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Biomedical subjects

M Stella

Publications and source records attributed to M Stella.

At least 37 records · Page 2Linked to original sources
PubMed1998

Preoperative and intraoperative radioimmunodetection of cancer pretargeted by biotinylated monoclonal antibodies.

The in vivo post-targeting of tumor by means of anti-carcinoembryonic-antigen (CEA) monoclonal antibodies (MAbs) and the avidin-biotin three-step system was tested by immunoscintigraphy and radioimmunoguided surgery (RIGS) in six patients with primary or recurrent rectal cancer. The patients were preoperatively injected with 1 mg of FO23C5 (anti-CEA) and/or B72.3 anti-tumor-associated glycoprotein (TAG-72) biotinylated MAb; after 24 hours, 1 mg of avidin was administered, and, after a further 24 hours, biotin labeled to Indium-111 (In111) was injected. Preoperative imaging was obtained by means of a gamma camera, and a portable gamma-detecting probe (Neoprobe 1000) was intraoperatively used to count tumor and surrounding normal tissue. Eight tumor sites were localized in the six patients. Four lesions were identified preoperatively and six intraoperatively with a mean tumor-to-normal-tissue (T/NT) ratio of 1:8. This method allowed preoperative scintigraphy and intraoperative radioimmunodetection to be performed with a single radioactive compound injection of biotin labeled to In111 within few days before surgery.

Adult↗
PubMed1998

Low IGF-I levels are often uncoupled with elevated GH levels in catabolic conditions.

Increased GH together with decreased IGF-I levels pointing to peripheral GH insensitivity in critically ill patients have been reported by some but not by other authors. To clarify whether elevated GH levels are coupled with low IGF-I levels in all catabolic conditions, basal GH and IGF-I levels were evaluated in patients with sepsis (SEP, no.=13; age [mean+/-SE]=59.2+/-1.2 yr), trauma (TRA, no.=16; age=42.3+/-3.4 yr), major burn (BUR, no.=26; age=52.8+/-4.2 yr) and post-surgical patients (SUR, no.=11; age=55.0+/-4.7 yr) 72 hours after ICU admission or after cardiac surgery. GH and IGF-I levels were also evaluated in normal subjects (NS, no.=75; age=44.0+/-1.5 yr), in adult hypopituitaric patients with severe GH deficiency (GHD, no.=54; age=44.8+/-2.3 yr), in patients with liver cirrhosis (LC, no.=12; age=50.4+/-2.8 yr) and in patients with anorexia nervosa (AN, no.=19; age=18.7+/-0.8 yr). Basal IGF-I and GH levels in GHD were lower than in NS (68.6+/-6.4 vs 200.9+/-8.7 microg/l and 0.3+/-0.1 vs 1.4+/-0.2 microg/l; p<0.01). On the other hand, AN and LC showed IGF-I levels (70.4+/-9.1 and 52.4+/-10.5 microg/l) similar to those in GHD while GH levels (10.0+/-2.8 and 7.9+/-2.1 microg/l) were higher than those in NS (p<0.01). IGF-I levels in SEP (84.5+/-8.8 microg/l) were similar to those in GHD, AN and LC and lower than those in NS (p<0.01). IGF-I levels in BUR (105.2+/-10.9 microg/l) were lower than in NS (p<0.01) but higher than those in GHD, AN, LC and SEP (p<0.01). On the other hand, in TRA (162.8+/-17.4 microg/l) and SUR (135.0+/-20.7 microg/l) IGF-I levels were lower but not significantly different from those in NS and clearly higher than those in GHD, AN, LC, SEP and BUR. Basal GH levels in SEP (0.6+/-0.2 microg/l), TRA (1.8+/-0.5 microg/l), SUR (2.2+/-0.5 microg/l) and BUR (2.2+/-0.5 microg/l) were similar to those in NS, higher (p<0.05) than those in GHD and lower (p<0.01) than those in AN and LC. In conclusion, our data demonstrate that low IGF-I levels are not always coupled with elevated GH levels in all catabolic conditions. Differently from cirrhotic and anorectic patients, in burned and septic patients GH levels are not elevated in spite of very low IGF-I levels similar to those in panhypopituitaric GHD patients. These findings suggest that in some catabolic conditions peripheral GH insensitivity and somatotrope insufficiency could be concomitantly present.

