Showing papers by "University of Bologna published in 1990"

Knapsack Problems: Algorithms and Computer Implementations

Abstract: Introduction knapsack problem bounded knapsack problem subset-sum problem change-making problem multiple knapsack problem generalized assignment problem bin packing problem. Appendix: computer codes.

Clues on the Hot Star Content and the Ultraviolet Output of Elliptical Galaxies

Abstract: Les galaxies elliptiques emettent un flux significatif de rayonnement aux longueurs d'onde au-dessous d'environ 2000 A, avec le flux croissant pour la longueur d'onde decroissante. Les caracteristiques les plus significatives de cette branche UV observee dans les galaxies elliptiques et S0 sont passees en revue, et la dispersion de la metallicite dans ces galaxies est discutee. Les problemes et complexites inherents aux candidats d'etoiles vieilles uniques sont ensuite discutes, divers scenarios unifies pour ces candidats sont exposes, et les manieres possibles de generer la correlation UV - metallicite observee sont discutees. Les candidats binaires sont egalement presentes. Tous les candidats sont reexamines dans le contexte des populations stellaires vieilles qui ont ete resolues en etoiles individuelles, i.e., les amas globulaires galactiques, le bulbe de la Voie Lactee et de M 31.

Antenna effect in luminescent lanthanide cryptates: a photophysical study

Abstract: — Excited state emission and absorption decay measurements have been made on the cage-type cryptate complexes [M bpy.bpy.bpy]n+, where Mn+= Na+, La3+, Eu3+, Gd3+ or Tb3+ and [bpy.bpy.bpy] is a tris-bipyridine macrobicyclic cryptand. Excitation has been performed in the high intensity 1π-π* cryptand band with maximum at about 300 nm. Experiments have been carried out in H2O or D2O solutions and at 300 and 77 K to evaluate the rate constants of radiative and nonradiative decay processes. For Mn+= Na+, La3+ and Gd3+ the lowest excited state of the cryptate is a 3ππ* level of the cryptand which decays in the microsecond time scale at room temperature in H2O solution and in the second-millisecond time scale at 77 K in MeOH-EtOH. For Mn+= Eu3+, the lowest excited state is the luminescent 5D0 Eu3+ level which in H2O solution is populated with 10% efficiency and decays to the ground state with rate constants 2.9 × 103 s_1 at room temperature and 1.2 × 103 s−′ at 77 K. The relatively low efficiency of 5D0 population upon 1ππ* excitation is attributed to the presence of a ligand-to-metal charge transfer level through which 1ππ* decays directly to the ground state. For Mn+= Tb3+ the lowest excited state is the luminescent 5D4 Tb3+ level. The process of 5D4 population upon 1ππ* excitation is ˜100% efficient, but at room temperature it is followed by a high-efficiency, activated back energy transfer from the 5D4 Tb3+ level to the 3ππ* ligand level because of the relatively small energy gap between the two levels (1200 cm_1) and the intrinsically long lifetime of 5D4. At 77 K back energy transfer cannot take place and the 5D4 Tb3* level deactivates to the ground state with rate constant 5.9 × 102 s-′ (H2O solution). The relevance of these results toward the optimization of Eu3+ and Tb3+ cryptates as luminescent probes is discussed.

Primary chemotherapy and delayed surgery (neoadjuvant chemotherapy) for osteosarcoma of the extremities the istituto rizzoli experience in 127 patients treated preoperatively with intravenous methotrexate (high versus moderate doses) and intraarterial cisplatin

