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A Palumbo

Publications and source records attributed to A Palumbo.

At least 73 records · Page 4Linked to original sources
PubMed1994

In situ localization of apoptosis in the rat ovary during follicular atresia.

Apoptosis is a type of physiologic cell death that occurs in many tissues and be regulated by peptide growth factors. Recent studies indicate that apoptosis occurs in the ovary during follicular atresia in several animal species, including the rat, pig, chicken, baboon, and rabbit. The purpose of this study was to demonstrate, through in situ identification of apoptotic cells in intact ovarian sections, the sites in which apoptosis occurs in the rat ovary in different functional states. We evaluated the presence of apoptosis in three models: immature rats, eCG-treated rats and adult cycling rats. Paraffin ovarian sections were pretreated with proteinase K and then end-labeled with biotinylated deoxyuridine triphosphate (dUTP) by incubation with the enzyme terminal deoxynucleotidyl transferase (TDT). They were then stained through use of avidin-conjugated peroxidase with 3,3'-diaminobenzidine as the substrate. Healthy antral and preantral follicles had no staining. The nuclei of granulosa cells of preantral and antral atretic follicles were positively stained in all the animal groups. Scattered theca cells were also stained. Stromal cells were consistently negative. Positive controls were sections pretreated with DNase I; these displayed intense staining of all nuclei. Negative controls, in which either terminal TDT or its biotinylated substrate was omitted, were appropriately negative. This study represents a systematic analysis of apoptosis in the rat ovary at different functional stages and supports the hypothesis that apoptosis is involved in the process of follicular atresia.

Animals↗
PubMed1994

Recombinant interferon-gamma inhibits the in vitro proliferation of human myeloma cells.

Interferon-alpha (IFN-alpha), interferon-gamma (IFN-gamma) and dexamethasone (DEX) have shown anti-tumour effects in multiple myeloma (MM) cells. Bone marrow plasma cells from 39 MM patients were cultured to clarify the intensity and specific activity of each compound on bromo-deoxyuridine (BrdUrd) uptake and immunoglobulin (Ig) secretion. BrdUrd uptake was inhibited by recombinant human IFN-gamma (100 U/ml) and by DEX (10(-6) M). The stimulation index (StI), i.e. labelling index (LI) of treated samples/controls, was 0.49 +/- 0.09 (mean +/- standard error of the mean, M +/- SEM), P = 0.0003, and 0.52 +/- 0.07 (M +/- SEM), P < 0.0001, respectively. Ig secretion was reduced by IFN-alpha (100 U/ml) and DEX. The secretion index (SI), i.e. Ig quantitation of treated samples/controls, was 0.04 (M +/- SEM), P < 0.0001, and 0.52 +/- 0.04 (M +/- SEM), P < 0.0001, respectively. Finally, IFN-gamma inhibits BrdUrd uptake only and IFN-alpha secretion only. In 18 patients the simultaneous addition of IFN-alpha plus IFN-gamma mainly parallel the effect of IFN-gamma on BrdUrd uptake and IFN-alpha on secretion, but not result in any additive or synergistic effect, though both BrdUrd uptake and Ig secretion were decreased to about the same extent as with DEX. These data indicate that the combination of IFN-alpha plus IFN-gamma and DEX are the strongest inhibitors of both BrdUrd uptake and secretion. Since IFN-alpha and IFN-gamma appear to have a different mechanism of action, their combined use could be considered as a possible new treatment strategy.

Bone Marrow↗
PubMed1994

Primary plasma cell leukaemia.

Among 750 previously untreated patients with multiple myeloma, 27 (4%) presented with plasma cell leukaemia. All but one patient had high tumour mass and, when compared with comparable patients without leukaemia, more frequent extraosseous involvement, thrombocytopenia, high serum lactate dehydrogenase and hypodiploid plasma cells. Most patients also had complex cytogenetic abnormalities. Treatment with standard melphalan-prednisone was ineffective, with a median survival of 2 months, but more intensive chemotherapy induced responses in approximately one-half of the patients, with a median survival of 20 months. Primary plasma cell leukaemia usually results from the proliferation and extramedullary expansion of immature plasma cells and requires prompt and intensive chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

Photochemistry of 5-S-cysteinyldopa.