Adolescent↗
PubMed1998

Primary ex vivo culture of keratinocytes isolated from hypertrophic scars as a means of biochemical characterization of CD36.

The CD36 antigen is a molecule which is ectopically expressed on epidermal keratinocytes of hypertrophic scars and is a good candidate for a marker for a broad range of skin pathologies. Most marker studies have been performed using immunohistochemical techniques on fixed skin sections. Our aim was to investigate the biochemical features of the CD36 expressed in pathological keratinocytes and to find an in vitro model for the study of the regulation of its expression. Here we show how keratinocytes isolated from hypertrophic scars can be cultivated in vitro and employed as a model for the study of these cells. We demonstrated that the antigenic features of the CD36 expressed on keratinocytes of hypertrophic scars are identical to those described for the CD36 expressed by other cell types. The molecule was expressed on the surface of keratinocytes which were non-adherent in vitro. Adherent and proliferating keratinocytes, as well as normal keratinocytes, were CD36 negative both at the surface and intracellularly. The in vitro proliferating cells from hypertrophic scars, but not the normal keratinocytes, showed intracellular expression of CD36 after long-term culture and cell stratification, suggesting a regulated expression of CD36 in pathological keratinocyte differentiation.

Adult↗
PubMed1998

High incidence of sperm sex chromosomes aneuploidies in two patients with Klinefelter's syndrome.

In this study we have investigated the arrangement of sex chromosomes in sperm from two severe oligozoospermic patients, apparently affected by the classic form of Klinefelter's syndrome (KS). Multicolor fluorescence in situ hybridization has been used to recognize chromosomes X, Y, and 8 in sperm from patients and 10 fertile men with normal 46,XY karyotype. In patients affected by KS, we detected important numerical sex chromosome abnormalities (approximately 20%). In all normal fertile men, X- and Y-bearing spermatozoa were present in a 1:1 ratio. On the contrary, in our patients the frequency of 23,Y-bearing sperm was strongly reduced compared with that of both 23,Y sperm in the controls and 23,X sperm in the same subject affected by KS, resulting in a 23,X-/23,Y-bearing sperm ratio of 2:1. Moreover, the frequency of 24,XY disomic sperm was significantly higher in the absence of the 22,0 hypoaploidy expected from a common origin from a nondysjunction during the first meiosis in a normal 46,XY cell. In conclusion, the results of the present study demonstrate a peculiar distribution of sex chromosomes in sperm from two patients with KS, in agreement with the hypothesis that 47,XXY germ cells are able to complete the meiotic process by producing mature spermatozoa.

Adult↗
PubMed1997

Chromosome aberrations in hospital workers: evidence from surveillance studies in Italy (1963-1993).

Hospital workers are occupationally exposed to various agents known or suspected to induce chromosome damage, the most studied being ionizing radiation. To determine the extent of chromosome damage in peripheral blood lymphocytes in this population, taking into account temporal changes and job titles, a re-analysis of cytogenetic studies performed in four Italian laboratories in the period 1965-1993 was carried out. A total of 871 hospital workers and 617 controls, mainly coming from ad hoc studies or surveillance programs in occupational groups potentially exposed to ionizing radiation, were examined. The exposed to controls frequency ratio of chromosome aberrations was evaluated as the measure of effect within each dataset by job title, using multivariate Poisson regression analysis, which allowed an efficient control of confounding. Increased frequency of chromosome-type aberrations among exposed subjects was found in all datasets, especially in those dealing with older data. Significantly higher frequencies are reported for various job titles, particularly for orthopedists, radiologists, anesthesists, and nurses among paramedical occupations. Decrease in exposure to ionizing radiation in hospital workers was documented through a targeted study in the critical group of radiologists. A similar time-related reduction in the frequency of chromosome-type aberrations also has been reported by the surveillance studies carried out over the most recent decades. These data substantiate the use of chromosome-type aberrations as biomarkers of exposure in this occupational setting in the period evaluated. However, the increases observed also in workers with doubtful exposure to ionizing radiation indicate that other chromosome-damaging agents may be involved and, in turn, suggest the extension of surveillance to a larger number of occupations.

