Biomedical subjects

F Giorgi

Publications and source records attributed to F Giorgi.

At least 37 records · Page 2Linked to original sources

PubMed1998

Mono- and polyclonal antibodies as probes to study vitellin processing in embryos of the stick insect Carausius morosus.

During embryonic development, insect vitellins (Vt) are degraded by limited proteolysis to yield a number of lower-molecular weight polypeptides. The aim of the present study was to identify these polypeptides in the embryo and to verify how they relate to Vt polypeptides deposited in the oocyte during vitellogenesis. To this end a panel of poly- and monoclonal antibodies (Pab, Mab) was raised against Vt polypeptides and employed by immunoelectrophoresis and immunoblotting on embryos belonging to different developmental stages. Through this approach three major staining patterns were observed. First, Mab 4 reacts with both polypeptides B1 and E20, suggesting that polypeptide B1 is gradually trimmed to yield polypeptide E20 in late embryos. Second, Mab 12 is specific for polypeptide A3 which is retained unchanged throughout embryogenesis. Third, Pab anti-A2 and Mab 13 show that polypeptide A2 is processed to yield polypeptide E9 through limited proteolysis. In conclusion, the staining patterns reported in this study show that Vt polypeptides in developing embryos of the stick insect Carausius morosus undergo at least two major processing events concerning polypeptides B1 and A2.

Animals↗

PubMed1998

Vitellogenin is glycosylated in the fat body of the stick insect Carausius morosus and not further modified upon transfer to the ovarian follicle.

Synthesis and secretion of vitellogenin (Vg) polypeptides were studied in egg-laying females of the stick insect Carausius morosus following in vivo exposure to [35S]-methionine and acetyl-N-[3H]-glucosamine. The specificity of radioisotope incorporation was assessed by in vitro inhibition with tunicamycin and carbohydrate extraction with endo-glycosidase H. Vg polypeptides change in molecular weight during synthesis in the fat body and are not further modified upon transfer to the haemolymph or to the oocyte, suggesting that they are already fully glycosylated prior to secretion. Radioactivity in the fat body was initially distributed over cisternae of the rough endoplasmic reticulum and gradually transferred to the Golgi apparatus. Within an hour of exposure, electron-dense granules budding from the trans-Golgi network became preferentially labeled. Radioactivity in the ovarian follicle was restricted to the yolk granules of the cortical ooplasm and to the amorphous material lying within the intercellular channels of the follicular epithelium. This amorphous material was also shown to react positively when tested with a monoclonal antibody raised specifically against a Vg polypeptide.

Animals↗

PubMed1997

Native vitellins are modified during ovarian development in the stick insect Carausius morosus (Br.).

Vitellins from ovarian follicles and newly laid eggs of the stick insect Carausius morosus were examined by ion exchange chromatography on a HPLC Mono Q column. Under these conditions, vitellins from newly laid eggs resolved as two distinct peaks, referred to as VtA and VtB, that eluted at 8.5 and 12.0 min, respectively. On native gels, both VtA and VtB separated into two different variant forms (VtA' and VtA", VtB' and VtB"). By two-dimensional gel electrophoresis, VtA' and VtA" were shown to contain polypeptides A1, A2 and A3. On the other hand, VtB' and VtB" appeared to comprise polypeptides B1 and B2 and B1, A1, A2, B2 and A3*, respectively. A similar Vt polypeptide composition was also observed by size-exclusion chromatography of vitellins from newly laid eggs. Vitellins from early vitellogenic ovarian follicles resolved into a single chromatographic peak at 7.5 min that coeluted with a major peak from the hemolymph of egg-laying females. Ovarian follicles progressively more advanced in development exhibited a more complex chromatographic profile, consisting of three separate peaks. By two-dimensional gel immunoelectrophoresis, vitellins from ovarian follicles appeared to consist of two closely related, immunologically cross-reacting antigens that gradually shifted apart as ovarian development proceeded to completion. By size-exclusion chromatography, each Vt from ovarian follicles was shown to consist of a unique set of polypeptides different from those listed above. Single ovarian follicles were fractionated into yolk granules and yolk fluid ooplasm and tested by immunoblotting against Mab 12. Under these conditions, VtA variant forms in yolk granules and yolk fluid ooplasm reacted differently. Sections from ovarian follicles in different developmental stages were exposed to Mab 12 and stained with a peroxidase-conjugated, goat anti-mouse antibody. Regardless of the developmental stage attained, staining for peroxidase was restricted to free yolk granules, suggesting that native vitellins in stick insects are structurally modified upon fusion into the yolk fluid ooplasm.

