PubMed Health⌕ Search

Biomedical subjects

A Sabatini

Publications and source records attributed to A Sabatini.

At least 19 recordsLinked to original sources
PubMed2002

Expression of the neurokinin 1 receptor in the rabbit retina.

Substance P is the preferred ligand for the neurokinin 1 (NK1) receptor. In vertebrate retinas, substance P is expressed by amacrine, interplexiform and ganglion cells. Substance P influences the activity of amacrine and ganglion cells and it is reported to evoke dopamine release. We investigated NK1 receptor expression in the rabbit retina using affinity-purified NK1 receptor antibodies. NK1 receptors were expressed by two distinct populations of retinal neurons. One is a population of ON-type bipolar cells characterized by axonal arborizations that ramified in the inner plexiform layer near the ganglion cell layer. Double-label studies showed that NK1 receptor-expressing bipolar cells were distinct from rod bipolar cells and from other immunocytochemically identified types of cone bipolar cells. Their density was about 2250 cells/mm2 in the visual streak and 1115 cells/mm2 in ventral mid-periphery. They were distributed in a non-random pattern. In the outer plexiform layer, the dendrites of these bipolar cells converged into heavily immunostained clusters having a punctate appearance. The density of these clusters in mid-peripheral ventral regions (about 13000 clusters/mm2) was similar to the reported cone density [Famiglietti and Sharpe (1995) Vis. Neurosci. 12, 1151-1175], suggesting these dendrites contact all cone photoreceptors. The second NK1 receptor expressing cell population corresponds to the tyrosine hydroxylase-containing amacrine cell population. NK1 receptor immunostaining was localized to the cell body and processes, but not to the processes that form the 'rings' that are known to encircle somata of AII amacrine cells. These findings show that NK1 receptor immunoreactivity is localized to a population of ON-type cone bipolar cells and to dopaminergic amacrine cells, suggesting that substance P acting on NK1 receptors influences multiple retinal circuits in the rabbit retina.

Amacrine Cells↗
PubMed2000

In vivo (31)P-MRS assessment of cytosolic [Mg(2+)] in the human skeletal muscle in different metabolic conditions.

Cytosolic free [Mg(2+)] can be assessed in vivo by (31)P-MRS from the chemical shift of beta-ATP. The reliability of in vivo measurements depends on the availability of appropriate in vitro calibration curves obtained by using solutions that mimic the in vivo cytosolic conditions as far as possible. We build a semi-empiric equation that correlates the chemical shift of beta-ATP to free [Mg(2+)] taking into account the amount of Mg(2+) bound to all other ligands in solution. Our experiments resulted in a reliable ten-parameters equation directly usable to assess the cytosolic free [Mg(2+)] of human skeletal muscle at rest, during work and recovery. Our experiments also resulted in a new equation that allows the assessment of cytosolic pH from the chemical shift of Pi taking into account the measured free [Mg(2+)]. To perform simultaneous calculation of free [Mg(2+)] and pH in the skeletal muscle in different metabolic conditions we developed a specific software package available on Internet (http://www.unibo.it/bioclin) together with another program based on the equation previously obtained to calculate cytosolic free [Mg(2+)] in the human brain. The reliability and effectiveness of our equations and software were tested on the calf muscles of healthy volunteers at rest, during work and recovery.

Adult↗
PubMed1999

Cortical silent period in patients with amyotrophic lateral sclerosis.

Transcranial magnetic stimulation (TMS) during a muscle contraction induces a motor-evoked potential (MEP) in the skeletal muscle followed by a cessation of EMG activity, the cortical silent period (C-SP). The C-SP is a useful parameter to indicate the activation of the motor system. Accurate determination of the C-SP can be important in amyotrophic lateral sclerosis (ALS), a progressive disorder of unknown etiology characterised by degeneration of upper and lower motor neurons. The aim of this study was to evaluate the sensitivity of C-SP as an index of motor system involvement, in ten patients affected by ALS, with a mean duration of the disease: 5. 5+/-3.4 months, by means of an objective computer-aided method to measure C-SP and its relationship to stimulation intensity. C-SP duration was significantly reduced in ALS patients compared to controls at low stimulation intensity corresponding to an MEP threshold increased by 15%. While in less severely affected patients C-SP duration approached control values at higher stimulation intensities (25 and 50% upper MEP threshold), in more severe ALS subjects it showed a further reduction, allowing them to be discriminated.