Adult↗
PubMed1997

Combination of monoclonal antibodies for radioimmunoguided surgery.

The use of a cocktail of monoclonal antibodies in intraoperative radioimmunodetection of colorectal tumour has been evaluated in 14 patients. Eight patients had primary and six recurrent colorectal cancer. Three different monoclonal antibodies were used included B72.3, recognizing TAG72 antigen, FO23C3 and FO23C5 directed against two epitopes of CEA. The antibodies were labeled with 125I. During surgery the radioactive emission of tumour and normal tissue was evaluated by a gamma detecting probe. Ten patients showed positive intraoperative results and in particular 6 (75%) of the 8 patients with primary tumour and 4 (67%) of the 6 patients with recurrence, with a mean tumour to normal tissue ratio of 2.2. Intraoperative radioimmunodetection was instrumental in modifying the therapeutic approach in two patients with recurrent cancer but in none of the patients with a primary presentation. Immunohistochemical analysis, to evaluate TAG72 and CEA antigen expression, was performed in 13 cases. CEA antigen was expressed in 8/13 cases and TAG72 in 5/13. Thus the sensitivity was 38.5% and 61.5% with B72.3 and anti-CEA monoclonal antibodies respectively, while in combination the sensitivity was 71.4%. The use of a cocktail of different antibodies improved the sensitivity of intraoperative radioimmunodetection of colorectal tumours, when compared with a single antibody injection. This approach might improve the clinical use of radioimmunodetection.

Adult↗
PubMed1997

Age-related increase of baseline frequencies of sister chromatid exchanges, chromosome aberrations, and micronuclei in human lymphocytes.

Intra- and interindividual variations of baseline frequencies of cytogenetic end points in lymphocytes of human populations have been reported by various authors. Personal characteristics seem to account for a significant proportion of this variability. Several studies investigating the role of age as a confounding factor in cytogenetic biomonitoring found an age-related increase of micronucleus (MN) frequency, whereas contradictory results were reported for chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs). We have quantitatively evaluated the effect of age on SCE, CA, and MN through the analysis of a population sample that included data from several biomonitoring studies performed over the last few decades in 12 Italian laboratories. The large size of the data set, i.e., more than 2000 tests for each end point, allowed us to estimate the independent effect of age, taking into account other covariates, such as sex, smoking habits, occupational exposure, and inter- and intralaboratory variability. A greater frequency of the mean standardized values by increasing of age was observed for all of the end points. A leveling off was evident in the last age classes in the trend of MN frequencies. Frequency ratios (FRs), which express the increase of the cytogenetic damage with respect to the first age classes, i.e., 1-19 years, were estimated using Poisson regression analysis after adjustment for the potential confounding factors and confirmed the increasing trend by age class for all three end points. The most dramatic increase was observed for MN, with a FR that approaches the value of 2 at the age class 50-59 (FR, 1.97; 95% confidence interval, 1.43-2.71) and remains substantially unchanged thereafter. The trend of FRs for CA is more homogeneous, with a constant rise even in the older classes, whereas the frequency of SCE increases with age to a lesser extent, reaching a plateau in the age class 40-49 and the maximum value of FR in the age class over 70 (FR, 1.14; 95% confidence interval, 1.07-1.23). In conclusion, our results point to an age-related increase of the chromosome damage in lymphocytes and emphasize the need to take into account the potential confounding effect of this variable in the design of biomonitoring studies based on chromosome damage.

Adolescent↗
PubMed1996

Cytogenetics of pediatric central nervous system tumors.

A cytogenetic analysis was performed on short-term cultures of 43 previously untreated childhood central nervous system neoplasms of various histology. The cells were obtained from pediatric patients, none of whom had received therapy before karyotypic evaluation. Successful chromosome studies were performed on 24 tumors. The most commonly detected structural abnormalities involved chromosomes 1 and 17. Other structural chromosome abnormalities involved chromosomes 3, 6, 8, 9, 11, 12, and 20.