The photochemical behavior of 5-S-cysteinyldopa (5-S-CD), a colorless product of melanocyte metabolism, was investigated in neutral phosphate buffer with biologically relevant UV radiation. Exposure of 5-S-CD to pyrex-filtered UV light (wavelengths > 320 nm) was found to induce an oxygen-dependent reaction, leading to, besides abundant polymeric materials, the benzothiazine derivatives I and II (two diastereoisomers). Superoxide dismutase exerted a small inhibitory effect on 5-S-CD consumption, whereas other active oxygen scavengers had no effect on the reaction course. Addition of glutathione as a hydrogen donor completely suppressed the reaction. With UVB light (wavelength range 280-320 nm) photolysis of 5-S-CD proceeded mainly with formation of 3,4-dihydroxyphenylalanine, arising presumably by photohomolytic cleavage of the S-CH2 bond followed by desulfuration. These results are of interest in relation to the high susceptibility of fair-complexioned individuals to actinic damage and skin cancer.

Cysteinyldopa↗
PubMed1994

Impaired leukotriene B4 release by neonatal polymorphonuclear leukocytes.

Leukotriene B4 (LTB4) is a potent mediator of inflammation generated by polymorphonuclear leukocytes (PMN) in response to an appropriate stimulus. It acts as a chemoattractant and stimulates PMN functions, amplifying their inflammatory response. Newborn infants show an increased susceptibility to infections in which PMN dysfunctions play the main role. In this work, LTB4 release from neonatal polymorphonuclear cells was assessed to investigate whether a defect was detectable. Blood was obtained from the umbilical cord of 10 full-term healthy neonates and 10 adult controls. The LTB4 production from purified PMN suspensions was induced by three different stimuli: the calcium ionophore A23187, serum-treated zymosan, and formyl-methionyl-leucyl-phenylalanine at final concentrations of 2 microM, 10 mg/mL, and 10 microM, respectively. The kinetics of LTB4 release were studied for up to 30 min by assaying the supernatants of the stimulated cells with a specific RIA. The LTB4 release, undetectable in resting PMN, was strongly stimulated by the A23187, peaking at 5 min, with significantly higher levels (t test, p < 0.01) in newborn than in adult PMN preparations (mean +/- SD: 12.46 +/- 2.96 and 6.21 +/- 2.09 ng/10(6) cells, respectively). In comparison, serum-treated zymosan-stimulated PMN released smaller amounts of LTB4. The levels peaked at 10 min and were significantly (t test, p < 0.01) lower in newborn than in adult samples (mean +/- SD: 0.71 +/- 0.22 and 3.19 +/- 1.06 ng/10(6) PMN, respectively). Finally, when the PMN were stimulated by formyl-methionyl-leucyl-phenylalanine, the release of LTB4 was highly variable both in newborn and in adult samples, as previously reported.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Inhibitory effect of melanin precursors on arachidonic acid peroxidation.

A possible role of melanin precursors in lipid peroxidation was investigated using the lipoxygenase catalysed oxygenation of arachidonic acid (AA) as a model system. Polarographical monitoring of oxygen consumption showed that, among the metabolites examined, 5,6-dihydroxyindole (DHI) was the most active in inhibiting AA oxygenation catalysed by 15-lipoxygenase. The inhibition was found to be concentration-dependent with an IC50 value of 15 microM. Similar effects were observed in the case of the 5-lipoxygenase promoted reaction. Periodical HPLC analysis of the oxidation mixture showed that, in the presence of DHI, the rate of substrate consumption is markedly reduced. The inhibitory potency was significantly increased either by preincubation of DHI with the enzyme or by increasing the time of residence of the indole in aerated buffer solutions prior to contact with the enzyme. Addition of catalase to the incubation mixture resulted in a partial removal of DHI inhibition. From these and other experiments, an inhibition mechanism is proposed which involves inactivation of the enzyme by reactive species, especially hydrogen peroxide, arising from DHI autoxidation.

Animals↗
PubMed1993

Mutational activation of N- and K-ras oncogenes in plasma cell dyscrasias.

