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Biomedical subjects

A Signore

Publications and source records attributed to A Signore.

At least 73 records · Page 4Linked to original sources
PubMed1987

Class-II and IL2 receptor positive cells in the pancreas of NOD mice.

The aberrant expression of Class-II molecules on pancreatic B cells in Type 1 (insulin-dependent) diabetes is still a matter of debate. In order to verify if Class-II molecules are expressed on islet cells in the NOD mouse we have studied 21 female mice of different ages (5 to 22 weeks). Serial cryostat pancreas sections were stained with monoclonal rat antibodies against Class-II antigens (P7/7) and the IL2 receptor (AMT-13). Our results show no Class-II expression by endocrine cells at any age, whereas about 25-32% of mononuclear cells infiltrating the islets were Class-II positive, and only 6-9% were IL2 receptor positive. No staining, except of occasional tissue macrophages, was observed in the pancreas of BALB/c, CBA or B10.SCSN mice. Our data are in contrast with those recently published and therefore the reality of expression of Class-II molecules by islet cells of NOD mice should be viewed with caution.

Animals↗
PubMed1987

Labelling of interleukin-2 (IL-2) with 123-iodine with retention of its capacity to bind to activated lymphocytes.

Human recombinant interleukin-2 (IL-2) was labelled with Iodine-123 using modified Bolton and Hunter method. Separation from free iodine was performed by gel filtration chromatography using a Sephadex G10 column. HPLC analysis of labelled IL-2 showed that 98% of TCA precipitable radioactivity eluted in a single peak. The immunoreactivity of 123I-labelled IL-2 was determined by divert binding using the Fluorescence Activated Cell Sorter (FACS) and by receptor binding assay of IL-2 to activated lymphocytes. To demonstrate in vivo binding to activated lymphocytes, 123I-labelled IL-2 was injected intravenously into a newly diagnosed diabetic BB/Wistar rat. Higher radioactivity was detected in the pancreas and in the lymph nodes of the BB/W rat compared to a normal rat. These preliminary data show that 123I-labelled IL-2 retains its immunoreactivity and capacity to bind to activated lymphocytes both in vitro and in vivo and may be used for in vivo localization of lymphocytic infiltration in Type 1 diabetes.

Animals↗
PubMed1987

In vivo kinetics of 123I-labelled insulin: studies in normal subjects and patients with diabetes mellitus.

Radioactive tracer techniques using 131I- and 125I-insulin have been applied to study insulin metabolism. A simple method to label human insulin with 123I to a high specific activity is described. We have used this radiotracer to study insulin kinetics in vivo in normal subjects and in two groups of diabetic patients. The rate of decline in plasma radioactivity was shown to be significantly reduced in patients with diabetes. There were no significant differences in the time-activity profiles of liver and kidneys between the groups studied. This technique may provide insight into the mechanism of some forms of insulin resistance.

Adult↗
PubMed1985

Study of the diurnal variation of human lymphocyte subsets.

The diurnal variation of peripheral white cells and in particular of different lymphocyte subsets has been investigated in 11 normal subjects. Monoclonal antibodies (Mab) phenotyping total T lymphocytes (UCHT1), cytotoxic/suppressor (UCHT4), helper T cells (Leu 3a), B lymphocytes (231) and K/NK cells (H25) have been used. In addition to the traditional parametric statistics, the chronobiological approach of cosinor was adopted in order to inferentially obtain the waveform covering the 24-hr period. Cosinor analysis validated the existence of a significant rhythm for leucocytes (p = 0.04, lymphocytes (p = 0.03), and Leu 3a positive cells (p = 0.04). The best fitting period was equal to 28 hr. No circadian rhythm was documented for lymphocyte subsets positive for Mab UCHT4, 231, H25, by testing the variability with a frequency ranging from 1 cycle every 12hr to 1 cycle every 28 hr. By the non-inferential analysis of temporal curves, a significant peak of Leu 3a positive cells at 20.00 hr (p less than 0.001) was observed. The acrophase has been recorded by cosinor analysis at 20.36 hr. We conclude that the circadian variability of Leu 3a positive cell profile must be taken into account when the helper/suppressor ratio is calculated. The time-dependence of this lymphocyte subpopulation suggests that when therapy with corticosteroids is considered in autoimmunity, it should be planned by keeping the peak of Leu 3a positive cells as a marker time.

