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Biomedical subjects

G Ferrari

Publications and source records attributed to G Ferrari.

At least 271 records · Page 15Linked to original sources
PubMed1988

Characterization of papillomavirus polypeptides from bovine cutaneous fibropapillomas.

Virions of bovine papilloma virus (BPV) were isolated from a pool of cutaneous bovine fibropapillomas and purified by CsCl gradient centrifugation. SDS-PAGE revealed several polypeptides with an Mr ranging from 76K to 19K. Western blot analysis of the viral isolate identified additional polypeptides when a rabbit anti-BPV serum was used, but only the main capsid component of 57K when a rabbit antiserum raised against human papillomavirus was used. The viral preparation was then 125I-labelled and further purified by gel filtration. SDS-PAGE of immunoprecipitates of the anti-BPV serum with different fractions from the chromatographic column revealed the polypeptides of 76K, 57K and 28K to be viral structural components. The 28K polypeptide, not previously characterized, was shown to be composed of several molecular forms, migrating over a pH range of 3.5 to 4.6 when analysed by two-dimensional PAGE. Following SDS-PAGE performed under non-reducing conditions, the 28K and 76K polypeptides and the main capsid component of 57K appeared to be linked by disulphide bridges to form hetero- or homopolymers.

Animals↗
PubMed1988

Continuous computerized monitoring of hemodynamic parameters during acetate dialysis, bicarbonate dialysis, and acetate-free biofiltration.

The effects of continuous, computerized, non-invasive hemodynamic monitoring on the appearance of intradialytic symptoms, aided by preventive therapeutic maneuvers, were evaluated in 30 critically ill patients undergoing regular acetate dialysis. The hemodynamic behavior was assessed by a system that interfaces a personal computer with a blood pressure monitor and to a transthoracic electrical impedance-measuring instrument. Monitoring allowed us to reduce significantly the frequency of some important intradialytic symptoms such as nausea, vomiting, and hypotension. The same monitoring system was used acutely to characterize differing hemodynamic behaviors during acetate dialysis (AD), bicarbonate dialysis (BD), and acetate-free biofiltration (AFBF). AD showed a prevalent vasodilation effect with a compensatory increase in heart rate and higher cardiac output values, which were not sufficient to maintain blood pressure stability. BD and AFBF were characterized by a more efficient vasoconstrictor effect and good hemodynamic stability. AFBF, despite a 1 h reduction in session length compared to BD, did not present significant differences in hemodynamic response resulting from session shortness or other technical changes.

Acetates↗
PubMed1988

Transport of thiamine by brush-border membrane vesicles from rat small intestine.

1. Microvillous vesicles obtained by a Ca2+ precipitation method from the intestine of adult Wistar albino rats were incubated at 25 degrees C with [35S]- or [3H]thiamine of high specific activity. 2. The time course of thiamine uptake was not influenced by the presence of Na+ or K+ nor by the absence of alkaline cations in the incubation medium. 3. At concentrations below 1.25 microM, thiamine was taken up mainly by a saturable mechanism with apparent Km = 0.8 microM and Vmax = 0.35 pmol mg protein-1 4 s-1. At higher concentrations, a non-saturable uptake mechanism prevailed. 4. The thiamine taken up was transferred to the intravesicular space. No thiamine phosphoesters could be detected in the vesicles. 5. The vesicular transport of thiamine was inhibited competitively by several thiamine derivatives and structural analogues, including: cold thiamine; thiamine monophosphate (inhibition constant, Ki = 33 microM); pyrithiamine (Ki = 1.7 microM); 2'-ethylthiamine (Ki = 27 microM); 5-chloroethylthiamine (Ki = 70 microM): Amprolium (Ki = 55 microM); 4'-oxythiamine (Ki = 510 microM).

Animals↗
PubMed1988

Intestinal transport of thiamin and thiamin monophosphate in rat everted jejunal sacs: a comparative study using some potential inhibitors.

