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Biomedical subjects

F Baldoni

Publications and source records attributed to F Baldoni.

At least 19 recordsLinked to original sources
PubMed1998

Characterization of catechol- and chlorocatechol-degrading activity in the ortho-chlorinated benzoic acid-degrading Pseudomonas sp. CPE2 strain.

Pyrocatechase activity was studied in the Pseudomonas sp. CPE2 strain, which is capable of growing on 2-chlorobenzoic and 2,5-dichlorobenzoic acid, giving rise to catechol and 4-chlorocatechol, respectively, as intermediate metabolites. The CPE2 crude extract was found to metabolize both catechol and 4-chlorocatechol. Enzymatic as well as phenotypic studies performed both on this strain and on a mutant strain lacking the chlorocatechol-degrading genes were consistent with the presence of two catechol-cleaving enzymes, one active mainly against catechol (pyrocatechase I) and the other with broader substrate specificity (pyrocatechase II). The latter enzyme also appeared to be induced when CPE2 cells were grown on 2-chlorobenzoic acid, thus contributing to catechol metabolism, in addition to pyrocatechase I. Despite the presence of a large plasmid in CPE2 cells, the chlorocatechol-degrading genes, highly homologous to the clc operon, were located on the chromosome. The selection at relatively high frequency of mutant strains with altered growth capabilities and which lacked the chlorocatechol-degrading genes suggests a transposon-like character for these catabolic genes in the CPE2 strain.

Biodegradation, Environmental↗
PubMed1996

The aminoterminal phosphotyrosine binding domain of Shc associates with ZAP-70 and mediates TCR dependent gene activation.

T-cell antigen receptor stimulation results in recruitment to the zeta chain and phosphorylation both of the syk family protein tyrosine kinase ZAP-70 and of the Shc adaptor protein, which transduces activating signals to Ras. Both ZAP-70 and Ras are required for T-cell activation. We have investigated the functional link between these two molecules in TCR signaling. She was found to associate with ZAP-70 in response to TCR triggering. This association was dependent on the presence of the aminoterminal phosphotyrosine binding (PTB) domain of She. The analysis of She binding to a potential PTB domain binding site on ZAP-70 confirmed the interaction of the She PTB domain with ZAP-70 and identified the ZAP-70 phosphotyrosine residue involved in this interaction. To test the role of the She PTB domain in transducing TCR derived signals we measured the effects of the isolated She PTB domain on the activation of the T-cell specific transcription factor NF-AT. The isolated She PTB domain was designed to compete non productively with endogenous She for binding to up-stream tyrosine phosphorylated proteins and thus interfere with coupling to regulators of Ras activation. A significant inhibition of NF-AT activation by TCR triggering was observed, showing a functional involvement of She in TCR signaling through its PTB domain and suggesting an important role for She association with ZAP-70.

Amino Acid Sequence↗
PubMed1996

2-Chlorobenzoic acid and 2,5-dichlorobenzoic acid metabolism by crude extracts of Pseudomonas sp. CPE2 strain.

Crude extracts of Pseudomonas sp. CPE2 strain, which is capable of growing on 2-chlorobenzoic acid (2-CBA) and 2,5-dichlorobenzoic acid (2,5-dCBA) in the absence of other carbon sources, were found to be capable of bioconverting 2-CBA and 2,5-dCBA to catechol and 4-chlorocatechol, respectively, by a reaction requiring molecular oxygen and exogenous NADH. Extracts obtained from 2-CBA-grown cells in the presence of 2-CBA and from 2,5-dCBA-grown cells in the presence of 2,5-dCBA were found to have activities similarly influenced by the assay parameters pH, temperature, and by concentration of oxygen, protein, Fe2+, FAD and NADH in the assay medium. In addition, the activity of the two crude extracts in the presence of 2-CBA or 2,5-dCBA was described by very similar Michaelis-Menten kinetic parameters. These observations led to the speculation that a unique broad-spectrum chlorobenzoate 1,2-dioxygenase catalyses the 2-CBA and 2,5-dCBA metabolism both in 2-CBA- and 2,5-dCBA-grown CPE2 cells.