Animals↗

PubMed1997

Integument ultrastructure of Oestrus ovis (L.) (Diptera:Oestridae) larvae: host immune response to various cuticular components.

The nasal bot fly, Oestrus ovis, was investigated to establish which specific cuticular component is most immunogenic to infested sheep and how larval cuticle attains a protective role, if any, against the host immune system. To accomplish these goals, larval cuticle was extracted by a variety of agents and tested against immune sera from infested sheep and experimentally immunized rabbits. The cuticle substructure remaining after extraction was examined to localize various immunogenic components. O. ovis larval integument comprises an inner cellular layer, the epidermis, and an overlying cuticle layer. In 3rd instar larvae, the cuticle comprises 2 additional layers: the procuticle with numerous pore canals and the epicuticle which includes the wax canals. Three additional layers, altogether comprising the cuticulin layer, are present external to the epicuticle. The epicuticle is completed by apposition of an amorphous electrondense material extending for up to 1 micron in thickness. When fixed with ruthenium red, cuticle becomes heavily stained all along the epicuticular surface in larvae of all developmental stages. However, in 3rd instar larvae, ruthenium red deposits are restricted to the cuticulin layer alone. By gel electrophoresis, 3rd instar larval cuticle is shown to contain a number of polypeptides ranging in molecular weight from 180 to 4.5 kDa. The number and relative concentration of low molecular weight polypeptides was shown to vary in relation to the extraction media employed. Cuticular fragments examined after extraction exhibit an altered ultrastructure. When tested by immunoblotting, the cuticular polypeptides most reactive against sheep antisera are in the range of 180-56 kDa. A similar reaction was also detected with sera from rabbits infested experimentally with O. ovis larvae. Results are interpreted in relation to differential polypeptide distribution within the larval cuticle and to accessibility of the host immune system.

Animals↗

PubMed1997

Mitoxantrone, fluorouracil, and L-folinic acid in anthracycline-pretreated metastatic breast cancer patients.

In this phase II trial we have evaluated the activity and toxicity of a combination regimen containing mitoxantrone, L-leucovorin, and fluorouracil in patients with advanced breast cancer pretreated with anthracyclines. Forty-six patients were included into the study; they received a total of 227 cycles of chemotherapy. Median age was 63 years (range 34-78), median performance status was 80 (range 60-100). Visceral metastases were present in 37 patients, 6 patients had bone involvement only, while 3 patients had soft tissue/lymph node disease. Median number of previous chemotherapy regimens for advanced disease was 2 (range 1-3). Ten patients had anthracycline primary resistance (progressive disease during treatment). Twenty-three patients received mitoxantrone 12 mg/sqm day 1; fluorouracil 370 mg/sqm and L-folinic acid 100 mg/sqm days 1-3 administered every three weeks. Another group of 23 patients were treated with the same regimen using a prolonged 5FU/L-FA schedule (5 days). Two complete responses and 6 partial responses were recorded with the 3-day schedule; 7 partial responses in the 5-day schedule (overall response rate 32.6%, 95% C.I. 19-46%). Two partial responses were observed in patients with anthracycline primary resistance. Median response duration was 9 months (range 3-16). Hematologic toxicity was mild: grade 3-4 leukopenia was recorded in 5 patients, grade 3-4 thrombocytopenia in 3 patients. Grade III-IV stomatitis and diarrhea was recorded in 4 and 5 patients respectively (all receiving the 5-day 5-FU/L-FA schedule). Cardiac toxicity was observed in two cases. This regimen proved active in advanced breast cancer following anthracycline-containing chemotherapy, and the 3-day schedule could be offered to such patients with acceptable toxicity.

