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Biomedical subjects

M Ricci

Publications and source records attributed to M Ricci.

At least 109 records · Page 6Linked to original sources
PubMed1996

Relationship between thallium-201 uptake by supratentorial glioblastomas and their morphological characteristics on magnetic resonance imaging.

Single-photon emission tomography (SPET) with thallium-201 is used in the assessment of patients with gliomas because the amount of 201Tl accumulated by the tumoral cells increases in proportion to the degree of tumour malignancy, thus making it possible to differentiate high-grade from low-grade gliomas or recurrences from radiation necrosis. However, in large areas of tissue such as those examined in 201Tl SPET studies, the uptake of 201Tl may vary considerably even in tumours with the same histological diagnosis, as occurs in glioblastomas (GBMs). In order to evaluate the possible influence of the macroscopic characteristics of tumours on 201Tl uptake, we studied a series of 13 patients with histologically proven GBMs, comparing magnetic resonance imaging (MRI) parameters such as tumour dimensions, perilesional oedema, intratumoral necrosis and contrast enhancement with the degree of 201Tl uptake. The patients underwent both 201Tl SPET and MRI before surgery. The 201Tl index (tumour/contralateral unaffected brain) was calculated using two different region of interest (ROI) methods: the first employed irregular large ROIs (3.2+/-13.9 cm2) including pixels with more than 50% maximum activity; the second employed regular square small ROIs (2.7 cm2) centered on the maximum activity of the lesion. Of the MRI morphological parameters studied, only necrosis significantly reduced the degree of 201Tl uptake in GBMs when larger ROIs were used. However, by using small regular ROIs the influence of necrosis on 201Tl uptake was found to be less relevant. Since necrosis is related to tumour proliferative activity and represents a negative prognostic factor in astrocytoma, a possible underestimation of 201Tl uptake due to intratumoral necrosis must be carefully evaluated.

Brain↗
PubMed1996

Host recognition behaviour predicts host suitability in the entomopathogenic nematode Steinernema carpocapsae (Rhabditida:Steinernematidae).

Steinernema carpocapsae (Rhabditida: Steinernematidae) host recognition behaviour was assessed and compared with 2 measures of host suitability. Previous research showed that S. carpocapsae infective juveniles respond to host cues in a hierarchical order, with attraction to Galleria mellonella volatiles being stimulated by contact with G. mellonella cuticle. We measured host recognition behaviour by calculating the percentage response of S. carpocapsae infective juveniles to volatiles produced by G. mellonella last instars after the nematodes were exposed to the cuticle of 11 candidate arthropod hosts and 2 control surfaces. Host suitability was measured by nematode-induced mortality to candidate hosts at 2 nematode doses and the level of reproduction supported by each host. The highest recognition response was scored for Agrotis ipsilon (Lepidoptera: Noctuidae). This insect also incurred nearly 100% mortality due to nematode infection and supported the highest level of reproduction. Non-insect arthropods tested (Chilopoda and Isopoda) stimulated no behavioural response and were not susceptible to nematode infection. Other insect species elicited intermediate levels of the recognition response. There were significant correlations between behavioural response and nematode-induced mortality at the lower dose. The level of reproduction supported by the candidate hosts was also correlated with S. carpocapsae behavioural response.

Animals↗
PubMed1996

Motor recovery after stroke. Morphological and functional brain alterations.

The aim of this study was to evaluate the relationships of morphological and CBF patterns with both the severity and the evolution of the motor deficit in the late phase of stroke and, in particular, to identify morphological and/or functional brain alterations associated with a persistent severe motor deficit or a poor, delayed motor recovery. We analysed CT/MRI and single photon emission tomography (SPET) findings from 37 patients studied in the chronic phase of stroke (mean duration +/- SD = 3.6 +/- 1.6 months), whom we were able to follow clinically for a period of 3 months. The eventual degree of motor recovery correlated significantly (negatively) with the time since stroke at entry, but not with the severity of neurological impairment at entry. The volume, side and location (cortical or subcortical) of the infarct did not correlate with either the severity or the evolution of the motor deficit. Patients with a CT/MRI lesion of the parietal lobe (n = 8) showed a more severe motor deficit than those with other cortical locations. The severity of the motor deficit correlated significantly (negatively) with CBF values in the supplementary motor area (SMA) and parietal areas of the damaged hemisphere, and in the contralateral undamaged primary motor cortex. The degree of motor improvement correlated significantly (positively) with CBF values in the contralateral undamaged thalamus, lentiform and caudate nuclei, and premotor cortex. In the late phase of stroke, the severity of the motor deficit may be positively associated with the functional impairment of associative parietal and frontal areas of the damaged hemisphere. The functional impairment of the basal ganglia-frontal network in the undamaged hemisphere seems to be related to a poor, delayed motor recovery.