Abstract: Between March 1983 and June 1986 127 patients with localized osteosarcoma of the extremity were treated with neoadjuvant chemotherapy. Preoperative chemotherapy consisted of two cycles of methotrexate (MTX) (high or moderate doses) followed by 6 days by cisplatin (CDP). Surgery was an amputation or a rotation plasty, or a limb salvage. Necrosis was good in 52% of cases, fair in 36%, and poor in 12%. Postoperative chemotherapy consisted of Adriamycin (doxorubicin [ADM]) and bleomycin (BCD) for poor responders; and ADM, MTX, and CDP for fair responders. Good responders were treated as fair responders or with only MTX and CDP. At a 47-month follow-up, 66 patients remained continuously disease free and 61 patients developed metastases. Six of these patients had also a local recurrence. According to the grade of necrosis, the cumulative disease-free probability at 5 years was 67% for good responders, 42% for fair responders, and for poor responders 10% at 45 months. According to the doses of MTX, survival at 5 years was 58% for patients who received high doses and 42% for patients treated with moderate doses. No differences in the rate of survivors were observed between amputated patients and patients treated with limb salvage. The authors conclude that (1) a limb salvage procedure is possible in about 70% of cases and as safe as demolitive surgery, if adequate surgical margins are achieved; (2) good responders have a better prognosis than fair and poor responders if postoperative chemotherapy is sufficiently prolonged and also includes ADM; (3) a different postoperative chemotherapy for poor responders did not improve their prognosis; and (4) a multidrug regimen using high doses of MTX is probably more effective than moderate doses.

Lymphohistiocytic T-cell lymphoma (anaplastic large cell lymphoma CD30+/Ki-1 + with a high content of reactive histiocytes)

Abstract: We describe 13 cases of a peculiar lymphoid tumour containing very large numbers of reactive histiocytes. The tumours occurred in young patients (mean age 14.8 y) who presented with systemic symptoms and superficial lymphadenopathy. Microscopic examination revealed a diffuse effacement of lymph node structure due to the presence of histiocytes intermingled with a variable number of anaplastic large lymphoid cells. The latter, in some cases, were isolated, while in others they were arranged in clusters or were diffusely present in residual sinuses. The large anaplastic cells expressed the activation markers CD30 (Ki-1), CD25 (interleukin-2 receptor), CD70 (Ki-24) and Ki-27, as well as varying combinations of T-associated molecules. The histiocytes expressed lysozyme and the CD11b (C3bi-R), CD11c (p150, 95) CD14, CD68 (KPI) and Ber-Mac3 antigens. Double staining with the antibody Ki-67 demonstrated that the proliferating components were the CD30-positive cells and not the histiocytes. T-cell receptor beta gene rearrangements were shown in three cases tested. The patients responded well to aggressive chemotherapy and nine are still alive, eight in complete remission. It is suggested that the tumour represents a well-defined clinico-pathological entity originating from activated T-lymphocytes.

Myelofibrosis with myeloid metaplasia: clinical and haematological parameters predicting survival in a series of 133 patients

Abstract: The prognostic value of 12 clinical and haematological parameters, recorded at diagnosis, in myelofibrosis with myeloid metaplasia (MMM) was retrospectively analysed in a consecutive series of 133 patients followed for a minimum of 60 months. Multivariate analysis showed that the following features were associated with a significantly shorter survival: (1) short period of time (less than 13 months) between first symptoms and diagnosis; (2) anaemia (haemoglobin less than 10 g/dl); (3) leucocyte count greater than 12 x 10(9)/l; (4) peripheral blood granulocyte precursors greater than 10%. Age, splenectomy and percentage of peripheral blood metamyelocytes were found significantly to affect survival only from univariate analysis, whereas sex, size of spleen, thrombocytopenia and thrombocytosis were of no prognostic significance. These data suggest that a more intensive chemotherapy might be useful for younger patients with bad prognostic factors at diagnosis.

Nocturnal Paroxysmal Dystonia with Short‐Lasting Attacks: Three Cases with Evidence for an Epileptic Frontal Lobe Origin of Seizures

Abstract: The epileptic or nonepileptic origin of nocturnal paroxysmal dystonia (NPD) has been debated. We studied three patients with frequent attacks during non-REM sleep. During prolonged video-EEG monitoring, two patients had a convulsive seizure after a typical NPD episode and on these occasions EEG showed epileptiform discharge. In the three patients, attacks occurred repeatedly with different intensity, representing "fragments" of the same seizure. These fragments of the attack could occur periodically every 20-40 s. We postulate that short NPD attacks are actually epileptic seizures originating from the frontal lobes. The rhythmicity of the episodes may be due to rhythmic oscillation of cortical function during non-REM sleep.

