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Biomedical subjects

M Negri

Publications and source records attributed to M Negri.

At least 73 records · Page 4Linked to original sources
PubMed1991

[General balanced anesthesia and propofol in ablation of the arterioventricular junction].

The Authors compare the results of general balanced anaesthesia and propofol in the anaesthetic management of closed-chest ablation of A-V junction. The best results were obtained with propofol because of the lower incidence of cardiovascular complications. Therefore propofol is a suitable agent in the anaesthetic management of closed-chest ablation of the A-V junction.

Aged↗
PubMed1991

Pulse oximetry in the evaluation of the painful hand after arteriovenous fistula creation.

Five patients with a side-to-side arteriovenous fistula complaining of pain, numbness, and cold sensation were evaluated by pulse oximetry. Low SaO2 was noticed in all five. Closure of a major proximal venous collateral vessel eliminated the steal and resulted in SaO2 correction and was followed by clinical amelioration. Pulse oximetry proved to be a helpful adjunct in the evaluation of the painful hand after creation of an arteriovenous fistula. By applying the pulse oximeter to the patient's affected limb, we were able to determine whether the pain was a result of ischemia and if the correction of the steal improved oxygenation.

Arteriovenous Shunt, Surgical↗
PubMed1990

T cell subpopulations in vitiligo: a chronobiologic study.

The circadian rhythms of helper (CD4) and suppressor (CD8) T cells from the peripheral blood of 12 vitiligo patients (seven with active disease, five with static) and 12 healthy control subjects were studied. Patients with active vitiligo had a lower percentage of CD4+ cells than did control subjects at 0000 hours and at 0600 and 1200 hours; there were no differences between these values in patients with static vitiligo and those in control subjects. The percentage of CD8+ cells were lower at 1200 and 1800 hours in both active and static vitiligo patients than in control subjects. Cosinor analysis of the CD4+ cells showed a circadian rhythm in static vitiligo, whereas the rhythmicity was lost in active vitiligo. CD8+ cells did not show any circadian rhythm in either active or static vitiligo. Our data show more striking aberrations for T cell subtypes in active vitiligo than in static vitiligo. They suggest that cell-mediated immunity may play a role in the pathogenesis of the disease.

Adolescent↗
PubMed1990

Beta-endorphin, insulin, ACTH and cortisol plasma levels during oral glucose tolerance test in obesity after weight loss.

In order to clarify a possible relationship between opioid peptides and glucose homeostasis in obesity we studied Beta-Endorphin (B-Ep), ACTH, cortisol and insulin plasma levels in response to an oral glucose tolerance test (OGTT) in 8 subjects after a hypocaloric diet for 90 days. We obtained through this treatment a weight loss superior to 30% of the initial weight excess (WE) compared with ideal body weight. Moreover, we compared the obtained results with our preliminary study that was performed with the same protocol but without caloric restriction. B-Ep was measured by RIA after silicic acid extraction and G75 Sephadex column chromatography. ACTH, insulin and cortisol were measured directly on plasma by an RIA method. Basal and during OGTT-induced levels of glucose, insulin, ACTH and cortisol decreased in comparison with the values obtained before diet. Conversely, B-Ep remained higher than normal both in the basal condition and during OGTT, and showed values consistently similar to those before diet. These data show that hyperinsulinemia is corrected by weight loss, while hyperbetaendorphinemia remains unchanged. Accordingly, it can be suggested that no direct relationship occurs between hyper-B-Ep-hyper-IRI in obesity. A further insight into the role of hyper-B-Ep in obesity is, thus, necessary, assuming as hypothesis that the increase in B-Ep may be a cause and not a corollary of the polymorphic aspects of obesity.

Adrenocorticotropic Hormone↗
PubMed1990

Expression of HOX homeogenes in human neuroblastoma cell culture lines.

