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Biomedical subjects

A Salvaggio

Publications and source records attributed to A Salvaggio.

At least 55 records · Page 3Linked to original sources
PubMed1994

Hippocampal hypoglycaemia-activated K+ channels: single-channel analysis of glucose and voltage dependence.

The effect of glucose on kinetics and the voltage-dependent characteristics of glucose-sensitive channels in hippocampal neurons were examined with the cell-attached mode of the patch-clamp technique. Recordings of a 100-pS K+ channel in the presence or absence of glucose demonstrate that the increase in channel open state probability (Po) induced by glucose deprivation (40- to 400-times the control in high-glucose medium) was largely due to a decrease in the global amount of time spent by the channel in a long-lived closed state. The Po value of the same 100-pS channel was also found to increase (by approx. 80-times) following a depolarization of 40 mV from rest, the main factor responsible for this being a dramatic shortening of the long closed-times on depolarization. Another glucose-sensitive channel of smaller conductance (approx. 10 pS) showed a similar dependence of Po on glucose, but different dependence on voltage, with long openings at the same hyperpolarized potentials where the 100-pS channel was almost always closed. Our results indicate that the action of glucose on the kinetics of hippocampal channels closely resembles that of ATP-sensitive channels in pancreatic beta-cells. Furthermore, they indicate that the two types of glucose-sensitive channels found in hippocampal neurons, differing not only in their single-channel conductance but also in the dependence on voltage, could play different roles in the responses of these cells to modified energetic supply.

Animals↗
PubMed1994

Relation between carotid artery atherosclerosis and time on dialysis. A non-invasive study in vivo.

Patients undergoing maintenance hemodialysis have a high cardiovascular mortality but there are conflicting reports in the literature regarding the possibility of an accelerated atherosclerotic process in these patients. The aim of this study was to assess, in vivo, the extent of atherosclerotic lesions in the common carotid arteries and in the aorta of patients undergoing hemodialysis and their relation to clinical variables and risk factors. An ultrasonic system was employed to measure intimal-medial thickness in the carotid arteries and compliance in the aortic iliac axis. A positive significant relation emerged between carotid intimal-medial thickness and the length of time on dialysis (p < or = 0.001). Furthermore there was a significant correlation between intimal-medial thickness and LDL cholesterol (p < or = 0.001). No correlation was found between aortic-iliac compliance and the clinical variables considered. Non-invasive examination of the peripheral arteries with ultrasound could be a useful technique in the follow-up of patients on dialytic treatment; it could aid in the identification of the patients who are at increased vascular risk.

Aorta, Abdominal↗
PubMed1993

Sexual transmission of hepatitis C virus and HIV-1 infection in female intravenous drug users.

We examined the relationship between the presence of antibody to HCV and sexually transmitted diseases in 151 female, intravenous drug users aged 17-43 years. Anti-HCV was present in 49 of 66 HIV-1-negative women (74.2%), and 63 of 85 HIV-1-positive women (74.1%). Anti-HCV seropositivity was significantly related to sexually transmitted infections (Ureaplasma urealyticum infections excluded) in HIV-1-seronegative women, but not in HIV-1-positive women. Also, in HIV-1-negative subjects. Trichomonas vaginalis infections (and infections with M. hominis) were significantly related to anti-HCV seropositivity, and a positive relation between the number of sexual partners and the presence of anti-HCV was demonstrated. In HIV-1-positive subjects a shared use of needles and syringes was more likely, and an increased parenteral exposure to HCV may decrease the relative contribution by sexual transmission. However, in HIV-1-negative subjects, sexual transmission of HCV appears to be both a possible and important means of transmission.

Adolescent↗
PubMed1993

An electrophysiological method to assess the distribution of the sensory propagation velocity of the digital nerve in normal and diabetic subjects.

We report a new computer-assisted collision method to evaluate sensory conduction velocity (SCV) distribution in the digital nerve of the middle finger in normal subjects and in insulin-dependent diabetic subjects without any neurological impairment. Distribution curves were monomodally shaped in controls, indicating a greater proportion of fibers with relatively slow conduction velocity and a lesser proportion of fibers with faster velocity. In most diabetic nerves, a monomodal trend of the SCV distribution indicated a definite reduction in high and intermediate SCV. In a small proportion of nerves, the SCV distribution tended to be bimodal, with an absolute maximum corresponding to lower velocities and a relative maximum to intermediate-fast velocities. Slowing of the intermediate velocity, or loss of fibers of intermediate velocity, can be hypothesized to represent the early electrical evidence of a subclinical polyneuropathy in insulin-dependent diabetic subjects.