Rat everted jejunal sacs were incubated for 15 and 30 min at 37 degrees C in oxygenated Krebs-Henseleit buffer, pH 7.4, containing 0.2 microM [3H]-thiamin (3H-T) or [3H]-thiamin monophosphate (3H-TMP) with and without 10 mM 1-phenylalanine (PAL) or 2.5 mM levamisole (LEV). The concentrations of 3H-T and its phosphoesters in sac wall and serosal fluid were determined by a radiometric method after electrophoretic separation. In separate experiments, thiamin pyrophosphokinase (TPKase) and thiamin pyrophosphatase (TPPase) activities were determined in mucosal scrapings, with and without PAL or LEV, by using a radiometric and a colorimetric method, respectively. 3H-TMP was transported partly unchanged by an active mechanism similarly to 3H-T, but less efficiently. During transport, 3H-TMP was also enzymatically transformed to thiamin (T) and thiamin pyrophosphate, which accumulated in the tissue. In the serosal fluid, the concentration of 3H-TMP exceeded that of 3H-T. Presence of PAL or LEV with 3H-T or 3H-TMP in the incubation medium reduced the serosal transport and the tissue content of T compounds. LEV caused a dose-dependent inhibition of TPKase without affecting TPPase, whereas PAL inhibited both activities to about the same extent. These results indicate that the transport of TMP involves a number of different processes similar to those responsible for T transport. The effects of PAL and LEV underline the importance of phosphorylation-dephosphorylation coupling.

Animals↗
PubMed1988

Retroviral heterogeneity in mouse lymphomas.

Provirus modifications which can occur in tumors may lead to tumor antigenic variants. To investigate this possibility we compared the restriction fragment length patterns of mouse mammary tumor virus (MMTV), murine leukemia virus and xenotropic and mink cell-focus inducing (MCF)-related sequences, using Southern blot analysis, in a panel of Balb/c and C57BL/6 lymphomas, some of which were known to express novel histocompatibility (H) antigens. The results indicate differences in amplification and novel integration sites of retroviral sequences in all tumors analyzed, the number of new sequences depending on the specific retroviral sequence. A relationship has been found between integration of new MMTV sequences and a known susceptibility to lysis by syngeneic alloactivated lymphocytes in the same group of tumors. The possibility that retroviruses can induce the expression of novel histocompatibility antigens on tumors is discussed.

Animals↗
PubMed1988

Long-term effects of parathyroidectomy on cardiac and autonomic nervous system functions in haemodialysis patients.

Ten patients receiving regular haemodialysis therapy who underwent parathyroidectomy for secondary hyperparathyroidism were investigated to evaluate the effects of parathyroid hormone on left ventricular and autonomic nervous system functions. The study which included M-mode echocardiography and autonomic nervous system tests (hormonal and cardiovascular response to the postural test, cold pressor test, handgrip test, diving reflex test and Valsalva manoeuvre) were performed prior to parathyroidectomy, and 5-8 months after, on a nondialysis day. The cardiovascular response and plasma noradrenaline changes to postural test remained unchanged following parathyroidectomy. The resting heart rate decreased from 73.1 +/- 2.4 to 66.4 +/- 2.3 beats/min (P less than 0.05) but mean blood pressure did not change post-parathyroidectomy. Mean blood pressure and heart rate changes during the cold pressor test, handgrip test, diving test and Valsalva manoeuvre were unaffected by parathyroidectomy. End-diastolic and end-systolic dimensions, fractional fibre shortening, mean velocity of fibre shortening and the ratio of the pre-ejection period to the left ventricular ejection time were normal prior to parathyroidectomy and remained unchanged following it. This study suggests that the reduction in parathyroid hormone concentrations obtained by parathyroidectomy does not significantly modify heart function and autonomic nervous system activity in the long term.

Adult↗
PubMed1988

Effectiveness of antibiotic prophylaxis according to the nutritional status in patients undergoing contaminated procedures.