Biodegradation, Environmental↗
PubMed1995

Distinct signaling properties identify functionally different CD4 epitopes.

The CD4 coreceptor interacts with non-polymorphic regions of major histocompatibility complex class II molecules on antigen-presenting cells and contributes to T cell activation. We have investigated the effect of CD4 triggering on T cell activating signals in a lymphoma model using monoclonal antibodies (mAb) which recognize different CD4 epitopes. We demonstrate that CD4 triggering delivers signals capable of activating the NF-AT transcription factor which is required for interleukin-2 gene expression. Whereas different anti-CD4 mAb or HIV-1 gp120 could all trigger activation of the protein tyrosine kinases p56lck and p59fyn and phosphorylation of the Shc adaptor protein, which mediates signals to Ras, they differed significantly in their ability to activate NF-AT. Lack of full activation of NF-AT could be correlated to a dramatically reduced capacity to induce calcium flux and could be complemented with a calcium ionophore. The results identify functionally distinct epitopes on the CD4 coreceptor involved in activation of the Ras/protein kinase C and calcium pathways.

Adaptor Proteins, Signal Transducing↗
PubMed1995

Human naive T cells activated by cytokines differentiate into a split phenotype with functional features intermediate between naive and memory T cells.

We have recently shown that CD45RA+CD4+ naive T cells can be activated to proliferate by a combination of IL-2, TNF-alpha and IL-6, but, at variance with TCR-mediated activation, they do not acquire the CD45RO molecule. This prompted us to investigate the phenotype of these cells and the functional features they display upon TCR stimulation. Naive T cells expanded by cytokines, though remaining CD45RA+, express a variety of activation and adhesion molecules which are peculiar to effector or memory T cells. Naive cells primed by cytokines, when activated with anti-CD3 mAb, produce a broad spectrum of cytokines, express CD40 ligand, but are unable to help B cells for Ig synthesis. A subset of CD4+CD45RA+RO-T cells with a phenotype (HLA-DR-, VLA-2+ or IL-2R+) similar to that of cells activated by cytokines in vitro can be found in vivo. These results demonstrate that activation signals delivered by cytokines, in the absence of TCR stimulation, can activate naive T cells to proliferate and differentiate into a 'split phenotype' with elements common to both naive and memory T cells. This novel antigen-independent activation may help to maintain the naive T cell repertoire and facilitate the antigen-responsiveness of naive T cells.

Adult↗
PubMed1995

Stressful events and psychological symptoms in patients with functional urinary disorders.

The relationship between micturition, stressful events, and psychological symptoms was studied in 58 female patients with functional micturition disorders (urethral syndrome) and 21 control patients. All received three questionnaires (Symptom Questionnaire, Illness Behavior Questionnaire, and the Biographic Questionnaire). Analysis highlighted the appearance of the urethral syndrome in highly stressful situations and the increase in the patient's anxiety, depression, dysphoria, hostility, and irritability. A tendency to complain of other psychophysiologic symptoms was also noted.

Adult↗
PubMed1994

Splenic autotransplantation after splenectomy: tuftsin activity correlates with residual splenic function.

This study set out to determine the relationship between splenic function (as assessed by the percentage of pitted red cells) and tuftsin activity, and to confirm the return of effective splenic function after splenectomy for trauma. Twenty-three patients (13 men) took part. Ten of mean age 48.5 (range 30-74) years had had the spleen removed for traumatic rupture and 13 of mean age 49.7 (range 23-66) years had undergone elective splenectomy. At the time of the study all patients had had the spleen removed a minimum of 1 year previously (mean 6.1 (range 1-15) years). Fifty healthy volunteers matched for sex and age were also studied. In each subject, residual splenic function was evaluated by counting the percentage of pitted red cells. Tuftsin activity was also determined. A highly significant negative correlation was found between pitted red cell percentage and tuftsin activity (rs = -0.80, P < 0.001). Compared with healthy controls (mean 21.6 (range 13-37) per cent), tuftsin activity was significantly reduced both in patients who had undergone splenectomy for trauma (mean 4.4 (range 0-9) per cent; P < 0.0001) and in those who had had elective splenectomy (mean 0; P < 0.0001). Tuftsin activity was significantly (P < 0.001) more depressed after elective than traumatic splenectomy. These data confirm a decrease in tuftsin activity following splenectomy and show that this deficit is significantly greater after elective than emergency removal. These observations confirm that residual splenic function is often present after traumatic splenectomy.