Action Potentials↗
PubMed1993

Peripheral autonomic involvement in the carpal tunnel syndrome.

The sympathetic skin response (SSR), evoked from the middle finger of both hands by electrical stimuli to the median nerve (MN) at the wrist, was studied in 21 patients with bilateral carpal tunnel syndrome (CTS) and in 16 patients with monolateral CTS (14 at the right and 2 at the left side) without clinical signs of autonomic involvement. In monolateral and bilateral CTS there was a decrease in the SSR areas of both sides. In monolateral CTS the decrease was greater contralaterally to the lesion. A decrease in the SSR in CTS generally indicates a local blockade of sympathetic nerve excitability due to MN entrapment. Contralateral reduction of the sympathetic response suggests an involvement of the efferent pathway of the autonomic reflex far from the lesion at the wrist. However, dispersion of the excitement over a long distance and throughout numerous synaptic connections may affect contralateral more than homolateral SSR excitability. Finally, sympathetic damage in CTS is in accord with the anatomo-functional correlation (in the peripheral nerve and ganglia) between somatic sensory, which were most markedly involved in our patients, and sympathetic afferent nerve fibers.

Adolescent↗
PubMed1993

Catecholamines and blood pressure in obstructive sleep apnea syndrome.

To evaluate the release of catecholamines and their relationship with systemic blood pressure (BP) in normotensive patients with obstructive sleep apnea syndrome (OSAS), diurnal and nocturnal urinary norepinephrine (NE) and epinephrine (E) excretion in 12 normal subjects and in 10 OSAS patients were compared; in addition, nocturnal NE and E excretion were measured in the patients while receiving short-term CPAP. Blood pressure was continuously monitored in the patients during both nights of urine collection. In normal subjects, both NE and E excretion decreased from day to night. In the patients without CPAP, only NE excretion decreased at night, and BP increased from wakefulness to sleep; both NE and E excretion were higher in patients than in normal subjects. With CPAP, which prevented apneas, only E excretion decreased with respect to the previous night, while BP no longer increased during sleep. The extent of nocturnal E decrease with CPAP was not correlated to BP variations. These results suggest that in normotensive OSAS subjects, sympathetic nervous system activity, based on NE excretion, is continuously increased and is not affected by short-term CPAP treatment. Conversely, adrenal activity, based on E excretion, is also increased, but it tends to be normalized by short-term CPAP. No clear relationship could be found between sympatho-adrenal behavior and BP during sleep.

Adult↗
PubMed1992

Hypoglycemia-activated K+ channels in hippocampal neurons.

Channels linking the electrical and metabolic activities of cells (KATP channels) have been described in various tissues, including some brain areas (hypothalamus, cerebral cortex and substantia nigra). Here we report the existence in hippocampal neurons of K+ permeant channels whose activity is regulated by extracellular glucose. They are open at the cell resting potential and respond to transient hypoglycemia with a reversible increase in activity. The one type so far characterized has a conductance of approximately 100 pS in isotonic K+, is inhibited by the sulphonylurea glibenclamide (1 microM), and is activated by the potassium channel opener lemakalim (0.1-1 microM). These data provide a direct demonstration of the presence, in hippocampal neurons, of glucose-sensitive channels that could belong to the KATP family.

Adenosine Triphosphate↗
PubMed1992

Prevalence of anti-HCV in subjects of various age groups.

812 serum samples from 382 males and 430 females from various age groups were examined. All the samples were tested for anti-HCV hepatitis C virus, anti-HBc and HBsAg with an enzymeimmunoassay. The total serum prevalence was 2.9% for anti-HVC, 22.2% for anti-HBc and 4.6% for HBsAg. The seropositivity rates of anti-HCV and anti-HBc tended to increase with age, while for HBsAg a more regular pattern was observed for the different subject groups. The fact that anti-HCV are more frequently found together with HBV markers confirms the existence of similar modes of transmission of the two viruses.

