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Biomedical subjects

L Ricci

Publications and source records attributed to L Ricci.

At least 55 records · Page 3Linked to original sources
PubMed1994

Anatomoclinical and chronobiological aspects of sudden death in elderly subjects.

Anatomoclinical and chronobiological aspects of sudden death (SD) of 671 subjects observed at the Emergency Room of Ferrara Hospital from January 1983 to December 1991 were prospectively investigated. 3 groups stratified by age were considered: group A with age < 65 years (no. = 251, 37.4%), group B with age between 65 and 74 years (no. = 210, 31.3%), and group C with age > or = 75 years (no. = 210, 31.3%). SD was classified on the basis of either anatomopathological (i.e.: acute myocardial infarction, acute myocardial failure, intracerebral hemorrhage, rupture of aortic aneurysm, pulmonary embolism), and clinical findings (i.e.: arrhythmic death and circulatory failure death). Patients were grouped into six 4-hour periods according to the time of onset of symptoms, and circadian distribution was tested for uniformity by a chi 2 test for goodness of fit. The analysis found in group C an increased frequency of SD due to pulmonary embolism and rupture of aortic aneurysm, and an increment of males/females ratio in deaths from cardiac causes. In group C the mean age of SD, in particular from acute myocardial infarction, pulmonary embolism or arrhythmic death proved higher in females compared to males. Only for group B was a significant circadian periodicity found for SD from acute myocardial infarction and arrhythmic death, with a peak in the morning.

Age Factors↗
PubMed1993

Chronobiological aspects of acute cerebrovascular diseases.

The study was aimed at further investigating the circadian and circannual patterns of stroke onset. Study design and type of participants: 977 strokes (475 in men and 502 in women) concerning 926 subjects (457 men and 469 women) admitted to Ferrara Hospital in two calendar years (1990-1991), were prospectively investigated. The strokes were classified as based on cerebral infarction (CI), transient ischemic attack (TIA) and cerebral hemorrhage (CH: subarachnoid and intracerebral hemorrhage). Two statistical models of analysis were used. The assessment of circadian and circannual periodicity was performed utilizing the single cosinor method. A separate analysis was performed after distribution of events into 6-hour intervals, and chi-square test for fit was applied to the number of observed versus expected cases. The majority of strokes occurred in the morning between 7 a.m. and noon (35% of cases) and the hypothesis of a uniform distribution of the time onset was rejected on the basis of the chi-square for all subtypes of stroke. A circadian rhythm was found for CI and TIA with acrophase at the 11.56 and 12.41 respectively. Also a circannual periodicity was found for CI with a prevalent peak in October. The spectral analysis detected a circadian cycle for CH having a period of 4 h, and a circannual cycle for TIA with a period of 4 months. This study confirms that stroke is a high-chrono-risk disease, with specific circadian and circannual rhythms. This is very important for a better understanding and control of the underlying factors and in terms of prevention.

Acute Disease↗
PubMed1993

Sudden death may show a circadian time of risk depending on its anatomo-clinical causes and age.

The aim of this study was to determine whether the time of occurrence of sudden death exhibits a circadian rhythm depending on its different anatomoclinical causes. A longitudinal prospective investigation of 610 nonhospitalized subjects who died suddenly in the Emergency Room of Ferrara Hospital between January 1983 and December 1990 was conducted. All subjects underwent autopsy. Sudden death was classified on the basis of the following pathological causes; acute myocardial infarction, acute myocardial failure, intracerebral hemorrhage, rupture of aortic aneurysm, pulmonary embolism, and clinical causes, i.e., arrhythmia and circulatory failure. The investigated cases were stratified into 2 groups according to age; Group A = age < 70 years (n = 301, 49.3%), and Group B = age > or = to 70 (n = 309, 51.7%). The assessment of circadian rhythmicity was performed utilizing the single cosinor method. The results by cosinor analysis found a circadian rhythmicity for cases of sudden death (peak at 14.04, n = 610, p = 0.036), and in particular for females (peak at 13.12, n = 200, p = 0.004). Spectral analysis detected a statistical ultradian cycle in males having an 8-hour period (p = 0.015). A statistically significant circadian rhythm was found for cases of sudden death due to acute myocardial infarction (peak at 15.28, n = 330, p = 0.013), pulmonary embolism (peak at 11.46, n = 56, p = 0.003) and arrhythmia (peak at 13.08, n = 291, p = 0.04). In Group A no significant circadian rhythm was found, whereas in Group B a significant rhythmicity was found for sudden death from cardiac causes at 13.32 (n = 249, p = 0.015), from myocardial infarction at 15.02 (n = 154, p = 0.018) and from arrhythmia at 13.07 (n = 122, p = 0.014). Different circadian patterns of onset of sudden death may be shown in various subgroups of patients, due not only to different pathophysiologic mechanisms but also to anatomo-clinical aspects.

