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Biomedical subjects

G Frigerio

Publications and source records attributed to G Frigerio.

At least 19 recordsLinked to original sources
PubMed2001

DCEP (dexamethasone, cyclophosphamide, etoposide, and cisplatin) is an effective regimen for peripheral blood stem cell collection in multiple myeloma.

DCEP (dexamethasone, cyclophosphamide, etoposide, and cisplatin) has proved to be an effective salvage therapy for refractory-relapsed MM patients. Little is known, however, about its potential as mobilizing therapy. The aim of this study was to evaluate the efficacy of DCEP in mobilizing PBSC and to define its toxicity. Fifty-five MM patients received DCEP followed by G-CSF as part of high-dose programs including autologous transplantation. At the time of mobilization, 40 patients had previously received VAD only, and 15 alkylating agents. Mobilization was successful (minimum number of CD34(+) cells 2 x 10(6)/kg) in 48/55 patients (87%), and 41/55 patients (75%) collected >4 x 10(6)/kg CD34(+) cells. Of the seven patients who did not mobilize stem cells, five (71%) had been previously exposed to alkylating agents. The median number of CD34(+) cells harvested was 5.8 x 10(6)/kg (range 2.1-22.4). There was no treatment-related mortality. The side-effects of DCEP were always tolerable. No neutropenia <1000/microl nor thrombocytopenia <50,000/microl were observed. No patient required transfusion as a consequence of therapy, or hospitalization for septic complications. In conclusion, DCEP, in addition to its demonstrated anti-tumor activity, is an effective regimen for mobilizing peripheral blood progenitor cells in myeloma patients, with little or no side-effects. These properties render DCEP a useful regimen for the debulking and mobilization phase of high-dose programs for multiple myeloma.

Adult↗
PubMed2000

COP I domains required for coatomer integrity, and novel interactions with ARF and ARF-GAP.

We performed a systematic mapping of interaction domains on COP I subunits to gain novel insights into the architecture of coatomer. Using the two-hybrid system, we characterize the domain structure of the alpha-, beta'-, epsilon-COP and beta-, gamma-, delta-, zeta-COP coatomer subcomplexes and identify links between them that contribute to coatomer integrity. Our results demonstrate that the domain organization of the beta-, gamma-, delta-, zeta-COP subcomplex and AP adaptor complexes is related. Through in vivo analysis of alpha-COP truncation mutants, we characterize distinct functional domains on alpha-COP. Its N-terminal WD40 domain is dispensable for yeast cell viability and overall coatomer function, but is required for KKXX-dependent trafficking. The last approximately 170 amino acids of alpha-COP are also non-essential for cell viability, but required for epsilon-COP incorporation into coatomer and maintainance of normal epsilon-COP levels. Further, we demonstrate novel direct interactions of coatomer subunits with regulatory proteins: beta'- and gamma-COP interact with the ARF-GTP-activating protein (GAP) Glo3p, but not Gcs1p, and beta- and epsilon-COP interact with ARF-GTP. Glo3p also interacts with intact coatomer in vitro.

ADP-Ribosylation Factors↗
PubMed1998

The Saccharomyces cerevisiae early secretion mutant tip20 is synthetic lethal with mutants in yeast coatomer and the SNARE proteins Sec22p and Ufe1p.

Tip20p is an 80 kDa cytoplasmic protein bound to the cytoplasmic surface of the endoplasmic reticulum (ER) by interaction with the type II integral membrane protein Sec20p. Both proteins are required for vesicular transport between the ER and Golgi complex. Recently, sec20-1 was found to be defective in retrograde transport. A collection of temperature-sensitive tip20 mutants are shown to be lethal in combination with ufe1-1, a target SNARE of the ER and ret2-1, yeast delta-COP. A subset of tip20 mutants was found to be lethal in combination with sec20-1, sec21-1, sec22-3 and sec27-1. Since all pairwise combinations of a tip20 mutant, sec20-1, and ufe1-1 are lethal, Tip20p and Sec20p might be part of the docking complex for Golgi-derived retrograde transport vesicles. Since carboxy-terminal tip20 truncations are lethal in combination with mutants in three coatomer subunits, Tip20p might be involved in binding or uncoating of COPI coated retrograde transport vesicles.

Amino Acid Sequence↗
PubMed1997

The Sec20/Tip20p complex is involved in ER retrieval of dilysine-tagged proteins.

Sec20p and Tip20p were previously identified as two interacting proteins involved in early steps of the secretory pathway in Saccharomyces cerevisiae. Here we describe a novel temperature-sensitive allele of TIP20 and analyze its phenotype. While sec20 and tip20 mutants exhibited a defect in forward ER-to-Golgi transport at the non-permissive temperature, both were also defective for retrieval of various dilysine-tagged proteins from the Golgi back to the endoplasmic reticulum (ER) at lower temperature. Dilysine-dependent Golgi localization of Emp47p was also defective in both mutants. These results suggest a role for the Sec20/Tip20p complex in retrieval of dilysine-tagged proteins back to the ER.

