Bird diversity-environment relationships in urban parks and cemeteries of the Neotropics during breeding and non-breeding seasons

Background

Urbanization will increase in the next decades, causing the loss of green areas and bird diversity within cities. There is a lack of studies at a continental scale analyzing the relationship between urban green areas, such as parks and cemeteries, and bird species richness in the Neotropical region. Bird diversity-environment relationships in urban parks and cemeteries may be influenced by latitudinal gradients or species-area relationships. However, the seasonal variation of species diversity- environment has not been analyzed at a continental scale in the Neotropics.

Methods

Bird surveys were conducted in 36 cemeteries and 37 parks within 18 Neotropical cities during non-breeding and breeding seasons. Bird diversity was assessed through Hill numbers, focusing on species richness, the effective number of species derived from Shannon index and the Simpson index. Environmental variables included latitude, altitude, and local scale variables such as area size, habitat diversity and pedestrian traffic.

Results

Species richness and Shannon diversity were higher during the breeding season, whereas Simpson diversity did not vary between seasons. During both seasons, species richness increased with area size, was negatively related to altitude, and was the highest at 20° latitude. Species richness was also positively related to habitat diversity, pedestrian traffic, and was highest in suburban areas during the non-breeding season. Shannon and Simpson diversity showed significant relationships with habitat diversity and area size during the breeding season. Bird diversity was similar between parks and cemeteries.

Discussion

Our results showed that urban parks and cemeteries have similar roles in conserving urban bird diversity in Neotropical cities. However, species diversity-environment relations at the continental scale varied between seasons, highlighting the importance of conducting annual studies.

Function of cryopreserved pig aortas

OBJECTIVES

This paper analyzes the influence of storage in the gas phase or liquid phase on grafts, together with the thawing method (15 degrees C/min or 100 degrees C/min) on the postthawing activity of pig cryopreserved arterial grafts (aortas).

MATERIALS AND METHODS

Obtainment of arterial grafts (aortas) was from pigs with an ischemic time not greater than 2 h. Each aorta was divided into five fragments and assigned randomly to one control group of fresh aorta and four groups of cryopreserved aortas: group 1: gas phase/slow thawing; group 2: gas phase/rapid thawing; group 3: liquid phase/slow thawing; and group 4: liquid phase/rapid thawing. After the incubation in antibiotic solution, the cryopreservation in RPMI medium +10% DMSO was carried out and the level of cooling used was a reduction of 1 degrees C/min. The contraction and relaxation responses of the fresh and frozen/thawed arteries were carried out in organ baths.

RESULTS

After thawing, the sensitivity to various agonists and maximal responses to the endothelium-dependent and independent relaxant agents were decreased. The maximal responses to the tested vasoconstrictors (KCl and noradrenaline) were, respectively, 13% and 24% of the responses obtained in unfrozen aortas. The endothelium-independent relaxant responses to sodium nitroprusside (SNP) were reduced and important reductions of the endothelium-dependent relaxant responses to acetylcholine were produced.

CONCLUSIONS

The cryopreservation of pig aortas under the conditions used in this study led to a decrease in the contractility of the pig aortas, as well as a decrease in the endothelium-independent relaxant responses. On the other hand, no apparent preservation of the endothelium-dependent relaxant responses was observed.

Sulfoxide-controlled S(N)2' displacements between cyanocuprates and epoxy vinyl sulfoxides

Two short and convergent routes have been devised for the preparation of enantiomerically pure acyclic epoxy vinyl sulfoxides. These substrates undergo highly regio- and stereoselective S(N)2' displacements with lithium cyanocuprates to give alpha'-alkylated, gamma-oxygenated Z alpha,beta-unsaturated sulfoxides in moderate to good yields and with good to excellent diastereoselectivities. The absolute configuration of the newly formed carbon-carbon bond is primarily controlled by the chiral sulfur atom, which in a nonreinforcing situation can override the intrinsic anti tendency of the vinyl oxirane moiety and forces the cuprate to undergo syn addition. The hydroxy vinyl sulfoxide functionality of the resulting adducts should allow for subsequent asymmetric transformations thus enhancing the synthetic usefulness of this methodology.