Adult↗

PubMed1996

Granisetron plus dexamethasone in moderately emetogenic chemotherapy: evaluation of activity during three consecutive courses of chemotherapy.

In this study we evaluated the antiemetic activity of a combination of 3 mg granisetron in a short i.v. infusion followed by 12 mg dexamethasone i.v. in 64 patients with cancer receiving moderately emetogenic chemotherapy scheduled in a single day. No patient had previously undergone chemotherapy and three consecutive cycles were evaluated. Response to antiemetic treatment was graded as follows: complete response, no episodes of vomiting; major response, only one episode; minor response, two to four episodes; failure, more than four episodes. Nausea was graded as absent, mild, moderate or severe (patients bedridden). At the first cycle a complete protection from acute vomiting and nausea was achieved in 95% and 73% of patients respectively; the rate of complete response for delayed vomiting was 90%, while 45% of patients complained of delayed nausea. The antiemetic and antinausea efficacy remained substantially unchanged during the second and third cycles of chemotherapy. Constipation and headache were the most frequent adverse events. In conclusion this antiemetic regimen appears very effective in preventing nausea and vomiting in moderately emetogenic chemotherapy.

Adult↗

PubMed1996

Assessing quality of life in patients with cancer: a comparison of a visual-analogue and a categorical model.

A simple instrument for self-assessment of quality of life (QL) in patients with cancer was elaborated using a linear analogue scale (LAS). The instrument was based on five questions, exploring different functional areas; the same questions were also addressed in a parallel format, where problems were seen from an opposite point of view (positive/negative). The LAS was given to 222 patients, for a total of 372 tests collected. Internal consistency was satisfactory (Cronbach's alpha = 0.75); QL score was significantly correlated to parameters of disease. Concordance between scales, as judged by comparison of parallel formats, was statistically significant but poor. A questionnaire was then elaborated with similar items, based on a categorical scale. A direct comparison between LAS and our questionnaire was made on a group of 41 patients. Internal consistency was poor for the LAS (alpha = 0.58) and good for the questionnaire (alpha = 0.93); Spearman's rank correlation coefficients were disappointing for the LAS and good for the questionnaire; the questionnaire was judged reliable in 82.9% of cases, the LAS in 29.3% only; the questionnaire score, and not the LAS score, was significantly correlated with PS and disease status. In conclusion, many patients appeared unable to correctly interpret the visual-analogue scale; the categorical scale was more immediate and correctly understood by the large majority of patients; the correlation between score and important parameters of QL was maintained, and internal consistency was excellent, indicating a satisfactory reliability of this instrument.

Adult↗

PubMed1996

Cardiac and gastric effects of histamine H2 receptor antagonists: no evidence for a correlation between lipophilicity and receptor affinity.