Alleles↗
PubMed1994

Retrieval of HDEL proteins is required for growth of yeast cells.

The ERD2 gene of Saccharomyces cerevisiae encodes the receptor which retrieves HDEL-containing containing ER proteins from the Golgi apparatus. Viable erd2 mutants have been isolated that show no obvious HDEL-dependent retention of the luminal ER protein BiP, suggesting that retrieval of HDEL proteins is not essential for growth. However, cells that lack Erd2p completely have a defective Golgi apparatus and cannot grow. This observation led to the suggestion that the receptor had a second function, possibly related to its ability to recycle from Golgi to ER. In this paper we investigate the requirements for Erd2p to support growth. We show that mutations that block its recycling also prevent growth. In addition, we show that all mutant receptors that can support growth have a residual ability to retrieve BiP, which is detectable when they are overexpressed. Mere recycling of an inactive form of the receptor, mediated by a cytoplasmic KKXX sequence, is not sufficient for growth. Furthermore, saturation of the receptor by expression of an HDEL-tagged version of pro-alpha factor inhibits growth, even of strains that do not show obvious BiP retention. We conclude that growth requires the HDEL-dependent retrieval of one or more proteins, and that these proteins can be recognized even under conditions where BiP is secreted. Genetic screens have failed to identify any one protein whose loss could account for the Erd2p requirement. Therefore, a growth may require the retention of multiple HDEL proteins in the ER, or alternatively the removal of such proteins from the Golgi apparatus.

Amino Acid Sequence↗
PubMed1994

Biphasic diurnal periodicity in bleeding from peptic ulcer.

OBJECTIVE: To evaluate if there was periodicity in the manifestations of gastrointestinal bleeding (hematemesis and melena). METHOD: This is a multicenter prospective study carried out in the Endoscopy Units of eight hospitals. At the time of the emergency endoscopy, the following data were collected: age, sex, endoscopic diagnosis, solar hour of the first hematemesis (vomiting of bright red or tarry black material) and of the first melena (black or bloody soft stools), and any drugs taken during the week before the bleeding episode, regardless of the dose. RESULTS: 806 patients were studied. Bleeding was from peptic ulcer in 405 patients (50%), from esophageal varices in 197 (24%), and from other sources in the remainder. Analysis using single cosinor statistics showed a nonrandom distribution in bleeding from peptic ulcer, whether presenting first with hematemesis (p = 0.02) or melena (p = 0.03). There were two peaks at 6:45 AM and 6:45 PM for hematemesis and at 7:25 AM and 7:25 PM for melena, representing a biphasic diurnal (ultradian) rhythm. CONCLUSIONS: This study shows that bleeding due to peptic ulcer has a biphasic diurnal periodicity. This has potential importance for the pathogenesis of bleeding, for the management of gastrointestinal hemorrhage and the administration of drugs known to cause peptic ulcer bleeding.

Adolescent↗
PubMed1993

A Saccharomyces cerevisiae cyclophilin resident in the endoplasmic reticulum.

Cyclophilins are cyclosporin A sensitive peptidyl-prolyl cis-trans isomerases found in the cytoplasm of a wide range of species from Escherichia coli to man. Cyclophilin homologues are translocated into mitochondria, the endoplasmic reticulum and the bacterial periplasmic space. Here, the nucleotide sequence of a non-essential fifth Saccharomyces cerevisiae cyclophilin homologue encoded by chromosome XII is presented. As expected from its hydrophobic signal sequence and a hydrophilic carboxy terminus ending in the tetrapeptide HDEL, epitope-tagged cyclophilin D was found associated with the endoplasmic reticulum.

Amino Acid Isomerases↗
PubMed1992

Irritable bowel syndrome. Still far from a positive diagnosis.

The diagnosis of irritable bowel syndrome requires the exclusion of any associated organic disease: a positive diagnosis would avoid expensive and potentially dangerous diagnostic procedures. A scoring system has been proposed for positive diagnosis where more than 44 points excluded organic digestive disease. The aim of this study was to determine the usefulness of this scoring system in a different setting. Patients (1257) consecutively referred to our medical division were admitted to the study and 270 of these, complaining of abdominal symptoms, were scored on the Kruis system method. The positive predictive value (53.8% for men and 81.5% for women) and the sensitivity (46.7% and 59.5%) did not appear to be adequate. The negative predictive value (91.6% and 87.3%) and the specificity (93.5 and 95.4%) gave higher results, but two cases of neoplasia and nine cases of other organic digestive diseases were not identified or suggested. We believe that this scoring system may be useful only as a first step in a diagnostic flow chart.