Mammalian genes containing a class-I homeobox (HOX genes) are highly expressed in the embryonic nervous system. As a first step towards the molecular analysis of the role these genes play in neural cells, we studied the expression of four human HOX genes in five neuroblastoma (NB) cell lines - SK-N-BE, CHP-134, IMR-32, SK-N-SH and LAN-1 - during the process of differentiation induced by treatment with retinoic acid (RA). The four genes, HOX1D, 2F, 3E and 4B, located at corresponding positions in the four HOX loci, share a high degree of sequence similarity with the Drosophila Deformed homeotic gene and constitute a homology group, group 10. One of these genes, HOX1D, is not expressed in the cells used, whereas the other three are highly expressed in untreated and RA-induced NB cells, even though the expression pattern in the various lines is slightly different for the three genes. Our analysis reveals a complex and specific expression pattern in these lines, paving the way to an identification of different NB-cell populations by means of specific HOX gene expression schemes. On the other hand, in every line studied, morphological maturation toward a neuronal differentiated phenotype appears to be associated with increased HOX gene expression.

Amino Acid Sequence↗
PubMed1990

Growth hormone does not inhibit its own secretion during prolonged hypoglycemia in man.

In man, continuous infusion of GH-releasing hormone (GHRH) does not sustain GH secretion, unlike prolonged hypoglycemia. To further evaluate this difference in the stimulation of GH release we measured GH concentrations for 3 h during prolonged insulin-induced hypoglycemia and GHRH-(1-29)NH2 (100 micrograms/h) infusion in normal individuals. We also assessed the GH response to combined and separate administration of insulin and GHRH. Plasma GH levels increased during prolonged hypoglycemia and remained elevated for the third hour (22-24 micrograms/L). GH concentrations increased during GHRH infusion, peaked at 60 min (23.5 micrograms/L), and rapidly declined. Thus, our findings confirmed that prolonged hypoglycemia, unlike GHRH infusion, sustained elevated GH levels and that these high levels did not appear to influence GH secretion from the pituitary. Changes in FFA did not account for the sustained GH secretion. FFA levels initially declined during insulin infusion, but after 3 h of hypoglycemia they returned to near-basal values (basal, 0.1 +/- 0.02 g/L; 180 min, 0.09 +/- 0.02). The maximal GH concentration attained during the combined insulin and GHRH test was significantly higher than that with the insulin tolerance test or GHRH test (insulin plus GHRH, 71.9 +/- 13.5; insulin tolerance test, 34.2 +/- 2.9; P less than 0.025; GHRH test, 27.9 +/- 3.2; P less than 0.02), indicating an additive effect on GH secretion. These data suggest that insulin-induced hypoglycemia stimulates GH secretion through a mechanism partly independent of GHRH. The release from somatostatin inhibition and stimulation through other neuropeptides (e.g. galanin) is suggested as possible causes of hypoglycemia-induced GH secretion.

Adult↗
PubMed1990

Carotid endarterectomy under local anesthesia supplemented with neuroleptic analgesia.

Surgical treatment of the carotid artery is being performed increasingly under local rather than general anesthesia. The advantage of local anesthesia is that neurologic function can be continuously assessed while the carotid arteries are cross-clamped, and unnecessary shunting can, thus, be avoided, with resulting sedation, analgesia, alpha blockade and blood pressure stability. The main objection to the use of local anesthesia is the anxiety of the patient. We overcame this difficulty in a series of 42 patients by supplementing the local anesthetic with neuroleptic analgesia. The possible disadvantages of neuroleptic administration are apnea and prolonged sedation. Only one of the patients we studied required an intraluminal shunt. One patient died of cardiac disease and one suffered an early postoperative stroke, which subsequently resolved. We believe that local anesthesia, supplemented by neuroleptic sedation and analgesia to overcome patient anxiety, should be more widely used for carotid endarterectomy.

Aged↗
PubMed1990

[Transcatheter fulguration of the atrioventricular junction in supraventricular hyperkinetic arrhythmia. Immediate and long-term results].

