene spermatocytes.

Animals↗
PubMed1990

Safe and effective, prolonged administration of epsilon aminocaproic acid in bleeding from the urinary tract.

A total of 9 patients with macroscopic hematuria from various causes, none with evidence of disseminated intravascular coagulation, received low oral, divided doses (approximately 150 mg. per kg. per day) of epsilon aminocaproic acid for up to 21 consecutive days. The hematuria was controlled effectively without overt clinical reactions. Parameters of hepatic and renal function, indicators of muscular damage, were studied in detail in 3 patients. No significant abnormalities were found. The use of small doses of epsilon aminocaproic acid was not accompanied by significant complications and appeared to be effective in special situations for the control of urinary bleeding. This therapy may have indications in a number of urological states accompanied by excessive hematuria.

Adult↗