Search PubMed⌕ Search

Biomedical subjects

I Castelli

Publications and source records attributed to I Castelli.

12 recordsLinked to original sources
PubMed1996

Renal vascular responses to high and low ionized calcium: influence of norepinephrine in the isolated perfused rat kidney.

OBJECTIVE AND DESIGN: The aim of this study was to examine the influence of norepinephrine (NE) on renal vascular responses to high (1.88 mmol/L) and low (0.56 mmol/L) perfusate-ionized calcium ([Ca2+]) in the isolated perfused kidney of the rat. High and low [Ca2+] encompassed the clinical concentration range in this multiexperiment, randomized trial. MATERIALS AND METHODS: Rats (n = 25), ranging in age from 3 to 4 months, were anesthetized and the ureter and renal artery were cannulated. The right kidney was perfused with oxygenated, warmed albumin (67 g/L) containing Krebs-Henseleit buffer and placed in a thermostated chamber without interruption of flow. In protocol A (n = 7), steady-state high [Ca2+] (1.88 mmol/L) and low [Ca2+] (0.56 mmol/L) were instituted in randomized order in each experiment under basal conditions. In protocol B (n = 9), the same interventions were instituted during constant rate NE infusion. Changes in renal flow were measured at constant perfusion pressure (110 mm Hg), and renal vascular resistance (RVR) was calculated. Renal function was assessed by clearance of [14C]inulin and by fractional excretion of sodium. With NE-induced preconstriction, the increase in RVR observed during high [Ca2+] was +17.8 +/- 1.8% of control, and the decrease in RVR observed during low [Ca2+] was -35.9 +/- 8.2% of control. Both values were greater by a factor of 2 than corresponding results obtained under basal conditions (7 +/- 2.1% vs. -13.5 +/- 4.1% of control, respectively, p < 0.05). Whereas the decrease in glomerular filtration rate with high [Ca2+] was not significantly influenced by NE pretreatment (-9 +/- 1.8% of control with high [Ca2+] in combination with NE vs. 4.1 +/- 0.7% of control under basal conditions), the increase in glomerular filtration rate with low [Ca2+] was significantly greater in the presence of NE (12 +/- 0.7 vs. 102 +/- 8.5% of control, p < 0.01). CONCLUSIONS: Whereas under basal conditions renal vascular effects of high and low [Ca2+] (varied within the clinical concentration range) are small, the changes recorded with the same interventions after NE pretreatment are increased by a factor of > 2. Hypercalcemia-induced renovascular constriction and decreased function are unfavorable, especially in patients who are at risk for renal dysfunction from other causes.

Animals↗
PubMed1995

Panleukopenia-like syndrome of FeLV caused by co-infection with FeLV and feline panleukopenia virus.

To study the effect of interferon on feline leukemia virus (FeLV) infection, 30 specific pathogen free (SPF) cats were infected with the apathogenic FeLV A Glasgow. Unexpectedly, between 5 and 8 weeks after FeLV infection, all 19 cats with persistent FeLV infection but not the FeLV-negative cats died from a panleukopenia-like syndrome. No feline panleukopenia virus (FPLV) antigen was found in feces by latex agglutination, enzyme-linked immunosorbent assay (ELISA) or immunoelectron microscopy. No enteropathogenic bacteria were found. Histopathology revealed changes resembling those of FPLV infection such as destruction of crypts and pancytopenia of bone marrow. Neither clinical signs nor seroconversion to FPLV could be induced by transmitting intestinal extracts to two SPF cats. However, FPLV antigen was demonstrated by immunofluorescence assay in intestinal cryostat sections of diseased animals. FPLV could also be demonstrated in intestinal extracts by immunoelectron microscopy, by latex agglutination and ELISA after anti-FPLV antibodies were removed from immune-complexed FPLV by ultracentrifugation over a CsCl gradient at pH 2.0. From these experiments it was concluded that the panleukopenia-like syndrome of FeLV may not be caused by FeLV alone but at least in some cases by co-infection with FeLV and FPLV. In addition, some form of 'cooperation' between FeLV and FPLV must be postulated because neither virus alone induced symptoms.

Animals↗
PubMed1995

Comparative effects of esmolol and labetalol to attenuate hyperdynamic states after electroconvulsive therapy.