1. A series of histamine H2 receptor antagonists with different lipophilicity were tested in cardiac and gastric assays in order to reveal possible differences in receptor affinity. Lipophilicity of the compounds was expressed as CLOG P (theoretically-determined logarithm of octanol:water partition coefficient) and log k' (logarithm of capacity factor, experimentally-determined by reverse-phase high performance liquid chromatography). 2. Aminopotentidine (APT) and iodoaminopotentidine (I-APT), which are both lipophilic compounds, behaved as insurmountable antagonists of histamine responses in rat isolated gastric fundus (pKB = 6.20 +/- 0.16 and 6.89 +/- 0.19, respectively) and guinea-pig isolated papillary muscle (pKB = 6.34 +/- 0.37 and 6.81 +/- 0.26, respectively). They were approximately as effective as ranitidine (RAN) in reducing histamine-induced acid secretion in the anaesthetized rat, ID50 values being 0.018 +/- 0.02, 0.020 +/- 0.03 and 0.036 +/- 0.01 mumol kg-1 i.v. for APT, I-APT and RAN, respectively. Both APT and I-APT had a significantly longer duration of action than RAN. 3. The hydrophilic compound, SK&F 92857, was inactive up to 10 microM in modifying histamine-induced acid secretion in the isolated rat stomach. In the papillary muscle, low concentrations (0.1-1 microM) of this compound produced a competitive antagonism of the histamine responses (pA2 value = 7.38 +/- 0.11), while a higher concentration (10 microM) significantly reduced the maximal response to histamine. 4. RAN competitively antagonized histamine effects with a comparable affinity in cardiac and gastric preparations (pA2 values were 6.42 +/- 0.09 and 6.78 +/- 0.38 in heart and stomach, respectively). 5. Results obtained in this study clearly showed that the discrepancies between gastric and cardiac effects observed for some H2 antagonists are not explained solely by differences in lipophilicity of compounds. Moreover, the significant correlation found between CLOG P and log k' parameter, which takes into account, besides their lipophilicity, the ionization of the molecules, suggests that ionization has a similar influence for all the molecules on the partition between the lipophilic and aqueous phase.

Animals↗

PubMed1995

Molecular similarity matrices and quantitative structure-activity relationships: a case study with methodological implications.

Recently, statistical analysis of molecular similarity matrices has been applied to the quantitative structure-activity relationship (QSAR) analysis of a number of molecular series. This paper addresses a number of methodological issues relative to the similarity matrices. A series of halogenated aliphatic hydrocarbons, for which the mutation (aneuploidy) induction ability had previously been determined, was used as test bench. The chemical information carried by the similarity matrices was shown to overlap to a considerable extent the information carried by the classical descriptors (physical chemical and quantum mechanical parameters). A good QSAR was obtained on the basis of the similarity matrices, in analogy with that obtained with the classical descriptors; however, the similarity matrices neither complemented the classical descriptors nor were able to improve on their performance. The effect of the compound's spatial orientation on the similarity values was also investigated.

Aneuploidy↗

PubMed1995

A fat body-derived protein is selectively sulfated during transit to ovarian follicles in the stick insect Carausius morosus.

A monoclonal antibody raised against ovarian follicles of the stick insect Carausius morosus reacted with two related polypeptides of 157 and 85 kDa in both the ovary and the hemolymph. In vitro cultured fat body proved capable of releasing the 157-kDa polypeptide into the culture medium and processing it to the lower-molecular-weight polypeptide of 85 kDa. This was further demonstrated by in vitro exposure to [35S]methionine. Under the same culturing conditions, ovarian follicles proved incapable of synthesizing and/or secreting the 85-kDa polypeptide. However, in vivo [35S]methionine-labeled ovarian follicles released both polypeptides when cultured in vitro for up to 24 hr. Vitellogenin polypeptides were labeled in vivo following exposure to [3H]glucosamine, while 157- and 85-kDa polypeptides were labeled only in ovarian follicles exposed in vivo to sodium [35S]sulfate. Under in vitro conditions, the 157-kDa polypeptide could be labeled with sodium [35S]sulfate only if ovarian follicles were cocultured with fat body. No sulfation occurred in fat body or ovarian follicles cultured separately. These experiments suggest that the 157-kDa polypeptide is a fat body-derived polypeptide that is sulfated upon transfer to the ovarian follicle.

Animals↗

PubMed1995

Larval salivary gland proteins of the sheep nasal bot fly, (Oestrus ovis L.), are major immunogens in infested sheep.

Tissue extracts from larval instars of the sheep nasal bot, Oestrus ovis, were resolved by gel electrophoresis under both native and denaturing conditions. Polypeptides resolved under these conditions were tested by immunoblotting against sera of infested sheep. Of all tissues examined in this study, salivary glands proved to be major immunogens in infested sheep. Salivary gland polypeptides were also detected in the washing solution as larval secretory products (LSP). To a minor extent, a few polypeptides from the larval cuticle were also found to be immunogenic, but they did not contribute to LSP. These results were further corroborated by nasal infestation of rabbits that also developed specific antibodies against larval salivary gland polypeptides from Oestrus ovis.