Aged↗
PubMed1996

In vivo assessment of free magnesium concentration in human brain by 31P MRS. A new calibration curve based on a mathematical algorithm.

Free cytosolic [Mg2+] can be assessed in vivo by 31P MRS from the chemical shift of beta-ATP which in turn depends on the fraction of total ATP complexed to Mg2+ ions. The reliability of these in vivo measurements depends on the availability of an appropriate in vitro calibration to determine the limits of chemical shifts of unbound ATP and Mg-ATP complexes, using solutions that mimic the in vivo cytosolic conditions as far as possible. We used an algorithm and software to allow a quantitative definition of the Mg(2+)-binding molecules to build a semi-empirical equation that correlates the chemical shift of the beta-ATP signal to the [Mg2+] taking into account the amount of Mg2+ bound to all other constituents in solution. Our experiments resulted in a simple and reliable equation directly usable to assess in vivo the free cytosolic magnesium concentration of human brain by 31P MRS. Our method is also flexible enough to make it suitable for in vivo measurements of [Mg2+] in other organs and tissues.

Adenosine Triphosphate↗
PubMed1995

Nuclear magnetic resonance as a tool for determining protonation constants of natural polyprotic bases in solution.

The acid-base properties of the tetramine 1,5,10,14-tetraazatetradecane H2N(CH2)3NH(CH2)4NH(CH2)3NH2 (spermine) in deuterated water have been studied at 40 degrees C at various pD values by means of NMR spectroscopy. Both one-dimensional 13C[1H] spectra and two-dimensional 1H/13C heterocorrelation spectra with inverse detection have been recorded. A calculation procedure of general validity has been developed to unravel the effect of rapid exchange between the various species in equilibrium as a function of pD of the solution. The method of calculation used in this part of the new computer program, HYPNMR, is independent of the equilibrium model. HYPNMR has been used to obtain the basicity constants of spermine with respect to the D+ cation at 40 degrees C. Calculations have been performed using either 13C[1H] or 1H/13C data individually, or using both sets of data simultaneously. The results of the latter calculations were practically the same as the results obtained with the single data sets; the calculated errors on the refined parameters were a little smaller. After appropriate empirical corrections for temperature effects and for the presence of D+ in contrast to H+, the calculated constants are compared with spermine protonation constants which have been determined previously both from potentiometric and NMR data.

Carbon Isotopes↗
PubMed1995

Forcipomyia (Pterobosca) paludis (Macfie, 1936) (Diptera, Ceratopogonidae) on adult dragonflies (Odonata) in Sardinia, Italy.

Ceratopogonid midges, referred to Forcipomyia paludis, were recorded from five dragonfly species in Sardinia, Italy. All ceratopogonids were females and almost all were in the last phase of the gonotrophic cycle (gravid females). Although a parasitic association cannot be excluded, no evidence was obtained of the midge biting activity, neither by direct observation nor indirectly, by detecting the expected lesions on the host cuticle. The attachment to dragonflies of F. paludis (perhaps an autogenous species) might fit well with the hypothesis of a phoretic association which would favour the long range dispersal of the gravid females.

Animals↗
PubMed1992

[Parasitic helminths of the cecum and colon of equidae in Italy].