The attempt to restrict as much as possible the use of the antibiotics in surgery is related with the recent introduction of short term antibiotic prophylaxis. In this study the possibility to select among patients undergoing contaminated procedures those who can benefit more from short term antibiotic prophylaxis was considered. With this aim the nutritional status of 302 patients according to three parameters: serum albumin, total iron binding capacity and weight loss, was assessed. Results obtained from short term antibiotic prophylaxis with clindamycin and gentamicin in 149 patients (53.6% malnourished) were compared with those obtained in 153 patients (49.6% malnourished) who were not treated peroperatively. Wound infection rate in patients who received antibiotic prophylaxis was 6% versus 15% in the group which did not receive antibiotics peroperatively (p less than 0.025). A significant reduction was observed in malnourished patients while in the well-nourished the decrease was not significant. Malnourished patients seem to gain a specific benefit from antibiotic prophylaxis.

Adolescent↗
PubMed1988

Development and survival of neurons in dissociated fetal mesencephalic serum-free cell cultures: I. Effects of cell density and of an adult mammalian striatal-derived neuronotrophic factor (SDNF).

The use of CNS cultures for detection and quantification of neuronotrophic activity in the CNS has been analyzed. In particular the development, i.e., neurotransmitter uptake characteristics, and survival of dopaminergic and GABAergic neurons in fetal mouse (E13)-dissociated mesencephalic cells cultured in serum-free, hormone-supplemented medium have been assessed as a function of culture time and cell density. At all times, more than 98% of the cells were classified as neurons on the basis of immunocytochemical criteria. Results indicate that the increase of cell density in vitro significantly enhances specific high-affinity dopamine uptake per dopaminergic cell and cell survival. This effect is not limited to the dopaminergic cells and suggests that the development of neurotransmitter-related traits and cell survival are influenced by cell density-derived trophic signals. The above-mentioned cultures and parameters have also been used to detect neuronotrophic activity in adult mammalian brain extracts or more purified preparations. In particular, bovine striatal extracts contain activity capable of increasing high-affinity neurotransmitter uptake parameters and cell survival of at least the dopaminergic and GABAergic neurons present in the culture system. The neuronotrophic activity from bovine striatum has been partially purified and is associated with a fraction whose main component is a basic protein of approximately 14 kDa.

Animals↗
PubMed1987

Thermosensitivity of anterior hypothalamic-preoptic neurons during the waking-sleeping cycle: a study in brain functional states.

The thermosensitivity of anterior hypothalamic-preoptic neurons was studied in cats during the waking-sleeping cycle. Direct cooling and warming of the anterior hypothalamic-preoptic region was accomplished with water-perfused thermodes. Neuronal thermosensitivity was determined by means of the linear regression analysis of firing rate changes vs anterior hypothalamic-preoptic temperature changes. A total of 117 neurons were classified as thermosensitive during wakefulness and synchronized sleep (20.1% of the studied neurons). Cold-sensitive neurons outnumbered warm-sensitive neurons by 3.7:1. The homeothermic states, wakefulness and synchronized sleep, are characterized by similar frequency distributions of neuronal thermosensitivity, although variable changes in single neuron thermosensitivity are state-dependent. Such changes underlie the quantitative differences in homeothermic regulation between these states. The impairment of thermoregulation during desynchronized sleep is characterized by a different frequency distribution of neuronal thermosensitivity resulting from both a drop in the responsiveness to thermal stimulation of a majority of neurons and a reversal in the sensitivity to cooling and warming of a minority of neurons. In conclusion, only the frequency distribution of thermosensitivity in the neuronal population is indicative of changes in the thermoregulation paradigm across behavioral states.

Action Potentials↗
PubMed1987

Immunocytochemical localization of pyrazine-binding protein in bovine nasal mucosa.

Polyclonal antibodies have been raised against purified bovine pyrazine-binding protein, a protein that binds the odorant 2-isobutyl-3-methoxypyrazine. These antibodies have been utilized in immunocytochemical experiments to localize the pyrazine-binding protein in bovine nasal mucosa. Tissue fragments, macroscopically identified as olfactory and respiratory mucosa, were fixed in Bouin's fluid and embedded in paraffin. Consecutive serial sections were processed for immunofluorescence studies and restained either with haematoxylin-eosin or with periodic acid Schiff-Alcian Blue. In both olfactory and respiratory mucosa, only seromucous tubulo-acinar glands were specifically labelled. These glands are located in the lamina propria underlying typical respiratory epithelium, even in those tissues that are macroscopically defined as olfactory mucosa.

Animals↗