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Biomedical subjects

G Piperno

Publications and source records attributed to G Piperno.

At least 19 recordsLinked to original sources
PubMed2005

Primary leiomyosarcoma of the fallopian tube: a case report.

A primary leiomyosarcoma (LMS) arising from the left fallopian tube in a perimenopausal 48-year-old woman is reported. Primary tubal LMS is an uncommon, exceedingly rare neoplasm, accounting for only a few reported cases so far. To our knowledge, the present case is the 17th tubal LMS reported in the English-language literature. The diagnosis is usually made at the time of laparotomy for a pelvic or adnexal mass or other gynaecological indications. As in ovarian neoplasms, the mainstay of treatment is represented by debulking surgery consisting of total abdominal hysterectomy, bilateral salpingo-oophorectomy, random biopsies, peritoneal washing and excision of all the abdominal tumour masses. Although the approach is radical, the clinical behaviour is very poor. The role of adjuvant radio- or chemotherapy still remains unsolved.

Fallopian Tube Neoplasms↗
PubMed2004

Genetic and pathologic significance of 1p, 17p, and 18q aneusomy and the ERBB2 gene in colorectal cancer and related normal colonic mucosa.

Among chromosome defects in colon cancer, deletions in 1p, 17p, and 18q have been reported as frequent events. To verify this, we investigated 1p, 17p, and 18q aneusomy in 60 colorectal cancers and their surrounding mucosa by means of fluorescence in situ hybridization (FISH). We also evaluated ERBB2 gene (alias HER-2/neu) amplification in a subset of tumors. The genetic picture in tumors was correlated with chromosomal alterations in normal colonic mucosae, as well with clinicopathologic variables. A population of cells in morphologically normal epithelium possesses genetic aberrations common to those in colon cancer, although in different percentages. No significant difference emerged in terms of fraction of nuclei with 17p monosomy between primary tumors and distal mucosal samples. Of tumor samples aneusomic for the three chromosomes, 58.3% also showed aneusomy in related normal colonic mucosa. In neoplastic samples, significant correlation existed between 1p aneusomy and mucosal component (P<0.007), between 17p aneusomy and increased depth of invasion (T3-T4) (P<0.05), and between 18q aneusomy and tumor site (P<0.03). None of the evaluated samples, neoplastic or normal, showed ERBB2 gene amplification.

Adult↗
PubMed2004

Role of P53 and Bcl-2 in advanced rectal carcinomas treated with adjuvant therapy.

Rectal adenocarcinomas is usually associated to a poorer outcome than colon cancers. In this study we analyzed the impact on overall survival of p53 and Bcl-2, evaluated by immunohistochemical techniques, in 126 advanced rectal cancer patients submitted to 5 fluorouracil based adjuvant therapy. Shorter overall survival was observed in patients bearing p53 positive and Bcl-2 negative tumors, although in multivariate analysis only p53 emerged as independent predictor of a worse outcome. These results seem to indicate that, in stage III-IV rectal cancer, p53 alterations may identify high risk patients to be enrolled in more aggressive and/or innovative adjuvant/neoadjuvant treatments.

Adult↗
PubMed2003

Uterine sarcoma: twenty-seven years of experience.

PURPOSE: A correlation of treatment for uterine sarcoma with outcome, prognostic importance of pathology, and clinical parameters. PATIENTS AND METHODS: One hundred forty-one patients (median age: 56 years, range: 19-85 years) with a histologically verified uterine sarcoma were identified from a database compiled at the Royal Marsden Hospital and the University of Florence between 1974 and 2001. Seventy-two patients had leiomyosarcoma, 42 had mixed müllerian tumors, 22 had endometrial stromal sarcoma, 1 hemangiopericytoma, 1 rhabdomyosarcoma, and 3 patients had unspecified sarcoma. According to FIGO classification, Stage I, II, III, and IV tumors were identified in 71, 13, 31, and 26 patients, respectively. RESULTS: At the time of analysis, 73.7% of patients were dead, and 26.3% were alive with a median survival of 2 years from initial diagnosis. Univariate analysis for cause-specific survival demonstrated statistical significance for histology (p = 0.02), grade (p = 0.003), stage (p = 0.007), and age (p = 0.02). Multivariate analysis demonstrated significant prognostic values for stage (p = 0.02) and histology (p = 0.05) only. Postoperative radiotherapy with a total dose higher than 50 Gy seems to be significant (p = 0.001) in reducing local recurrence. CONCLUSIONS: Our data favor treatment for Stages I, II, and III of uterine sarcoma with radical surgery plus radical dose irradiation comprising both external beam radiotherapy and brachytherapy.