Adult↗
PubMed1985

Effect of unlabeled indium oxine and indium tropolone on the function of isolated human lymphocytes.

The purpose of this study was to compare the effect of indium oxine and indium-tropolone complexes (nonradiolabeled) on the function of isolated human lymphocytes. peripheral lymphocytes were obtained from 15 normal volunteers and incubated with indium oxine or indium tropolone according to the standard techniques currently used when cells are radiolabeled for subsequent in vivo studies. The phytohemagglutinin-induced (PHA) lymphocyte transformation and a more specific lymphocyte functional test (the mixed lymphocyte reaction) were performed following incubation with the indium complexes. The results indicate that PHA transformation is not affected by either indium oxine or indium tropolone, whereas both chelates reduced the mixed lymphocyte reaction. This suggests that these substances have a selective toxic effect only on a functionally distinct lymphocyte subset (i.e., the cytotoxic T cells) and indicates that there is no significant difference between the two indium chelates in terms of their effect on lymphocyte function.

Adult↗
PubMed1985

Inhibition of the receptor for interleukin-2 induced by carbimazole: relevance for the therapy of autoimmune thyroid disease.

Evidence has been accumulated that the anti-thyroid drugs used in the treatment of Graves' disease may have immunosuppressive properties but the exact mechanism of action is still unclear. In the present study, we have investigated the in vitro effect of carbimazole (CBZ) on the expression of lymphocyte differentiation antigens and on suppressor cell activity. The incorporation of radiolabelled methimazole (35S-MMI, the active metabolite of CBZ) by resting and mitogen stimulated lymphocytes was also investigated. CBZ at concentrations of 60 microM significantly inhibited the expression of the receptor for interleukin-2 (as defined by the anti-TAC monoclonal antibody [MoAb]) by lymphocytes stimulated with phytohaemagglutinin. The expression of an early activation antigen (as characterized by the 4F2 MoAb) was not affected. Twenty-four hour pre-incubation of cells with different concentrations of CBZ or medium alone did not change the lymphocyte response to mitogenic stimulation, thus suggesting no effect of the compound on suppressor cell function. Finally, there were no significant differences in the uptake of 35S-MMI between resting and stimulated lymphocytes. These data suggest that the immunosuppressive effect of CBZ may be due to its effect of reducing the expression of the receptor for interleukin-2 on lymphocytes undergoing full activation. This property of CBZ could be of relevance in the therapy of autoimmune thyroid diseases (not only Graves' disease) which are characterised by the presence of activated T cells in the thyroid and in circulation.

Adult↗
PubMed1985

Homing and circulation of indium-111-labelled leucocytes. A post-mortem study.

The history of a patient with a suspected ischemic brain infarct undergoing an indium-111-tropolone white cell labelled test is reported. The patient, who died 12 h after injection of the labelled cells, suffered of a brain haemorrhage. The post-mortem examination has allowed for the first time the measurement of radioactivity in different organs following the injection of indium-111-labelled leucocytes. High radioactivity was found only in tissues affected by inflammatory processes and in the lymphonodes draining the corresponding areas. This report clearly indicates the importance of this method for the study of white cell localization and circulation to the sites of infections.

Cerebral Hemorrhage↗
PubMed1983

Labelling of lymphocytes with indium 111 oxine: effect on cell surface phenotype and antibody-dependent cellular cytotoxicity.

Indium 111 oxine is currently used to label peripheral lymphocytes in order to study the kinetics of these cells in vivo. Since the quantity of radioisotope for labelling is still a matter of controversy, we have investigated in vitro the effect of increasing the concentration of indium 111 oxine on the lymphocyte surface phenotype and the antibody-dependent cellular cytotoxicity (ADCC) using lymphocytes from normal subjects. The cell surface phenotype, as evaluated by 2 monoclonal antibodies, was not affected whereas ADCC, at any of the doses used, was significantly reduced compared to the baseline value. The implications of these results for the use of indium 111 oxine for the in vivo studies are discussed.

