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Biomedical subjects

G Galli

Publications and source records attributed to G Galli.

At least 91 records · Page 5Linked to original sources
PubMed1996

Cholesta-5,7,9(11)-trien-3 beta-ol found in plasma of patients with Smith-Lemli-Opitz syndrome indicates formation of sterol hydroperoxide.

The Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive disorder characterized by accumulation of cholesta-5,7-dien-3 beta-0l caused by a deficiency of the enzyme desaturating this sterol to cholesterol. In addition to other unusual sterols recently found in plasma of patients with SLOS, namely cholesta-5,8-dien-3 beta-ol and 19-nor-cholesta-5,7,9 (10)-trien-3 beta-ol we have detected a trienol and we describe here its identification as cholesta-5,7,9 (11)-trien-3 beta-ol by GC-MS and by comparison with a synthetic standard. We tested the possibility that the trienol may be formed by radical oxidation of cholesta-5,7-dien-3 beta-ol accumulated in plasma of patients with SLOS because it is known to be formed by decomposition of 7-hydroperoxy-cholesta-5,8-dien-3 beta-ol, which is a product of cholesta-5,7-dien-3 beta-ol photooxidation. Incubation of cholesta-5,7-dien-3 beta-ol with rat liver microsomes in the presence of ADP/Fe2+ and NADPH gave rise to a number of oxygenated sterols. Among these, analysis by particle-beam LC-MS under CI conditions indicated the presence of 7-hydroperoxy-cholesta-5,8-dien-3 beta-ol and of cholesta-5,7,9(11)-trien-3 beta-ol which is known to derive from the oxidation of the 7-hydroperoxide. From these results we conclude that cholesta-5,7-dien-3 beta-ol accumulated in tissues of patients with SLOS may be oxidized by oxygen radicals giving rise to oxygenated sterols. Some of these compounds may be toxic and may contribute to worsen the pathological picture in patients with SLOS.

Animals↗
PubMed1995

Autocrine interleukin-1 beta regulates both proliferation and apoptosis in EL4-6.1 thymoma cells.

We demonstrate here that EL4-6.1 cells, a mouse thymoma that expresses high levels of membrane interleukin (IL)-1 receptors, produce IL-1 beta as an autocrine regulatory factor. Endogenous IL-1 beta sustains both proliferation and apoptosis: during the exponential phase, it mainly promotes proliferation, while during the plateau phase of cell growth, it induces death by apoptosis. Additionally, we show that exogenous IL-1 beta added to EL4-6.1 cells in lag phase induces apoptosis in a portion of the cells and proliferation in the remaining cells. Therefore, IL-1 beta can exert two completely opposite effects on a single cell type, depending on the state of the target cell.

Animals↗
PubMed1995

Chlorpromazine inhibits nitric oxide-mediated increase in intracellular cGMP in a mouse teratocarcinoma cell line.

Chlorpromazine is a phenothiazine with a structure similar to that of methylene blue. Since methylene blue is a well known inhibitor of nitric oxide-induced cyclic GMP accumulation, we investigated whether chlorpromazine had the same effect. Cyclic GMP accumulation, induced in a mouse teratocarcinoma cell line (P19) by sodium nitroprusside (a nitric oxide releasing agent), was inhibited by both methylene blue (IC50 0.34 microM) and chlorpromazine (IC50 35 microM). Chlorpromazine's action was probably directed specifically at soluble guanylate cyclase, since the drug had no effect on ADP-ribosylation in rat hippocampus, another nitric oxide-affected, but cGMP-independent event.

Adenosine Diphosphate Ribose↗
PubMed1995

The upregulating effect of dexamethasone on tumor necrosis factor production is mediated by a nitric oxide-producing cytochrome P450.

Dexamethasone (DEX) is a well-known inhibitor of tumor necrosis factor (TNF) production when given shortly before lipopolysaccharide (LPS). However, DEX (10 mg/kg, ip) potentiates TNF production when administered 24-48 hr before LPS (16 micrograms/kg, ip). We have found that this is probably due to DEX induction of cytochrome P450 3A, which is known to produce nitric oxide (NO). The upregulating effect of DEX on TNF production is associated with increased NO production. Both the upregulation of NO and of TNF production by DEX are inhibited by co-administration of the P450 3A inhibitor troleandomycin (TAO, 40 mg/kg, ip). These data suggest that P450 3A-generated NO might be involved in TNF induction.