Transcatheter direct-current ablation of the atrio-ventricular junction is a recently developed technique in the treatment of medically refractory supraventricular tachycardia. Twenty patients underwent this procedure between July 1987 and May 1989 and were followed-up for a mean period of 8.3 +/- 6 months (range 1-23). Indication for ablation included atrial flutter in 4 patients, atrial fibrillation in 8, atrial tachycardia in 1, atrio-ventricular nodal re-entrant tachycardia in 4, atrioventricular re-entrant tachycardia (concealed pathway) in 2, permanent junctional reciprocating tachycardia in 1. These arrhythmias were resistant to a mean of 3.3 +/- 1.7 antiarrhythmic drugs. A mean of 1.4 +/- 0.59 (range 1-3) electrical shocks, with a mean energy of 285 +/- 135J (range 200-700), were delivered during 1-2 sessions. In all patients a persistent complete atrio-ventricular block was achieved. Immediate complications included transient hypotension in 2 pts, acute pulmonary edema in 1, premature ventricular complexes in 4, non sustained ventricular tachycardia in 4, sustained ventricular tachycardia in 1. Late complications included thrombophlebitis of the right femoral vein in 2 pts; one of them died suddenly as a result of massive pulmonary embolism 10 days after the procedure. Follow-up evaluation reveals chronic complete atrio-ventricular block in all patients. Symptoms related to pre-existing arrhythmia are absent in all pts and none of them is currently taking antiarrhythmic drugs. Two patients with DDD pacing had pacemaker mediated re-entrant tachycardia and 1 patient with VVIR pacing developed a pacemaker syndrome. This experience confirms that transcatheter fulguration of atrio-ventricular junction is an effective technique. However, possible severe complications related to the procedure suggest this approach be restricted to patients with very symptomatic and drug-refractory supraventricular tachyarrhythmias.

Aged↗
PubMed1989

[2 cases of acute sickle cell crisis in subjects with sickle cell trait following high altitude exposure].

We present two patients with sickle cell trait (HbAS) who developed acute sickle cell crisis after passive exposure to high altitude on the Jungfraujoch (3454 meters, 11,333 ft). Both suffered splenic infarction and the first patient also presented with acute renal failure. Splenic infarction is known to be a complication of altitude exposure in carriers of the trait, whereas acute renal failure due to altitude exposure alone has as far as we know never been described in the literature. These forms of high altitude complications are totally unusual in Switzerland.

Adult↗
PubMed1989

Circadian rhythm of natural killer cell activity in vitiligo.

Ten patients with vitiligo, either in the active (six cases) or static (four cases) phase, and twelve healthy control subjects were studied with a standard cytotoxicity assay to evaluate the circadian rhythm of natural killer cell activity from peripheral blood mononuclear cells. The natural killer cell activity was measured at the zero, sixth, twelfth, and eighteenth hours of the day. The results demonstrated that patients with vitiligo had significantly higher natural killer cell activity compared with normal controls. When patients with static and active vitiligo were compared, those with the static form had increased natural killer cell activity at all times except noon, whereas those with active form had increased natural killer cell activity only at 0600 and 1800. These changes shifted the acrophase of the circadian rhythm of each group. Indeed, by cosinor analysis, both patients with vitiligo and normal controls had similar circadian rhythms, but the acrophase was shifted from 0602 in control subjects to 0435 in the ten patients with vitiligo. The acrophase in the six patients with active vitiligo was found to be closest to that of normal controls (0508). These findings indicate that natural killer cell activity abnormalities are more marked in the static rather than in the active form of vitiligo.

Adult↗
PubMed1988

Vertical banded gastroplasty for the treatment of morbid obesity.

We report the technique and results of vertical banded gastroplasty in 86 morbidly obese patients. At 12 months, the patients had lost a mean of 57% of their excess body weight; 36 months, they had lost 70%. The most severe early complication was perforation of the esophagus. Other complications included disruption of the vertical staple line in three cases and migration of the mesh band. We were able to achieve satisfactory weight reduction in all patients over a period of 36 months. In view of the good results, reduced morbidity, and absence of mortality, we feel that vertical banded gastroplasty is the surgical treatment of choice for morbid obesity at present.