Aged↗
PubMed1995

Presurgical integrated MRI/SPECT localization of the sensorimotor cortex in a patient with a low-grade astrocytoma in the rolandic area.

We describe the case of a young man who, despite the presence of a tumour in the left sensorimotor cortex, exhibited no motor deficit. Integrated MRI/SPECT-CBF study during motor activation was aimed at determining which cerebral areas were involved in movement execution in this patient and their relationship with the tumour. CBF changes during motor activation were located in two motor areas: anteriorly and medially to the tumour in the left frontal lobe (+29%) and in the right medial frontal cortex (+43%). Integrated MRI/SPECT images provided both an anatomical and functional definition of the motor areas in a patient with a rolandic tumour and could prove useful in determining preoperatively an appropriate surgical strategy.

Adolescent↗
PubMed1995

Prolonged muscular flaccidity after stroke. Morphological and functional brain alterations.

Patients with a motor deficit due to ischaemic stroke usually develop muscular spasticity, but in some cases they may remain with a prolonged muscular flaccidity which impairs their recovery. Little is known about the causes of these two different functional outcomes. We correlated CT/MRI and 99mTc HM-PAO SPECT with clinical findings in 42 patients at a mean time interval of 3 months after stroke. The patients were divided into two cohorts with either flaccid (prolonged muscular flaccidity) or spastic (muscular spasticity) hemiparesis. Although patients with prolonged muscular flaccidity had a greater motor deficit, the mean structural volume of the ischaemic lesion was similar to that of the muscular spasticity cohort. There was a significantly higher prevalence of structural involvement of the lentiform nucleus in prolonged muscular flaccidity cases. Relative perfusion in the lentiform nucleus, thalamus and contralateral cerebellar hemisphere was significantly lower in prolonged muscular flaccidity than in muscular spasticity patients. A subgroup with only subcortical structural lesions also showed significantly lower relative perfusion in the ipsilateral frontal association areas. A primary involvement of the lentiform nucleus by the structural lesion seems to be crucial for the persistence of flaccidity after stroke. However, cerebral blood flow (CBF) changes in other structurally intact regions indicate their additional role. It is likely that both subcortical-cortical loops involved in motor control, i.e. cortex-basal ganglia-thalamus-cortex and cortex-pons-cerebellum-thalamus-cortex, are more widely and more severely affected in patients with prolonged muscular flaccidity.

Adult↗
PubMed1995

Chronic lymphocytic leukaemias and non-Hodgkin's lymphomas by histological type in farming-animal breeding workers: a population case-control study based on job titles.

OBJECTIVES: A population based case-control study was conducted in a highly agricultural area in the north east of Italy to evaluate the association between farming and animal breeding and the risk of developing non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukaemia (CLL). METHODS: Occupational histories and other data were collected by personal interview on 164 NHLs, 23 CLLs, diagnosed in 1988-90, and on 977 controls. This paper only reports the results of the analysis relative to the coding of job titles through the modified International Labour Office (ILO) classification. Estimates of odds ratios (ORs) for occupational variables were calculated, after adjustment for sex, age, altitude of municipality, first degree familiarity, and previous Herpes zoster infection. RESULTS: From the analysis of the most frequent occupational categories, no occupation showed a significantly high risk. When the two job titles farmers only and farmer-breeders who are also involved in animal breeding are classified within the extremely varied occupation of agriculture or animal-breeding or fishing, a high risk for NHLs and CLLs is seen in the farmer-breeders (OR 1.79, 95% CI 1.22 - 2.63). Analyses according to histological type show that the risks are concentrated in CLLs and in low grade NHLs. No effect or trend by period at work or duration of employment in farming and animal breeding was found. CONCLUSION: Subjects working in agriculture associated with animal breeding are at high risk of NHL/CLLs, particularly CLLs and low grade NHLs. This finding could be related to the use of chemicals in agriculture or to exposure to animal transmitted diseases or specific chemicals used in animal breeding.

Adolescent↗
PubMed1995

Structure activity studies on chemically modified homologues of the antibiotic phytotoxic leucinostatin A.

