Differential effects of arginine vasopressin on isolated guinea pig heart function during perfusion at constant flow and constant pressure

8-Arginine vasopressin (AVP) is a powerful coronary vasoconstrictor as well as peripheral vasoconstrictor, but AVP also is reported to have negative cardiac inotropic and chronotropic effects in vitro and in vivo. Our aim was to examine the direct effects of coronary vasoconstriction by AVP on cardiac function and metabolism in isolated guinea pig hearts perfused either at a constant perfusion pressure (CPP) of 55 mm Hg or at a constant coronary flow (CCF) equal to the initial natural flow at constant pressure. Coronary vasoconstriction was elicited by perfusing hearts with increasing concentrations of AVP in random order. Variables assessed were atrial heart rate (HR), atrioventricular (AV) conduction time, left ventricular pressure (LVP), coronary flow, inflow and outflow O2 tensions, O2 delivery (Do2), oxygen consumption (MVo2), percentage oxygen extraction (%O2E) and cardiac efficiency (HR-LVP/MVo2). We found that AVP increased coronary vascular resistance more at CCF than at CPP. The decrease in coronary flow, as a function of AVP at CPP, produced concentration-dependent decreases in heart rate, LVP, and MVo2, a decrease in Do2/MVo2, increases in AV conduction time and %O2E, and no significant change in cardiac efficiency. In contrast, the increase in perfusion pressure as a function of AVP at CCF caused no change in HR and AV conduction time, much smaller decreases in LVP and Do2/MVo2, a smaller increase in %O2E, an increase rather than a decrease in MVo2, and a decrease in cardiac efficiency. Our results indicate that larger decreases in HR, LVP, MVo2, and Do2/MVo2, and the larger increases in AV conduction time and %O2E with the AVP-induced decrease in CF at CPP are consistent with myocardial depression resulting from reduced global perfusion. However, cardiac efficiency was maintained at CPP because the decreased HR and LVP product (cardiac work) matched the decrease in MVo2. At CCF, AVP did not directly produce myocardial depression, but the small time-dependent decrease in LVP over time was not matched by the increase in MVo2, so that cardiac efficiency was not maintained. The demonstration of an increase in MVo2 despite no change or a decrease in cardiac work by coronary vasoconstriction with AVP at CCF, but not at CPP, suggests that cardiac O2 use is dependent more on maintenance of CF, despite increased resistance to perfusion, rather than on maintenance of perfusion pressure. Our data agree that Gregg's phenomenon results from a hydraulic effect to distend coronary vasculature because when flow is not allowed to decrease during vasoconstriction, MVo2 increases even though HR is unchanged and LVP is slightly decreased. This is supported by the finding that AVP does not increase coronary vascular resistance during CCF as much as during CPP, so that O2 supply is better maintained to match MVo2.

Posttraumatic stress disorder in patients with traumatic brain injury and amnesia for the event?

Frequency of DSM-III-R posttraumatic stress disorder (PTSD) was studied in 47 active-duty service members (46 male, 1 female; mean age 27 = 7) with moderate traumatic brain injury and neurogenic amnesia for the event. Patients had attained "oriented and cooperative" recovery level. When evaluated with a modified Present State Examination and other questions at various points from study entry to 24-month follow-up, no patients met full criteria for PTSD or met criterion B (reexperience); 6 (13%) met both C (avoidance) and D (arousal) criteria. Five of these 6 also had organic mood disorder, depressed type, and/or organic anxiety disorder. Posttraumatic amnesia following moderate head injury may protect against recurring memories and the development of PTSD. Some patients with neurogenic amnesia may develop a form of PTSD without the reexperiencing symptoms.

