Biomedical subjects

A Cavallini

Publications and source records attributed to A Cavallini.

At least 37 records · Page 2Linked to original sources

PubMed2001

Subcortical dementia associated with striking enlargement of the Virchow-Robin spaces and transneural degeneration of the left mammillo-thalamic tract.

We report a case of subcortical dementia in a 68-year-old woman. MR examination of the patient's brain revealed two types of alterations as a possible cause of the dementia, both anomalous in respect of their entity and incidence: the first was a striking enlargement of the Virchow-Robin spaces, and the second an anterograde transneural degeneration of the left mammillo-thalamic tract and mammillary body secondary to a lacunar infarction of the ipsilateral anterior thalamus.

Aged↗

PubMed2001

Estrogens and colorectal cancer.

In recent years, several lines of epidemiologic, clinical and experimental evidences have been reported showing that estrogen hormones may be involved in malignant colorectal tumors. The sex differences in site-specific incidence, the increased incidence of colonic cancer in women with breast cancer, the protective effect of increasing parity and the reduced risk among women taking postmenopausal hormones, are all elements suggesting that sex hormones may play a role. Male rats experimentally exposed to the carcinogen dimethylhydrazine, have twice the risk of developing colon cancer and significantly shorter survival times than their female counterparts. Along with the clinical, experimental and epidemiologic findings there are also biologic reasons why estrogen may be protective. Most estrogen action appears to be exerted via the estrogen receptors (ERs) on target cells. ERs have been reported in several solid tumors including gastrointestinal neoplasms such as esophageal, gallbladder, gastric and colorectal cancer. At the end of 1995, a second ER (ER-beta) was cloned from the rat prostate cDNA library and subsequently, the human and mouse homologs. Its demonstration in normal and neoplastic human colorectal tissues and "in vitro" in colonic epithelial cells, has renewed interest in investigating the existence of two ER subtypes. The presence of two ERs could explain the selective actions of estrogens on different target tissues and, particularly, on the gastrointestinal tract. Finally, our studies suggest that estrogens and their receptors play an important role in the growth and progression of colorectal tumors, by interacting with other molecules required for cell proliferation like growth factors and polyamines.

Animals↗

PubMed2001

Alpha-dihydroergocryptine and predictive factors in migraine prophylaxis.

OBJECTIVE: A double-blind, crossover study was carried out to compare the efficacy of alpha-dihydroergocryptine mesylate (10 mg twice daily) vs propranolol (40 mg twice daily) in the prophylaxis of migraine without aura, and to identify possible predictors of therapeutic response by evaluating the symptomatological profile of individual migraine attacks and the autonomic cardiovascular response to noradrenergic and dopaminergic (cold pressor, bromocriptine) tests. PATIENTS AND METHODS: Forty migraineurs (10 males, 30 females) were randomized according to a two-period (3-month), two-treatment, crossover design. Efficacy was assessed using quantitative data recorded in the patient's headache diary. Data were evaluated using the Wallenstein's method. RESULTS: Both drugs showed a significant reduction in all the efficacy variables (headache attacks, days with headache, analgesic consumption) with no difference between treatments. Neither a bromocriptine test, nor a cold pressor test nor the symptomatological profile of individual migraine attacks differed between the two groups of migraine patients. Ten patients experienced at least one adverse drug reaction during the first period of the crossover design, 5 being treated with alpha-dihydroergocryptine and 5 with propranolol. CONCLUSIONS: It is concluded that alpha-dihydroergocryptine is an effective medication for migraine prophylaxis. The biochemical tests and the type of psychological profile cannot be used to predict drug response.

Adrenergic alpha-Antagonists↗

PubMed2001

White and UV light effects on cell nuclei in the aurea genotype of Lycopersicum esculentum L.

The effects of white light and UV light on chromosome endoreduplication, chromatin conformation and RNA synthesis were analysed in the hypocotyl cortical cylinder of the cv UC-105 of tomato and its isogenic mutant aurea, deficient in photoactive phytochrome A at the etiolated stage. Short white light or UV irradiations were administered to 4-day-old seedlings grown in the dark. White light had no effect on the mean ploidy level in the cv UC-105, but it increased the ploidy level in the aurea mutant. This is explained by hypothesizing that phytochrome inhibits endoreduplication, while cryptochrome stimulates it. UV light produced a higher ploidy in both genotypes, possibly because of residual action of cryptochrome at this wavelength or of specific UV-responsive photoreceptor. White light or UV light transiently increased heterochromatin amounts in the diploid nuclei of cv UC-105, and produced higher levels of RNA transcription than continuous dark. It is suggested that these responses were mediated by phytochrome, because they were lacking in the aurea mutant.