Esophageal Perforation↗
PubMed1988

Increased proteolytic activity of erythrocyte membrane in spur cell anaemia.

In a case of 'spur cell anaemia' (SCA) a reduced esterified/free cholesterol ratio was found in plasma, in LDL and HDL fractions and an increased cholesterol/phospholipid (C/PL) molar ratio in erythrocyte membrane. Cation transport was normal with the exception of Li-Na counter-transport was decreased. An increased intrinsic membrane proteolytic activity (IMPA) was demonstrated by the generalized reduction or, sometimes, disappearance of protein bands on SDS-PAGE in patient ghosts when the proteolysis was allowed. This characteristic was found to be transferable to normal cells by incubation in SCA-plasma; moreover membrane C/PL molar ratio was augmented after incubation. Normal plasma was not able to normalize IMPA of SCA cells 'in vitro', even if it induced a remarkable decrease of membrane C/PL molar ratio. Nevertheless IMPA normalization did occur 'in vivo', when the SCA cells were exposed to therapeutic 'plasma exchange' (3.3 litre/week). The results suggest the following conclusions: (a) in our SCA patient there is an increased IMPA; (b) this feature, as well as membrane lipid alteration, is transferable to normal erythrocytes; (c) this case seems to demonstrate, for the first time in our knowledge, a modulating effect of plasma on IMPA in erythrocytes.

Acanthocytes↗
PubMed1988

Plasma melatonin levels in psoriasis.

Melatonin is synthesized and secreted by the pineal gland. A daily rhythm of melatonin secretion, with high plasma values during the dark period, has been found in all vertebrates studied so far. In psoriatics, several hormones, including GH and prolactin, have altered chronobiology, and some studies in humans suggest that melatonin affects the levels of GH and prolactin. We investigated circadian melatonin rhythm in 13 male psoriatics and 13 healthy males with an RIA specific for measuring the hormone in plasma. Samples were taken at 6 a.m., 8 a.m., 12.00, 4 p.m., 8 p.m. and 2 a.m. Differences in (mean +/- SD) plasma melatonin levels were analysed by Student's t-test. Our results show that psoriatic patients had lost the nocturnal peak and usual circadian rhythm of melatonin secretion. Levels of melatonin were significantly lower than in controls at 2 a.m., and higher at 6 and 8 a.m. and at 12 noon. Further investigations of this disorder of melatonin secretion in psoriasis are needed to understand its significance.

Adult↗
PubMed1988

Effects of dietary fish oil on malondialdehyde production and glutathione peroxidase activity in hyperlipidaemic patients.

In 20 adult patients suffering from hyperlipidaemia we measured the lipid composition of erythrocyte membrane, the glutathione peroxidase activity in both erythrocytes and platelets, the production of malondialdehyde by platelets stimulated with thrombin, as well as the level of plasma selenium, retinol and alpha-tocopherol, before and after 8 weeks of fish oil supplementation (20 ml daily). We noted a remarkable reduction in plasma triglycerides which was associated with a significant decrease in blood pressure; moreover, we noted a reduction in the amount of arachidonic acid compensated by an increment of omega-3-fatty acid (particularly eicosapentaenoic and docosahexaenoic acids). The dietary supplementation with fish oil was associated with a significant increase in glutathione peroxidase activity in both erythrocytes and platelets. On the contrary, the production of malondialdehyde, which was originally higher than normal in hyperlipidaemics, was inhibited significantly after fish oil (p less than 0.001). Whereas no changes were observed in the concentration of plasma selenium and alpha-tocopherol, an increment of plasma retinol occurred. These data indicate that in hyperlipidaemics there is a proaggregant status; this situation may be normalized by using a dietary supplementation of fish oil; the increase of polyunsaturated fatty acids on the cell membrane, with a possible increment of the formation of lipoperoxides, induced by fish oil, is compensated by an increased activity of the scavenger enzyme glutathione peroxidase.

Adult↗