Adult↗
PubMed1992

The independent effect of habitual cigarette and coffee consumption on blood pressure.

The authors investigated the possible relation between habitual cigarette and coffee consumption and blood pressure (BP) levels in 7506 men and 2095 women. The study population were managers and employees examined in northern Italy between 1986-1988. In particular, the hypothesis of a substantial independence between smoking-BP and coffee-BP was tested. BP levels were corrected for age, body mass index, physical activity, and alcohol consumption by analysis of covariance. Significantly, smoking was inversely related to BP, both in men (SBP, P < 0.001, DBP, P < 0.001) and women (SBP, P = 0.001, DBP, P = 0.012). In particular, the BP of non-smoking men, SBP/DBP, was 131.0/83.5, whereas in male smokers up to and over 20 cigarette/day, BP was 128.1/82.0 and 128.1/82.1 respectively. Coffee consumption was related to BP levels in men (SBP, P < 0.001; DBP, P = 0.009), but not in women (SBP, P = 0.320; DBP, P = 0.982). BP in male subjects was 131.3/83.5 in non-drinkers, 130.7/83.3 in those drinking 1-3 cups/day, 128.4/82.6 and 127.2/81.8 in drinkers of 4-5 and over 5 cups/day, respectively. No significant interactions were demonstrated, thus the relationship between habitual smoking and coffee consumption with BP appears to agree with an additive model.

Adult↗
PubMed1992

Coronary "open" endarterectomy and reconstruction: short- and long-term results of the revascularization with saphenous vein versus IMA-graft.

From June 1984 to December 1990, 96 patients underwent "open" coronary endarterectomy and reconstruction. In 50 patients (group 1), a saphenous vein (SV) graft was used to reconstruct and bypass 54 coronary vessels. In 46 patients (group 2), 46 coronary vessels were reconstructed with an SV patch and then bypassed with the internal mammary artery (IMA): Seventy-four LAD coronary arteries (36 in group 1 and 38 in group 2) were treated with these procedures. Operative mortality was 8% in group 1 and 2.1% in group 2. Five patients (10%) in group 1 and 1 patient (2.1%) in group 2 developed perioperative myocardial infarction. The early postoperative patency of the reconstructed vessels was 84.6% in group 1 and 92.5% in group 2. Angiographic controls were performed between 30 and 36 months after operation in 18 patients (72%) of group 1 and in 16 patients (69%) of group 2 with patency rates of 66.7% and 81.5%, respectively. A further angiographic study performed between 54 and 60 months after operation of 9/22 patients of group 1 and 5/9 patients of group 2 did not show any additional closure of the endarterectomized vessels. Three- and 5-year survival analyzed by the Kaplan-Meier method was 79.6% and 69.7%, respectively, in group 1 and 86.8% for both the 3- and 5-year survival in group 2. After a mean follow-up of 51.0 and 35.5 months, 62.8% of the surviving patients of group 1 and 75.6% of group 2 were asymptomatic.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

High sensitivity of glutamate uptake to extracellular free arachidonic acid levels in rat cortical synaptosomes and astrocytes.

By using both synaptosomes and cultured astrocytes from rat cerebral cortex, we have investigated the inhibitory action of arachidonic acid on the high-affinity glutamate uptake systems, focusing on the possible physiological significance of this mechanism. Application of arachidonic acid (1-100 microM) to either preparation leads to fast (within 30 s) and largely reversible reduction in the uptake rate. When either melittin (0.2-1 microgram/ml), a phospholipase A2 activator, or thimerosal (50-200 microM), which inhibits fatty acid reacylation in phospholipids, is applied to astrocytes, both an enhancement in extracellular free arachidonate and a reduction in glutamate uptake are seen. The two effects display similar dose dependency and time course. In particular, 10% uptake inhibition correlates with 30% elevation in free arachidonate, whereas inhibition greater than or equal to 60% is paralleled by threefold stimulation of arachidonate release. In the presence of albumin (1-10 mg/ml), a free fatty acid-binding protein, inhibition by either melittin, thimerosal, or arachidonic acid is prevented and an enhancement of glutamate uptake above the control levels is observed. Our data show that neuronal and glial glutamate transport systems are highly sensitive to changes in extracellular free arachidonate levels and suggest that uptake inhibition may be a relevant mechanism in the action of arachidonic acid at glutamatergic synapses.

