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Biomedical subjects

S Cozzi

Publications and source records attributed to S Cozzi.

At least 19 recordsLinked to original sources

Temperature-activity relationship for the intestinal Na+-K+-ATPase of Sparus aurata. A role for the phospholipid microenvironment?

The temperature dependence for Na(+)-K(+)-ATPase has been examined in the proximal-distal axis of the intestine of gilthead seabream (Sparus aurata), i.e. pyloric caeca (PC), anterior intestine (AI) and posterior intestine (PI). Data derived from the Arrhenius plots showed differences in terms of temperature discontinuity points ( Td) (13.29 degrees C, 16.39 degrees C and 17.48 degrees C for PC, AI and PI, respectively) and activation energy ratios (Ea(2)/Ea(1)) obtained at both sides of Td (2.38, 1.98 and 1.78, for PC, AI and PI, respectively). The analyses of polar lipids showed differences in the levels of certain fatty acids among intestinal regions. The content of each fatty acid and different fatty acid ratios were correlated with the corresponding Td and Ea(2)/Ea(1) values. Regression analyses revealed the existence of strong negative correlations between docosahexaenoic acid (22:6n-3, DHA) or the DHA/monoenes ratio and Td. No obvious relationships were observed for other polyunsaturated fatty acids (PUFA) nor saturated fatty acids. The results obtained in the present study indicate that the heterogeneous values of Td displayed by the Na(+)-K(+)-ATPase along the intestinal tract could be related to a modulatory role of certain fatty acid within the lipid microenvironment of the enzyme.

Animals↗

Surgical tracheostomy versus percutaneous dilatational tracheostomy. A prospective-randomized study with long-term follow-up.

BACKGROUND: To compare surgical tracheostomy (ST) versus percutaneous dilatational tracheostomy (PDT) in terms of complication rates. In particular we specifically studied the late tracheal complications of both methods by means of endoscopic controls of patients up to 6 months after the procedures. METHODS DESIGN: prospective-randomized clinical study. SETTING: University-affiliated tertiary care referral hospital. PATIENTS: 50 consecutive translaryngeally intubated patients with respiratory failure were randomized to undergo either ST (25 patients) or endoscopic guided PDT (25 patients). RESULTS: ST was performed in 41+/-14 min versus 14+/-6 min for PDT (p<0.0001). There was no procedure-related death. In the ST group there were no intraoperative complications. In the PDT group 2 intraoperative complications (minor hemorrhages) were observed. In the ST group 9 early postoperative complications occurred: one minor bleeding, 7 stomal infections and one accidental decannulation. In the PDT group only one early postoperative complication (minor bleeding) occurred. Early postoperative complication rates were 36% for ST and 4% for PDT. In the ST group there were no late tracheal complications. In the PDT group 2 late tracheal complications (one segmental malacia and one stenosis at the level of the stoma) were observed. CONCLUSIONS: This study confirms that PDT is a simpler and quicker procedure than ST and that it has a lower rate of early postoperative complications. Late tracheal complications were more frequent, although the difference was not statistically-significant, in the PDT group. Further investigations of long-term outcome following PDT are therefore necessary.

Adult↗

Segmental heterogeneity in the biochemical properties of the Na+-K+-ATPase along the intestine of the gilthead seabream (Sparus aurata L.).

The activity of the Na+-K+-ATPase along the intestinal mucosa of the gilthead seabream has been examined. Under optimal assay conditions, found at 35 degrees C, pH 7.5, 2-5 mM MgCl2, 5 mM ATP, 10 mM K+ and 200 mM Na+, maximal Na+-K+-ATPase activities were found in the microsomal fraction of pyloric caeca (PC) and anterior intestine (AI), which were more than two-fold the activity measured in the microsomes from the posterior intestine (PI). Na+-K+-ATPase activities from PC, AI and PI displayed similar pH dependence, optimal Mg2+/ATP and Na+/K+ ratios, affinities for Mg2+ and ATP, and inhibition by vanadate. However, considerable differences regarding sensitivity to ouabain, inhibition by calcium and responses to ionic strength were observed between segments. Thus, Na+-K+-ATPase activity from the AI was found to be ten-fold more sensitive to ouabain and calcium than the enzyme from the PC and PI and displayed distinct kinetic behaviours with respect to Na+ and K+, compared to PC and PI. Analysis of the data from the AI revealed the presence of two Na+-K+-ATPase activities endowed with distinguishable biochemical characteristics, suggesting the involvement of two different isozymes. Regional differences in Na+-K+-ATPase activities in the intestine of the gilthead seabream are compared with literature data on Na+-K+-ATPase isozymes and discussed on the basis of the physiological differences between intestinal regions.