Adolescent↗
PubMed1996

High-efficiency expression gene cloning by flow cytometry.

Our goal was to develop a convenient and widely applicable procedure for gene cloning based on flow cytometry. To this purpose, we have developed an efficient protocol for DNA transfection and selection of rare transfectants. Transfection by calcium phosphate co-precipitation was extensively investigated. The use of specific batches of calcium chloride, of carrier DNA purified in guanidinium thiocyanate, and of plasmid DNA banded in cesium chloride proved crucial for high efficiency of transfection. Several tissue culture parameters were also found critical. With the optimized procedure we can transfect almost 100% of the COS-7 cells with cDNA encoding cell surface antigens or green fluorescent protein. Moreover, we routinely obtain high average levels of expression. Efficient cell sorting in flow cytometry was achieved by subtracting the cell autofluorescence background, by displacing stained cells in the red dimension, and by combining fluorescein-conjugated primary and secondary antibodies. Efficient recovery of the transfected DNA constructs was obtained from 2500-3000 cells directly sorted in Hirt lysis buffer. Using the above protocol we have cloned by expression the gene encoding Trop-2, a cell surface glycoprotein expressed by human carcinomas.

Animals↗
PubMed1996

A functional homologue of goosecoid in Drosophila.

We have cloned a Drosophila homologue (D-gsc) of the vertebrate homeobox gene goosecoid (gsc). In the Gsc proteins, the pressure for conservation has been imposed on the homeodomain, the functional domain of the protein: sequence homology is limited to the homeodomain (78% identity) and to a short stretch of 7 aminoacids also found in other homeoproteins such as Engrailed. Despite this weak homology, D-gsc is able to mimic gsc function in a Xenopus assay, as shown by its ability to rescue the axis development of a UV-irradiated embryo. Moreover, our data suggest that the position of insect and vertebrate gsc homologues within a regulatory network has also been conserved: D-gsc expression is controlled by decapentaplegic, orthodenticle, sloppy-paired and tailless whose homologues control gsc expression (for BMP4 and Otx-2), or are expressed at the right time and the right place (for XFKH1/Pintallavis and Tlx) to be interacting with gsc during vertebrate development. However, the pattern of D-gsc expression in ectodermal cells of the nervous system and foregut cannot easily be reconciled with that of vertebrate gsc mesodermal expression, suggesting that its precise developmental function might have diverged. Still, this comparison of domains of expression and functions among Gsc proteins could shed light on a common origin of gut formation and/or on basic cellular processes. The identification of gsc target genes and/or other genes involved in similar developmental processes will allow the definition of the precise phylogenetic relationship among Gsc proteins.

Amino Acid Sequence↗
PubMed1996

Bellini duct carcinoma. A clinical and in vitro study.

OBJECTIVE: Bellini duct carcinoma (BDC) is a rare and highly aggressive renal tumor whose histogenesis is still a matter of debate although a putative origin from collecting ducts has been proposed. METHODS: A primary tumor cell culture was obtained from a BDC of a 57-year-old man who presented with a mass of the right kidney. The patient died from disease progression 18 months after diagnosis. The light and ultrastructural features were consistent with previous reports on BDC. The expression of low (Ker 18) and high (Ker 5, Ker 8, Ker 10) molecular weight keratins was studied. RESULTS: The BDC tumor cells displayed strong positivity for keratins, 5, 8 and 18 but did not react with the anti-keratin 10 antibody. Northern blot analysis of total mRNA revealed expression of the c-erbB-1 oncogene unlike two conventional clear cell carcinomas of the kidney used as control. Cytogenetic analysis revealed an aneuploid karyotype: 53,XY,del(1)(p34),+iso(1q),+iso(5p),+4,+7,+8,-14,del(16)(q22). No submicroscopic deletion on p14-21 and p26 regions of the short arm of chromosome 3 was detected on Southern blot analysis. CONCLUSIONS: The absence of structural changes in the short arm of chromosome 3 (usually present in hereditary and sporadic renal cell carcinomas) in the presence of chromosomal abnormalities observed in malignant lesions of urothelial origin confers to BDC a unique genetic profile among papillary tumors of the kidney.