Albumins↗
PubMed1992

Multiple intra-articular treatment of rheumatoid arthritis: a randomized prospective study comparing rifamycin SV with pefloxacin.

In a randomized, prospective study the efficacy and tolerability of extensive multiple intra-articular administrations of two antibiotics, rifamycin SV and pefloxacin, were evaluated in 40 patients with classical or definite rheumatoid arthritis. Total weekly doses of 525 mg rifamycin or 560 mg pefloxacin were given for 10 weeks, and 12 months after treatment all clinical indices, erythrocyte sedimentation rate and C-reactive protein improved significantly in the rifamycin group. Some of the treatment indices (morning stiffness, severity of pain by visual analogue scale, grip strength and Ritchie's index) were already improved when the treatment ended, whereas others (erythrocyte sedimentation rate, C-reactive protein, number of painful and swollen joints) improved progressively during the follow-up. In the pefloxacin treatment group all indices except C-reactive protein and severity of pain determined using a visual analogue scale were significantly improved 12 months after treatment. Comparison of the two treatments showed a significant difference in erythrocyte sedimentation rate (P less than 0.047), Ritchie's index (P less than 0.036) and C-reactive protein (P less than 0.028) in favour of rifamycin.

Aged↗
PubMed1992

Acute effects of oxygen administration on transmural pulmonary artery pressure in obstructive sleep apnea.

In order to investigate the role of hypoxia on the cyclic oscillation of transmural pulmonary artery pressure (PAP) in obstructive sleep apnea, oxygen was administered during one half of the night to six patients affected by obstructive sleep apnea syndrome during a nocturnal polysomnographic study. In each patient, transmural PAP measurements were performed on 15 randomly selected apneas recorded while breathing room air, and on 15 during O2 administration. During O2 administration in all patients, apneas were associated with a higher oxyhemoglobin saturation (SaO2), a smaller SaO2 swing, and a higher transcutaneous PCO2. The mean highest level of transmural PAP in the apneic episodes, commonly reached at their end, was significantly lower than while breathing room air in only two patients; however, due to a decrease in the mean lowest PAP level (at the beginning of apneas), the extent of the PAP increase within apneas did not differ between air and O2 breathing; these patients showed the smallest increase in transcutaneous PCO2 in our sample. End-apneic transmural PAP during O2 administration was significantly higher in one subject (for systolic values) and was not significantly different in the remaining three subjects. The extent of the increase in transmural PAP within apneas was greater in one patient; it was smaller in another one, but only for the diastolic values; and it did not differ significantly with respect to the value observed while breathing room air in all of the other subjects. The results suggest that hypoxia in obstructive apneas, at least in some patients, may lead to a steady increase in PAP, detectable both at the beginning and at the end of the episodes; conversely, the increase in PAP within apneas does not seem to be influenced by the simultaneous decrease in SaO2.

Air↗
PubMed1991

Coffee and cholesterol, an Italian study.

In the present study, conducted in northern Italy between 1986 and 1989, the authors investigated the possible association between coffee consumption and serum cholesterol levels in 8,983 subjects, 7,432 men and 1,551 women, managers and employees aged 18-65 years, who were examined during a program of preventive medicine upon an agreement between various companies and the Centro Diagnostico Italiano. Analysis of covariance was used to compare the serum cholesterol levels of the subjects subdivided according to coffee consumption, along with age, body mass index, alcohol consumption, cigarette smoking, and physical activity. An important relation was demonstrated between coffee intake and cholesterol, particularly in the men, the differences in serum cholesterol in the coffee users compared with the nonusers being 6.1 +/- 1.4 (standard error) mg/dl for consumers of 1-3 cups/day (3.4 +/- 1.4 mg/dl after adjustment for age, body mass index, alcohol and cigarette consumption, and physical activity), 9.9 +/- 1.6 mg/dl for those drinking 4-5 cups/day (5.8 +/- 1.6 mg/dl after adjustment), and 14.8 +/- 2.0 mg/dl for those drinking over 5 cups/day (9.6 +/- 2.0 mg/dl after adjustment). This relation remained substantially unvaried when nonsmokers and smokers were analyzed separately. It has been suggested that it is coffee prepared by boiling rather than other methods that has a hypercholesterolemic effect. Our observations demonstrate an interesting relation between coffee and cholesterol, even though the coffee drunk in Italy is mainly filtered and nonboiled. However, our finding is not necessarily in disagreement with the above hypothesis since, when coffee is prepared in the Italian way (with the mocha method), ground coffee is preheated by steam and more importantly, the water passes through the ground coffee at a higher temperature than with the other brewing methods.