Adult↗
PubMed1983

Studies of peripheral blood lymphocytes in Crohn's disease. Circulating activated T cells.

Peripheral blood mononuclear cells have been investigated in 43 patients with Crohn's disease (CD) by means of a panel of 4 monoclonal antibodies (UCHT1, UCHT4, 4F2, 5E9). A decrease of total T cells (UCHT1+) (p less than 0.01) and a slight increase of cytotoxic/suppressor T cells (UCHT4+) were observed. Evidence of T-cell activation, as shown by the highly significant increase of 4F2+ and 5E9+ cells, was also found. The latter finding lends support to the concept that cell-mediated immune phenomena are an important feature in CD.

Adult↗
PubMedDate not supplied

A multi-centre randomized trial of two different doses of nicotinamide in patients with recent-onset type 1 diabetes (the IMDIAB VI).

BACKGROUND: Intensive insulin therapy is the gold standard by which Type 1 diabetes is treated. In addition to this therapy, administration of nicotinamide (NA) can be beneficial. This concept is reinforced by the results of a recent meta-analysis of the use of NA in patients with recent-onset Type 1 diabetes. METHODS: In this study we compared two different doses of NA in 74 patients with duration of Type 1 diabetes <4 weeks (mean age 13 years). Patients were randomly allocated in blind to two treatment groups: 38 patients received a dose of 25 mg/kg (b.w.) of NA and 36 patients received a dose of 50 mg/kg (b.w.) of NA. Intensive insulin therapy was carried out in order to optimize metabolic control as soon as possible after diagnosis and to maintain blood glucose level as near to normal as possible. Response to therapy was monitored throughout the study by investigating the occurrence of clinical (complete) remission defined, according to the recommendations of the International Diabetes Immunotherapy Group, as restoration of normal fasting and post-prandial blood glucose without any insulin administration for more than 2 weeks. Moreover, the integrated measures of metabolic control (C-peptide, HbA(1c) and insulin dose) were analysed at 3- month intervals up to 1 year after diagnosis. RESULTS: There were no significant differences in the integrated measures of metabolic control between the two NA treated groups either at onset of the disease or at each 3-month interval up to 1 year after diagnosis, although there was a tendency toward higher insulin dosages in the 50 mg NA group. No significant differences were observed in the rate of clinical remission between the two groups. CONCLUSION: We conclude that patients with recent-onset Type 1 diabetes treated with two different doses of NA, in addition to intensive insulin therapy, show similar residual beta-cell function 1 year later. Since both doses of NA are likely to be effective in reducing beta-cell dysfunction, the smaller dose of 25 mg/kg NA would be sufficient as a higher dose may induce insulin resistance.

Adolescent↗
PubMedDate not supplied

Randomized trial comparing nicotinamide and nicotinamide plus cyclosporin in recent onset insulin-dependent diabetes (IMDIAB 1). The IMDIAB Study Group.

A 1-year open randomized controlled multicentre trial was carried out on 90 patients with recent onset (< 4 weeks) insulin-dependent diabetes (IDDM) to compare the effect of nicotinamide (NCT) with the combination NCT and low dose cyclosporin (CyA) on clinical remission and optimization of metabolic control during the first year from diagnosis. Three groups of patients were randomly assigned to receive for 12 months either NCT 25 mg kg-1 day-1 (n = 30) or NCT 25 mg kg-1 day-1 + CyA 5 mg kg-1 day-1 (n = 30), the latter adjusted to maintain 12 whole blood trough levels of 83 nmol l-1; a third group of patients (n = 30) receiving insulin only acted as a control group for spontaneous remission and metabolic control. Clinical remission (i.e. suspension of insulin therapy with normal metabolic parameters for more than 2 weeks according to the International Diabetes Immunotherapy Group) was achieved at 3 months in 6/30 NCT treated patients and in 1/30 NCT + CyA treated patient (p = 0.05); no remission was observed in control patients. At 6 months the number of patients achieving remission in each group was 4/29, 3/27, and 1/29, respectively (p = NS). One year after diagnosis 4/27 NCT treated, 2/25 NCT+CyA treated but 0/28 of the control patients were in remission (NCT vs control p = 0.05). Clinical remission lasted longer (7 +/- 3 SD months) in NCT treated patients than in NCT+CyA treated or control patients (p < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Imaging of leukocytic infiltration in human cerebral infarcts.