Nucleus-driven multiple large-scale deletions of the human mitochondrial genome: a new autosomal dominant disease.

Abstract: We studied several affected and one nonaffected individuals belonging to three unrelated pedigrees. The pathological trait was an autosomal dominant mitochondrial myopathy due to large-scale multiple deletions of the mitochondrial genome. Clinically, symptomatic patients had progressive external ophthalmoplegia, muscle weakness and wasting, sensorineural hypoacusia, and, in some cases, vestibular areflexia and tremor. The muscle biopsies of all patients examined showed ragged-red fibers, neurogenic changes, and a partially decreased histochemical reaction to cytochrome c oxidase. Multiple mtDNA heteroplasmy was detected in the patients by both Southern blot analysis and PCR amplification, whereas the unaffected individual had the normal homoplasmic hybridization pattern. These findings confirm and add further details to the existence of a new human disease--defined clinically as a mitochondrial myopathy, genetically as a Mendelian autosomal dominant trait, and molecularly by the accumulation of multiple, large-scale deletions of the mitochondrial genome--that is due to impaired nuclear control during mtDNA replication.

Malignant Tumors of the Peripheral Nerves

Abstract: What we mean by malignant neurinoma is a sarcoma which originates from a peripheral nerve or occurs within neurofibromatosis. These clinical and anatomo-surgical criteria are essential, as there are no constant and undebatable histological elements which distinguish this sarcoma from a fibrosarcoma.

Hyperplastic and hypertrophic growth of lateral muscle in Dicentrarchus labrax (L.). An ultrastructural and morphometric study.

Abstract: In this EM study of lateral muscle in Dicentrarchus labrax, we observed that during the larval period, growth of the presumptive red and white muscle layers occurs both by hypertrophy (as fibres already present at hatching complete their maturation) and by production of new fibres in germinal zones specific to the two muscle layers. In the first half of larval life the presumptive white muscle increases in thickness by the addition, superficially, of new fibres derived from a germinal zone of presumptive myoblasts lying beneath the red muscle layer. In the second half of larval life new fibres produced in this same zone form the intermediate (or pink) muscle layer. Dorsoventrally the myotome grows throughout larval life, largely by addition of new fibres from germinal zones at the hypo- and epi-axial extremities. Towards the end of larval life all these germinal zones are becoming exhausted, but another source of fibres arises as satellite cells, associated with large-diameter presumptive white muscle fibres, are activated to produce new fibres. The addition of small, new fibres gives the white muscle its mosaic appearance. Morphometric analysis of fibre diameters in the white muscle confirms that whereas these hyperplastic processes are important during the larval and juvenile periods, when growth is very rapid, they have ceased by the time the adult stage is attained. By contrast, fibre hypertrophy continues through into adult life. The presumptive red muscle consists initially of a monolayer of fibres present only near the lateral line, and during larval life it grows hypo- and epi-axially by addition of fibres derived from myoblasts already present in these areas at hatching. Lying superficially to the presumptive red muscle monolayer there is a near-continuous layer of external cells with a "flattened" profile. During the second half of larval life, differentiation of these external cells into myoblasts provides the source of new fibres which are added to the red muscle layer. This process, which occurs initially in the region around the lateral line and later spreads outwards, is responsible for the increase in thickness of the red muscle.

Keratin-positive epithelioid angiosarcoma of thyroid. A report of four cases.

Abstract: We present four cases of a malignant thyroid tumor showing morphologic, immunocytochemical, and ultrastructural features of endothelial cell differentiation. The tumor cells had epithelioid features and displayed strong immunoreactivity for keratin. There was no evidence of follicular or C-cell differentiation in any instance. We interpreted these cases as keratin-positive epithelioid angiosarcomas. The findings presented here support the existence of primary malignant vascular tumors in the thyroid even in the presence of keratin positivity, a marker traditionally regarded as indicative of epithelial differentiation.