Animals↗

PubMed1995

Defective natural killer cell cytotoxic activity in feline immunodeficiency virus-infected cats.

Flow cytometry has been employed to study NK cell cytotoxic activity in cats infected with feline immunodeficiency virus. The results show that animals infected for 12 months or more have decreased levels of NK cell cytotoxic activity in their blood. The impairment could not be overcome by in vitro treatment of effector cells with interleukin 2. Additional results suggest that the NK cells of infected cats are defective, in that they are still able to bind to target cells but have a reduced ability to kill them.

Animals↗

PubMed1993

Ultrastructural analysis of Drosophila ovarian follicles differing in yolk polypeptide (yps) composition.

Drosophila ovarian follicles were examined ultrastructurally to study the vesicular traffic in the cortical ooplasm. The endocytic pathway leading to the production of yolk spheres was visualized following in vivo or in vitro exposure to peroxidase. The Golgi apparatus and the yolk spheres of wild-type ovarian follicles were preferentially labelled by fixation with osmium zinc iodide (OZI). Labelling of wild-type ovarian follicles was compared to that of several mutant follicles--L186/Basc, fs(2)A17 and ap4--which are defective in vitellogenesis. In these mutants, the Golgi apparatus and the vesicles nearby were either scantly labelled or not labelled at all. In oocytes from flies homozygous for the gene fs(1)1163, the Golgi apparatus was labelled as in the controls, but no yolk spheres appeared to be labelled with OZI at any of the developmental stages. In several Drosophila strains, the pattern of OZI label in the cortical ooplasm was seen to vary in relation to the number of yp structural genes. In starved Drosophila females, OZI labelling of the cortical ooplasm appeared restricted to the Golgi apparatus and to an extended tubular network. A similar labelling pattern was also detected in in vitro cultured vitellogenic follicles. Refeeding, topical application of juvenile hormone analogue to starved females or hormone addition to the culture medium, all caused the yolk spheres to become labelled with OZI and to incorporate peroxidase. These observations prove that impairing endocytic uptake by either mutation or lack of juvenile hormone prevents fusion of coated vesicles and tubules with the yolk spheres and leads them instead to form an intermediate cell compartment with Golgi-derived vesicles.

Animals↗

PubMed1990

Electrophoretic analysis of type I collagen from bovine Achilles tendon: comparison between the extracted raw material and the freeze-dried product.

The present study was aimed at verifying if the freeze-drying process has any effect on the polypeptide composition of the collagen extracted from bovine Achilles tendon in an acetic acid gelified form. Data from our laboratories showed that the freeze-drying process renders the collagen gel essentially insoluble; under these conditions the collagen sample can no longer be analyzed by gel electrphoresis. We found that treatment of the sample with pepsin in acid environment, followed by precipitation with ammonium sulphate yields an insoluble fraction that is susceptible of being analyzed by polyacrylamide gel electrophoresis. The The electrophoresis, run under standard conditions, shows that six major subunits, corresponding to alpha, beta and gamma polypeptides, can be revealed in the sample treated in this way. So the freeze-dried collagen exhibits a polypeptidic composition that is basically identical to that shown by the collagen gel, with regard to the fraction precipitated with ammonium sulphate. Otherwise the pattern of the enzymatic hydrolysis was investigated by measuring the hydroxyproline content, and so the collagen content using the 7.46 conversion factor from hydroxyproline to the scleroprotein collagen, in the various steps of the hydrolysis itself: the analytical results showed no differences between the freeze-dried collagen and the gelified form; this confirms that the lyophilization process does not alter the polypeptidic composition of the collagen in any way.

Achilles Tendon↗

PubMed1989

Osteocalcin as a biological marker in the therapeutic management of breast cancer bone metastases.