Intestinal helminths from coecum and colon were studied in 93 equidae including 40 horses, 36 donkeys and 17 mules. A total of 38 species, 36 nematodes and 2 cestodes, were identified as follows: 1) Triodontophorus serratus, 2) Triodontophorus brevicauda, 3) Strongylus equinus, 4) Strongylus edentatus, 5) Strongylus vulgaris, 6) Cyathostomum tetracanthum, 7) Cyathostomum coronatum, 8) Cyathostomum labiatum, 9) Cyathostomum labratum, 10) Cyathostomum alveatum, 11) Cyathostomum pateratum, 12) Cyathostomum catinatum, 13) Cyathostomum sagittatum, 14) Cylicodontophorus bicoronatus, 15) Cylicocyclus radiatus, 16) Cylicocyclus auriculatus, 17) Cylicocyclus elongatus, 18) Cylicocyclus nassatus, 19) Cylicocyclus insigne, 20) Cylicocyclus leptostomus, 21) Cylicostephanus calicatus, 22) Cylicostephanus poculatus, 23) Cylicostephanus minutus, 24) Cylicostephanus longibursatus, 25) Cylicostephanus hybridus, 26) Cylicostephanus goldi, 27) Cylicostephanus ornatus, 28) Cylicostephanus skrjabini, 29) Poteriostomum ratzii, 30) Gyalocephalus capitatus, 31) Parascaris equorum*, 32) Probstmayria vivipara, 33) Draschia megastoma*, 34) Habronema muscae*, 35) Habronema majus*, 36) Setaria equina*, 37) Anoplocephala perfoliata, 38) Paranoplocephala mamillana. The asterisked species are those not usually localized in the examined material. The most frequent parasites were found in all three hosts. Species 1, 4, 6, 9, 10, 12, 21, 22, 30 and 35 showed significant differences in prevalence between horses and donkeys, the mule generally having intermediate values. Multiple infections and total worm burden appear to decrease in older animals (> 15 years). Parasite associations occur mostly at random as expected from the values of the respective total prevalences. Some significant excesses on expected values were recorded but not significant deficits. The total worm burden increases with the number of parasite species and the increase appears to follow an exponential pattern.

Animals↗
PubMed1991

[Further data on the spread to Genoa of Aedes albopictus].

Further data are presented on the presence of Aedes albopictus in the town of Genoa (Italy) where this oriental mosquito was first reported in September 1990. Scattered foci of Ae albopictus were documented during the 1991 summer months in spite of a rather long and rigid '90-'91 winter season with temperatures frequently below 0 degree C. The newly imported mosquito shows the capacity to become a permanent pest in Italy where it could also increase the probability of transmission of pathogens such as arboviruses and filariae.

Aedes↗
PubMed1990

[Aedes albopictus in Italy and possible diffusion of the species into the Mediterranean area].

Aedes albopictus (Skuse), the important Asian vector mosquito recently introduced in United States and Brazil, is reported from Genoa, North Italy. The infestation was discovered in a kindergarten pre-school center in September 1990 just after the summer holidays. Many discarded tires, well known to provide excellent breeding places for Ae albopictus, had been left in the school playground to be used as toys by the children. After sampling a few biting mosquito specimens for identification, the local health service carried out on September 18 an extensive indoor/outdoor treatment with pyrethroid insecticide. The extent of the infestation in the city of Genoa and in other areas of the Ligurian region has not been evaluated since the identification of the species was available in October, at the end of Ae albopictus reproductive period. A general survey in various Italian regions is being planned for the 1991 spring-summer period. The present record, together with the previous report of Ae albopictus in Albania, clearly supports the hypothesis of a spreading of the species in the Mediterranean area.

Aedes↗
PubMed1989

Field studies on inversion polymorphism in Anopheles superpictus from southern Italy.

Polytene chromosome studies were carried out on various population samples of Anopheles superpictus from different localities in Southern Italy. More than 7,000 female specimens, mostly obtained from daytime collections of indoor resting mosquitoes, were successfully scored for nurse cell polytene chromosomes. Night biting samples were also examined in some localities. Only one chromosomal polymorphism, due to a paracentric inversion involving the central third of the 2L arm, was recorded in all samples. In all localities, the inverted 2La arrangement showed remarkably stable frequency although the populations examined were isolated from each other and at least some of them have presumably been subject to bottle neck in recent years because of insecticide treatments or ecological changes affecting the availability of breeding places. Departures from the Hardy-Weinberg expectations, indicating an excess of heterokaryotypes, were noted and critically analysed by comparing samples obtained simultaneously in the same locality from different cow sheds, from different sections of the same cow shed and from night and day catches in the same cow shed. The phenomenon was not found uniformly distributed among indoor resting samples: significant departures from the Hardy-Weinberg expectations were observed in some cow sheds but not in others situated nearby or even adjacent to them. These results did not support the hypothesis that the excess of heterokaryotypes is due to their greater longevity or to differential mortality in the preimaginal stages. It is suggested that different karyotypes may react differently to microclimatic specific conditions, since the Hardy-Weinberg disequilibrium was mostly observed in samples from resting sites that were more lit and subject to wider climatic variation.

