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Biomedical subjects

A Conte

Publications and source records attributed to A Conte.

At least 37 records · Page 2Linked to original sources
PubMed2002

Spread of electrical activity at cortical level after repetitive magnetic stimulation in normal subjects.

In normal subjects, focal repetitive transcranial magnetic stimulation (rTMS) of the hand motor area evokes muscle potentials (MEPs) from muscles in the hand (target muscles) and the arm (non-target muscles). In this study we investigated the mechanisms underlying the spread of MEPs induced by focal rTMS in non-target muscles. rTMS was delivered with a Magstim stimulator and a figure-of-eight coil placed over the first dorsal interosseus (FDI) motor area of the left hemisphere. Trains of 10 stimuli were given at a suprathreshold intensity (120% of motor threshold) and at frequencies of 5, 10 and 20 Hz at rest. Electromyographic (EMG) activity was recorded simultaneously from the FDI (target muscle) and the contralateral biceps muscle and from the FDI muscle ipsilateral to the side of stimulation (non-target muscle). rTMS delivered in trains to the FDI motor area of the left hemisphere elicited MEPs in the contralateral FDI (target muscle) that gradually increased in amplitude over the course of the train. Focal rTMS trains also induced MEPs in the contralateral biceps (non-target muscle) but did so only after the second or third stimulus; like target-muscle MEPs, in non-target muscle MEPs progressively increased in amplitude during the train. At no frequency did rTMS elicit MEPs in the FDI muscle ipsilateral to the site of stimulation. rTMS left the latency of EMG responses in the FDI and biceps muscles unchanged during the trains of stimuli. The latency of biceps MEPs was longer after rTMS than after a single TMS pulse. In conditioning-test experiments designed to investigate the cortical origin of the spread, a single TMS pulse delivered over the left hemisphere at an interstimulus interval (ISI) of 50, 100 and 150 ms reduced the amplitude of the test MEP evoked by a single TMS pulse delivered over the right hemisphere; and a conditioning rTMS train delivered over the left hemisphere increased the amplitude of the test MEP evoked by a single TMS pulse over the right hemisphere. A conditioning rTMS train delivered over the left hemisphere and paired magnetic shocks (test stimulus) at 3 and 13 ms ISIs over the right hemisphere reduced MEP inhibition at the 3-ms ISI but left the MEP facilitation at 13 ms unchanged. Using a control MEP size matched with that observed after a conditioning contralateral rTMS, we found that paired-pulse inhibition remained unchanged. Yet a single TMS conditioning pulse sufficiently strong to evoke a MEP in the contralateral FDI and biceps muscles simultaneously (as rTMS did) left paired-pulse inhibition unchanged. We conclude that the spread of EMG activity to non-target muscles depends on cortical mechanisms, mainly including changes in the excitability of the interneurones mediating intracortical inhibition.

Adult↗
PubMed2002

Protein kinases mediate nitric oxide-induced apoptosis in the insect cell line IPLB-LdFB.

The involvement of protein kinases (PKA, PKC and PKB) in nitric oxide (NO)-induced apoptosis with sodium nitroprusside plus N-acetyl-L-cysteine in the IPLB-LdFB cell line from the insect Lymantria dispar was investigated. The presence of protein kinase-like molecules was demonstrated by Western blot analysis. The role of the kinases in programmed cell death was analysed in cytofluorimetric experiments by incubating the insect cells with H-89 (a specific inhibitor of PKA), calphostin C (an inhibitor of PKC) or wortmannin (an inhibitor of phosphatidylinositol 3-kinase). The results show that PKA is correlated with the induction and PKC and PKB with the prevention of NO-induced insect cell death. Moreover, NO-induced apoptosis involves the release of cytochrome c.

Androstadienes↗
PubMed2002

Modulation of viscero-somatic H-reflex during bladder filling: a possible tool in the differential diagnosis of neurogenic voiding dysfunctions.