Adult↗
PubMed2003

Bio-pathological factors of prognostic value in colorectal adenocarcinomas.

About 40% of patients bearing a colorectal carcinoma will develop local or distant tumor recurrences. Integrated analyses of biopathological markers, predictive of tumor aggressiveness, may offer a more rational approach to adjuvant therapy planning. To this end we analyzed the correlation between p53 accumulation, bcl-2 expression with cell proliferation, DNA ploidy, and conventional histological parameters, by testing the prognostic significance of these variables in a series of 214 patients bearing a colorectal carcinoma. When these parameters were examined in the univariate analysis, significantly shorter disease free and overall survival were observed in patients bearing p53+ and bcl-2- tumors. In the multivariate analysis p53 accumulation and bcl-2 expression emerged as independent predictors respectively of worse and better clinical outcome also in Dukes' B stage identifying patients at higher risk to develop liver metastases.. These results indicate that in colorectal adenocarcinomas a biological profile, based on the combined evaluation of p53 and bcl-2, can be useful in identifying high risk patients to be enrolled in an adjuvant setting mainly in early stage of the disease.

Adenocarcinoma↗
PubMed2001

Protein particles in Chlamydomonas flagella undergo a transport cycle consisting of four phases.

We used an improved procedure to analyze the intraflagellar transport (IFT) of protein particles in Chlamydomonas and found that the frequency of the particles, not only the velocity, changes at each end of the flagella. Thus, particles undergo structural remodeling at both flagellar locations. Therefore, we propose that the IFT consists of a cycle composed of at least four phases: phases II and IV, in which particles undergo anterograde and retrograde transport, respectively, and phases I and III, in which particles are remodeled/exchanged at the proximal and distal end of the flagellum, respectively. In support of our model, we also identified 13 distinct mutants of flagellar assembly (fla), each defective in one or two consecutive phases of the IFT cycle. The phase I-II mutant fla10-1 revealed that cytoplasmic dynein requires the function of kinesin II to participate in the cycle. Phase I and II mutants accumulate complex A, a particle component, near the basal bodies. In contrast, phase III and IV mutants accumulate complex B, a second particle component, in flagellar bulges. Thus, fla mutations affect the function of each complex at different phases of the cycle.

Algal Proteins↗
PubMed1998

Distinct mutants of retrograde intraflagellar transport (IFT) share similar morphological and molecular defects.

A microtubule-based transport of protein complexes, which is bidirectional and occurs between the space surrounding the basal bodies and the distal part of Chlamydomonas flagella, is referred to as intraflagellar transport (IFT). The IFT involves molecular motors and particles that consist of 17S protein complexes. To identify the function of different components of the IFT machinery, we isolated and characterized four temperature-sensitive (ts) mutants of flagellar assembly that represent the loci FLA15, FLA16, and FLA17. These mutants were selected among other ts mutants of flagellar assembly because they displayed a characteristic bulge of the flagellar membrane as a nonconditional phenotype. Each of these mutants was significantly defective for the retrograde velocity of particles and the frequency of bidirectional transport but not for the anterograde velocity of particles, as revealed by a novel method of analysis of IFT that allows tracking of single particles in a sequence of video images. Furthermore, each mutant was defective for the same four subunits of a 17S complex that was identified earlier as the IFT complex A. The occurrence of the same set of phenotypes, as the result of a mutation in any one of three loci, suggests the hypothesis that complex A is a portion of the IFT particles specifically involved in retrograde intraflagellar movement.