[Economic aspects of modern inhalation anesthetics with sevoflurane as an example]

The economic impact of the new German health care laws requires an awareness of cost-effectiveness when using newer drugs. The main goal in patient care, i.e., effective treatment, must be achieved by the rational use of restricted resources at a maximum degree of effectiveness. Economic aspects of the new inhalational anaesthetics such as sevoflurane are discussed in this article. The cost of inhalational anaesthetic agents accounts for up to 5% of all the running expenses of an anaesthesia department. The consumption and cost of an inhalational agent depend on fresh gas flow, vapour setting, and duration of anaesthesia. Comparing the cost for 1 MAC-h of anaesthesia, desflurane is more expensive at current market prices than sevoflurane and isoflurane. However, at low or minimal fresh gas flows, the price for one MAC-h is almost the same for these volatile anaesthetics. Total intravenous anaesthesia using propofol is even more expensive, partly due to wastage, i.e., opened ampoules with a remainder of propofol that has to be discarded after each case. When choosing an anaesthetic agent, the price of 1 ml liquid anaesthetic is an important factor. However, the overall cost-effectiveness analysis must balance the cost of the agent with its pharmacodynamic advantages such as more rapid recovery from anaesthesia. Furthermore, the indirect costs of side effects have to be taken into account. For example, nausea and vomiting lead to a prolonged stay in the recovery room after anaesthesia for outpatient surgery, which in turn incurs additional costs for antiemetic drugs and the extra time for nursing care. Therefore, a lower incidence of nausea and vomiting and a more rapid recovery from anaesthesia leading to earlier discharge from the recovery room may compensate for the higher price. Volatile agents account for up to 1% of the total intraoperative costs. In analysing the costs of 1 h of anaesthesia, other products such as plasma substitutes and blood products account for a much higher proportion than anaesthetic agents, and reductions or increases in costs pertaining to these products have a bigger impact on overall costs than do volatile anaesthetics. We conclude that volatile anaesthetics account for only a minor portion of the anaesthesia department budget and the cost of anaesthesia delivery. The higher market price of the new agents may be compensated for by the economic impact of fewer side effects and a shorter post-anaesthesia stay in the hospital. In analysing data for sevoflurane, this agent may be cost-effective, for example, for outpatient anaesthesia.

Clonal and temporal patterns of nasopharyngeal penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae stains in children attending a day care center

The nasopharyngeal carriage of penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae (PSSp and PRSp, respectively) was analyzed in 116 children attending a day care center in Rouen, France, by three observation periods in November, January, and March of the winter of 1993 to 1994. The carriage rate of S. pneumoniae was found to be 47.7, 47.3, and 49.6% at each different observation period, and PRSp accounted for 42.2, 40.3, and 40.6% of pneumococcal isolates, respectively. The 52 isolates recovered in November were distributed in 34 electrophoretic types (ETs) by multilocus enzyme electrophoresis; 15 PRSp isolates, all of serotype 23F, belonged to a clonal complex of five ETs, representing the dominant population of PRSp in November. The temporal pattern of S. pneumoniae carriage was studied in 17 children who were colonized at the three periods by multilocus enzyme analysis of their isolates. The PSSp isolated, exhibiting distinct ETs, were transient only among these day care attendees. In contrast, most of the PRSp isolated in January and March belonged to the clonal complex. Thus, this PRSp population was resident in the day care center throughout the study period.

Effects of continuous (CPAP) and bi-level positive airway pressure (BiPAP) on extravascular lung water after extubation of the trachea in patients following coronary artery bypass grafting

OBJECTIVE

To evaluate the effects of continuous positive airway pressure (CPAP) and bi-level positive airway pressure (Bi-PAP) on extravascular lung water during weaning from mechanical ventilation in patients following coronary artery bypass grafting.

DESIGN

Prospective, randomized clinical study.

SETTING

Intensive care unit at a university hospital.

PATIENTS

Seventy-five patients following coronary artery bypass grafting.

INTERVENTIONS

After extubation of the trachea, patients were treated for 30 min with CPAP via face mask (n = 25), with nasal BiPAP (n = 25), or with oxygen administration via nasal cannula combined with routine chest physiotherapy (RCP) for 10 min (n = 25).