OBJECTIVE: Despite evidence that the activation of visceral afferents modulates spinal motoneurone activity in humans, the circuits responsible for this modulation remain unclear. The aim of the present study was to assess the effect of urinary bladder filling on the excitability of somatic spinal motoneurones in patients affected by overactive bladder secondary to neurogenic and non-neurogenic causes in both patients with bladder underactivity and normal subjects by means of a urodynamic evaluation. METHODS: In order to evaluate the influence of bladder filling on somatic reflexes, we studied the H-reflex evoked by electrical stimuli applied to the tibial nerve at the popliteal fossa and recorded from the soleus muscle. The H-reflex was tested in the following conditions: (1). empty bladder; (2). medium bladder filling; (3). maximum bladder filling; (4). five minutes after bladder emptying. The H-reflex amplitude at empty bladder was considered as the control value. RESULTS: In healthy subjects, we observed a progressive reduction in the H-reflex amplitude during bladder filling. In spinal cord-injured patients affected by a neurogenic overactive bladder, bladder filling failed to inhibit the H-reflex amplitude; a decrease in the H-reflex amplitude similar to that displayed by normal subjects was observed in patients with a non-neurogenic overactive bladder. By contrast, H-reflex behavior was unmodified in neurogenic underactive bladder patients and was similar to normal subjects in psychogenic underactive patients. CONCLUSIONS: As behavior of the H-reflex varies during bladder filling in neurogenic and non-neurogenic overactive bladder patients as well as in neurogenic and non-neurogenic underactive bladder patients, H-reflex modulation may be considered a useful tool in the differential diagnosis of voiding dysfunctions.

Adult↗
PubMed2002

Peripheral neuropathy with hypomyelinating features in adult-onset Krabbe's disease.

We describe three brothers suffering from Krabbe's disease with onset in the fifth decade. The proband showed a complete deficiency of leukocyte enzyme galactocerebrosidase and was found to be heterozygous for two previously described mutations: G > A809 and 502T/del consisting of a 30 kb deletion. In all three brothers the neurological examination showed features of asymmetrical peripheral neuropathy associated with pyramidal signs and the electrophysiological examination showed a generalized slowing of nerve conduction velocities. Two patients died at 59 and 61 years of age due to respiratory failure. Both the proband and his brother underwent a sural nerve biopsy. In the former the most striking finding was the presence of uniformly thin myelin sheaths without evidence of demyelination; a complete absence of fibers was found in the latter. Our findings confirm that peripheral neuropathy may be the presenting feature of late-onset Krabbe's disease. Hypomyelination rather than demyelination may represent the distinguishing pathological finding of this condition.

Adult↗
PubMed2002

Bilateral spike-and-wave discharges in a hemi-deafferented cortex.

We studied a patient with a history of absence attacks in childhood in whom an absence status with bilateral spike-and-wave discharges developed after a top-of-the-basilar syndrome. Surprisingly, even though the ischemic lesion involved the left thalamus alone, spike-and-wave discharges were recorded from the two hemispheres. Three days after antiepileptic treatment (sodium valproate 500mg 3 times a day) began, electroenceplalographic recordings and consciousness became normal.

Action Potentials↗
PubMed2002

Effect of lecithin on epicutaneous absorption of diclofenac epolamine.

The epicutaneous application of nonsteroidal antiinflammatory drugs in localized rheumatic diseases results in a highly targeted antiinflammatory action and is associated with reduced systemic effects. The new diclofenac epolamine (DHEP) salt is much more soluble both in water and in lipid solvent than other diclofenac salts. The pharmaceutical addition of lecithin to DHEP leads to the formation of mixed micelles with high affinity to the cellular component, which guarantees the absorption of the active ingredient. We performed a bioavailability randomized, cross-over study to compare the plasma profiles of diclofenamic acid after repeated epicutaneous administration of the new topical formulation with those of the marketed DHEP formulation without lecithin. Based on a randomization list, 12 healthy volunteers were asked to apply one of the two formulations twice a day for 10 consecutive days. The other formulation was given after a washout period of 1 week. Blood samples were collected before the morning epicutaneous dose on days 1, 3, 5 and 8 of treatment and on day 10 at different sampling times until 24 h after the application. The pharmacokinetic analysis showed a significantly higher plasma concentration of diclofenamic acid after the application of DHEP lecithin, which indicates a better saturation of the subcutaneous tissues underlying the application site. This also indicates increased local availability of the active principle. In conclusion, the new DHEP formulation with lecithin should have a therapeutic advantage compared with the formulation without lecithin, even in cases of short- to medium-term treatments.

Adjuvants, Pharmaceutic↗
PubMed2001

Endocarditis caused by Aspergillus species in injection drug users.