The synthesis and a conformational study of a number of homologues of the well known antibiotic, phytotoxic leucinostatin A are reported. The circular dichroism of all the compounds are discussed. Some conclusions on the SAR of these compounds are drawn. The influence of the alpha-helical conformation and/or the increased lipophile character on their interesting biological activities is emphasized.

Amino Acid Sequence↗
PubMed1995

[Recurrent brief depression].

The initial conception of manic depressive illness by Kraepelin included short and mild depressive and hypomanic states in the nosologic category of affective illness. The concept of recurrent brief depression was further confirmed in recent community and general practice studies. The diagnostic criteria for recurrent brief depression requires the presence of at least five of nine depressive symptoms analogous to the symptoms of major depression, yet a duration of less than two weeks (in general 1 to 3 days), a recurrence of at least 12 times a year, and the evidence of work impairment. The 1-year prevalence in the general population is about 5% and the lifetime prevalence 16%. Recurrent brief depression may develop into major depression and vice versa in about the same percentage of cases. Patients with combined major and recurrent brief depression are more severely affected, have a higher suicide attempt rate, and have an increased frequency of treatment--seeking than patients with only one condition. Recurrent brief depression is typically characterized by monthly occurring short-lived depressive episodes, with an erratic, relapsing and chronic course and significant suicide risk. The duration of these episodes in clinical samples was of 3-5 days on average, with a medium number of episode a year of 20. The onset of episodes is sudden and patients progress rapidly to the severe levels of depression. Resolution of the symptoms also tends to be rapid. The suddeness of the episodes may contribute to the relationship reported with suicidal behaviour. This is a disabling illness because of the frequency with which the episodes recur reported as erratic "irregularly regular".(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

[Treatment of chronic obliterative arteriopathy of the legs in the second Fontaine's stage. Personal experience with a buflomedil-pentoxifylline-defibrotide combination].

The authors provide evidence for the efficacy of the buflomedil-pentoxifylline-defibrotide combination for treatment of lower limb chronic obstructive arterial disease, Fontain stage II. Improvement of walking autonomy obtained with these agents ranged from 50 to 100% in 29 of 36 patients (relative frequency = 0.80).

Aged↗
PubMed1995

[Trematode parasites of Italian bats].

Data are presented on bat trematodes in Italy, whose previous list included only the following five species: Plagiorchis vespertilionis, Plagiorchis asper, Mesotretes peregrinus, Prosthodendrium chilostomum, Prosthodendrium longiforme. Between 1945 and 1981, 289 bats were examined belonging to 13 species. A total of twelve trematode species were identified, nine of which are recorded for the first time in Italy: Lecithodendrium linstowi, Lecithodendrium granulosum, Lecithodendrium rotundum, Prosthodendrium herardovae, Prosthodendrium hurkovaae, Prosthodendrium parvouterus, Pycnoporus heteroporus, Matovius rhinolophi, Parabascus lepidotus. For each parasite species, hosts, localities and number of specimens/host are reported. Special attention is devoted to P. vespertilionis with description of specimens remarkably different from the type form, to L. linstowi for peculiar specimens from Rhinolophus hipposideros, and to M. rhinolophi with additions to the original description especially concerning the vitelline glands' structure. Pycnoporus macrolaimus, identified in a collection of bat trematodes of the Institute of Parasitology of the University "La Sapienza" of Rome, is also recorded for the first time in Italy.

Animals↗
PubMed1994

The nonapeptide leucinostatin A acts as a weak ionophore and as an immunosuppressant on T lymphocytes.

Earlier studies have disclosed that leucinostatin A, a hydrophobic nonapeptide antibiotic, assumes an alpha-helical secondary structure in nonpolar environments. The present report demonstrates that the peptide acts as a weak ionophore facilitating the transport of mono-and divalent cations through the plasma membrane of T lymphocytes and through artificial membranes. Leucinostatin A does not change the thymidine uptake of both resting mouse thymocytes and peripheral blood lymphocytes but dose-dependently prevents the activation of T lymphocytes by tetradecanoyl-phorbol-acetate and by anti-T cell receptor antibody.

Amino Acid Sequence↗
PubMed1994

Mesial temporal cortex hypoperfusion is associated with depression in subcortical stroke.