Adenosine Triphosphate↗

Use of a new diagnostic catheter for transradial internal mammary artery angiography early after minimally invasive coronary bypass.

We describe a new diagnostic catheter specifically designed for selective catheterization of the left internal mammary artery via the ipsilateral radial approach. We used this catheter to assess the patency of the distal mammary-left anterior descending coronary artery anastomosis in 30 consecutive patients early after minimally invasive direct coronary artery bypass grafting. The new catheter design allowed easy and fast engagement of the left internal mammary artery leading to optimal vessel opacification in all cases. Angiography revealed graft problems in seven (23.3%) patients, two of whom required anastomosis revision, surgical in one case and with PTCA in the other. No LIMA injury occurred as a result of selective catheterization. Patients with functionally normal anastomosis were discharged on the same day of the diagnostic procedure.

Aged↗

Elective coronary stent implantation in cardiogenic shock complicating acute myocardial infarction: in-hospital and six-month clinical and angiographic results.

Effective treatment of patients with acute myocardial infarction and cardiogenic shock depends on restoring persistent patency of the infarct-related artery. Coronary stenting, reducing abrupt or delayed closure related to dissection and suboptimal result, may improve PTCA results in cardiogenic shock. Eighteen patients (14 males and 4 females, mean age 59 +/- 7 years), referred to catheterization laboratory for acute myocardial infarction and shock, had elective stent implantation during 14 primary and 4 rescue PTCA. Time delay between shock onset and PTCA was 4.1 +/- 3 hr (range, 30 min to 12 hr). The IRA was LAD in seven patients (38%), LCx in two (11%), and RCA in eight (45%). One patient (5.%) had distal LMCA occlusion. Stent deployment was successful in 100% of patients and resulted in TIMI 3 flow in 13 (72%) patients. In 13 (72%) cases, cardiogenic shock gradually resolved and the patients were discharged alive. Five patients (28%) died because of irreversible hemodynamic deterioration without evidence of reinfarction. At 6-month follow-up, all the discharged patients were alive and no patient had reinfarction or recurrent angina. Heart transplant was required in one patient 5 months after stenting because of refractory congestive heart failure. Angiography demonstrated patency of all the coronary arteries treated, with TIMI 3 flow in all patients. Stent restenosis rate was 30%, and target lesion revascularization with CABG or re-PTCA was not required in any case. LV function improved from 39% +/- 15% to 51% +/- 15% (P < 0.01). Elective coronary stenting is an effective treatment for acute myocardial infarction complicated by cardiogenic shock and may improve acute and long-term survival.

Aged↗

Successful dissolution of occlusive coronary thrombus with local administration of abciximab during PTCA.

Treatment of intracoronary thrombus poses difficult problems and may result in severe complications. We used a local delivery catheter (InfusaSleeve, LocalMed, Palo Alto, CA) to treat an occlusive coronary thrombus that was refractory to systemic thrombolysis and conventional angioplasty. After local administration of 10 mg of abciximab with this catheter there was successful resolution of coronary thrombus and vessel recanalization. Cathet. Cardiovasc. Intervent. 48:211-213, 1999.

Abciximab↗

Seasonal fluctuations of DIN/DIP and DON/DOP ratio in the northern Adriatic Sea.

Within the frame of PRISMA 1 "Biogeochemical cycles" research project (April 1995-January 1996) the quantities and the compartments of dissolved nitrogen and phosphorus have been studied in the northern Adriatic basin, considering also the organic pools. The research aimed to provide a better understanding of nutrient availability and to investigate the possible factors which promote the phenomenon of mucilage formation. For this purpose, the availability and the ratios between dissolved nitrogen and phosphorus considering both inorganic and organic fractions have been studied in relation to variations of river outflow and of biological activities. The results obtained reveal the large importance of organic nitrogen (annual average 16 microM) and phosphorus (annual average 0.13 microM) in contributing to the total nutrient availability (annual average total dissolved nitrogen: 29 microM and phosphorus: 0.18 microM) and the pronounced seasonal variability mainly ascribable to biological processes of uptake and remineralization. Furthermore, beside the well documented unbalanced ratio between inorganic nitrogen and phosphorus, the results obtained point out, for the first time, the unbalance also in the organic compartment (ratio between organic nitrogen and phosphorus ranges between 50 and 530), whose consequences might be important in relation to the phenomenon of mucilage formation.