We studied 18 patients (age range, 53-90 yr) with at least one cardiovascular risk factor who were treated with electroconvulsive therapy (ECT) and compared effects of five pretreatments: no drug; esmolol, 1.3 or 4.4 mg/kg; or labetalol, 0.13 or 0.44 mg/kg. Each patient received all five treatments, during a series of five ECT sessions. Pretreatment was administered as a bolus within 10 s of induction or anesthesia. Doses of methohexital and succinylcholine were constant for the series of treatments and the assignment to no drug or to drug and dose was determined by randomized block design. Measurements of systolic and diastolic blood pressure (SBP, DBP) and heart rate (HR) were recorded during the awake state and 1, 3, 5, and 10 min after the seizure. The deviation of ST segments from baseline was measured by an electrocardiogram (ECG) monitor equipped with ST-segment analysis software. The results (mean +/- SEM) show that without pretreatment, there were significant (P < 0.05) peak increases in SBP and HR (55 +/- 5 mm Hg and 37 +/- 6 bpm, respectively), recorded 1 min after the seizure. Comparable reductions (by approximately 50%) in these peak values were achieved after esmolol (1.3 mg/kg) or labetalol (0.13 mg/kg), and cardiovascular responses were nearly eliminated after the same drugs in doses of 4.4 and 0.44 mg/kg, respectively. The deviation of ST-segment values from baseline in any lead was not measurably influenced by either antihypertensive drug. SBP values were lower after labetalol 10 min after the seizure, but not after esmolol. Asystolic time after the seizure was not significantly longer with either drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1995

Three cases of blunt chest trauma caused by constant compression mechanisms.

Three patients (survivors) with isolated blunt chest traumas caused by constant compression mechanisms with known forces are reported on. The low velocity but high compression forces of the accidents, the effect on ventilation and oxygenation, specific early management and follow-up, clinical signs, and underlying complications of these patients are described and discussed.

Accidents↗
PubMed1995

Nitric oxide dose-response study in the isolated perfused rat kidney after inhibition of endothelium-derived relaxing factor synthesis: the role of serum albumin.

The dose-response relationship of steady-state nitric oxide (NO) administration on renal vascular resistance in isolated rat kidneys (IPRK) perfused at constant pressure was investigated after inhibition of NO synthesis with NG-monomethyl-L-arginine (L-NMMA). To study the influence of biological thiols on renovascular NO effects, experiments were carried out with Krebs-Henseleit (KH) perfusate solutions alone, and in combination with bovine serum albumin (KH-ALB). Steady-state administration of NO by gassing the perfusate with 0 to 340 ppm NO led to graded decreases in renovascular tone. The minimal effective NO perfusate concentration in the absence of endogenous NO synthesis was about 6 to 8 nM, whereas a near-maximal effect was observed with approximately 200 nM. The presence of albumin reduced the speed of onset of renal vasodilation and the maximal effect at a given concentration of NO. After termination of NO administration, NO-induced vasodilation persisted in KH-ALB perfused kidneys for 30 min, whereas KH-perfused kidneys showed a rapid reconstriction. These findings suggest that the prolonged, potent renal vasodilation was caused by a reaction of bovine serum albumin (BSA) with oxides of nitrogen to form S-nitroso-BSA. Nitrosothiol levels in the KH-ALB perfusate were found to be proportional to the concentration of NO administered. The above-mentioned findings, confirmed in identical experiments with diethylamine NONOate, a novel NO-liberating substance, support the biological importance of S-nitrosothiols (RS-NO) in the action and metabolism of endothelium-derived relaxing factor (EDRF) in the IPRK.

Animals↗
PubMed1994

Prolonged decrease in heart rate variability after elective hip arthroplasty.

The pattern of postoperative heart rate variability may provide insight into the response of the autonomic nervous system to anaesthesia and surgery. We have obtained spectral (fast Fourier transform) and non-spectral indices of heart rate variability from electrocardiographic recordings, sampled during continuous perioperative Holter monitoring in 15 otherwise healthy patients with an uncomplicated postoperative course, undergoing elective hip arthroplasty with either spinal or general anaesthesia. In both groups, total spectral energy (0.01-1 Hz), low-frequency spectral energy (0.01-0.15 Hz) and high-frequency spectral energy (0.15-0.40 Hz) decreased after surgery to 32% (95% confidence interval (CI) 10.5; P < 0.01), 29% (95% CI 12.5; P < 0.01) and 33% (95% CI 12.5; P < 0.01) of their preoperative values, respectively, and these indices remained suppressed for up to 5 days. Non-spectral indices decreased to a similar extent. These findings indicate a substantial and prolonged postoperative decrease in both parasympathetic and sympathetic influence on the sinus node.

Aged↗
PubMed1993

[Quality of emergency admission (resuscitation, REA) and first aid in multiple trauma].