Circulating osteocalcin (BGP), the major noncollagenous bone protein, is elevated in patients with certain metabolic bone disease while its behavior in cancer patients, particularly those with bone metastases, is unclear. We measured circulating BGP in 37 healthy females, in 13 female patients with benign breast disease, and in a group of 51 cancer patients (breast, lung, prostate, and bladder) with and without bone metastases, before and after 4'-epidoxorubicin (4'-Epidx) therapy (4'-Epidx 120 mg/m2 every 3 weeks). Under basal conditions, mean BGP levels of all of these subjects fell within the normal range of 2.0-5.0 ng/ml (mean +/- SD, 4.8 +/- 1.0 ng/ml). In cancer patients without bone metastases BGP levels measured before and after 4'-Epidx therapy were not significantly different (4.4 versus 4.6 ng/ml). Only in breast cancer patients with multiple bone metastases was circulating BGP higher after the onset of antiblastic treatment and through the entire course of therapy, accompanied by bone pain remission and regression of bone lesions (BGP = 6.7 +/- 1.3 ng/ml). Thus an increase in BGP concentration can be considered as a biological marker of recovered osteoblast activity during therapeutically induced stabilization or regression of skeletal metastatic lesions.

Adult↗

PubMed1988

[Photocoagulation with the argon laser in cystoid macular edema in retinal venous occlusions. Apropos of 68 cases].

Sixty-eight consecutive eyes with cystoid macular edema due to venous occlusion were treated by grid laser photocoagulation. The diagnosis of cystoid macular edema was based on both the biomicroscopic and angiographic findings. The treatment was applied with blue-green or green argon laser. The criteria for treatment were the presence of cystoid macular edema, visual acuity of 0.5 or less and duration of the venous occlusion for more than 6 months. The technique of treatment included direct photocoagulation of certain microaneurysms and of collateral dilatations exhibiting fluorescein leakage in the macular area, followed by grid photocoagulation applied to the area of cystoid edema. No laser burn was placed within 300 microns of the center of the macula. The patients were followed for periods of 6 to 24 months with a mean follow-up of 15 months. Forty-five eyes presented with a branch vein occlusion. Photocoagulation resulted in the decrease or disappearance of macular edema in 42 of these eyes (93%) and the improvement of visual acuity by 0.2 or more in 12 (27%). Twenty-three eyes presented central vein occlusion. In these cases, photocoagulation resulted in the decrease or disappearance of macular edema in 20 eyes (87%), and visual acuity improved by 0.2 or more in 4 (17%). These results indicate that grid laser photocoagulation is an effective method, reducing persistent cystoid macular edema due to venous occlusion. However, visual results were better in the branch vein occlusions than in the central vein occlusions.

Aged↗

PubMed1988

A morphological analysis of collagen extracted from bovine Achilles tendon.

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Achilles Tendon↗

PubMed1985

Development of gap junctions in normal and mutant ovaries of Drosophila melanogaster.

An ovarian follicle of Drosophila consists of an oocyte, 15 nurse cells, and hundreds of follicular epithelial cells. A freeze-fracture analysis of the surfaces between glutaraldehyde-fixed ovarian cells showed that all three cell types were interconnected by gap junctions. This is the first report of gap junctions between adjacent nurse cells, between nurse cells and oocytes, and between follicle cells and oocytes in Drosophila. Since we did not observe intramembranous particle clumping into crystalline patterns and since structurally different gap junctions occurred at different times in development and at different cell-cell interfaces, it is unlikely that fixation artifacts influenced particle distribution in our experiments. A computer-assisted morphometric analysis showed that the extent, size, and morphology of gap junctions varied with development and that these junctions can cover up to 9% of the cell surfaces. To test the role of gap junctions in follicular maturation, we studied ovaries from flies homozygous for the female sterile mutation fs(2)A17, in which follicles develop normally until yolk deposition commences. During the development of mutant follicles, gap junctions became abnormal before any other morphological aspect of the follicle. These studies show that gap junctions are available to play an important role in coordinating intercellular activities between all three cell types in ovarian follicles of Drosophila.

Animals↗