The circulating white blood cells of patients with brain infarction were labelled in vitro with Indium-111 tropolonate; the cells were reinjected to study the inflammatory process by gamma camera imaging. Eight patients with acute cerebral ischemic infarct were studied during the first two weeks after the onset of neurological symptoms. In seven cases a well defined area of increased radioactivity was revealed in the infarcted hemisphere indicating active migration and tracking of labelled leukocytes in cerebral infarct. This method allows monitoring of the cellular inflammatory response in human cerebral infarcts and adds another imaging technique.

Acute Disease↗
PubMedDate not supplied

Effects of Nd: YAG laser irradiation on the root canal wall dentin of human teeth: a SEM study.

The purpose of this study was to observe the morphological and histological changes on the root canal walls after Nd:YAG laser application. Twenty vital, recently extracted single-rooted human teeth were used for this study. Root canals were cleaned and shaped by a conventional step-back technique--by means of k files up to a 20 k-file type at working length--and subsequently shaped by Ni-Ti root-canal rotary instrumentation up to 30/06 and irrigated with 2.5% hypochlorite solution. Ten teeth (control group) were left unlased, while the other ten teeth were irradiated with Nd:YAG laser by means of a 320 microns fibre inserted in the root canal at 1 mm from the apex with a power of 1.5 Watt and a frequency of 15 pps for five seconds in retraction with rotating movements. The control specimen showed debris and smear layer on the root canal surface obscuring the dentin tubules. The root canal walls irradiated with Nd:YAG laser showed a clear glazed surface, some open dentinal tubules and some surface craters with cracks. Such results confirm that smear layer and debris are removable with Nd:YAG laser, however clearing all root canal walls is still difficult and, if the energy level and duration of application are inadequate, a certain degree of thermal damage and morphological changes in dentin structure are observable.

Aluminum Silicates↗
PubMedDate not supplied

Effect of Tenidap, a novel anti-inflammatory compound on islet lymphocytic infiltration and diabetes incidence in the non obese diabetic (NOD) mouse.

Tenidap, a novel compound inhibiting cyclooxygenase and lipoxygenase, also possessing an inhibitory effect on interleukin-1 secretion by in vitro activated macrophages, has been administered to the non obese diabetic (NOD) mouse to evaluate its action on the induction and progression of insulitis and the diabetes incidence. Animals were allocated to three groups (group A: control group; group B: 12 mg/kg/day Tenidap; group C: 36 mg/kg/day Tenidap); female animals only were followed up to investigate the effect on diabetes incidence. The administration of Tenidap influenced the natural course of insulitis in male NOD mice; thus, at 60 and 100 days of age the mean percentage of infiltrated islets was significantly reduced compared to control animals (p less than 0.02). Moreover the severity of lymphocytic infiltration at 60 days of age was reduced in male mice of group B and C compared to control mice (p less than 0.004 and p less than 0.0001, respectively) whereas at 100 days of age this difference was not significant. However the progression towards severe insulitis in male animals receiving Tenidap was halted compared to control animals. Tenidap had also a significant dose dependent effect at 60 days on the severity of lymphocytic infiltration (group B vs. group C, p less than 0.01). By contrast, this agent had no effect on the degree of insulitis and diabetes incidence in female NOD mice. In both sexes at the end of follow-up a significant reduction in body weight was observed in animals of Group C compared to control animals (p less than 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