The frequency of N- and K-ras oncogene mutations was investigated in plasma cell dyscrasias. Genomic DNAs from 128 patients were selected for this study: 30 monoclonal gammopathies of undetermined significance, 8 solitary plasmacytomas, 77 multiple myelomas (MM), and 13 plasma cell leukemias (PCL). A two-step experimental approach was devised. All samples were screened for mutations by single-strand conformation polymorphism analysis. DNA fragments displaying an altered electrophoretic mobility were further studied by direct sequencing to confirm and characterize the nature of the mutations. Ras mutations are not randomly distributed because they are detectable only in MM (9%) and PCL (30.7%). N-ras codons 12, 13, and 61 and K-ras codon 12 were found to be mutated, but N-ras codon 61 mutation was the most frequent finding (63.6%). In conclusion, ras mutations were found in PCL, and in a subset of MM characterized by advanced-stage disease and adverse prognostic parameters. Furthermore, based on our findings, it is possible to speculate that ras mutations represent a late molecular lesion in the process of multistep carcinogenesis.

Base Sequence↗
PubMed1993

Inositol tri-phosphate inhuman and ascidian spermatozoa.

Using a specific protein binding assay we have shown that a spermatozoon of the ascidian Ciona intestinalis contains 1.58 +/- 0.74 x 10(-19) moles of inositol 1,4,5-tri-phosphate (InsP3), while a human spermatozoon contains 6.4 +/- 0.14 x 10(-19) moles. Induction of the acrosome reaction (AR) in both species, by exposure to the calcium ionophore A23187, does not significantly alter levels of InsP3, suggesting that phosphatidylinositol (PI) turnover is not necessary for the calcium ionophore induced AR. Furthermore, PI turnover in ascidian spermatozoa appears to be insensitive to lithium and phorbol ester. The high intracellular concentration of InsP3 in spermatozoa, corresponding to 50-200 microM, suggests it may play a role in egg activation.

Acrosome↗
PubMed1993

Immunohistochemical localization of renin and angiotensin in the ovary: comparison between normal women and patients with histologically proven polycystic ovarian disease.

OBJECTIVE: This study was designed to test the hypothesis that the ovarian renin-angiotensin system may play a role in polycystic ovarian disease (PCOD). DESIGN: The immunohistochemical distribution of renin and angiotensin in ovaries from seven women with histologic diagnosis of PCOD was compared with that of normal ovaries. RESULTS: The large cystic follicles of polycystic ovaries (PCO) presented intense immunostaining for renin and angiotensin in both theca and granulosa cells (GCs). In developing follicles of normal ovaries, the immunostaining was restricted to the theca cell layer, with the exception of the immediately preovulatory follicles which displayed intense positivity of granulosa as well as theca cells. Atretic follicles of normal ovaries showed staining of both theca and GCs. In both normal and PCO, patches of hilus cells were intensely stained. Luteal cells also consistently stained both in normal ovaries and in the occasional corpus luteum present in polycystic ovaries. CONCLUSIONS: This study highlights the link between the ovarian renin-angiotensin system and those ovarian compartments known to be actively engaged in androgen secretion and/or luteinization and suggests that there may be an association between the ovarian renin-angiotensin system and PCOD.

Adult↗
PubMed1993

Interferon plus glucocorticoids as intensified maintenance therapy prolongs tumor control in relapsed myeloma.

Interferon-alpha-2b (IFN) has been demonstrated to prolong remission duration and survival in responding multiple myeloma (MM) patients. The aim of this study was to intensity maintenance therapy adding glucocorticoids (GLU) to the standard IFN therapy. Twenty-eight relapsed MMs with stable disease or response after conventional chemotherapy received IFN+GLU. The treatment included 3 megaunits of IFN 3 times a week continuously until relapse, plus 4 days pulsed high-dose dexamethasone (40 mg/day for 4 days every 28 days for 6 consecutive months every 12 months) in patients < 70 years, or oral prednisone (PDN, 50 mg 3 times a week) in patients > 70 years, both until relapse. Conventional chemotherapy induced a response in 12/28 MMs. For all patients the actuarial median progression-free survival from relapse was 24 months and the survival from relapse 42 months with no difference between responding and nonresponding patients. The first duration of tumor control, i.e. the interval from diagnosis to first relapse, was shorter than the period between first and second relapse in 11/28 patients (40%). Toxicity was mild and oral PDN significantly increased the subjective tolerability of IFN. These findings indicate that IFN+GLU after induction chemotherapy may prolong the duration of tumor control in relapsed MM.

Aged↗
PubMed1992

5,6-Dihydroxyindole-2-carboxylic acid is incorporated in mammalian melanin.