Carcinoma, Papillary↗
PubMed1996

The influence of progress in the treatment of severe burns on the quality of life.

The problems related to burns treatment can be considered among the oldest and most passionating in history of medicine. Since the early forties amazing progresses have been done in the comprehension of the physiopathology of burns. The fast development of resuscitating techniques determined a remarkable reduction of mortality in the first phase; in a similar way through new concepts in the project and construction of intensive care facilities dedicated to burns, where patients can be isolated and a high standard of environmental control can be guaranteed, together with new topical and systemic antibacterial treatment protocols, a significant reduction of infectious complications has been achieved. Concerning surgical treatment early tangential excision and cultured epidermal grafts can be considered the cornerstones of burn therapy. Quality of life of burnt patients have been greatly ameliorated by these technical advances. Burn sequelae however remain the main concern of survivors because of the many controversial aspects of burn scar physiopathology and treatment. Along my career many endeavours I dedicated in this important research field. I will then report the results of most interesting clinical and experimental studies carried out in the last 30 years by our group in collaboration with basic researchers. All the work done in this domain enhance our hope that good results can really improve quality of life in burns: this is the goal for those who dedicated the whole life to relieve the suffering of these badly injured patients.

Anti-Bacterial Agents↗
PubMed1995

Cloning of the gene encoding Trop-2, a cell-surface glycoprotein expressed by human carcinomas.

We have cloned by expression the cDNA encoding Trop-2, a cell-surface glycoprotein expressed by most human carcinomas. Formal proof of the identity of the clone is the hybridization to DNA and RNA from genomic TROP2 transfectants. TROP2 is a single-copy gene in human cells, hybridizes to a single 1.8-kb mRNA from expressing sources and encodes a 35,709 Da type-1 transmembrane protein with a single transmembrane domain. TROP2 is essentially identical to GA733-1. Thus, we have proven that GA733-1, for which a protein product had not been identified, is a functional gene. TROP2 is also homologous to TROP1/KSA/GA733-2, confirming the serological similarities between the 2 molecules. The homology between the Trop-1 and Trop-2 peptides is clustered in 2 extracytoplasmic domains and in the transmembrane/cytoplasmic region. Twelve cysteines and a potential cytoplasmic tyrosine phosphorylation site are also conserved. Trop-1 and Trop-2 are homologous to serum IGF-II-binding proteins and appear as signal transducers. Thus, they likely represent novel cell-surface receptors and may play a role in regulating the growth of carcinoma cells. On the other hand, we have found no evidence for a role of Trop-2 and Trop-1 as homophilic adhesion molecules.

Amino Acid Sequence↗
PubMed1995

An immunohistochemical study on cutaneous sensory receptors after chronic median nerve compression in man.

Carpal tunnel syndrome represents the most frequent chronic compressive neuropathy in man and hence may be investigated as a spontaneous model of peripheral nerve damage and repair. In the present report the fate of nerve fibers in the digital skin after long-lasting median nerve compression has been investigated immunohistochemically in comparison to normal digital skin, with special consideration to sensory endings and encapsulated receptors. The presence has been documented of the neurospecific marker PGP 9.5, the glia-associated protein S-100, and the neuropeptides CGRP and CPON which are mainly associated with the sensory and sympathetic nerve fibers respectively. The morphology and distribution of nerve fibers and corpuscles appeared comparable to that of normal digital skin; a reduction in the density of sensory receptors has, however, been observed, although not to the degree that was expected to explain the clinical deficits. It has been also demonstrated that at least part of the CGRP-containing sensory and CPON-containing sympathetic axons may survive unaltered even in patients with a long clinical history of profound sensorial impairment. An apparent discrepancy between the maintenance of nerve fibers and the sensory disturbances and the frequent observation of prompt postoperative recovery even after years of compression results from this investigation. The correlation of immunohistochemical observations and functional scores may not be considered conclusive. It must, however, be discussed if the sensorial impairment in this syndrome might have, at least in some cases, not only an anatomical but also an electrophysiological basis.