Age Factors↗
PubMed1992

Constitutive synthesis of polyoma antisense RNA renders cells immune to virus infection.

Mouse fibroblasts were stably transfected with expression plasmids in which sequences of the early region of polyomavirus were inserted both in sense and antisense orientation. The cell lines that synthesize in the antisense orientation, a 1195-bp viral genome fragment covering the Ori, Cap, ATG, and all of the early mRNA splicing sites acquire resistance to viral infection. Smaller fragments covering Ori, Cap, and ATG sites or the splicing sites, as well as fragments cloned in sense orientation, failed to confer cell immunity to polyoma infection. The resistance proved to be directly dependent upon the specific antisense RNA and to be inversely proportional to the multiplicity of infecting polyoma.

Animals↗
PubMed1992

Sudden death from pulmonary thromboembolism: chronobiological aspects.

The aim of this study was to determine whether sudden cardiac death from pulmonary embolism exhibits any chronobiological rhythm. Five hundred and seven consecutive subjects dying suddenly outside of hospital and brought into our Emergency Department from January 1983 to December 1989 were studied. The time and date of event were accurately recorded. All subjects underwent autopsy and 48 of them were found to have died of pulmonary embolism (23 males, mean age 73.9 +/- 8 years and 25 females, mean age 76 +/- 12 years). All data were analysed by means of single cosinor[19,20]. In the subjects with pulmonary emboli both a circadian and a circannual rhythmicity were found, with a significant acrophase respectively in the morning (h.min. 11.46, P = 0.003) and in winter (-19.3, P = 0.009).

Aged↗
PubMed1992

Mutations in the VP1 coding region of polyomavirus determine differentiating stage specificity.

Polyomavirus mutants capable of replicating in undifferentiated murine C2 myoblasts were selected and characterized. These mutants grow normally in 3T6 mouse fibroblast cells, and they do not complement the wild-type virus in coinfection experiments of C2 myoblasts. Of 12 isolates, 10 possess duplications of the regulatory region including the enhancer A domain. On the bases of the regulatory region structure and the presence and length of the enhancer duplication, the mutant viruses could be grouped into three classes. One mutant class (e.g., PyMB3) possesses an enhancer duplication of 91 bp identical to that of a previously characterized polyomavirus mutant, PyNB11/1. We have demonstrated that this enhancer duplication gives rise at its junction to a novel recognition motif for the transcriptional factor NF-1 (M. Caruso, C. Iacobini, C. Passananti, A. Felsani, and P. Amati, EMBO J. 9:947-955, 1990). The regulatory region PyMB3 virus recombined in a wild-type genome context maintains the mutant phenotype. The other two types of mutants, one with a 30-bp enhancer duplication (e.g., PyMB40) and one with a wild-type enhancer structure (e.g., PyMB27), possess two similar but distinct 6-bp deletions in the same region of the VP1 coding gene. In both cases, the ability to replicate in undifferentiated C2 myoblasts is strictly correlated to the mutation in the VP1 coding region.

Amino Acid Sequence↗
PubMed1990

Effect of chronic administration of verapamil in Duchenne muscular dystrophy.