Animals↗
PubMed1995

A simple method for estimating the skeletal uptake of diphosphonates.

It is possible to obtain an estimate of the bone uptake of diphosphonates after 3 h (BU) on the basis of the difference between the dose administered and the sum of the component eliminated in the urine plus the component present in the extra-osseous volume of distribution. The results of this simple method have been compared in 15 patients using whole body retention at 24 h (determined by means of a complete urine collection) and the ratio of plasma concentrations of 51Cr-EDTA/99Tcm-HMDP after 3 h (DPS). Both DPS and BU can be used on a practical basis, and therefore be used routinely with scintigraphy. The added advantage is that, for BU, the use of a second radiopharmaceutical is avoided.

Adult↗
PubMed1995

Characterization of the locus encoding the [Ni-Fe] sulfhydrogenase from the archaeon Pyrococcus furiosus: evidence for a relationship to bacterial sulfite reductases.

The hydBGDA genes, which encode the four subunits beta, gamma, delta and alpha of the [Ni-Fe] hydrogenase from the archaeon Pyrococcus furiosus, have been isolated and sequenced using a PCR/IPCR-based strategy. From the sequence analysis it appears that the four structural genes are tightly linked and organized in a single transcription unit. The hydD and hydA gene products are related to the small and the large subunits of several archaeal and eubacterial [Ni-Fe] hydrogenases with an overall degree of sequence relatedness ranging from 35% to 50% (identity + similarity). In particular, the amino acid sequence motifs involved in the accommodation of nickel and iron-sulfur clusters are conserved. In addition, the database search revealed that the hydB and hydG gene products are homologous to the asrA- and asrB-encoded subunits of the sulfite reductase enzyme from Salmonella typhimurium. This is particularly interesting in view of the recent finding that the P. furiosus hydrogenase appears to be a bifunctional enzyme endowed with both proton- and sulfur-reducing activities.

Amino Acid Sequence↗
PubMed1995

[The scintigraphic prediction of residual lung function after lobectomy in patients with bronchial carcinoma].

The scintigraphic prediction of residual pulmonary function after pneumonectomy has been validated in a number of studies while scintigraphy is not standardized in case of lobectomy. This study was aimed at investigating the accuracy of the scintigraphic prediction of post-lobectomy lung function using Wernly method. We examined 43 patients with bronchial carcinoma: 20 of them underwent pneumonectomy and 23 underwent lobectomy. The pulmonary function data (vital capacity, CV, and forced expiratory volume in one second, VEMS) predicted by quantitative lung scan were compared with those observed in the postoperative follow-up. A good correlation between predicted and observed data was obtained in both the pneumonectomized group (r = 0.77 and 0.78 for CV and VEMS, respectively; p < 0.005) and the lobectomized group (r = 0.74 and 0.79 for CV and VEMS, respectively: p < 0.005). It can be concluded that the method used for the scintigraphy prediction of post-lobectomy pulmonary function is as accurate as the post-pneumonectomy method and can be used reliably in the clinical practice.

Aged↗
PubMed1995

Chlorpromazine inhibits tumour necrosis factor synthesis and cytotoxicity in vitro.