Adult↗
PubMed1990

[Transient hyperphosphatasemia in infants].

Striking transient increases in serum alkaline phosphatase in 2 infants are reported. Isoenzymes were studied in 2 infants and increased activity was found in bone as well as in liver fractions. Repeated serum determinations demonstrated a duration of about 4-6 weeks. The etiology is unknown but an infectious cause is discussed. The condition may be rather frequent but gives no obvious symptoms. It is important to know this condition to avoid unnecessary diagnostic procedures.

Age Factors↗
PubMed1989

Conservation of the paired domain in metazoans and its structure in three isolated human genes.

Sequences homologous to the paired domain of Drosophila melanogaster have been conserved in species as distantly related as nematodes, sea urchins, or man. In particular, paired domains of three human genes, HuP1, HuP2 and HuP48, have been isolated and sequenced. Together with four Drosophila paired domains, they fall into two separate paired domain classes named according to their Drosophila members, paired--gooseberry and P29 class. The P29 class includes the mouse Pax 1 and the human HuP48 gene which are nearly identical in their sequenced portions and hence might be true homologues. In addition to the paired domain, the two human genes HuP1 and HuP2 share the highly conserved octapeptide HSIAGILG with the two gooseberry genes of Drosophila. Possible functions of the paired domain are discussed in the light of a predicted helix-turn-helix structure in its carboxy-terminal portion.

Amino Acid Sequence↗
PubMed1988

The role of localization of bicoid RNA in organizing the anterior pattern of the Drosophila embryo.

The organization of the anterior pattern in the Drosophila embryo is mediated by the maternal effect gene bicoid. bcd has been identified in an 8.7-kb genomic fragment by germ line transformants that completely rescue the mutant phenotype. The major transcript of 2.6 kb includes a homeobox with low homology to previously known homeoboxes, a PRD-repeat and a M-repeat. In situ hybridizations reveal that bcd is transcribed in the nurse cells. The mRNA is localized at the anterior tip of oocyte and early embryo until the cellular blastoderm stage. The localization of the transcript requires the function of the maternal effect genes exuperantia and swallow while transcript stability is reduced by functions depending on posterior group genes.

Alleles↗
PubMed1986

Conservation of a large protein domain in the segmentation gene paired and in functionally related genes of Drosophila.

Extending our search for homologous domains of the Drosophila paired gene, two closely linked genes at the gooseberry locus have been isolated. Both genes are expressed with a single segment periodicity but with different spatial and temporal expression patterns. While the transcripts of one gene appear earlier and are equally distributed between ectoderm and mesoderm, those of the second gene accumulate preferentially in neuroblasts. The similarity of these expression patterns to the 14-band pattern of the paired gene suggests a functional relationship. Such a functional link may be reflected in the two structurally homologous domains shared with the paired gene: a new type of homeo box extended by 18 amino acids at the 5' end, and a new domain, the paired box, consisting of a sequence of 128-135 amino acids. Thus, together with the PRD repeat, the paired gene contains at least three different domains, each defining a gene set thought to be important for development.

Animals↗
PubMed1986

Structure of the segmentation gene paired and the Drosophila PRD gene set as part of a gene network.

The sequence of paired, a pair-rule gene required for segmentation in Drosophila, is presented. A search for genes with domains homologous to the paired gene was initiated and three homologues from a set of 12 were characterized with respect to temporal or spatial expression and sequence homologies. All four are transcribed in early development, one in the oocyte and during cleavage stages in the form of a gradient. In addition to the prd-specific his-pro repeat, some of the 12 genes contain M-repeats and two new types of homeo boxes not detectable by hybridization with the two known classes of homeo boxes. The observed linking of gene sets through combinations of homologies coding for protein domains is consistent with a general network concept of gene action.

Amino Acid Sequence↗
PubMed1983

[ Pathology of the colon associated with diverticulosis of the descending colon and the sigmoid. Instrumental clinical study ].

A retrospective survey was carried out on 87 patients with diverticulosis and 223 control subjects with a view to studying the incidence of colon pathology in association with diverticulosis of the colon. All subjects were given colonoscopies of the distal section of the colon. The survey revealed that the group of diverticulosis patients was, on average, older than the control group (72 v. 59 years). There was no significant difference in the performance or totality of the endoscopic examination. Subjective and objective symptomatology revealed no a priori evidence of pathology associated with diverticulosis. There was no statistically significant difference in the incidence of polyps, neoplasias, haemorrhoids or colon melanosis in the two groups.

Aged↗