The role of 5,6-dihydroxyindole-2-carboxylic acid (DHICA) in the biosynthesis of melanins has been studied by using the incorporation of specifically radiolabelled melanogenic precursors into melanins formed by melanocytes growing in vitro and in vivo. Extracts of mouse melanocytes and intact viable melanocytes were found to incorporate into melanin from 25% to more than 60% of [1-14C]tyrosine. Melanins from melanoma tumours grown in mice were radiolabelled with 3,4-dihydroxy[1-14C]phenylalanine, purified and chemoselectively decarboxylated. Determination of the 14CO2 evolved showed that at least 20% of the precursor incorporated in vivo retains the label in the form of non-aminoacidic aromatic-type carboxyl groups. These results provide the first unambiguous demonstration that DHICA is incorporated in physiologically relevant amounts in mammalian melanins.

Animals↗
PubMed1992

Early disappearance of murine plasmocytoma stem cells in long-term bone marrow culture.

Long-term bone marrow culture (LTBMC) was evaluated as a purging procedure in the murine plasmocytoma MOPC-315s system. MOPC-315s cells injected in Balb-c mice rapidly proliferate both in marrow and spleen, where macroscopic tumor colonies develop. A linear relationship between the number of injected cells and spleen colonies was observed, consistent with the presence of 1 clonogenic myeloma stem cell out of 1800 cells. In vitro, MOPC-315s cells are easily identifiable as rosette-forming cells (RFC+) with trinitrophenil acid (TNP) coated sheep red blood cells. When bone marrow (BM) cells containing 20-40% RFC+ were seeded in LTBMC, RFC+ rapidly decreased and were no longer detectable by day 14 of culture. Clonal Ig gene rearrangement was evident at time 0, but it was no more detectable later on. In addition, cells taken at days 14 and 21 of culture were no more tumorigenic when injected in vivo. The results suggest the efficacy of the LTBMC for the in vitro elimination of myeloma cells, including the neoplastic stem cells.

Animals↗
PubMed1992

Multiple independent immunoglobulin class-switch recombinations occurring within the same clone in myeloma.

Multiple myeloma (MM) is characterized by the expansion of terminally differentiated plasma cells. It is still uncertain whether the clonogenic fraction is confined to the plasma cell or pre-plasma cell compartment. We examined the immunoglobulin (Ig) rearrangement of myeloma heavily infiltrated bone marrow cells with a probe from the heavy chain J region (JH) and the BamHI, EcoRI and HindIII restriction enzymes which are appropriate for the detection of clonal VDJ recombination. In 23/39 MMs, clonal Ig gene rearrangement was detected with BamHI, EcoRI and HindIII enzymes. Unexpectedly, in 14/39 patients both BamHI and EcoRI failed to detect Ig rearrangement, whereas HindIII consistently demonstrated VDJ recombination. The 5' sites of BamHI, EcoRI and HindIII restriction fragments are precisely defined by the VDJ rearrangement. Since the 3' ends of BamHI and EcoRI restriction fragments are downstream from the switch mu region and change in size during switch recombination, the absence of rearranged bands is determined by several autonomous recombinations affecting the switch region. By contrast, the 3' ends of HindIII restriction fragments are upstream, their size does not vary during isotype switch allowing the constant detection of clonality. Accordingly, in 35% of patients the clonogenic fraction seems to originate from a pre-switch B cell. This B cell will differentiate to a mature plasma cell developing multiple independent switch recombinations, as the variable mechanism of switch recombination suggests.

Adult↗
PubMed1992

Multiple myeloma: intensified maintenance therapy with recombinant interferon-alpha-2b plus glucocorticoids.

Interferon-alpha-2b has been demonstrated to prolong remission duration and survival in responding multiple myeloma patients. The aim of this study was to evaluate intensification of this maintenance therapy through the addition of glucocorticoids. Eighteen myeloma patients at diagnosis received six-12 courses of conventional chemotherapy and then interferon + glucocorticoids. This treatment included 3 megaunits of interferon three times a week, plus 4 days of pulsed high-dose dexamethasone (40 mg/d for 4 d every 28 d for 6 months/year) in patients < 70 yr old, or oral prednisone (50 mg three times a wk) in patients > 70 yr old. Conventional chemotherapy induced an objective response in 13/18 patients and a further reduction of the M component (> 50%) was achieved during interferon + glucocorticoids treatment in 7/13. 4/18 patients relapsed with a median follow-up of 22 months (range 13-40). These findings indicate that interferon + glucocorticoids, after inductional chemotherapy, further reduces tumor burden and may prolong remission.

Adult↗