Adult↗
PubMed1992

S-100ab increases Ca2+ release in purified sarcoplasmic reticulum vesicles of frog skeletal muscle.

The S-100ab protein, a mixed isoform member of the S-100 family, stimulates Ca(2+)-induced Ca(2+)-release from sarcoplasmic reticulum vesicles purified from frog skeletal muscle cells. The effects of S-100ab appear to be specific and result from its peculiar characteristics rather than the fact that it is a calcium-binding protein. Moreover, the addition of S-100ab to the solution completely abolished the inhibition provoked when Ruthenium Red was added alone. Experiments that added labelled Ryanodine with and without S-100 indicated that the protein diminished the affinity of the alkaloid at its receptor site.

Animals↗
PubMed1992

Leucocyte aggregation in acute cerebrovascular disease.

We evaluated leucocyte aggregation in 26 patients with ischemic stroke and in 10 patients with transient ischemic attacks (TIA), previously untreated, within 24 h from the onset of symptoms. The evaluation was also performed in 30 healthy subjects matched for age and sex. Leucocyte aggregation was significantly higher in patients than in controls (p < 0.01 post hoc Tukey test). Within patients, those with stroke showed a significantly higher aggregation than those with TIA (p = 0.01 post hoc Tukey test). Moreover, stroke patients with the poorest outcome showed significantly higher values of leucocyte aggregation. These results indicate an involvement of leucocytes in cerebral ischemia and suggest that changes in their aggregability may play a role in the evolution of the disease.

Aged↗
PubMed1992

[Primary intrahepatic lithiasis].

Isolated intrahepatic lithiasis is a very rare condition in western countries; the reported case has to be added to the 29 cases described to date in the literature. The pathogenesis of this disease is unknown; physical and chemical bile alterations favouring lithogenesis is the most reliable hypothesis. In this case the Roux-en-Y hepaticojejunostomy with cutaneous stoma allowed us to perform periodic cleaning of intrahepatic bile ducts until complete elimination of all stones.

Bile Ducts, Intrahepatic↗
PubMed1992

[Primary intrahepatic lithiasis].

Isolated intrahepatic lithiasis is a very rare condition in western countries; the reported case has to be added to the 29 cases described to date in the literature. The pathogenesis of this disease is unknown; physical and chemical bile alterations favouring lithogenesis is the most reliable hypothesis. In this case the Roux-en-Y hepaticojejunostomy with cutaneous stoma allowed us to perform periodic cleaning of intrahepatic bile ducts until complete elimination of all stones.

Bile Ducts, Intrahepatic↗
PubMed1989

Urethral syndrome: a study in psychosomatic urology.

The authors studied a sampling of 50 female patients diagnosed with urethral syndrome (urinary symptoms and pain without infection or organic lesion) on purpose to explore some psychological aspects. The evaluation procedure began with a complete urodynamic examination followed by a clinical interview. After this all patients were given three questionnaires: Symptom Questionnaire, Illness Behaviour Questionnaire and a Biographic Questionnaire prepared specifically for this study. Statistical analysis of the data showed higher levels of hostility, irritability, anxiety, dysphoria and depression in the group of patients than in the control group. There was also a marked tendency to suffer from psychophysiological symptoms.

Adult↗
PubMed1988

Serum elastase 1 in clinical practice.