Adolescent↗
PubMed1991

Iron and ferritin in Italian subjects.

We studied the iron status of 400 Italian subjects, 200 men and 200 women, equally distributed in four 10-year age groups between 20 and 60 years. The frequency of iron deficiency was elevated in women of childbearing age. On average 13% of the women in the three younger age groups showed low serum ferritin levels and 16-18% a low transferrin saturation index. Only 6% of the women over 50 were iron deficient. Signs of iron deficiency were never observed in more than 2% of the men in the age groups under 50, with the percentage rising slightly in the men over 50. In the women an inverse correlation was found between serum ferritin levels and number of births [log ferritin (ng/ml) vs number of births, b +/- SE (b): -0.252 +/- 0.088] and between serum ferritin and duration of menstruation [log ferritin (ng/ml) vs duration of menstruation (days), b +/- SE (b): -0.160 +/- 0.065]. Furthermore, hemoglobin levels were 0.700 (+/- 0.248, SE) g/dl lower in the women with 'abundant menstrual flow', and hemoglobin levels correlated inversely with number of births [hemoglobin (g/dl) vs number of births, b +/- SE (b): -0.354 +/- 0.115]. Our study showed an elevated frequency of iron deficiency in women of reproductive age. The number of births and abundance of menstrual flow were both important factors in predisposing younger women to developing iron deficiency.

Adult↗
PubMed1991

Salmonellosis diagnosed by the laboratory of the 'L. Sacco' Hospital of Milan (Italy) in patients with HIV disease.

We reviewed the cases of typhoid fever (3 cases) and non-typhoid salmonellosis (62 cases) diagnosed from 1987 to 1989 in the Laboratory of Clinical Chemistry and Microbiology of the 'L.Sacco' Hospital, Milan. Two cases of typhoid fever and 24 cases of non-typhoid salmonellosis occurred in patients without clinical symptoms of HIV infection. One case of typhoid fever and 38 cases of non-typhoid salmonellosis occurred in patients with clinical symptoms of HIV infection. In AIDS patients living in the Milan province the annual incidence of non-typhoid salmonellosis was estimated to be 100-fold greater than that observed in the general population. In patients with non-typhoid salmonellosis, bacteremias was found only in subjects with HIV disease (P = 0.0009). The frequency of bacteremia was higher in patients with AIDS than in patients with other manifestations of HIV disease (P = 0.0356). Finally, a significant difference between patients with and without HIV disease was found with regard to Salmonella serotypes distribution (P = 0.0196).

Acquired Immunodeficiency Syndrome↗
PubMed1991

Body mass index and liver enzyme activity in serum.

The association between body mass index (BMI) and serum liver enzyme activity [gamma-glutamyltransferase (GGT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST)] was studied in 3167 subjects, 2373 men and 794 women. The subjects were managers and employees, ages 18-64 years, who were examined during a program of preventive medicine. Analysis of covariance was used to compare the serum liver enzyme activities (expressed as natural logarithms) of the subjects, who were subdivided according to BMI, while also considering age, alcohol and cigarette consumption, and physical activity. In men, the percentage increase in the geometric mean of liver enzyme activity of the obese subjects (BMI greater than 30 kg/m2) compared with that of the normal subjects (BMI less than or equal to 25 kg/m2) was 47.7% (P less than 0.001) for GGT, 55.3% (P less than 0.001) for ALT, and 19.7% (P less than 0.001) for AST; in women, the increase was 63.2% (P less than 0.01) for GGT, 58.4% (P less than 0.001) for ALT, and 7.3% (P greater than 0.05) for AST. Thus, our observations demonstrate a relation between BMI and serum liver enzyme activity.

Adolescent↗