Animals↗
PubMed1997

Transport of a novel complex in the cytoplasmic matrix of Chlamydomonas flagella.

Proteins necessary for maintenance and function of eukaryotic flagella are synthesized in the cell body. Transport of the inner dynein arm subunit p28(IDA4) in Chlamydomonas flagella requires the activity of the kinesin KHP1(FLA10), a protein inactive at restrictive temperature in fla10, a temperature-dependent mutant of flagellar assembly. To identify other molecules involved in active transport of inner dynein arms within flagella we searched for polypeptides of the cytoplasmic matrix of flagella that fulfill two conditions: they bind to p28 and require the activity of KHP1 to be present in flagella. We found that the cytoplasmic matrix of flagella contains a previously unidentified "17S" complex of at least 13 polypeptides that in part is associated with p28. The 17S complex is present at permissive but not at restrictive temperature in fla10 flagella. It also turns over in the cytoplasmic matrix more frequently than dynein arms within the axoneme. This evidence suggests that the 17S complex transports precursors of inner dynein arms within flagella.

Algal Proteins↗
PubMed1997

[Diagnostic accuracy of teleradiology in thoracic and abdominal diseases].

For one year now, teleradiology has linked the "S. Marcello" Hospital to the Department of Radiology of "Del Ceppo." Hospital in Pistoia, 30 kilometers away. Plain films are digitized (Lumiscan 50, Philips), transmitted over a dedicated standard telephone line and displayed at 1024 x 1024 x 8 bits. To study the diagnostic accuracy of teleradiology in chest and abdominal conditions, we digitized and transmitted to the Pistoia Dept. of Radiology, a sample of 156 (96 chest and 60 abdominal) emergency examinations made in "S. Marcello" Hospital from January through November, 1995. The patients were 81 women (mean age: 69 years) and 75 men (mean age: 66 years); the age range was 17-93 years. Three radiologists independently reviewed the images in the Pistoia Dept. of Radiology on a digital workstation enabled to manipulate images. They filled in some given forms specific for chest and abdominal radiography, which were compared with the same forms filled in by the radiologist in "S. Marcello" Hospital who reviewed plain films. The differences were never clinically important; they concerned emphysema (4 false positives and 2 false negatives), congestion of the hila (2 false positives and 2 false negatives) and abnormal air in small bowel and colon (2 false positives and 2 false negatives). We believe these differences to be related to interobserver variability. The diagnostic accuracy of monitor image interpretation by the three radiologists who reviewed digitized radiographs exceeded 96% for both chest and abdominal examinations, which figure compares with literature data on high resolution workstations.

Adolescent↗
PubMed1996

Inner dynein arms but not outer dynein arms require the activity of kinesin homologue protein KHP1(FLA10) to reach the distal part of flagella in Chlamydomonas.

Inner dynein arms, but not outer dynein arms, require the activity of KHP1(FLA10) to reach the distal part of axonemes before binding to outer doublet microtubules. We have analyzed the rescue of inner or outer dynein arms in quadriflagellate dikaryons by immunofluorescence microscopy of p28(IDA4), an inner dynein arm light chain, or IC69(ODA6), an outer dynein arm intermediate chain. In dikaryons two strains with different genetic backgrounds share the cytoplasm. As a consequence, wild-type axonemal precursors are transported to and assembled in mutant axonemes to complement the defects. The rescue of inner dynein arms containing p28 in ida4-wild-type dikaryons progressively occurred from the distal part of the axonemes and with time was extended towards the proximal part. In contrast, the rescue of outer dynein arms in oda2-wild-type dikaryons progressively occurred along the entire length of the axoneme. Rescue of inner dynein arms containing p28 in ida4fla10-fla10 dikaryons was similar to the rescue observed in ida4-wild-type dikaryons at 21 degrees C, whereas it was inhibited at 32 degrees C, a nonpermissive temperature for KHP1(FLA10). In contrast, rescue of outer dynein arms in oda2fla10-fla10 dikaryons was similar to the rescue observed in oda2-wild-type dikaryons at both 21 degrees and 32 degrees C and was not inhibited at 32 degrees C. Positioning of substructures in the internal part of the axonemal shaft requires the activity of kinesin homologue protein 1.