MEASUREMENTS AND RESULTS

Extravascular lung water (EVLW), pulmonary blood volume index (PBVI) and cardiac index (CI) were obtained during mechanical ventilation (T1), T-piece breathing (T2), interventions (T3), spontaneous breathing 60 min (T4) and 90 min (T5) after extubation of the trachea using a combined dye-thermal dilution method. Changing from mechanical ventilation to T-piece breathing did not show any significant differences in EVLW between the three groups, but a significant increase in PBVI from 155 +/- 5 ml/m2 to 170 +/- 4 ml/m2 could be observed in all groups (p < 0.05). After extubation of the trachea and treatment with BiPAP. PBVI decreased significantly to 134 +/- 6 ml/m2 (p < 0.05). After treatment with CPAP or BiPAP, EVLW did not change significantly in these groups (5.5 +/- 0.3 ml/kg vs 5.0 +/- 0.4 ml/kg and 5.1 +/- 0.4 ml/kg vs 5.7 +/- 0.4 ml/kg). In the RCP-treated group, however, EVLW increased significantly from 5.8 +/- 0.3 ml/kg to 7.1 +/- 0.4 ml/kg (p < 0.05). Sixty and 90 min after extubation, EVLW stayed at a significantly higher level in the RCP-treated group (7.5 +/- 0.5 ml/kg and 7.4 +/- 0.5 ml/kg) than in the CPAP-(5.6 +/- 0.3 ml/kg and 5.9 +/- 0.4 ml/kg) or BiPAP-treated groups (5.2 +/- 0.4 ml/kg and 5.2 +/- 0.4 ml/kg). No significant differences in CI could be observed within the three groups during the time period from mechanical ventilation to 90 min after extubation of the trachea.

CONCLUSIONS

Mask CPAP and nasal BiPAP after extubation of the trachea prevent the increase in extravascular lung water during weaning from mechanical ventilation. This effect is seen for at least 1 h after the discontinuation of CPAP or BiPAP treatment. Further studies have to evaluate the clinical relevance of this phenomenon.

[Neurologic side-effects of pharmacologic corticoid therapy]

Many side effects of steroid treatment have been reported. Even experienced neurologists may not know all important side effects to the nervous system. Autonomic nervous system dysfunction, psychosis and myopathy are more frequently encountered than dependency, reversible dementia, brain atrophy and benign intracranial hypertension. This review describes symptomatology, pathogenesis and treatment of these steroid-induced side effects.

Diagnostic and prognostic value of cerebral 31P magnetic resonance spectroscopy in neonates with perinatal asphyxia

The impact of depressed neonatal cerebral oxidative phosphorylation for diagnosing the severity of perinatal asphyxia was estimated by correlating the concentrations of phosphocreatine (PCr) and ATP as determined by magnetic resonance spectroscopy with the degree of hypoxic-ischemic encephalopathy (HIE) in 23 asphyxiated term neonates. Ten healthy age-matched neonates served as controls. In patients, the mean concentrations +/- SD of PCr and ATP were 0.99 +/- 0.46 mmol/L (1.6 +/- 0.2 mmol/L) and 0.99 +/- 0.35 mmol/L (1.7 +/- 0.2 mmol/L), respectively (normal values in parentheses). [PCr] and [ATP] correlated significantly with the severity of HIE (r = 0.85 and 0.9, respectively, p < 0.001), indicating that the neonatal encephalopathy is the clinical manifestation of a marred brain energy metabolism. Neurodevelopmental outcome was evaluated in 21 children at 3, 9, and 18 mo. Seven infants had multiple impairments, five were moderately handicapped, five had only mild symptoms, and four were normal. There was a significant correlation between the cerebral concentrations of PCr or ATP at birth and outcome (r = 0.8, p < 0.001) and between the degree of neonatal neurologic depression and outcome (r = 0.7). More important, the outcome of neonates with moderate HIE could better be predicted with information from quantitative 31P magnetic resonance spectroscopy than from neurologic examinations. In general, the accuracy of outcome predictability could significantly be increased by adding results from 31P magnetic resonance spectroscopy to the neonatal neurologic score, but not vice versa. No correlation with outcome was found for other perinatal risk factors, including Apgar score.

Retention of the antibiotic teicoplanin on a hydromer-coated central venous catheter to prevent bacterial colonization in postoperative surgical patients

OBJECTIVE

Antibiotic-coated intravascular catheters may be an effective means of decreasing bacterial colonization and subsequent catheter-related infection. The present study was designed to investigate the retention of the antibiotic teicoplanin on a hydromer-coated intravenous catheter and the effect of this antibiotic coating on catheter bacterial colonization.