BACKGROUND AND PURPOSE: This study was conducted to evaluate local cerebral blood flow changes in patients with depression after a subcortical stroke. METHODS: Clinical and neuropsychological assessments were performed in 15 patients with a single subcortical lesion. Depression was assessed by DSM-III-R. In addition, the Hamilton Rating Scale for depression, the Zung Self-Rating Depression Scale, and the Beck scale were administered to each patient. Single-photon emission-computed tomography study was performed with 99mTc hexamethylpropyleneamine oxime. RESULTS: In all patients cortical regions ipsilateral to subcortical lesions were significantly less perfused than the contralateral cortex. Cerebral blood flow values were significantly lower in depressed patients (n = 8) than in nondepressed patients (n = 7) only in the mesial temporal cortex of the affected hemisphere. Cerebral blood flow values in the mesial temporal cortex of the affected hemisphere significantly correlated with the severity of depression. CONCLUSIONS: Temporal lobe hypoperfusion may reflect a dysfunction of the limbic system, suggesting that this location may be critical for the occurrence of depressive symptoms in patients with subcortical stroke.

Aged↗
PubMed1994

[Effectiveness of quarterly assessment of CEA, TPA and GICA serum levels in gastric and colorectal carcinomas: Prospective study of 174 patients undergoing radical surgery].

One-hundred seventy four consecutive patients who underwent curative resection for gastric and colorectal cancer between 1983 and 1985, were studied prospectively to evaluate the roles of sequential CEA, TPA and GICA determinations and independent clinical examinations, in the early diagnosis of resectable recurrences. Sixty-six recurrences (33 from gastric and 33 from colorectal cancer) were detected between 6 and 42 months after primary surgery. In gastric cancer CEA, TPA and GICA showed a sensitivity of 64%, 73%, and 60%, and a specificity of 67%, 65% and 54% respectively. Nine patients (27%) underwent surgical treatment for the recurrent disease, and 4 of them (44.4%) had resectable recurrence, for a total resectability rate of 12%. Out of these four patients, three patients are still living after 12, 36 and 44 months respectively from re-operation without evidence of neoplastic disease. In one of these patients re-operation was performed on the basis of the elevation of the three markers, without any other clinical sign of disease, this patient had a resectable solitary hepatic recurrence. In colorectal cancer CEA, TPA and GICA showed a sensitivity of 73%, 73%, and 49%, and a specificity of 77%, 87%, and 97% respectively. Fourteen patients (42.4%) underwent surgical treatment for the recurrent disease, and 8 of them (57%) showed a resectable recurrence, for a total resectability rate of 24.2%. Six patients are still living after 9, 16, 21, 31, 41 and 53 months respectively from reoperation without evidence of neoplastic disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Allergen exposure induces the activation of allergen-specific Th2 cells in the airway mucosa of patients with allergic respiratory disorders.

Biopsy specimens were obtained from the bronchial or the nasal mucosa of three patients with grass pollen-induced bronchial asthma or rhinitis 48 h after positive bronchial or nasal provocation test with grass pollen extract. T cell clones (TCC), derived from these and control specimens, were then assessed for their phenotype, allergen-specificity, profile of cytokine secretion and ability to provide B cell help for IgE synthesis. Out of 50 and 61 CD4+ TCC derived from the bronchial mucosa of the two patient with atopic asthma 11 (22%) and 19 (31%), respectively, showed both proliferation and cytokine production in response to grass pollen allergens under major histocompatibility complex-restricted conditions. Of these 21 (70%) exhibited a clear-cut type 2 T helper (Th2) profile and induced IgE synthesis in autologous peripheral blood B cells in the presence of grass allergens. All the other 9 grass-specific clones showed a Th0 pattern of cytokine secretion, but only 1 provided moderate help for IgE synthesis. In contrast, the majority of TCC, derived under the same experimental conditions from the bronchial mucosa of two nonatopic patients with toluene diisocyanate-induced asthma, were CD8+ and most of them produced interferon-gamma or interferon-gamma and interleukin-5, but not interleukin-4, in response to nonspecific stimulation. Of 22 CD4+ TCC3 (14%) derived from the grass-stimulated mucosa of the patient with allergic rhinitis, but none of those derived from the unstimulated nostril of the same patient, exhibited proliferation and cytokine production in response to grass allergens. All had a clear-cut Th2 profile and provided help for IgE synthesis by autologous B cells. These data indicate that inhalation of the relevant allergen results in the activation of allergen-specific Th2 lymphocytes in the airway mucosa of patients with allergic respiratory disorders. These cells may play a central role in determining the nature of the inflammatory response in the airways of atopic patients.

Adult↗