PubMed Health⌕ Search

Biomedical subjects

A Poli

Publications and source records attributed to A Poli.

At least 145 records · Page 8Linked to original sources
PubMed1991

Ultrastructure of the cyst and life cycle of Sarcocystis sp. from wild sheep (Ovis musimon).

Sarcocystis sp. (Eimeriina: Sarcocystidae) is described as a heteroxenous coccidian with domestic dogs as an experimental definitive host and wild sheep (Ovis musimon) as natural intermediate hosts. Mature sarcocysts of this Sarcocystis sp. were examined by transmission electron microscopy. Sarcocysts in various muscle tissues were microscopic, had a thin primary cyst wall and septa and measured 81.0 x 30.5 microns. The cysts were located within muscle cells and were limited by a primary cyst wall (PCW). The cyst surface was highly folded forming densely packed projections. Between the PCW projections the surface of the cyst was marked with pit-like invaginations. The ground substance of the cyst formed a layer at the periphery of the cyst, filled the projections and formed septa which divided the cyst into compartments. Sarcocysts contained numerous bradyzoites that were 15.2 x 3 microns and few metrocytes 11.5 x 3.5 microns. Twelve days after ingesting Sarcocystis sp.-infected wild sheep meat, four dogs began passing sporocysts in their feces: two domestic cats did not pass oocysts or sporocysts after ingesting meat from the same animals. Sporocysts measured 14.8 x 9.9 microns.

Animals↗
PubMed1991

Unilateral hydrocephalus in a wild European brown hare (Lepus europaeus).

Macroscopic and histological study of a case of unilateral hydrocephalus in a young wild European brown hare (Lepus europaeus) is reported here. Morphological changes were mostly massive dilatation of the left lateral ventricle, atrophy of the cortex and a striking reduction of the corresponding white matter. Lymphocytic cell infiltrates and hemosiderin-laden macrophages in the choroid plexus and meninges also were observed. Although the exact cause of the lesions was not found all findings suggested a hydrocephalus of possible traumatic, infectious or congenital hypoplasia origin.

Animals↗
PubMed1991

Acute hepatosis in the European brown hare (Lepus europaeus) in Italy.

Since October 1986 an unusually high mortality has been observed both in wild European brown hares (Lepus europaeus) and in hare farms in Italy. Pathological alterations, including severe hepatosis, nephrosis, congestion and hemorrhages of tracheal mucosa and lungs, and splenic vascular congestion, were observed in 179 of 381 hares necropsied from 1986 to 1988. Jaundice also was seen in 30% of these hares. Histologically, the liver damage was characterized by coagulative necrosis, mainly located around the portal areas, or by degenerative changes. Hyperemia, focal hemorrhages and periportal mononuclear cell infiltration were also present. The epithelium of renal tubules showed the presence of various degrees of vacuolar degeneration and necrosis, and eosinophilic granular hyaline casts or homogenous proteinaceous material were found within the lumen of tubules. Only the adult hares were affected. In wild hare populations night counts revealed a reduction of the number of observed wild hares during the winter period which ranged from 27 to 40%, whereas in hare farms the mortality ranged from 30 to 90%. Bacteriological, parasitological, and toxicological investigations were unable to confirm the primary cause of these deaths. Negative stain electron microscopy and immunoelectronmicroscopy conducted since October 1988 on liver and spleen homogenates from hares with acute hepatosis revealed the presence of viral particles with morphological aspects resembling those of calicivirus, antigenically related to the etiological agent of viral haemorrhagic disease of rabbits.

Acute Disease↗
PubMed1991

[Cholesterolemia and ischemic cardiopathy: a causal relationship].

A consistent pool of data obtained in epidemiological and in intervention studies suggests that increased levels of plasma cholesterol are associated to an increased incidence of coronary events. Studies in which a reduction of cholesterol plasma levels was obtained with different approaches (using drugs, diets, surgical procedures) indicate that this reduction, whatever the technique adopted to obtain it, favorably affects the natural history of the atherosclerotic disease in human patients. This information, together with the biochemical evidences linking plasma lipids and lipoproteins with the process of atherogenesis, strongly supports the view that hypercholesterolemia is a causal factor in the development of coronary heart disease in man.

Cholesterol↗
PubMed1991

Pathology of naturally acquired Angiostrongylus vasorum infection in the red fox (Vulpes vulpes).

199 out of 509 foxes culled in a rabies control scheme, were shown to be infected with the metastrongylid parasite Angiostrongylus vasorum. Pathological lesions associated with angiostrongylosis in the fox are described and compared to reported lesions of A. vasorum infection in the dog. The lesions observed in the foxes seemed to be less severe and mainly confined to the ventral parts of the lung lobes which showed granulomatous pneumonia. Right ventricular hypertrophy of the heart was present in all infected foxes. It is believed that the fox population represents an important reservoir of A. vasorum.