Aspergillus endocarditis is a rare event; a very few cases have been reported in injection drug users (IDUs) and patients infected with human immunodeficiency virus (HIV). We report 2 proven cases and 1 highly suggestive case of Aspergillus endocarditis in IDUs, 2 of whom were infected with HIV, and discuss some related clinical and pathogenic aspects.

AIDS-Related Opportunistic Infections↗
PubMed2001

Role of pH on the calcium ion dependence of the nitric oxide synthase in the carp brain.

The role of pH on the calcium dependence of nitric oxide synthase (NOS) of Cyprinus carpio brain was investigated. This fish is known to survive prolonged periods of hypoxia. Under this condition, cerebral blood flow is no longer regulated by nitric oxide (NO). Nitric oxide synthase activity is pH dependent in the range of pH between 7.4 and 6.2 with a decrease when tissue acidifies. At acidic pH, the dependence of the NOS activity on the free Ca(2+) concentrations changes considerably and shows an EC(50) of 0.13 microM at pH 7.1 and of 5.1 microM at pH 6.2 for the soluble enzyme. The variation in the Ca(2+) dependence with acidification is greater for the soluble than for the particulate enzyme. This may be the main factor protecting sudden NO formation mainly during anoxic-normoxic transitions.

Acid-Base Equilibrium↗
PubMed2001

Bladder filling inhibits somatic spinal motoneurones.

OBJECTIVES: Despite evidence that the activation of visceral afferents modulates spinal motoneurone activity in humans the responsible circuits remain unclear. We investigated changes in spinal motoneurone excitability during bladder filling in 8 healthy subjects and in 8 patients with spinal cord lesions and 5 patients with multi-infarct encephalopathy. METHODS: Spinal motoneurone excitability was studied by analysing changes in H-reflex, F-wave and motor-evoked potential (MEP) size recorded from the calf muscles under different bladder filling conditions. RESULT: In normal subjects, maximal bladder filling significantly suppressed the H-reflex, F-wave and MEPs; after bladder voiding these responses returned to normal. In patients with encephalopathy maximal bladder filling strongly reduced H-reflex size; similarly to normal subjects H-reflex returned to control value after bladder voiding. In patients with spinal cord lesions, activation of bladder afferents left the H-reflex unchanged. CONCLUSIONS: These findings indicate that bladder distension induces post-synaptic inhibition of spinal motoneurones through a suprasegmental pathway, which is interrupted by rostral spinal cord lesions. This vesical-induced inhibition is probably mediated by the propriospinal system rather than by the diffuse noxious inhibitory control circuit.

Adult↗
PubMed2000

Prenatal exposure to misoprostol and vascular disruption defects: a case-control study.

Prenatal exposure to misoprostol has been associated with Moebius and limb defects. Vascular disruption has been proposed as the mechanism for these teratogenic effects. The present study is a multicenter, case-control study that was designed to compare the frequency of prenatal misoprostol use between mothers of Brazilian children diagnosed with vascular disruption defects and matched control mothers of children diagnosed with other types of defects. A total of 93 cases and 279 controls were recruited in eight participating centers. Prenatal exposure was identified in 32 infants diagnosed with vascular disruption defects (34.4%) compared with only 12 (4.3%) in the control group (P<0.0000001). Our data suggest that prenatal exposure to misoprostol is associated to the occurrence of vascular disruption defects in the newborns.

Abnormalities, Drug-Induced↗
PubMed2000

Urinary phytate in calcium oxalate stone formers and healthy people--dietary effects on phytate excretion.

The phytate urinary levels in a group of active calcium oxalate stone formers were studied and compared with those found in healthy people. Urinary phytate was significantly lower for stone formers. If deficit of the capacity to inhibit crystallization of calcium salts is considered an important factor related to calcium stone formation, the excretion of low phytate amounts could be an important risk factor in the development of this type of renal calculi. The influence of dietary phytate on urinary excretion was also studied. Clearly maintenance of a phytate-free diet significantly decreased the urinary excretion of phytate (about 50% after 36 h). This demonstrated the importance of dietary phytate in maintaining adequate urinary levels to permit effective crystallization inhibition of calcium salts and consequently preventing renal stone development.

Adult↗
PubMed1999

Differential activity of glycosaminoglycans on colony-forming cells from cord blood. Preliminary results.