Gels↗

7.5% hypertonic saline versus 20% mannitol during elective neurosurgical supratentorial procedures.

This prospective randomized clinical study was designed to compare the effects of equal volumes of 7.5% hypertonic saline solution (HS) or 20% mannitol (M) on brain bulk and lumbar cerebrospinal fluid pressure (CSFP) during elective neurosurgical procedures (aneurysm, arteriovenous malformation, or tumor). After informed consent, 50 American Society of Anesthesiologists physical Status I (ASA I) patients were randomly assigned to M (n = 25) or HS (n = 25) groups. Anesthesia protocol was identical for both, and variables monitored included mean arterial blood pressure (MAP), heart rate (HR), central venous pressure (CVP), CSF pressure (CSFP), arterial blood gases (PaCO2 30-35 mm Hg), serum sodium, potassium, and osmolality, and diuresis. The study period started before hypertonic solution administration (T0) and ended at the opening of the dura mater or 60 min after T0. Data were assessed with repeated measures analysis of variance and Student t test with Bonferroni correction (p < or = 0.05). MAP and CVP were the same in the two groups. After treatment, osmolality increased, and the increase at T15 was higher in HS-treated patients [316.6 +/- 9.3 vs. 304.0 +/- 12.0 (SD) mOsmol/kg; p < 0.001]. Sodium decreased after M and increased after HS. During the study, brain bulk was always considered satisfactory. CSFP was not different between M and HS groups and significantly decreased overtime (p = 0.0056) with no difference between treatments. The results of the present study demonstrate that hypertonic saline is as effective as mannitol in reducing the brain bulk and the CSFP during elective neurosurgical procedures under general anesthesia.

Blood Pressure↗

[Implantation of the Palmaz-Schatz stent in coronary vessels irrigating and non-irrigating necrotic myocardial areas: comparison of acute results and at mid-term].

Recent evidence suggests that higher restenosis rate is observed after coronary angioplasty of an infarct-related artery. Furthermore, angiographic restenosis seems associated with a deterioration of left ventricular function at follow-up. The aim of this study was to assess the acute results and angiographic restenosis following coronary artery stenting of infarct-related (Group 1) and non infarct-related coronary arteries (Group 2). We retrospectively analyzed the results of 381 consecutive patients treated with Palmaz-Schatz coronary stent implantation between May 1992 and January 1996. Stenting of the infarct-related artery was performed in 154 patients (Group 1), while 227 patients (Group 2) received stenting of the non infarct-related artery. Both groups had similar age, gender, clinical conditions and coronary angiographic pattern. There were no significant differences between groups, concerning type of stented coronary vessel (left anterior descending-LAD 52.4% vs non-LAD 47.6%, Group 1, LAD 59.5% vs non-LAD 40.5%, Group 2) and number of stents per patient (1.31 +/- 0.48 in Group 1, 1.18 +/- 0.56 in Group 2) and per coronary vessel (1.17 +/- 0.54 in Group 1, 1.09 +/- 0.46 in Group 2). The procedure was performed using similar maximal inflation pressures in both groups (13.3 +/- 2.9 atm in Group 1, 13.40 +/- 3.17 atm in Group 2). Technical success was achieved in 96.8% of Group 1 and in 96% of Group 2 patients. Acute coronary stenting success and major adverse events (acute myocardial infarction, emergency bypass, death) were similar in both groups of patients. No difference was found in restenosis rate at 6-month angiographic follow-up (Group 1 = 29.8%, Group 2 = 27%). In conclusion, this study indicates that stenting of infarct and non infarct-related coronary arteries has similar success and 6-month restenosis rates.

Coronary Circulation↗

Hypertonic saline fluid therapy following brain stem trauma.