Algal Proteins↗
PubMed1996

[Secondary liver lesions studied with double-helix spiral computed tomography: first experience].

The authors report their early personal experience with double-helix spiral CT (CT Twin Elscint) in the study of liver metastases. This work was aimed at optimizing the study technique and at assessing the diagnostic accuracy of this method. The high temperature developed by CT Twin and the presence of a double row of detectors permit to acquire proper length sequences (with 6.5 mm slice thickness) within a short scanning time which is easy for the patient to tolerate without breathing and moving. Two hundred and thirty patients were examined with US for focal hepatic lesions and then submitted to spiral CT: spatial and density resolution were higher with spiral CT than with US, and the former technique permitted the whole liver to be studied without any partial volume artifacts, which allowed us to confirm all the lesions depicted with US and to detect other lesions, missed at US, in 20% of patients. The choice of the proper time between contrast administration and sequence acquisition is sufficient to permit the detection of focal lesions, if the liver is studied in the portal phase. The authors stress the yield of spiral CT, especially with the double-helix technique, in studying liver metastases.

Adult↗
PubMed1995

The light chain p28 associates with a subset of inner dynein arm heavy chains in Chlamydomonas axonemes.

We show here that I2 and I3 inner dynein arm heavy chains of Chlamydomonas axonemes are resolved into two classes: one class associated with the protein p28 and the other associated with the protein caltractin/centrin. We have determined the nucleotide sequence of the gene encoding p28, a light chain that, together with actin and caltractin/centrin, is associated with inner dynein arms I2 and I3 of Chlamydomonas axonemes. p28 is a novel protein with affinity for a subset of the inner dynein arm heavy chains, but with no apparent significant homologies to tubulin- or actin-binding proteins. An antiserum specific for p28 showed that p28 is present along the entire axoneme. The same antiserum coimmunoprecipitated p28, actin, and dynein heavy chains 2' and 2. In contrast, an anti-caltractin/centrin antiserum coimmunoprecipitated caltractin/centrin, actin, and the heavy chains 2, 3, and 3'. It is likely that the dynein heavy chain 2 associated with p28, referred to as 2A, is a different polypeptide from dynein heavy chain 2 bound to caltractin/centrin, referred to as 2B. The complex formed by heavy chain 2B, actin, and caltractin/centrin is preferentially extracted by exposure to Nonidet P-40 and is missing in mutants lacking components 1 and 2 of the dynein regulatory complex.

Amino Acid Sequence↗
PubMed1995

ida4-1, ida4-2, and ida4-3 are intron splicing mutations affecting the locus encoding p28, a light chain of Chlamydomonas axonemal inner dynein arms.

We recently determined the nucleotide sequence of the gene encoding p28, a light chain of inner dynein arms of Chlamydomonas axonemes. Here, we show that p28 is the protein encoded by the IDA4 locus. p28, and the dynein heavy chains normally associated with it, are completely absent from the flagella and cell bodies of three allelic strains of ida4, named ida4-1, ida4-2, and ida4-3. We determined the nucleotide sequence of the three alleles of the p28 gene and found in each case a single nucleotide change, affecting the splice sites of the first, second, and fourth introns, respectively. Reverse transcriptase-polymerase chain reaction amplification of RNAs prepared from ida4 cells confirmed that these mutations prevent the correct splicing of the affected introns, thereby blocking the synthesis of full-length p28. These are the first intron splicing mutations described in Chlamydomonas and the first inner dynein arm mutations characterized at the molecular level. The absence in ida4 axonemes of the dynein heavy chains normally found in association with p28 suggests that p28 is necessary for stable assembly of a subset of inner dynein arms or for the binding of these arms to the microtubule doublets.

Animals↗