Undue delay between hospital admission and the beginning or urgent operative procedures is considered as a major mortality risk for polytraumatized patients in any trauma center. As part of a quality control study at our institution (Kantonsspital, University of Basel), the time spent for early resuscitation and diagnostic procedures was therefore prospectively recorded in 20 patients (mean age 38 years) with a mean ISS of 26.9 (range: 13 to 43). Time spent in the resuscitation room averaged 31.4 min (range: 10 to 50 min). Conventional radiographic diagnostic procedures took 34.7 more min (range: 20 to 60 min). An additional CT scan was performed in 15 patients requiring 19.5 min per region (head/thorax/abdomen/spine). Four patients underwent angiography necessitating 28 more min (mean). Time elapsed between admission and arrival of the patient in the OR or the ICU respectively accounted for an average of 89 min (range 22 to 200 min). For comparable injury severities this interval was shorter during the day than during the night (77 and 103 min respectively). Diagnoses established during this period were both accurate and comprehensive, as detectable from the low rate of missed diagnosis (three minor fractures). Although our results match favorably with figures reported in the literature we feel that further improvements could be achieved by performing the conventional radiographic procedures simultaneously with the early resuscitation in the resuscitation room. At present time, for reasons of X-ray protection, this is not possible in our institution.

Adolescent↗
PubMed1992

[Development of the helicopter-rescue concept in the Basel region].

1927 medical helicopter transports were performed in Basle between 1986 and 1989. Of the total flights, 173 transports without patients and 186 incubator transports were excluded from the study. Treatment and transportation were provided for 1085 victims of trauma (70.2%) and 461 medical-surgical patients (29.8%), mostly with life-threatening conditions. 589 trauma patients were treated at the scene of accident and later transported by helicopter to a nearby medical center (54.3%). The 4.3% rate of negative emergency flights is low. Since introduction of the helicopter rescue system at Basle in 1975, scene flights have increased from 29% in 1984 to 46% in 1989. 47.4% of all patients were categorized as seriously ill or severely injured. 36.4% of all patients required intubation and assisted ventilation. Of the trauma patients, 54.3% involved scene-flights requiring in-field intensive therapy. Helicopter transport provides not only a rapid source of transportation, but also vital medical assistance at the scene of emergency. Transport generally occurs only after stabilization of vital functions. These factors contribute to the low mortality before return flights (3%) as well as during transport (0.3%). We conclude that early aggressive in-field intensive therapy can help to decrease both morbidity and mortality in emergency-care patients.

Aircraft↗
PubMed1992

Perioperative myocardial ischemia in patients undergoing elective hip arthroplasty during lumbar regional anesthesia.

Perioperative myocardial ischemia predicts unfavorable outcomes and occurs in as many as 41% of patients with coronary artery disease or cardiac risk factors undergoing noncardiac surgery. To determine the prevalence of myocardial ischemia, we studied 52 consecutive unselected patients undergoing elective hip arthroplasty during lumbar regional anesthesia. Patients were continuously monitored for 6 days using a three-channel Holter monitor. Ninety-nine episodes of myocardial ischemia occurred in 16 patients (31%), six of whom were considered preoperatively to be at low risk for coronary artery disease. Forty-four percent of the ischemic episodes were preceded or accompanied by a heart rate greater than or equal to 100/min and 56% by a heart rate greater than or equal to 90 beats/min. Ninety-six percent of the ischemic episodes were clinically silent, and 82% were not related to patient care events. Thirteen episodes of myocardial ischemia occurred preoperatively, 1 intraoperatively, and 85 postoperatively. The incidence of postoperative ischemic episodes showed a circadian variation: 44% occurred between 6 AM and noon, 33% between noon and 6 PM, 17% between 6 PM and midnight, and 6% between midnight and 6 AM. Six adverse cardiac events occurred during hospitalization (three of the six among patients with perioperative ischemia) and an additional four events during a follow-up period of 12 months (all four events occurred among patients with perioperative ischemia). Patients with perioperative myocardial ischemia had a relative risk of 2.6 (95% confidence interval 1.3-5.2) to develop an adverse cardiac event postoperatively.

Aged↗
PubMed1992

Failure of continuous three-channel Holter monitoring to detect acute peri-operative myocardial infarction.

Continuous peri-operative three-channel Holter monitoring in a 70-year-old patient undergoing elective hip arthroplasty failed to show onset and progression of a lethal postoperative myocardial infarction, which was clearly visible in a 12-lead electrocardiogram. The modified bipolar leads used for Holter monitoring differed from the corresponding leads of the 12-lead electrocardiogram. The limitations of Holter monitoring applied to clinical management and research are highlighted.

Aged↗