Cell Nucleus↗

PubMed2001

Simulation of a stroke unit careflow.

This paper describes the development and use of a simulation model representing part of the medical practice within a Stroke Unit. In particular, we modelled the medical activities as described in a guideline for the ischemic stroke treatment, adopted by the Stroke Unit of our hospital. The Petri net formalism has been chosen for the model representation. The numerical parameters have been estimated both using a database of about 100 patients collected during the last two years, and eliciting knowledge from the neurologists. A commercial tool was used for performing simulations, while ad-hoc routines were written for tailoring the result presentation to the specific context. We consider simulation a very useful preliminary step for the subsequent implementation of a patient workflow (careflow) management system. In fact, simulation is based on the process model (the clinical practice guideline) and on the organisation model (human and technological resources), so allowing to detect bottlenecks in the care delivery organisation and to find the optimal resource allocation. For example, we show that simulation has been able to find some of the causes of the delay in the patients treatment, and accordingly, to suggest changes in the organisation.

Brain Ischemia↗

PubMed2000

Use of macroporous polypropylene filter to allow identification of bacteria by PCR in human fecal samples.

The detection of pathogenic bacteria directly in human fecal specimens by PCR, requires removal of PCR-inhibitory substances. To investigate whether five different macroporous filters (polypropylene, nylon, polyester, polyethylene, fluorocarbon) could retain polysaccharides, major PCR inhibitors, an in vitro model and human fecal samples were used. The in vitro model consisted of Xanthum gum solutions (3 mg/ml PBS), a bacterial polysaccharide, to which Helicobacter pylori cells were added. Fecal samples from healthy volunteers were spiked with H. pylori and Mycobacterium paratuberculosis cells. Polysaccharide concentrations were significantly reduced only by the polypropylene but not by the other filters. Accordingly, both Xanthum gum solutions and spiked fecal specimens became PCR positive only after filtration with the polypropylene filter. We conclude that this filter can be used to prepare a bacterial DNA template suitable for PCR analysis from human feces.

Bacteria↗

PubMed2000

Guideline-based careflow systems.

This paper describes a methodology for achieving an efficient implementation of clinical practice guidelines. Three main steps are illustrated: knowledge representation, model simulation and implementation within a health care organisation. The resulting system can be classified as a 'guideline-based careflow management system'. It is based on computational formalisms representing both medical and health care organisational knowledge. This aggregation allows the implementation of a guideline, not only as a simple reminder, but also as an 'organiser' that facilitates health care processes. As a matter of fact, the system not only suggests the tasks to be performed, but also the resource allocation. The methodology initially comprehends a graphical editor, that allows an unambiguous representation of the guideline. Then the guideline is translated into a high-level Petri net. The resources, both human and technological necessary for performing guideline-based activities, are also represented by means of an organisational model. This allows the running of the Petri net for simulating the implementation of the guideline in the clinical setting. The purpose of the simulation is to validate the careflow model and to suggest the optimal resource allocation before the careflow system is installed. The final step is the careflow implementation. In this phase, we show that the 'workflow management' technology, widely used in business process automation, may be transferred to the health care setting. This requires augmenting the typical workflow management systems with the flexibility and the uncertainty management, typical of the health care processes. For illustrating the proposed methodology, we consider a guideline for the management of patients with acute ischemic stroke.

Artificial Intelligence↗

PubMed2000

K-ras and p53 mutations in DNA extracted from colonic epithelial cells exfoliated in faeces of patients with colorectal cancer.

BACKGROUND: Exfoliated colonic epithelial cells in faeces provide a source of human DNA which may be analysed for the presence of tumour-induced modification. AIM: In the present study we investigated K-ras and p53 mutations in faeces of patients with colorectal carcinoma, to verify whether analysis of these mutations might identify a high percentage of patients with colorectal cancer. PATIENTS AND METHODS: Faeces, tumour and normal mucosa samples were taken from 26 patients. Polymerase chain reaction amplification and restriction enzyme analysis were performed to detect K-ras mutations; p53 gene mutations were identified by using polymerase chain reaction amplification and single strand conformation polymorphism. RESULTS: We were able to amplify the K-ras gene and exons 5-9 of the p53 gene in 100% of the faecal samples studied. K-ras and p53 gene mutations were detected in faeces in 26.9% and 50% of the cases, respectively. The two mutations were present together in 5 out of 26 patients. There was full agreement between the K-ras and p53 pattern observed in faecal DNA and that in tumour tissue DNA. CONCLUSIONS: Application of K-ras and p53 mutation gene analysis in the faeces may have clinical applications in the future. Since this genetic analysis is able to detect only 57.7% of patients with colorectal cancer, the study of other genes involved in colorectal carcinogenesis is necessary.