DESIGN

A prospective, randomized pilot study.

SETTING

Operating rooms (ORs) and an intensive care unit (ICU) at a university hospital.

PATIENTS

A consecutive group of 20 male patients undergoing major abdominal surgery.

INTERVENTIONS

Control (C; n = 10) or teicoplanin-coated (T; n = 10) single-lumen central venous catheters were inserted before surgery in the OR. Catheters were withdrawn at the discretion of the physicians in the ICU after various periods.

MEASUREMENTS

The teicoplanin content of the catheter material was assessed using a bioassay with Bacillus subtilis after complete elution of the antibiotic from the catheter. Bacterial colonization was measured using a quantitative culture technique after the catheter lumen had been flushed and the catheter segments sonicated.

MAIN RESULTS

Nearly three-quarters of the initial teicoplanin coating (374 +/- 103 micrograms; mean +/- SD) were released during the first day of catheterization, and after 36 h of intravenous catheterization, no antibiotic was retained on the catheter. No significant difference could be found either in the incidence of bacterial colonization between test (n = 3) and control (n = 4) catheters or in the number of colony-forming units (CFU) on the catheter segments (T, 263 +/- 104 CFU/cm; C, 372 +/- 294 CFU/cm; mean +/- SEM).

CONCLUSION

The retention of teicoplanin antibiotic coating on hydromer catheters is only short term if catheters are inserted intravenously. This may limit clinical antibacterial efficacy.

Circulating immune complexes and renal function in canine leishmaniasis

A third component of complement (C3) capture enzyme-linked immunosorbent assay was used to determine the concentration of IgG circulating immune complexes (CIC) in 91 dogs with naturally acquired leishmania infection and in a control group of 24 healthy dogs. Results were expressed as a percentage of a reference standard. Mean concentrations of CIC were significantly (P < 0.001) higher in leishmania-infected dogs (228.725 +/- 14.283%) than in controls (74.542 +/- 12.614%). An increase in CIC concentration was found in 57.1% of the leishmania-infected dogs. No significant differences could be recorded in CIC levels between males and females in either group. Infected dogs showing hypercreatininemia rendered a statistically significant (P < 0.030) higher serum CIC concentration than sick dogs with normal creatininemia. When hypercreatininemia (> or = 1.30 mg/dl) was used as an indicator for CIC increase, the positive predictive value obtained was 0.9 indicating that renal function impairment was associated with high serum CIC concentration in 90% of the infected dogs.

Inhaled nitric oxide selectively decreases pulmonary artery pressure and pulmonary vascular resistance following acute massive pulmonary microembolism in piglets

Acute massive pulmonary embolism increases pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR), which may lead to early right ventricular failure and subsequent cardiocirculatory deterioration. Inhaled nitric oxide (NO) selectively dilates pulmonary vessels in vivo. Thus, inhaled NO may be useful in preventing cardiocirculatory deterioration following pulmonary embolism. We investigated the effects of inhaled NO in the acute phase of massive pulmonary microembolism in 10 anesthetized and mechanically ventilated piglets (body weight, 18 +/- 2 kg). Microspheres of 300-microns diameter were injected i.v. in an amount sufficient to initially increase mean PAP to 45 mm Hg. Forty-five minutes after pulmonary embolization, the pretreatment control values were recorded. Thereafter, the piglets inhaled 40 ppm NO, and subsequently 80 ppm NO. When 40 ppm NO was inhaled, there was a significant decrease in systolic PAP (-10.3%; 44.5 +/- 2.2 to 39.9 +/- 2.4 mm Hg; p < 0.05) and mean PAP (-9.4%; 32.9 +/- 1.3 to 29.8 +/- 1.3 mm Hg; p < 0.05). PVR was changed by -13.6% (p = 0.07). Administration of 80 ppm NO resulted in a significant decrease in systolic PAP (-12.6%; to 38.9 +/- 1.9 mm Hg; p < 0.05), mean PAP (-11.9%; to 29.0 +/- 1.4 mm Hg; p < 0.05), and PVR (-19.4%; p < 0.05) compared with pretreatment values. Discontinuation of NO inhalation was associated with an immediate return to pretreatment values. Systemic hemodynamics and the arterial and mixed venous oxygen concentrations remained unchanged. We conclude that inhaled NO following acute massive pulmonary microembolism selectively decreases PAP and PVR without influencing systemic hemodynamics in piglets.