Heparin, heparan sulfate and chondroitin sulfate were evaluated for their possible role on proliferation and differentiation of hematological precursor cells from cord blood. For these purposes, different concentrations of glycosaminoglycans were added to methyl-cellulose in colony assay performed with human cord blood derived cells. A volume of 10 microg/ml heparin induces a significant increase of both granulocyte-monocyte and granulocyte colonies, and a decrease of erythroid-colonies, more evident in the presence of 100 microg/ml. Heparan sulfate-treatment induces a significant increase of all granulocyte-monocyte colonies derived from CFU-granulocyte-monocyte, CFU-granulocyte and CFU-monocyte precursors. A significant decrease of multipotent cells was also observed. On the other hand, chondroitin sulfate induces an increase of granulocyte-colonies and a decrease of erythroid-colonies. Glycosaminoglycans with different structure may be useful to increase the number of specific colonies. The selective and differential binding of glycosaminoglycans with several growth factors and the regulation of their activities is discussed.

Fetal Blood↗
PubMed1999

Indinavir crystallization and urolithiasis.

The crystallization of indinavir in synthetic urine at different pH values and indinavir concentrations was kinetically studied. It was found that precipitation time notably decreases at urinary pH values above 6.0. The effects of some products as potential crystallization inhibitors were studied. Some natural saponins such as escin and glycyrrhizic acid provoked a notable increase in the precipitation time of indinavir, this pointing out their possible use to prevent renal tubular solid deposition.

Chemical Precipitation↗
PubMed1999

Import risk analysis: the experience of Italy.

The authors propose a contribution to the possible revision of Chapters 1.4.1. and 1.4.2. of the International Animal Health Code (Code) of the Office International des Epizooties (OIE). In particular, data are presented to illustrate some of the inadequacies of both the rationale and the results of the method for risk assessment reported in the Code. The method suggested by the Code for risk assessment is based on the calculation of the 'probability of the occurrence of at least one outbreak' of a given disease following the importation of a given quantity of either live animals or animal products (unrestricted risk estimate). This is usually undertaken when dealing with rare events. For a country such as Italy, this method may not be particularly useful as the frequency of disease outbreaks is what should be estimated, so as to provide decision makers with appropriate and relevant information. Practical use of risk information generated by the use of the OIE risk assessment method for swine vesicular disease (SVD) would have encouraged the Chief Veterinary Officer of Italy to prohibit all imports of swine from the Netherlands and Belgium for at least two years in the early 1990s, with the consequential heavy economic losses for both Italy and the exporting countries. On the contrary, the number of actual outbreaks of the disease due to direct imports of swine from Member States of the European Union (EU), which occurred in Italy in 1992, 1993 and 1994 was very low (two to five outbreaks due to direct imports of swine from the Netherlands and one to two from Belgium). An example of a method for assessing the risks associated with high volumes of trade in commodities is also described. This method is based on the Monte Carlo simulation and provides the information required to evaluate the costs of the strategies compared. The method can be used to predict the number of outbreaks which are likely to occur following importation and enables a comparison to be made of alternative safeguards. This would lead to the selection of the most cost-effective one. The comparison is conducted using risk curves and allows a quantitative evaluation and comparison to be made of various scenarios, varying from an absence of safeguards to combinations of various safeguards.

Animals↗
PubMed1999

Urinary lithogen risk test: usefulness in the evaluation of renal lithiasis treatment using crystallization inhibitors (citrate and phytate).

OBJECTIVES: This paper presents the results of a test to globally determine the urinary risk factor of calcium stone formation in the evaluation of treatments using crystallization inhibitors, such as citrate and phytate. METHODS: Three groups of active calcium oxalate stone-formers have been selected. The lithogen urinary risk was determined using a specially designed disposable test before any medical treatment. After evaluation group I did not receive any treatment, group II was treated with potassium citrate and group III with a phytate-rich dietary complement. When 15 days had elapsed, the test to evaluate the risk of urinary calcium stone formation was applied again to the three groups. The main lithogenic biochemical parameters of each tested urine were also determined before and after treatment. RESULTS: An important number of calcium oxalate stone-formers with high urinary risk factor (positive test) became negative after medical treatment (52% of the citrate-treated patients and 50% of the phytate-treated patients), but only 7% of the untreated patients (1 patient) showed a decrease in their urinary risk factor for calcium stones (negative test) after 15 days had elapsed. When the treatment was not effective, in an important number of cases, the urine contained high levels of calcium or showed pH values greater than 6.5. CONCLUSION: From the obtained results it can be concluded that the test is useful to evaluate the efficacy of a given renal lithiasis medical treatment, and also the efficacy of the treatment of calcium oxalate renal lithiasis using crystallization inhibitors, such as citrate and phytate, in an important number of cases.