Intravenous hypertonic fluid therapy has been proposed to improve secondary ischemic injury after cerebrospinal trauma. We report the case of a 14-year-old boy with vasospasm of the intracranial vertebral arteries and ischemic brain stem damage following head trauma. The patient presented with severe tetraparesis and somatosensory (SSEPs) and brain stem auditory evoked potentials (BAEPs) impairment. The patient was treated with two subsequent hypertonic saline (HS) infusions, 2.7% and 5.4%, respectively, for a period of 48 sp, followed by standard hypervolemic therapy. After the first treatment with 2.7% HS, improvement of SSEPs without neurological improvement was apparent. Relative hypervolemia was subsequently maintained by administration of crystalloids and 20% albumin for 48 h. During standard hypervolemic therapy, no clinical and/or electrophysiological change occurred. The second infusion of 5.4% HS was concomitant with further amelioration of SSEPs and improvement of motor performance. Twelve hours after the second HS infusion, the neurological status returned to preinfusion levels, while SSEPs showed no further changes. BAEPs never changed during fluid therapy. No complication occurred secondary to the infusion of HS. This case report suggests that local improvement of brain stem perfusion following hypertonic fluid therapy accounts for or relevantly contributes to the neurological and SSEPs improvement of the patient.

Accidents, Traffic↗

Facilitation of coronary spasm by propranolol in Prinzmetal's angina: fact or unproven extrapolation?

BACKGROUND: Alpha-adrenergic activation enhances coronary vascular tone; beta-blockade leaves alpha-adrenergic vasoconstriction unopposed. Whether beta-adrenergic blockade facilitates coronary spasm in patients with Prinzmetal's angina is unknown. METHODS: Using quantitative angiography, we evaluated the response of normal and narrowed coronary arteries to intravenous propranolol, a cold pressor test (an alpha-stimulus), and the combination of the two in 15 patients with Prinzmetal's (group 1) and in 19 with classic (group 2) angina. From measurements of heart rate, systemic and pulmonary arterial pressures, and left and right ventricular ejection times, we derived the tension-time index per minute as a measure of the oxygen need (O2 demand) of the whole heart. RESULTS: In group 1, cold invariably constricted normal and diseased vessels, and in two patients elicited spasm at sites of significant lesions; these changes did not correlate with those in O2 demand. In group 2, the vasomotor reaction of normal and narrowed vessels in response to cold correlated with the modifications in O2 demand. After propranolol administration, (1) in normal vessels in both groups, the baseline luminal diameter varied in parallel with the changes in myocardial O2 demand; (2) narrowings in group 1 patients invariably dilated and in group 2 the caliber varied according to changes in O2 demand; (3) during cold stimulation, luminal narrowing in group 1 varied in parallel with O2 demand, and, in group 2, vessels were uniformly constricted. CONCLUSION: These results do not support the facilitation of coronary spasm by propranolol in Prinzmetal's angina and support the hypothesis that the contractility of coronary vessels in patients with this form of angina is different from that in the classic form.

Adult↗

Coronary angiographic features in 2,234 patients with clinical suspicion of coronary heart disease without modifiable risk factors.

Among 12,720 patients subjected to coronary angiography because of clinical suspicion of coronary heart disease, 2,234 (78% men and 22% women) were free from major modifiable coronary risk factors. They did not report alcohol consumption, use of antiplatelet or lipid lowering agents, oral contraceptives or sex hormones; there was no history of bilateral oophorectomy, smoking, diabetes mellitus, hypertension, or obesity; the ratio of total to high-density lipoprotein cholesterol was < or = 4.5. We examined lesions causing > or = 50% stenosis to total obliteration of the 3 great coronary arteries or of their major branches, and classified these patients as having single-, double-, or triple-vessel disease, or normal angiograms (no luminal irregularities). We related the extent of the coronary angiographic involvement to age and sex. From the fourth to the eighth decade of life: a) prevalence of normal angiography was significantly higher in women; b) percentage of cases with single-vessel disease was similar in both sexes and gradually reduced with aging; c) prevalence of double-vessel disease in women did not vary significantly, although a slight decline was seen at older ages; in men figures at the fifth and sixth decades were significantly greater than in women; d) percentages by decade of triple-vessel disease in males were 24, 34, 41, 49 and 57%, respectively; corresponding values in women were 11, 13, 15, 27 and 44% (p < 0.01 at each decade of age); with advances of age the sex gap in triple-vessel disease narrowed, but did not disappear. Thus, atherosclerosis tended with age to involve more vessels rather than more subjects in both genders, indicating that in the absence of modifiable coronary risk factors coronary vessels remained clearly susceptible to the influence of age, both in men and women. In these patients the feminine gender exerted a substantial protection that persisted for the entire span of life.