Fatal infection of coronary stent implantation

Among systemic infections occurring after percutaneous transluminal coronary angioplasty (PTCA) and coronary stent implantation, septic cardiac complications are rare. We report a new case of infective aneurysm of the left anterior descending coronary artery (LAD) following stent implantation. Infective mitral endocarditis due to Pseudomonas aeruginosa occurring a few weeks after stenting led to search for stent infection. Coronary angiography revealed a saccular aneurysm of the LAD. Despite surgical repair, a fatal outcome resulted.

Late intrauterine Cytomegalovirus infection: clinical and neuroimaging findings

Fetal Cytomegalovirus (CMV) infection in early pregnancy usually results in severe neurological handicap and sensorineural hearing loss with typical neuroradiological findings of calcification, migrational anomalies, disturbed myelination, and cerebellar hypoplasia. Infections acquired in late pregnancy have less prominent signs, such as microcephaly, hearing deficits, and minor neurological handicap. We report 7 children who presented with a similar clinical complex of signs: microcephaly, sensorineural hearing impairment, behavior problems with hyperactivity, reduced apprehension for pain in 5 of the 7, ataxia in 3, and hypotonia with clumsiness in 3 others. All manifested mild to severe developmental problems. Cranial CT revealed calcification in 4 of 6 patients. MRI in all 7 children showed patchy to confluent nonprogressive dysmyelination. Only 2 children had acute neonatal signs of congenital CMV infection. We assume that these children acquired CMV infection in the third trimester of gestation, leading to microcephaly, hearing loss, and neurological and developmental problems with typical neuroradiological signs.

Development of the genital peritoneal folds in sheep

Development of the genital peritoneum in the sheep was studied in embryos/fetuses that were 27-69 days old. The plica mesonephrica was the first visible fold of the urogenital organs of the embryos and was the origin of the proximal mesorchium or mesovarium. The plica suspensoria gonadalis fixed the gonad to the mesonephros and held the cranial genital ligament and the cranial part of the gubernaculum. The distal and the cranial part of the gernaculum. The distal mesorchium or mesovarium evolved from this fold. The inguinal fold fixed the caudal part of the gubernaculum. The suspensory fold of the gonad and plica inguinalis formed a system of serosal folds called the Plica gonadoinguinalis. The fold of the genital ducts had two parts, divided by the crossing with the gubernaculum. The mesepididymis or mesosalpinx evolved from the cranial part of the fold, while the caudal part was the origin of the mesoductus deferens or mesometrium. The caudal part of the right and left folds contributed to defining another system of peritoneal folds, the Plica genitalis. A rearrangement of some accepted terms in the nomenclature is proposed, as are some new terms. An analysis of the meaning of some terms, especially those applied to systems of peritoneal folds, is given to aid in their interpretation.

Different effect of inhaled nitric oxide on yucatan micropig with and without congenital ventricular septal defect

A strain of Yucatan micropigs is known to have heritable ventricular septal defects (VSDs) and thus may develop overflow pulmonary hypertension. Since inhaled nitric oxide (NO) selectively dilates pulmonary vessels, we determined its hemodynamic and co-agulatory effects in this new animal model. Eight Yucatan micropigs were anesthetized with midazolam, piritramide (a synthetic opioid) and vecuronium bromide. The presence and the size of the VSD were determined by using transesophageal color flow Doppler echocardiography. Four animals showed VSDs of 1-2 mm size. Inhaled NO was then administered with increasing inspired concentrations of 0, 5, 10, 20, 40, 80 and again 0 ppm NO for 10-min periods. NO inhalation did not affect heart rate, right cardiac output, mean arterial pressure, pulmonary arterial wedge pressure, or central venous pressure. Inhaled NO in animals with proven VSDs decreased pulmonary artery pressure (PAP) in a dose dependent manner; 5 ppm NO reduced mean PAP from 25 +/- 2.3 mm Hg to 18 +/- 0.8 mm Hg (p < 0.05), while pulmonary vascular resistance (PVR) decreased from 954 +/- 143 dyn.cm. s-5 to 661 +/- 88 dyn.cm.s-5 (p < 0.01) at the same dose. The maximum reduction in mean PAP and PVR occurred when 80 ppm NO was inhaled. Yucatan micropigs without VSDs did not respond hemodynamically to NO inhalation. Methemoglobin levels remained unchanged during the entire study. Platelet function was assessed according to the method of BREDDIN and BORN (BORN 1962). Initial aggregation and slope were affected when NO inhalation commenced. Yucatan micropigs with VSDs may represent a suitable model for further research of the in vivo effects of inhaled NO.