Citrates↗
PubMed1999

A rare case of polyostotic fibrous dysplasia assessed by bone scintigraphy with Tc-99m methylene diphosphonate (MDP).

A 66-year-old man affected by polyostotic form of fibrous dysplasia in consequence of worsening of lower extremity bone pain aggravated by walking and concomitant increase of serum alkaline phosphatase and osteocalcin, was subjected first to a radionuclide study. Bone scan demonstrated a pathological uptake of the radiotracer in the craniofacial bones, right scapula, left and right posterior ribs, right hemipelvis and lower extremities confirming the diagnosis but establishing especially the extent of bone involvement, greater than expected on the basis of symptoms and X-ray findings, underlying the importance of nuclear medicine imaging in the assessment and follow-up of this rare disease.

Aged↗
PubMed1999

Tick-borne diseases in ruminants of Central and Southern Italy: epidemiology and case reports.

Sera and blood from cattle and sheep were examined for the presence of Babesia and Theileria spp by microscopy and serology at the Parasitology Department of the Istituto Zooprofilattico Sperimentale of Abruzzo and Molise (IZSAM). Of the 47 bovine herds (323 animals) tested, 15 were found positive for Babesia bigemina and 1 for Babesia bovis. Two outbreaks occurred, one caused by B. bigemina and one by B. bovis. The B. bigemina outbreak occurred in Abruzzo and has been followed for two years. The isolate of B. bigemina was very pathogenic leading to the death of two cows out of 57. The vector responsible of the transmission appeared to be Rhipicephalus bursa. Parasites were observed in the erythrocytes for 30 days whereas sera were positive to indirect immunofluorescence (IFA) for at least one year. The B. bovis outbreak occurred in the province of Mantova (Northern Italy) in a group of 70 beef cattle imported from France. The infection resulted in the death of 5 animals and severe illness in another 6. In contrast with what occurred for Babesia infection, no clinical cases were recorded in cattle when species of Theileria were detected by microscopy. Of the 24 bovine herds (252 animals) tested for Theileria, 21 were found positive for the T. "sergenti"/buffeli/orientalis group. Single and mixed infection of T. "sergenti" and T. buffeli/orientalis were detected in herds of cross-bred cattle from Abruzzo and Marche. The parasites were identified by using a polymerase chain reaction which amplified DNA encoding p32/34. Most of the collected ticks (90%) were adults of R. bursa whereas the others were adults of Hyalomma detritum. During the period the animals have been observed (18 months), no clinical cases have been recorded and no associations have been found between blood abnormalities and animals found infected with Theileria. Prevalences of subclinically infected carriers increased from February till December (95.4%) even if the animals were indoors and no ticks were present. The prevalence then dropped dramatically six months later (76.7%). In calves less than 1 year old, the prevalence of infection significantly (p<0.05) increased with age, however intraerythrocytic stages of Theileria were found in the blood of three newborn calves (<7 days of age). Of the 18 ovine flocks tested for Babesia spp. (150 animals examined), 1 was positive for B. ovis and 2 for B. motasi. B. motasi infection was not associated with symptoms, while an outbreak of babesiosis caused by B. ovis occurred in Abruzzo. The infection resulted in the death of 3 animals (0.75% of the flock), two rams (20% of the total number) and a ewe, and severe illness in another 5 ewes (2% of the flock). Specimens of R. bursa and R. turanicus were collected from the infected animals. Of the 18 flocks (150 animals) examined, 12 were microscopically positive for Theileria spp. No clinical cases were recorded and identification at species level was not possible on the basis of morphological criteria. The prevalence distribution of infected herds and infected animals within herds and flocks have been calculated by a Monte Carlo simulation model, running 10,000 iterations. The most likely levels of prevalence of infected herds and infected animals within herds found for the species observed were as follows: 20% for B. bigemina with a prevalence within herd of 27%, 11% for B. bovis (18% within herd), 10% for Babesia ovis (19% within herd), 10% for B. motasi (17.5% within herd), 63% for Theileria in cattle (66% within herd) and 51% for Theileria in sheep (55% within herd).

Animals↗