Animals↗
PubMed1988

Housing the homeless mentally ill: a longitudinal study of a treatment approach.

In a one-year study of 49 homeless chronic mentally ill patients, the subjects, selected at admission for inpatient treatment, were randomly assigned to one of two groups. One group was placed in an experimental residential treatment program following discharge, and the other group received standard postdischarge care. Subjects were interviewed every four months during the year as well as at index hospitalization and discharge. Although the study remains exploratory due to the small sample size and case attrition, the authors found that compared with the control group, the subjects in the residential treatment program spent significantly more nights in adequate shelter, spent fewer nights in hospitals or undomiciled, and were more satisfied with and committed to their living arrangements.

Chronic Disease↗
PubMed1985

Polytene chromosomes of Orthopodomyia pulcripalpis (Diptera, Culicidae).

Orthopodomyia pulcripalpis is the only European representative of the tribe Orthopodomyiini (Diptera: Culicidae). Its chromosomal complement consists of three pairs of metaphase chromosomes, as it is typical of culicine mosquitoes. O. pulcripalpis shows, differently from other culicine species, polytene chromosomes of excellent cytological quality, easily obtainable from the larval salivary glands. A photomap of the polytene chromosomes of the species is described in the present paper together with some details on chromosomal polymorphism.

Animals↗
PubMed1983

Down and out in the city: the homeless mentally ill.

The plight of the homeless in New York City and other urban areas has become the focus of increasing attention. In an effort to clarify and understand the problems of the homeless, the authors studied the demographic characteristics, psychiatric diagnoses, histories, and dispositions of 100 homeless patients treated at Bellevue Psychiatric Hospital's emergency service. The most striking finding was that 96.6 percent of the sample had had a previous psychiatric hospitalization. Seventy-two percent of these homeless patients were diagnosed as suffering from schizophrenia; the second most common diagnosis was personality disorder, which accounted for 13.3 percent of the sample. The authors discuss other demographic findings of their study and explore the roots of the problem of homelessness, review the psychiatric literature on the subject, and delineate some of the unique treatment needs of this population.

Adult↗
PubMed1983

[Styloconops hamariensis n. sp. in Somalia (Diptera, Ceratopogonidae)].

A new species of the genus Styloconops (S. hamariensis n. sp.) is described on material collected in Somalia in the coastal area near Mogadiscio. This ceratopogonid midge is common during the rainy seasons and it has been observed biting on man and cattle. The new species is morphologically similar to S. spinosifrons from which it can be clearly differentiated for at least some diagnostic characters both in the female and male adults.

Animals↗
PubMed1979

Chromosomal differentiation and adaptation to human environments in the Anopheles gambiae complex.

Speciation in the Anopheles gambiae complex is reviewed and discussed with emphasis on the patterns of chromosomal differentiation, particularly at the intraspecific level. The significance of inversion polymorphism in gambiae and arabiensis (the two species of greatest medical importance) is evaluated with reference to recent field investigations carried out in Nigeria. In both sibling species some of the inversions show clinical geographical changes in frequencies, with evident correlations with climatic conditions and vegetation zones. Microgeographical variations in species distribution and in intraspecific inversion frequencies are also present, which appear mostly related to man-made environmental contrasts. Parallel indoor-/outdoor collections of samples from polymorphic populations of arabiensis and gambiae show that adult mosquitoes carrying certain inversion karyotypes do not distribute at random in relation to the human environment, being significantly more frequent in outdoor than in indoor samples, or vice-versa. Optimal habitat choice appears to be involved in such variations of indoor resting behaviour, since the chromosomal types carried by less endophilic individuals are those more adapted to humid climates, i.e. those which tend to avoid the higher nocturnal saturation deficit of the indoor environment. This phenomenon, producing non-uniform exposure of the vector population to residual insecticides sprayed in houses, might explain the mediocrity of the results of malaria control projects based on house-spraying against endophilic vectors in the African savannas.

Animals↗