Enhanced endothelium-dependent vasodilation in patients with cirrhosis

Experimental evidence indicates that an increased production of nitric oxide could play a role in the peripheral vasodilation of portal hypertension. To test this hypothesis in humans, we studied basal serum NO(2-) + NO3- levels and the response of forearm resistance vessels to increasing concentrations of methacholine chloride, sodium nitroprusside, and phenylephrine infused into the brachial artery of 12 cirrhotic patients and 10 controls. Forearm vascular resistance (FVR) was calculated from mean arterial pressure and forearm blood flow (FBF). Cirrhotics showed higher NO(2-) + NO3- levels (P < 0.05), higher FBF (P < 0.01), and lower FVR (P < 0.01) than controls. The reduction of FVR in response to every dose of methacholine was greater in cirrhotics than in controls; this was significant (P < 0.05) at the 3 and 10 micrograms/min doses. This response to methacholine was not modified by blockade of vascular prostacyclin. The response to nitroprusside was similar in both groups. The increase in FVR in response to every dose of phenylephrine was significantly (P < 0.01) lower in cirrhotics than in controls. In cirrhotics, a significant correlation (r = -0.81, P < 0.01) was found between the FVR response to the highest doses of methacholine and phenylephrine. In conclusion, cirrhotic patients show an enhanced endothelium-mediated vasodilation, which suggests an increased synthesis of nitric oxide. This defect may mediate the peripheral vasodilation and hyporeactivity to vasopressors of these patients.

[Oral premedication with clonidine in patients undergoing coronary revascularization surgery]

OBJECTIVES

To analyze the effect of premedication with clonidine on level of sedation, anesthetic requirements and hemodynamic repercussions in patients undergoing coronary revascularization.

PATIENTS AND METHODS

Thirty patients were divided into two groups and randomly assigned for premedication with clonidine 0.005 mg/kg p.o. (C) or lorazepam 0.03 mg/kg p.o. (L), along with morphine 0.15 mg/kg i.m. and scopolamine 0.005 mg/kg i.m. in a prospective double-blind study. The level of sedation before surgery and anesthetic requirements in the two groups were compared, as were systolic and diastolic arterial pressure, heart rate and hemodynamics during and after surgery. Fentanyl was used for anesthetic induction in boluses of 0.15 mg every 10 seconds; maintenance boluses of 0.5 mg were used up to a maximum dose of 0.07 mg/kg. If hemodynamic variables analyzed (systolic and diastolic arterial pressure and heart rate) were not kept within 30% of baseline values with this regimen, isoflurane was added.

RESULTS

No differences between the two groups were found for level of sedation. The total dose of fentanyl was lower in group C (0.052 +/- 0.002 mg/kg vs 0.058 +/- 0.002 mg/kg) (p < 0.05). The number of patients requiring isoflurane was similar (4/11 and 6/9) in both groups. The hemodynamic profile prior to extracorporeal circulation (ECC) revealed arterial pressures and heart rates to be lower in the group treated with clonidine (p < 0.05); after ECC systemic resistance in group C was lower (630 +/- 103 vs 795 +/- 106 din.s.cm-5) (p < 0.05) and this was not compensated for by a significant rise in cardiac index (2.62 +/- 0.09 vs 2.40 +/- 0.08 l/min/m2) at similar occlusion pressures.

CONCLUSIONS

Use of clonidine in the type of patient studied does not improve the level of sedation over that achieved with lorazepam. Fentanyl requirements decreased with clonidine. With respect to hemodynamic profile, systemic vascular resistance fell in the clonidine group after removal of ECC, and thus this drug offers no advantages for routine premedication.

[Use of high doses of aprotinin in cardiac surgery]

OBJECTIVES

To study the efficacy of aprotinin in reducing whole blood loss after cardiac surgery with extracorporeal circulation.