Chlorpromazine (CPZ) has been previously shown to protect against endotoxin [lipopolysaccharide (LPS)] lethality and inhibit the release of tumour necrosis factor in vivo. We investigated at the cellular level whether this was due to direct inhibition of tumour necrosis factor-alpha (TNF-alpha) synthesis, using LPS-stimulated THP-1 human monocytic leukemia cells. We also studied the effect of CPZ on human TNF-alpha action by assessing TNF-alpha cytotoxicity on mouse fibrosarcoma L929 cells. CPZ (1-100 microM) inhibited TNF-alpha production in THP-1 cells in a dose dependent manner by a maximum of 80%. This effect was comparable to that of two well-known inhibitory drugs, dexamethasone and cyclicAMP. Inhibition was also evident at the mRNA level. On the other hand CPZ (10-25 microM) also inhibited TNF-alpha activity: in fact it reduced the cytotoxicity of TNF-alpha on L929 cells (EC50 was increased four times) and could provide protection even as a post-treatment. CPZ inhibited TNF-induced apoptosis in L929 cells, as detected by analysis of nuclear morphology. However, since we showed that apoptosis was very limited, and was not the main mode of cell death in our conditions, this could not explain the overall protection. Since CPZ did not interfere with either the oligomerization state of TNF-alpha or its receptor binding, our data suggest that it reduced cytotoxicity by inhibiting some steps in the TNF-alpha signalling pathways.

Apoptosis↗
PubMed1995

[Excision and immediate suture technic in the treatment of pilonidal fistula. Our experience].

The authors report their personal experience of the "excision and primary suture" operating technique in the surgical treatment of pilonidal sinus. A rapid recovery by postoperative day 10 was achieved in 58 out of 60 cases treated (96.7%). Dehiscence of the surgical wound was observed in 2 cases (3.3%) following ischemic lesion caused by decubitus of the cutaneous margins and healing occurred by second intenti. No cases of short- or long-term recidivation were observed. The advantages of this method are the early return to working activities, minor patient discomfort and the reduced risk that the surgical would might become infected. Three basic stages for the successful outcome of this type of surgery have been identified as follows: 1) Although and accurate tricotomy of the sacro-coccigeal region. Antibiotic therapy is started about 2 hours before surgery. 2) The precise execution of the surgical technique. 3) The continuation of antibiotic therapy until postoperative day 7. Compressive medication is removed on postoperative day 4. If these three basic stages are respected, no cases of recidivation will occur.

Adolescent↗
PubMed1994

Formation of 22 and 24 carbon 6-desaturated fatty acids from exogenous deuterated arachidonic acid is activated in THP-1 cells at high substrate concentrations.

Deuterated arachidonic acid (AA, [2H8]20:4 n-6) 1-25 microM, is converted to other fatty acids, as evaluated by gas chromatography-mass spectrometry, in THP-1 cells. The major products, in the 1 to 10 microM range, are 22:4 (elongated) and 20:3 (reduced in 5). At 25 microM, 24:4, 24:5 and 22:5 accumulate, with [2H8]/[2H0] ratios higher than in AA. At high AA concentration preferential conversion to elongated fatty acids with 5 unsaturations, through a 6 desaturase takes place and the 4-desaturated 22:5 appears to be formed through beta-oxidation of 24:5.

Arachidonic Acid↗
PubMed1994

Characterization of the surfactin synthetase multi-enzyme complex.

Three subunits (srfAORF1, srfAORF2 and srfAORF3) of the Bacillus subtilis surfactin synthetase multi-enzyme complex have been identified by SDS-PAGE and Western blot analyses. In accordance with the sequence analysis of the surfactin (srfA) operon, the protein subunits have a molecular mass of 402,000 Da, 401,000 Da and 144,000 Da, respectively. Confirmation of the identity of the proteins was obtained by analysing the total protein content of a number of mutant strains which harbour deletions or insertions either in the srfA promoter or in different positions within the srfA operon. The three subunits were partially purified by means of a series of chromatographic steps including ion-exchange chromatography, hydrophobic chromatography and gel filtration chromatography. The partially purified proteins were used in activity assays to establish their amino-acid recognition specificity. In agreement with previously published results, this analysis showed that srfAORF1 recognizes glutamic acid and Leu, srfAORF2 recognizes Val, aspartic acid and Leu and srfAORF3 recognizes Leu. In addition, the subunits can activate and bind other amino acids, although with lower specificity. In particular, srfAORF1 binds Val, Ile and aspartic acid, srfAORF2 glutamic acid and Ile and srfAORF3 Ile and Val. Competition experiments as well as sequence comparison strongly suggest that the Leu binding sites of the three subunits can accept, beside Leu, Ile and Val. The kinetic parameters of srfAORF3 for Leu, Ile and Val have been determined.

Amino Acid Sequence↗