Angiostrongylus↗
PubMed1990

Effect of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in goldfish brain.

The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which selectively damages dopaminergic neurons in mammals, caused a marked depletion of tyrosine hydroxylase (TH) immunoreactivity in the goldfish brain. The concomitant ultrastructural observations showed the neurotoxic effect of MPTP on telencephalic, diencephalic and medullar neurons. The affected neurons revealed darkening of the cytoplasm and swelling of the mitochondria and the endoplasmic reticulum. Concomitant significant decreases in dopamine (DA) and noradrenaline (NA) levels were determined in the brain areas where morphological observations were performed. The loss of catecholamine levels was completely prevented by the treatment with the monoamine oxidase (MAO) inhibitor pargyline to prevent MPTP oxidation. The results indicate that in goldfish brain, acute MPTP administration causes selective catecholamine depletion, without altering the serotoninergic system.

Animals↗
PubMed1990

[Comparison of two-dimensional echocardiography and hemodynamic monitoring in acute myocardial infarct].

The aim of this study was to assess if in patients with acute myocardial infarction, two-dimensional echocardiographic asynergy index is correlated to hemodynamic parameters. Furthermore, we compared how reliable the 2 methods are to identify patients at a high risk of developing early left ventricular failure. Fifty-four consecutive patients (43 males, 11 females, mean age: 61 +/- 13 years with acute myocardial infarction were studied using hemodynamic monitoring and 2D-echocardiography within 24 hours from admission. The 2D-echo asynergy index, calculated on a 14-segment left ventricular model, was significantly correlated to heart rate (r = 0.49, p less than 0.001), pulmonary capillary wedge pressure (r = 0.47, p less than 0.001), systemic vascular resistance (r = 0.47, p less than 0.001), cardiac index (r = -0.46, p less than 0.001) and left ventricular stroke work index (r = -0.63, p less than 0.001). Both the asynergy index and the hemodynamic parameters were correlated to Killip clinical classification. In the sub-group of 46 patients initially classified as belonging to Killip class I or II, the patients who later developed left ventricular failure or those in whom it worsened showed a higher asynergy index and a greater impairment of left ventricular function when compared to the patients with an uncomplicated clinical course. The sensitivity of an asynergy index greater than or equal to 1 in predicting early cardiac failure was 75%, the specificity was 64%, the positive predictive value was 43% and the negative predictive value was 88%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Behavioral and biochemical changes following repeated administration of carbaryl to aging rats.

Motor, sensory and thermoregulatory functions were examined in aging rats (12 months) following two schedules of repeated po administration of the carbamate insecticide carbaryl and these effects were assessed in terms of blood cholinesterase activity. Administration of carbaryl (50 mg/kg) by gavage daily for 30 days resulted in a reduction of locomotor activity in the open-field and in an inhibition of cholinesterase activity within 30 min after the last treatment. Twenty-four h later, only the locomotor effect was evident. After 90 days of exposure to carbaryl in drinking water, no significant effects were observed. These findings suggest that repeated administration of carbaryl to aging rats can induce an impairment of motor function and a reduction of cholinesterase activity, while tolerance develops in some other parameters.

Acetylcholinesterase↗
PubMed1989

Comparison of a vasodilating beta-blocker and a cardioselective beta-blocker in long-term treatment of hypertension: a European multicentre study.

The therapeutic effectiveness and safety of indenolol, a vasodilating beta-blocker with beta 2-agonism, was compared with that of atenolol, a cardioselective beta-blocker, in a 1-year double-blind trial. A total of 143 hypertensive patients (diastolic blood pressure 95-115 mmHg after 1 month of placebo) were randomly allocated to either atenolol, 50 mg/day, or indenolol, 60 mg/day. If the target diastolic blood pressure (less than or equal to 90 mmHg) was not reached after 1 month, the beta-blocker was doubled. If the target was still not reached, a diuretic was added after 2 months and doubled after 4 months. There was a higher overall responsiveness and monotherapy was more effective in the atenolol group, but at the lower dose indenolol was more effective than atenolol; however, no differences between drugs were significant. Although the drop-out rate was higher with indenolol, withdrawals due to side effects were similar in both groups. Indenolol was as effective and safe as atenolol in long-term antihypertensive therapy.

Adrenergic beta-Antagonists↗
PubMed1989

Multiple colonization of the upper respiratory tract of Papua New Guinea children with Haemophilus influenzae and Streptococcus pneumoniae.

Nasal secretions from Papua New Guinea children were cultured using selective agents, to determine the prevalence of multiple colonization for both S. pneumoniae and H. influenzae. 29.5% of 156 and 53% of 93 carriage positive subjects harbored more than one type of S. pneumoniae and H. influenzae respectively. Of 95 strains of pneumococci isolated from multiply colonized children, 40% were relatively resistant to benzylpenicillin. In more than one half of the children in this group both penicillin sensitive and resistant serotypes coexisted. Significantly more penicillin resistant pneumococci were isolated from children with ready access to primary and regional health care services. Among H. influenzae the prevalence of multiple isolations due to nonencapsulated variants only, and encapsulated plus nonencapsulated organisms was similar. The commonest biotypes were types I, II, III and V, and each was similarly associated with multiple carriage.