Calcitonin Gene-Related Peptide↗
PubMed1994

Prospective multicenter study on CA 125 in postmenopausal pelvic masses.

The purpose of this study was to determine the diagnostic value of CA 125 in comparison with transabdominal ultrasound (US) in the evaluation of postmenopausal women with pelvic mass to detect malignant epithelial ovarian tumors. Postmenopausal patients with pelvic mass were studied with gynecologic examination, US and CA 125 determination. Three hundred eighty-eight patients were entered in the study. According to stratification based on US (probably benign, equivocal, possibly malignant) and CA 125 (< 35 U/ml, negative; between 35 and 65 U/ml, borderline; > 65 U/ml, positive), 290 patients were considered eligible for surgery. Specificity, sensitivity, positive and negative predictive value, and accuracy of US and CA 125 were calculated with respect to histological examination. Out of 290 operated patients, 134 had a benign ovarian pathology, 34 had extraovarian benign pathology, 106 had an ovarian malignancy, and 16 presented with an extraovarian malignant pathology. The results according to ovarian malignant pathology were as follows. CA 125 (> 65 U/ml): Specificity, 92.5%; sensitivity, 71.7%; accuracy, 83.3%. CA 125 (> 35 U/ml): Specificity, 82.0%; sensitivity, 78.3%; accuracy, 80.4%. US: Specificity, 77.6%; sensitivity, 84.9%; accuracy, 80.3%. Combination of US and CA 125 (> 65 U/ml): Specificity, 96.1%; sensitivity, 91.7%; accuracy, 94.3%. Determination of CA 125 is a highly specific method in predicting ovarian cancer in postmenopausal women with a pelvic mass. The association with US significantly improves the overall accuracy and may support therapeutical decision making by distinguishing between a significant percentage of women most likely to benefit from prompt intervention and women who may be managed following minor surgical diagnostic approach, such as fine-needle aspiration.

Adult↗
PubMed1994

Avidin-biotin system in radioimmunoguided surgery for colorectal cancer. Advantages and limits.

PURPOSE: Radiolabeled monoclonal antibodies (MAbs) have been reported to allow tumor intraoperative detection by means of a gamma-detecting probe. The technology is called the Radioimmunoguided Surgery (RIGS) system. The main inconveniences of the method are 1) the long interval needed for clearance of unattached MAbs from the patient's body, between the injection of the MAb and surgery, and 2) the low sensitivity of current MAbs used in detecting small tumors. We describe a new method to overcome these inconveniences using biotinylated MAbs and avidin in order to obtain a rapid blood clearance of the radiolabeled MAbs both anticarcinoembryonic antigen and antitumor-associated glycoprotein-72 MAbs. METHODS: Twenty patients with primary and recurrent colorectal cancer have been enrolled in the study; 125I-biotinylated MAbs FO23C5 (anticarcinoembryonic antigen) and B72.3 (antitumor-associated glycoprotein-72) followed by cold avidin were injected in 13 patients and 7 patients, respectively. RESULTS: A decrease of 94 +/- 3 percent of circulating radioactivity was achieved in 3 to 5 days. Patients underwent surgery approximately seven days after MAb injections rather than after four weeks. Tumors were localized in 14/20 (70 percent) patients (true positive), 2 (10 percent) were false negative, and 4 (20 percent) were true negative. The overall sensitivity level in early-stage primary cancers was 37 percent when related to the presence of disease and 75 percent when related to antigenic expression. The sensitivity for more advanced cancer and for recurrences was 100 percent. Moreover, the in vivo tumor targeting of biotinylated MAb was demonstrated in frozen tumor section by direct streptoavidin-peroxidase staining. CONCLUSIONS: The avidin-biotin system may enhance applicability and effectiveness of radioimmunoguided surgery (RIGS).

Antibodies, Monoclonal↗