1. In DMD patients the effect of chronic treatment with verapamil was investigated in the p-nitrophenylphosphatase from erythrocytes, the CK and LDH in serum and the functional activity of the muscle. 2. A different behaviour in the p-nitrophenylphosphatase from untreated compared to treated DMD patients and controls is supported by the following findings: (a) values of "n" altered in F- inhibition of the enzyme with Hill coefficients -1.43, -2.18 and -2.19; (b) Arrhenius plots between 16 and 40 degrees C with inflection points for the enzyme from treated DMD patients and controls and not from untreated DMD patients. 3. Although CK and LDH in serum and the muscular evaluation showed no statistical difference between both groups, evidence is presented that in treated DMD patients the interaction membrane-enzyme is different from untreated DMD patients.

4-Nitrophenylphosphatase↗
PubMed1990

Time-gated fluorescence spectroscopy of porphyrin derivatives incorporated into cells.

Time-gated fluorescence spectroscopy was performed on the tumour-localizing fraction (TLF) of haematoporphyrin derivative (HPD) incorporated into cells. Three different cell lines were incubated with 20 and 5 micrograms ml-1 of TLF for various time periods; they were then washed and resuspended in buffer. Fluorescence decay measurements and time-integrated and time-gated spectra were then obtained from the cell suspensions. Similar experiments were repeated using HPD containing 60% of the active material. The experimental results show a modification of the emission spectra for both drugs depending on the incubation time; this modification is more significant for the TLF. In particular, the emission peak observed in aqueous solution at 615 nm is shifted to 630 nm as a consequence of incorporation into cells, and the gated spectra indicate that the fluorescence emission is mainly related to monomers and unfolded polymeric chains. The ratio between the intensities of the two peaks depends on the relative amount of the TLF; the peak at 615 nm is more pronounced for HPD. The results obtained seem to indicate that both the composition of the drug and the metabolic properties of the biological environment strongly influence the uptake process and the fluorescence behaviour of the incorporated sensitizer.

Animals↗
PubMed1989

Toxicity of fenclor 42 in mice: effects on immunocompetent cells.

The aim of this study is to evaluate the effects of Fenclor 42 (a mixture of trichlorobiphenyls) on the immune system. A prolonged administration of this compound to CD2F1 mice resulted in a reduction of relative spleen and thymus weight according to the dose. Furthermore, spleen weights, total number of splenocytes and relative spleen weights decreased significantly also following a single treatment with 0.5 g/kg or 1 g/kg of Fenclor 42. An analysis of the functional activity of splenocytes pointed out that proliferative response to mitogens was also inhibited. Splenic parameters returned to normal values within 5 days after a single treatment and between 8 and 15 days after a subchronic administration. The functional activity of splenocytes was restored between day +5 and day +8 according to the different schedules of treatment. On the contrary, natural killer cell (NK) activity was never affected by Fenclor 42. Studies are in progress to elucidate the intimate mechanism of the toxicity of Fenclor 42 on immunocompetent cells.

Animals↗
PubMed1988

Induction of new antigenic properties on DTIC-treated L1210 clones.

In vivo treatment of mouse leukemia L1210 with DTIC can induce new antigens on tumor cells that are not detectable on parental cells and that are transmissible as a genetic character. Moreover, L1210/DTIC is rejected by syngeneic hosts. The aim of this study was to investigate whether DTIC selects pre-existing immunogenic clones rather than inducing ex novo new antigenic determinants and to verify the number of induced antigens. L1210 leukemia was cloned in vitro and 4 clones were treated in vivo with DTIC. All the treated clones displayed antigenic properties since they were rejected by syngeneic hosts. Cytotoxic T lymphocytes (CTL) activated against one DTIC clone could recognize and lyse the relevant target. One of these DTIC-modified clones (L4/DTIC) was recloned and the subclones were tested in vivo and in vitro. Two out of six subclones were rejected by syngeneic hosts. CTL specific against these two clones were able to recognize and lyse all the other clones to different degrees. The degree of susceptibility to lysis did not correlate with the capability to evoke an immune response in vivo. Based on these findings we conclude that DTIC does not select pre-existing clones but modifies the tumor cells antigenically, and that the antigenicity induced by DTIC in a cloned tumor line is due to the presence of common antigens shared to different degrees with treated cells.