Mapping of catalytic residues in the RNA polymerase active center

When the Mg2+ ion in the catalytic center of Escherichia coli RNA polymerase (RNAP) is replaced with Fe2+, hydroxyl radicals are generated. In the promoter complex, such radicals cleave template DNA near the transcription start site, whereas the beta' subunit is cleaved at a conserved motif NADFDGD (Asn-Ala-Asp-Phe-Asp-Gly-Asp). Substitution of the three aspartate residues with alanine creates a dominant lethal mutation. The mutant RNAP is catalytically inactive but can bind promoters and form an open complex. The mutant fails to support Fe2+-induced cleavage of DNA or protein. Thus, the NAD-FDGD motif is involved in chelation of the active center Mg2+.

Dopexamine maintains intestinal villus blood flow during endotoxemia in rats

OBJECTIVE

To determine the influence of dopexamine, a synthetic catecholamine ligand for dopaminergic and beta 2-adrenergic receptors, on alterations of the intestinal villus microcirculation in a model of normotensive endotoxemia.

DESIGN

Randomized, controlled trial.

SETTING

Experimental laboratory.

SUBJECTS

Twenty-one male Wistar rats.

INTERVENTIONS

Rats were treated with a continuous infusion of dopexamine (2.5 micrograms/kg/min; N = 7; group A) or 0.9% saline (n = 7; group B) during a study period of 120 mins. Both groups were given endotoxin (Escherichia coli lipopolysaccharide; 1.5 mg/kg Iv) over 60 mins. Animals in the control group (n = 7; group C) received a volume-equivalent infusion of 0.9% saline. Total volume substitution in all groups was 15 mL/kg/hr.

MEASUREMENTS AND MAIN RESULTS

Blood flow in the intestinal villi of the distal ileum was determined using in vivo videomicroscopy at baseline, and 60 and 120 mins after the endotoxin challenge. These blood flow determinations were done by an observer who was unaware of the previous treatment of the animals. In addition, mean arterial pressure was monitored at baseline, and 15, 30, 45, 60, 75, 90, 105, and 120 mins later. The administration of 1.5 mg/kg endotoxin alone (group B) resulted in a reduction of the intestinal villus blood flow to 74.8 +/- 9.5% of baseline after 60 mins, and to 61.1 +/- 8.5% of baseline after 120 mins (baseline: 7.4 +/- 0.6 nL/min; 60 mins: 5.3 +/- 0.8 nL/min; 120 mins: 4.4 +/- 0.5 nL/min; p < .05). This reduction of blood flow was associated with a decrease in the arteriolar diameters by 13.8 +/- 2.5% after 60 mins, and by 17.1 +/- 4.3% after 120 mins (p < .05 vs. baseline). In contrast, villus blood flow in the dopexamine group (group A) did not show statistically significant changes during the entire study period, despite the administration of endotoxin (baseline: 8.2 +/- 0.6 nL/min; 60 mins: 7.3 +/- 0.8 nL/min; 120 mins: 7.8 +/- 0.5 nL/min). No vasoconstriction of the villus arterioles was noted in this group. In control animals (group C), the blood flow (baseline: 8.1 +/- 1.6 nL/min; 60 mins: 7.6 +/- 1.4 nL/min: 120 mins: 7.8 +/- 1.4 nL/min) and the arteriolar diameters remained unchanged throughout the observation period. Mean arterial pressure did not differ between groups: it remained unaltered in all groups during the entire study period.