Using radioimmunoassay, we tested serum elastase 1 (E1), an enzyme secreted only from the pancreas, in 200 subjects as follows: 39 healthy subjects as controls, 56 patients with diseases of the digestive tract, 66 patients with hepatobiliary diseases, and 39 patients with pancreatic diseases. The serum E1 showed high specificity and proved very useful in the diagnosis of acute pancreatitis. However it was not useful in diagnosis of clinically silent chronic pancreatitis, nor in its functional evaluation. On the other hand, it was found to be a valuable guide in revealing a concomitant pancreatic pathology during hepatobiliary diseases. Further investigation is needed of the behavior of E1 in patients who have undergone a total pancreatectomy, where the enzyme remains measurable, and in those with an ileocolic disease in an acute phase where E1 is increased in many patients.

Adult↗
PubMed1987

Effect of somatostatin 14 on pure human pancreatic secretion.

While it is well known that large doses of somatostatin inhibit human pancreatic enzyme secretion, it is still unknown whether low doses are also effective and whether the peptide is able to inhibit bicarbonate production. Eight subjects with external transduodenal drainage of the main pancreatic duct performed after biliary tract surgery were studied. Somatostatin was infused at progressively increasing rates of 0.05, 0.15, 0.45, and 1.35 micrograms/kg/hr, for 30 min/dose, during pancreatic stimulation with secretin, 25 ng/kg/hr, and cerulein, 10 ng/kg/hr. Somatostatin, at the dose of 0.05 microgram/kg/hr (shown to produce blood levels similar to those measured after a meal) did not affect pancreatic secretion in any of the subjects. The successive three higher doses caused a significant and dose-dependent inhibition of protein concentration and output and of bicarbonate output. Bicarbonate concentration was slightly but significantly reduced only by the two highest doses of somatostatin. At each dose level, the inhibition of protein output was much more marked than the inhibition of bicarbonate output. The maximal inhibition of protein output (at 1.35 micrograms/kg/hr somatostatin) was 73.9 +/- 5.4%, and that of bicarbonate output was 55.9 +/- 6.4%. The results demonstrate that: (1) the administration of somatostatin at a low dose level does not affect human exocrine pancreatic secretion, at least under the experimental conditions of this study; and (2) the administration of larger doses of somatostatin inhibits pancreatic secretion of both protein and bicarbonate dose-dependently. The inhibitory effect on protein output is significantly greater than that on water and bicarbonate production.

Adult↗
PubMed1987

Serum pancreatic enzyme behavior during the course of acute pancreatitis.

The variations of serum levels of amylase, pancreatic isoamylase, lipase, trypsinogen, and elastase 1 were evaluated in 21 patients with acute pancreatitis. The patients were studied for a mean period of 7 consecutive days (range 5-12 days) after admission to the hospital. On the day of onset of acute pancreatitis, all enzyme levels were abnormally high; pancreatic isoamylase showed the greatest increase compared with its upper normal limit, whereas the increase increment for elastase 1 was the lowest. Subsequently, all enzyme levels except elastase 1 decreased in a parallel fashion. On the eighth day of the study only elastase 1 levels were above normal values in all patients examined, while abnormally high values of lipase were found in 85% of the patients, trypsinogen in 58% of the patients, pancreatic isoamylase in 43%, and total amylase in 23%. These results indicate that, for the early diagnosis of acute pancreatitis, the determination of any of these enzymes is equally efficient, but that elastase 1 is the most sensitive marker of acute pancreatic damage in later stages of the disease.

Acute Disease↗
PubMed1987

Pure pancreatic juice collection over 24 consecutive hours.

We collected pure pancreatic juice during an entire day and examined pancreatic secretory changes induced by ordinary meals in a male patient having an external drainage of the main pancreatic duct. The ingestion of breakfast, lunch, and dinner each caused a marked increase in pancreatic secretion above basal levels. The increase in both bicarbonate and protein output was very prolonged. The highest secretory outputs induced by meals were slightly higher than those produced by exogenous administration of submaximal doses of secretin and cerulein. The profile and magnitude of bicarbonate and protein secretion were similar.

Bicarbonates↗