Child↗
PubMed1988

Neurotoxic effect of 1-methyl-4-phenylpyridinium ion on dopaminergic neurons of the retina of goldfish.

Dopaminergic neurons of the goldfish retina were selectively destroyed after a single intravitreal injection of 1-methyl-4-phenylpyridinium ion (MPP+). The ultrastructural analysis of the retina 3 days after toxin administration shows darkening of some retinal neurons present in the inner nuclear layer including their cytoplasmic processes. Both uptake and release of dopamine were reduced in the toxin-injected retina, whereas choline acetyltransferase (ChAT) and glutamic acid decarboxylase (GAD) activities, as well as the uptake of D-[3H]aspartate were not affected.

1-Methyl-4-phenylpyridinium↗
PubMed1988

Ultrasonographic measurement of the common carotid artery wall thickness in hypercholesterolemic patients. A new model for the quantitation and follow-up of preclinical atherosclerosis in living human subjects.

Ultrasound high resolution B-mode imaging of human arteries allows in vivo an accurate and non-invasive determination of the thickness of the intimal-medial complex. A computer assisted procedure to measure this parameter at the level of common carotid arteries was developed. The average difference between duplicate thickness determinations was 4.6%. The thickness of the intimal medial complex of common carotid arteries was then measured in a group of hypercholesterolemic patients. This parameter was significantly greater in these patients as compared to controls (P less than 0.001). The prevalence of small plaques in the carotid arterial tree was also significantly increased in patients. Analysis of data showed that in controls, but not in patients, the thickness of the intimal medial complex increases with age (r = 0.46, P less than 0.05). Within the hypercholesterolemic group, intimal-medial complex values were greater in male patients and in smokers. It is concluded that the common carotid arteries of hypercholesterolemic patients show thickening of the intimal-medial complex. Cigarette smoking, male sex and age increase the extent of this modification. The determination of this parameter using a non-invasive technique may represent an important tool to monitor in vivo the progression and/or the regression of early atherosclerosis in man.

Adult↗
PubMed1988

Prevalence, ultrastructure of the cyst wall and infectivity for the dog and cat of Sarcocystis sp. from fallow deer (Cervus dama).

The prevalence of Sarcocystis sp. (Protozoa: Sarcocystidae) in fallow deer (Cervus dama) in Tuscany, Italy was determined by digestion technique and histological examination. Forty-four of 45 fallow deer were infected. Infections occurred in adult deer and in fawns. Samples from the heart were more intensively parasitized than samples from tongue, oesophagus and diaphragm muscle. With transmission electron microscopy, the primary cyst wall was folded and formed narrow, overlapping, sinuous projections which were often parallel to the cyst surface. Dogs fed heart samples from infected fallow deer shed sporocysts after 10-11 days. Cats fed the same samples did not shed any sporocysts.

Animals↗
PubMed1987

Effects of d,l-propranolol on apomorphine induced stereotyped behavior in rats.

The effects of d,l propranolol on stereotyped behavior induced by apomorphine administration was studied quantitatively. d,l Propranolol caused a 2.5 leftward displacement of the control dose-response curve constructed to apomorphine-induced stereotypy; the ED50 for apomorphine was reduced from 1.87 +/- 0.38 to 0.74 +/- 0.17. The potentiation was dependent on both d,l-propranolol and apomorphine doses. Results are discussed in the light of a possible interference of the central noradrenergic systems with the expression of dopaminergic-induced stereotyped behavior.

Animals↗
PubMed1986

Ultrastructural and neurochemical effects of the presumed cholinergic toxin AF64A in the rat interpeduncular nucleus.

We have studied the effect of the presumptive cholinergic neurotoxin, ethylcholine mustard aziridinium ion (compound AF64A), on ultrastructure and neurochemical markers in the rat interpeduncular nucleus (IPN). Stereotaxic injections of 1 nmol of AF64A resulted in extensive degeneration of synaptic terminals within 40 h. Ultrastructural damage to neuronal cell bodies, dendrites and axons was also sometimes observed at this stage. Five days after the injection, more severe degenerative changes were observed in a larger number of neuronal cell bodies, axons and dendrites. High affinity uptake of [3H]choline, but not [3H]GABA, was significantly decreased 24 h after toxin injection. Five days after the injection, not only choline acetyltransferase but also glutamate decarboxylase levels were significantly decreased. Our results suggest that, in addition to presynaptic cholinergic neurotoxicity, AF64A also leads to degenerative alterations of non-cholinergic neurons. Our electron microscopic observations constitute the first ultrastructural report on neuropathological damage caused by AF64A.

Animals↗