CONCLUSIONS

Dopexamine maintains intestinal villus arterial perfusion and prevents the vasoconstriction in villus arterioles during early normotensive endotoxemia. Therefore, further studies in critically ill patients will have to determine whether the early prophylactic use of dopexamine can limit ischemia and prevent the development of multiple organ failure.

[Chronobiology in medicine and surgery]

Chronobiology studies predictable variations, rhythms and trends in all forms of life. Each physiologic variable or system in an organism has a time structure which is genetically anchored and capable of being expressed in the absence of external cycles. However, it is normally adjusted by geophysical changes. Chronobiology quantifies rhythms by providing measures of amplitude and timing (phase and period), and a mean more precise than the arithmetic mean. The correct measurement of biological rhythms has led to considerable advances in the understanding of their underlying mechanisms of generation and expression. The use of information on rhythms is opening new opportunities in the prevention, diagnosis and treatment of disease. Chronobiology is also effective in the improvement of the quality of life by teaching self-help to the healthy individual.

Antinuclear antibodies in dogs with leishmaniasis

An indirect immunofluorescence method using rat liver as material was developed to determine the incidence of antinuclear antibodies in serum from 44 adult dogs naturally infected with leishmaniasis and, for comparative purposes, in a control group of 30 healthy dogs. Animals in both groups were of different breeds with a similar age distribution. Antinuclear antibodies were not detected in the healthy dogs and only 15.9% of the diseased dogs, 12.0% males and 21.1% females, were positive. The results indicate that in contrast to previously reported figures, the incidence of antinuclear antibodies is low in canine leishmaniasis at least when diagnosis is first made. In order to investigate whether antinuclear antibodies may play a role in the development of the renal damage observed in canine leishmaniasis, the concentrations of serum creatinine were related to the presence of antinuclear antibodies. Only 28.5% of the antinuclear antibodies positive infected dogs showed hypercreatininemia as did 32.4% of the antinuclear antibodies negative infected dogs. Thus, antinuclear antibodies are not significantly cause-effect related to the development of the renal lesions seen in canine leishmaniasis.

[Etomidate versus propofol for anesthesia in ambulatory cardioversion]

OBJECTIVE

This study compared the two short-acting intravenous anaesthetic agents, etomidate in lipid emulsion and propofol, for anaesthesia during elective outpatient cardioversion.

METHODS

After institutional approval and informed consent, 40 patients (ASA II/III) scheduled for cardioversion were studied. Patients with a left ventricular ejection fraction < 30% were excluded. The anti-arrhythmic medication was not discontinued, and no patient was given pharmacological premedication. Anaesthesia was induced either with etomidate (in lipid emulsion) 0.25 mg/kg or propofol 1.5 mg/kg. Both agents were administered over 30 seconds. Subsequent increments were given until the patients no longer followed verbal commands and the lid reflex was absent. Patients were allowed to breathe 40% oxygen via face mask. Artificial ventilation was performed if a patient became apnoeic for more than 20 seconds. The blood pressure was monitored continuously with the Finapres noninvasive blood pressure monitor, and the heart rate was recorded simultaneously. All data were collected electronically. The duration of anaesthesia was taken as the period from the start of induction until the opening of the eyes on command. For assessment of recovery from anaesthesia, patients were asked to perform a series of psychomotor tests.

RESULTS

The two groups were similar in their demographic and haemodynamic baseline data. In both groups, a significant decrease in blood pressure occurred 120 seconds after anaesthesia induction, which was due to the performance of the cardioversion. Five minutes after induction, the blood pressure returned to baseline in the etomidate group, while it remained below baseline in the propofol group. Propofol caused a significant decrease in heart rate. Significantly more patients needed artificial ventilation after propofol administration because of apnoea. Involuntary muscle movements occurred only in patients receiving etomidate. The immediate emergence from anaesthesia was faster after propofol. However, 15 minutes after awakening there was no difference in psychomotor skills between the two groups. No residual psychomotor impairment was evident 60 minutes after anaesthesia in any patient. All patients were discharged four hours after the cardioversion.

CONCLUSIONS

Because the recovery characteristics were similar in both groups, the occurrence of side effects may be a major factor when choosing between etomidate and propofol for outpatient cardioversion.