Animals↗
PubMed1988

DTIC xenogenized lines obtained from an L1210 clone: clonal analysis of cytotoxic T lymphocyte reactivity.

Antineoplastic compounds can induce on tumour cells new antigens that undetectable on parental cells and which are transmissible as a genetic character. In this study mouse leukaemia L1210 was cloned in vitro by limiting dilution and one cloned line was recloned in vivo. Four subcloned tumour cell lines (A,D,R,S) were xenogenized in vivo by DTIC treatment (A/DTIC, D/DTIC, R/DTIC, S/DTIC) following a schedule previously described. Up to 10(7) cells of these xenogenized subclones, injected i.p., were rejected by syngeneic hosts, although they grew in immunosuppressed hosts. The DTIC treated subclones were lysed by in vivo-primed, in vitro-restimulated (with the relevant subclone) lymphocytes. The cytotoxic lymphocyte activity was not strictly specific since parental, DTIC-untreated cells were also lysed, although less efficiently. CTL directed against the D/DTIC subclone were cloned by limiting dilution. Ninety-four CTL clones were assayed against L1210 subcloned cells, DTIC-treated and untreated, and against different murine tumours (syngeneic or allogenic). Three specific antigens could be identified in the 51Cr release assay. The DTIC subclones expressed one antigen that was specifically recognized by a set of CTL clones. A number of CTL clones were able to lyse the L1210 subcloned cell exclusively, targetting a tumour-associated antigen that did not appear to be modified in the DTIC-treated subclones. A third antigen was demonstrated in the parental and DTIC treated D subclone. On the basis of these results it was postulated that there was at least one common DTIC-inducible antigen specific and reproducible within an identical cell population. Moreover, DTIC treatment did not modify histocompatibility antigens or TAA pre-existing in L1210 cells. The findings discussed here provide new information about permanent xenogenization of tumour cells, which might be exploited for experimental chemo-immunotherapy of cancer.

Animals↗
PubMed1988

Amiodarone and thyroid status in refractory arrhythmias.

Out of 20 subjects selected for refractory arrhythmias, amiodarone therapy (200 mg/day) was efficacious in 85%. No statistically significant variations in electrocardiographic parameters (QTc) were observed; similarly, there was little evidence of side effects 1 year after initiation of treatment. These results were most likely due to the low daily dosage administered. We observed: 1) a significant increase in rT3 levels; 2) a decrease in TT3; 3) a uniform homeostasis of free fraction (FT3;FT4) These effects are all characteristic patterns of a "Low T3 Syndrome". The dosage of circulating amiodarone in 6 patients with borderline hormonal status (3 hyper- and 3 hypothyroidism) was not found to be an efficacious test for therapeutic monitoring. Identification of a statistically significant linear regression relationship between cumulative dose of amiodarone and rT3 levels may be a useful test in clinical practise for establishing more appropriate therapeutic dosages. Furthermore, it provides a guideline for threshold levels (maximum rT3 = 100-110 ng/dl) which are in close association with several side effects.

Adult↗
PubMed1988

[Multiple simultaneous stratigraphy. Results with a 5-plane system for pediatric use].

The authors report the results of a five-layer simultaneous multisection tomographic technique to be used in pediatric radiology, based on an appropriately selected series of Trimax rare-earth intensifying screens arranged in progressive speed order. The technique has been so far employed with excellent results in 100 children, especially during IVP, when X-ray examination is very frequently disturbed by ileocolic gas. The many advantages of the technique are emphasized: a) all sections are perfectly parallel and simultaneous, in the same respiratory phase and body position; b) film density is practically identical in all sections; c) there is considerable saving in time, machine consumption, and radiation dose.

Child↗