PATIENTS AND METHODS

Two groups of patients undergoing cardiac surgery with extracorporeal circulation were studied. Group I (n = 51) received 2 x 10(6) KIU (kallikrein inhibiting units) of aprotinin upon anesthetic induction, a similar dose in the extracorporeal circulation priming pump, and a maintenance dose of 500,000 KIU/h until removal from the operating theater. Group II (n = 51) was the control group. Patients that had previously undergone surgery with extracorporeal circulation were excluded, as were those being treated with anti-coagulants or anti-aggregants. Data recorded were blood volume, transfusions needed in the first 24 h, and blood derivatives used throughout the hospital stay. Postoperative kidney function was also determined. The occurrence of acute myocardial infarction in patients undergoing myocardial revascularization was also noted.

RESULTS

Group I required a mean of 2.40 U of concentrated red blood per patient during the first postoperative day, as opposed to a mean of 4.3 U in group II (p < 0.001). Blood loss through drains was also less in group I than in group II (431.82 vs 895.29 ml; p < 0.001). Total blood needed during the hospital stay was 3.50 units per patient in group I vs 5.40 U in group II (p < 0.001). Urea and creatinine were similar in the two groups before and after surgery (p = NS), and there were no significant differences in the number of cases of acute myocardial infarction in the two groups (3 in group I and 2 in group II).

CONCLUSIONS

Administration of high doses of aprotinin is an effective technique for reducing the need for whole blood in patients requiring extracorporeal circulation during surgery. The technique does not compromise kidney function or increase the risk of perioperative acute myocardial infarction.

[Pharmacological properties of aprotinin and its therapeutic use in heart surgery]

Aprotinin (Trasylol) is a protease-specific inhibitor that has been used for over 5 years in extracorporeal circulation (ECC) during cardiac surgery. Patients treated with this inhibitor have considerably less postoperative bleeding, along with correspondingly lower consumption of blood products. This article reviews the history of the drug, its pharmacokinetics and pharmacodynamics, its usefulness in biological sciences and its clinical application in cardiac surgery, as well as drug interactions and side effects.

[Peroperative management of the orthotopic implant of a Jarvik-7 total cardiac prosthesis]

A 31 years old woman with a terminal phase dilated cardiomyopathy and a ventricular ejection fraction of 0.12 was admitted to our hospital to be included in the cardiac transplantation program. When entering the hospital her condition worsened and she suffered an electromechanical dissociation that needed cardiopulmonary resuscitation. Few hours later, energetic medical treatment could not improve her haemodynamic situation. Having no adequate organ available for emergency transplantation, a total orthotopic prosthesis (Jarvik-7-70) implantation was decided. Anesthesia was maintained with fentanyl (50 micrograms/kg), droperidol (0.23 mg/kg) and diazepam (0.25 mg/kg). There were no incidents during or after extracorporeal circulation bypass; despite the use of furosemide (100 mg) and mannitol (1 g/kg) diuresis was less than 40 ml/h. After by-pass, pulmonary hypertension was observed and treated with sodium nitroprusside (1 microgram/kg/min) and isoproterenol (5 micrograms/kg/min), as well as increasing the right ventricle working pressure of the device from 40 to 70 mmHg, obtaining haemodynamic stabilization and good tissular perfusion. After operation, the patient arrived to the Recovery Unit in a steady situation, with a cardiac index of 2.87 l/min/m2 and a diuresis of 150 ml/h. Some other aspects of the anaesthetic management are also discussed in this paper.

[Artificial heart. Management and clinical utilization]

The improved results of heart transplantation and the need to support hemodynamically those patients with cardiac failure while waiting for a suitable donor has heralded the development of mechanical ventricular assist pumps and the total artificial heart (TAH) as a bridge to transplantation. There are nowadays several TAH in use. The aim of this paper is to describe the current clinical model of the Utah University (model Jarvik-7) and its present or potential clinical applications and indications for use. The world experience up to August 1988 is reviewed.