Adenocarcinoma↗

PubMed2000

Hepatitis C virus (HCV) infection and liver-related mortality: a population-based cohort study in southern Italy. The Association for the Study of Liver Disease in Puglia.

BACKGROUND: Hepatitis C virus (HCV) is a common cause of chronic liver diseases but the degree to which these diseases contribute to liver-related mortality is not well established. The aim of this study was to estimate the absolute and relative effects of HCV infection on liver-related mortality. METHODS: A population random sample of 2472 subjects aged > or = 30 years was enrolled and followed up from 1985 to 1996. At enrollment, a structured interview and a clinical evaluation were performed. Serum samples were tested using HCV ELISA and RIBA HCV. Outcomes were overall and liver-related mortality and tracing procedures included review of office and hospital records, death certificates, and interviews with general practitioners, attending hospital and next of kin. Statistical analysis was performed using Poisson and binomial prospective data regression. RESULTS: Crude overall and liver-related mortality rates were 7.66 (95% CI : 6.68-8.79) and 0.9 (95% CI : 0.3-2.2) per 10(3) person-years, respectively. For HCV infection effect, incidence rate ratio and difference (per 10(3) person-year), risk ratio and difference were 27.5 (95% CI : 6.5-115.6), 4 (95% CI : 3-7), 33.1 (95% CI : 7.8- 139.3) and 0.06 (95% CI : 0.04-0.08), respectively; all measures were adjusted for age at death, sex and daily alcohol intake. CONCLUSIONS: The results show a strong relative but weak absolute effect of HCV infection on liver-related mortality in the 10-year period considered. Poisson and binomial models are virtually equivalent, but the choice of the summarizing measure of effect may have a different impact on health policy.

Adult↗

PubMed2000

Characterization and expression of DNA sequences encoding putative type-II metallothioneins in the seagrass Posidonia oceanica.

Posidonia oceanica is a marine phanerogam, largely widespread in the Mediterranean sea, representing an important food substrate for many marine organisms. A progressive reduction of P. oceanica meadows has been reported, due to anthropogenic coastal activity. Studying mechanisms by which this species responds to environmental stresses, three DNA sequences putatively encoding metallothioneins (MTs) have been isolated, by PCR. Two sequences, Pomt2a (accession no. AJ249603) and Pomt2b (accession no. AJ249602), show high similarities with genes encoding type-II MTs and are interrupted by two and one intron, respectively. The third sequence, Pomt2c (accession no. AJ249604), is supposed to be a pseudogene, originated by retrotranscription of the Pomt2b mRNA. These sequences belong to a multigene family with at least five members. Northern hybridizations indicated that MT transcripts accumulation is constitutive and seasonally regulated. MT encoding RNAs increase after rhyzome harvesting and (at a lesser extent) after 15 d of cultivation in an aquarium. As for animal MTs, transcripts accumulation is observed also after exposure to trace metals such as copper and cadmium. In the case of copper, the effect depends on concentration. Finally, taking into consideration the great interest in studying the biogeochemical cycle of mercury in the Mediterranean basin and since P. oceanica is commonly considered a bioindicator of this metal, the effect of mercury treatments on the accumulation of MT transcripts has been analyzed: in only a few experiments a small increase in the level of transcripts was recorded, suggesting that MTs are not key elements in the mercury accumulation by this species.

Amino Acid Sequence↗

PubMed1999

Expression of a dehydrin gene during embryo development and drought stress in ABA-deficient mutants of sunflower (Helianthus annuus L.).

The synthesis of a particular class of proteins, the dehydrins, is a common response to drought in plants. Dehydrins are known to be synthesized by the cell in response to abscisic acid, which represents a link between environment and nuclear activity, though dehydrin genes may be expressed even constitutively. We have investigated the relationship between abscisic acid (ABA) and accumulation of a dehydrin mRNA in sunflower, in which a dehydrin cDNA (HaDhnla) was isolated. In particular, we studied changes in the steady-state level of dehydrin transcripts in two mutants for ABA synthesis and accumulation: nd-1 (an albino, non-dormant and lethal mutant with a very low ABA content and no ABA accumulation in response to stress) and w-1 (a wilty mutant, with reduced ABA accumulation) during embryo and plantlet development and drought stress. Differences between genotypes were observed through embryogenesis: w-1 shows a lower content of dehydrin transcripts in the early stages compared to control plants, indicating that ABA affects dehydrin mRNA accumulation; however, dehydrin transcripts level appears independent of ABA content in late embryogenesis. Also during drought stress in w-1 adult leaves, ABA is not quantitatively related to the steady-state level of the HaDhn1a transcripts. Finally, data on nd-1 mutant show a high level of dehydrin transcripts after drought stress in plantlet cotyledons and leaflets. These results indicate the existence of two regulation pathways of HaDhn1a transcripts accumulation, an ABA-dependent and an ABA-independent one, which may have cumulative effects.