Polyamines and ethylene in relation to adventitious root formation in Prunus avium shoot cultures

Abstract: An attempt was made to identify some of the hormonal factors that control adventitious root formation in our Prunus avium micropropagation system in order to improve rooting in difficult‐to‐root genotypes. Changes in endogenous contents of free polyamines were determined at intervals during auxin‐induced rooting of shoot cultures. Accumulation of putrescine and spermidine peaked between days 9 and 11. Spermine was only present in traces, Exogenously supplied putrescine or spermine (50‐500 μM), in the presence of optimal or suboptimal levels of indolebutyric acid (IBA), had no effect on rooting percentage or root density, except for spermine at 500 μM. At this external concentration spermine caused a substantial accumulation in both free spermine and putrescine. The use of several inhibitors of polyamine biosynthesis, namely α‐difluoromethylornithine (DFMO), α‐difluoromethylarginine (DFMA), dicyclohexylammonium sulphate (DCHA) and methylglyoxal‐bis‐guanyl‐hydrazone (MGBG) alone or in combination in the 0.1 to 5 μM range, resulted in an inhibition of rooting that was partially reversed by the addition of the corresponding polyamine. Cellular polyamine levels were significantly reduced by DFMO and DFMA but not by DCHA and MGBG, Labeled putrescine incorporation into spermidine increased somewhat in the presence of the ethylene synthesis inhibitor aminoethoxyvinylglycine (AVG). A system based on [3,4‐14C]methionine incorporation was used to measure ethylene synthesis by the in vitro cultured shoots. Label incorporation was drastically reduced by 10 μM AVG and increased 3.5‐fold in the presence of 50 μM IBA with respect to controls (no IBA). Labeled methionine incorporation into spermidine increased to some extent when ethylene synthesis was inhibited by AVG. Adding the ethylene precursor 1‐aminocyclopropane‐l‐carboxylic acid (ACC) to the rooting medium significantly inhibited rooting percentage; AVG caused the formation of a greater number of roots per shoot but delayed their growth. Supplying the shoots with both compounds resulted in an intermediate rooting response, in which both rooting percentage and root density were affected. These results indicate that polyamines may play a significant role at least in some stages of root formation. The polyamine and ethylene biosynthetic pathways seem to be competitive but under our conditions, the enhancement of one pathway when the other was inhibited, was not dramatic. Although IBA promoted ethylene synthesis, AVG, which drastically reduced it, also promoted root formation. Thus, the auxin effect on root induction cannot be directly related to its ability to enhance ethylene synthesis. Copyright © 1990, Wiley Blackwell. All rights reserved

Endocrine function and morphological findings in patients with disorders of the hypothalamo-pituitary area: a study with magnetic resonance.

Abstract: Evaluation of the sellar area was performed with magnetic resonance imaging in 101 patients (age range 0.8-27 years) with hypopituitarism, isolated diabetes insipidus, hypogonadotrophic hypogonadism, and central precocious puberty. The hypopituitary patients (n = 70) included multiple pituitary deficiency (n = 23), pituitary deficiency with diabetes insipidus (n = 5), and isolated growth hormone deficiency (n = 42). The patients with multiple pituitary deficiency showed pathological morphological findings in all cases, with stalk and posterior lobe always involved. The group with associated diabetes insipidus had abnormal stalk in four of five cases and posterior lobe not visible in all cases. Only five of 42 (12%) patients with isolated growth hormone deficiency had abnormalities of the sellar area. In two out of four patients with isolated diabetes insipidus posterior lobe was not seen. All patients with hypogonadotrophic hypogonadism (three with Kallmann's syndrome, one Prader-Willi syndrome, and two idiopathic hypogonadism) appeared normal. In precocious puberty (n = 21) the three patients with onset of symptoms before age 2 years exhibited a hypothalamic hamartoma, whereas in the others with onset of puberty between age 2 and 7 the magnetic resonance image was normal in 17 of 18 patients. The probability of finding a pathological magnetic resonance image was considerably high in our patients with multiple pituitary deficiency, isolated diabetes insipidus, and precocious puberty with very early onset of symptoms. On the contrary, purely functional abnormality is suggested in most patients with isolated growth hormone deficiency, hypogonadotrophic hypogonadism, and precocious puberty with later onset of symptoms.