Adult↗

Coronary angiographic patterns in hypertensive compared with normotensive patients.

Patients in this study were assessed by coronary angiography because of classic effort angina and a positive exercise test. Of these patients, 320 had untreated primary hypertension and 320, similar in age and gender distribution, were normotensive. In all patients coronary angiography documented that at least one major epicardial branch was restricted by 50% or more. Prevalence of single- and double-vessel disease in the fourth and fifth decades of life was similar in the two populations and in both tended to decline with age. Prevalence of triple-vessel disease was also similar in the two populations in the fourth and fifth decades; in either population it rose with age and reached a peak at the seventh decade of life. The percentages of hypertensive patients in the sixth and seventh decades with triple-vessel disease was significantly (p less than 0.01) greater (40% and 50%, respectively) than the corresponding values in normotensive individuals (25% and 31%, respectively). The left main coronary artery was not significantly more involved in the high blood pressure group. Pressure was moderately and similarly raised at any age in hypertension; serum cholesterol and triglyceride levels, blood glucose, and smoking habits were comparable in the two populations. These results suggest that hypertension does not accelerate the appearance of significant coronary narrowing or multiple vessel involvement. Starting from the sixth decade, the natural age-related evolution of coronary disease seems to be aggravated in hypertensive subjects, as reflected by an augmented number of diseased vessels. This process is probably related to high blood pressure in itself; whether the severity of hypertension might also exert an influence is not deducible from this study.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

Fluxplus, a microcomputer program for interactive calculation of 'in vitro' solute fluxes, uptakes and accumulations in studies of intestinal transport.

A new microcomputer program for interactive comparisons, analysis and calculation of in vitro solute transepithelial fluxes and nutrient uptakes and accumulations by intestinal tissues is described. The program is written in Microsoft GWBASIC for the widely distributed IBM-PC. Flux, uptake and accumulation values are obtained by computation from initial sequential data files and stored in sequential or random-orgaized files, depending on the specific process. Computed unidirectional fluxes are saved together with their associate electrical variables. The program calculates univariate statistics for unidirectional and net fluxes, and allows comparisons between selected groups of experiments by using the Student's t-test. An homocedasticity test is also provided. Active uptake or accumulations of solutes are calculated by substracting the predicted diffusive values at a determined concentration to total uptake or accumulation and from this, kinetic parameters are computed. The program was designed to be user-friendly and includes several functions to permit the user to manage and examine stored data. Examples of outputs illustrate applications of the program.

Animals↗

Acute coronary vasomotor effects of nifedipine and therapeutic correlates in syndrome X.

In 18 patients (12 women) presenting with effort-induced chest pain and normal coronary angiograms (syndrome X), 10 mg sublingual nifedipine increased the lumen of major coronary arteries (quantitative angiography) by 13 +/- 10% (p less than 0.01), coronary blood flow (thermodilution) by 23 +/- 26% (p less than 0.05), norepinephrine plasma concentration by 60 +/- 42% (p less than 0.01) and decreased the global ST-segment shift during the effort stress test from 8.8 +/- 4.1 to 7 +/- 6.8 mm (p less than 0.03) at comparable maximal workload and at unchanged double product. There was a correlation (positive) of changes in flow with changes in coronary lumen diameter (r = 0.65, p less than 0.01) with ST-segment response to exercise (r = 0.83, p less than 0.001) and with (inverse) norepinephrine plasma concentration (r = -0.70, p less than 0.01); no correlation was found between ST-segment response and changes in arterial lumen diameter. In a few cases, nifedipine did not improve or even worsened the response to exercise; coronary flow was unchanged or decreased and norepinephrine plasma levels were modestly or greatly increased, respectively. After 4 weeks of treatment with nifedipine (10 to 20 mg 4 times daily), the effort ST-segment shift was further decreased to 4.4 +/- 3.5 mm (p less than 0.03) despite a slightly increased double product. Plasma norepinephrine values, as compared to those after acute nifedipine, were decreased by 40% in patients with further improvement and were unchanged in patients whose exercise performance did not vary.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Sublingual↗