Abscisic Acid↗

PubMed1999

Alpha-dihydroergocryptine in the prophylaxis of migraine: a multicenter double-blind study versus flunarizine.

This multicenter, double-blind, clinical study was designed to compare the efficacy and safety of alpha-dihydroergocryptine and flunarizine in the prophylaxis of migraine without aura. One hundred thirty-five patients fulfilling the diagnostic criteria of the International Headache Society were enrolled at five neurologic centers. The study design included a 1-month pretreatment phase with placebo; a 6-month, double-blind, double-dummy treatment phase with alpha-dihydroergocryptine (10 mg twice daily) or flunarizine (5 mg once daily); a further 3-month follow-up phase without treatment. Efficacy was assessed using the patient's diary. Laboratory tests, vital signs, and adverse events were monitored. Analysis of covariance for repeated measures was performed on the intent-to-treat sample. Both treatments led to a significant reduction in the frequency of migraine, days with headache, and use of relief medication. Overall, 51% of those treated with alpha-dihydroergocryptine and 49% of those treated with flunarizine were responders (50% or greater reduction in attack frequency), the average percentage of reduction being 64% with alpha-dihydroergocryptine and 51% with flunarizine. There was no significant difference between the two groups in terms of incidence of adverse events; dizziness and weight gain were the most frequent observed adverse events with alpha-dihydroergocryptine and flunarizine, respectively. Based on the overall improvement in migraine parameters, alpha-dihydroergocryptine can be recommended for use in migraine prophylaxis.

Adult↗

PubMed1999

Bromocriptine test in the evaluation of patients with syncope of unknown aetiology. A case-control study.

The aim of the present study was to evaluate, through a case-control study, the specificity of the upright tilt test with bromocriptine as a marker of neurally mediated syncope of unknown aetiology. We have compared upright tilt test with bromocriptine (2.5 mg p.o.) in patients with syncope of unknown aetiology and controls. A total of 23 patients and controls matched by age and sex had upright tilt test with bromocriptine. The upright tilt test procedure consisted of 10 min in supine position, 10 min of 60 degree head-up tilt and a further 10 min with the subject supine; this procedure was performed in baseline condition and 60, 120, 180 and 240 min after the administration of bromocriptine. The protocol end points were the development of syncope or presyncope in association with hypotension with or without bradycardia. A positive response to bromocriptine test was found in 78% (95% CI, 61% to 95%) of patients and in 13% (95% CI, 0% to 26%) of controls (P<0.001). No significant differences were detectable among patients and controls showing a positive response to the test. Bromocriptine test seems to be a useful alternative tool for the diagnosis of neuromediated syncope also suggesting that dopaminergic supersensitivity may, at various and to varying degrees, play a role in the pathogenesis of syncopal episodes.

Adolescent↗

PubMed1999

Molecular epidemiology of hepatitis C virus infection in an area of hyperendemicity in southern Italy: a population-based study.

In a cohort of subjects from Italy, anti-hepatitis C virus (HCV) and HCV RNA [HCV(+) subgroup] prevalences were 24.6 and 79.6%, respectively. HCV types 1b and 2a/c accounted for 95% of infections. Adjusted alanine aminotransferase levels were higher in males than in females and in RNA-positive subjects than in RNA-negative subjects regardless of HCV type. Genotype distribution was unrelated to demographic variables.

Alanine Transaminase↗

PubMed1998

Effect of generalised sympathetic activation by cold pressor test on cerebral haemodynamics in healthy humans.

There is no general agreement regarding several aspects of the role of the sympathetic system on cerebral haemodynamics such as extent of effectiveness, operational range and site of action. This study was planned to identify the effect of a generalised sympathetic activation on the cerebral haemodynamics in healthy humans before it is masked by secondary corrections, metabolic or myogenic in nature. A total of 35 healthy volunteers aged 20-35 underwent a 5 min lasting cold pressor test (CPT) performed on their left hand. The cerebral blood flow (CBF) velocity in the middle cerebral arteries and arterial blood pressure were recorded with transcranial Doppler sonography and with a non-invasive finger-cuff method, respectively. The ratio of arterial blood pressure to mean blood velocity (ABP/Vm) and Pulsatility Index (PI) were calculated throughout each trial. CPT induced an increase in mean ABP (range 2-54 mmHg depending on the subject) and only a slight, though significant, increase in blood velocity in the middle cerebral artery (+2.4 and +4.4% on ipsi- and contralateral side, respectively). During CPT, the ratio ABP/Vm increased and PI decreased in all subjects on both sides. These changes began simultaneously with the increase in blood pressure. The increase in ABP/Vm ratio is attributed to an increase in the cerebrovascular resistance, while the concomitant reduction in PI is interpreted as due to the reduction in the compliance of the middle cerebral artery. The results suggest that generalised increases in the sympathetic discharge, causing increases in ABP, can prevent concomitant increases in CBF by acting on both small resistance and large compliant vessels. This effect is also present when a slight increase in blood pressure occurs, which suggests a moderate increase in the sympathetic discharge, i.e. when ABP remains far below the upper limit of CBF autoregulation.

Adult↗

PubMed1998

Preeclampsia, preterm delivery and infant cerebral palsy.

OBJECTIVE: To evaluate the association between preeclampsia and cerebral palsy among preterm infants. STUDY DESIGN: A cohort study of 345 singleton preterm (24 to 33 weeks gestation) infants delivered at an institution where no mothers received magnesium sulphate. We investigated the relationship of preeclampsia to the development of infant cerebral palsy (spastic quadriplegia, hemiplegia or diplegia) at two years' corrected age. Potential confounders were controlled for by politomous logistic regression analysis. RESULTS: The prevalence of cerebral palsy in surviving infants from normotensive and preeclamptic pregnancies was 13.4% (38/284) and 3.3% (2/61), respectively (P=0.026 by Fisher exact test). After control for potential confounders (gestational age, infant gender, birthweight standard deviation score, mode of delivery), the likelihood of infant cerebral palsy was reduced by preeclampsia (odds ratio 0.16, 95% confidence interval=0.04-0.74 for infants from preeclamptic versus normotensive pregnancies being palsied). CONCLUSION: Among preterm infants, the protective effect of preeclampsia against cerebral palsy is manifest in the absence of magnesium sulphate utilization.

Adult↗

PubMed1998

Cerebral visual impairment in periventricular leukomalacia.

Infants with cerebral palsy (CP) frequently present cerebral visual impairment (CVI) often caused by damage to retrochiasmatic pathways. This is particularly true of subjects with damage to the periventricular white matter. Thirty-eight preterm infants with periventricular leukomalacia (PVL) diagnosed by MRI were examined to correlate binocular visual acuity with neuroradiological findings. Binocular visual acuity was evaluated using Teller Acuity Cards and a complete ophthalmological examination was also performed. Three infants with ROP III were excluded from the sample. The age of observation ranged from 20 months to 5 and a half years (mean 42 months). The possible involvement of the optic radiations and/or of the calcarine cortex was detected by brain MRI. Twenty-three infants (66%) presented visual impairment. Of these, 9 (26%) were totally or nearly totally blind and 14 (40%) were low vision children. The other 12 (34%) had normal (2) or near normal (9) vision. MRI findings correlated with visual acuity; a relationship was detected between the degree of visual acuity and the reduction of the peritrigonal white matter, and also between the degree of visual acuity and the extent of calcarine atrophy. This report clearly establishes a relationship between visual impairment and specific MRI findings in children with PVL. Teller Acuity Cards and MRI are useful for detecting potential visual impairment and for improving both the clinical diagnosis of these disorders and the therapeutic approach to these subjects.

Atrophy↗

PubMed1998

Transient nystagmus in delayed visual maturation.

Two infants who presented with wide-amplitude and high-frequency nystagmus and lack of visual awareness in the first 3 months of life were studied. No ocular abnormalities were found. Neurodevelopmental examination, visual evoked potentials and electroretinograms were normal. One infant underwent MRI which resulted in normal findings. Two months later both patients showed increased visual responsiveness and a gradual reduction of the nystagmus amplitude. By 5 months of age nystagmus was no longer detectable and both infants appeared to be visually, developmentally, and neurologically normal. Follow-up at 3 years of age for subject 1 and at 11 months for subject 2 showed that both the infants maintained the normal ophthalmological and neurological assessments. We diagnosed delayed visual maturation with oculomotor involvement.

Brain↗