Contaminated landslide runout deposits in rivers - Method for estimating long-term ecological risks.

The potential catastrophic event of a landslide bringing contaminants to surface waters has been highlighted in public media, but there are still few scientific studies analyzing the risk of landslides with contaminated soil. The aim of this study is to present a method to estimate the risk of potential long-term ecological effects on water bodies due to contaminated soil released into a river through a landslide. The study constitutes further development of previous work focusing on the instantaneous (short-term) release of contaminants and associated effects. Risk is here defined as the probability of surface water failing to comply with environmental quality standards (EQS). The transport model formulation is kept simple enough to allow for a probabilistic analysis as a first assessment of the impact on the river water quality from a landslide runout deposit containing contaminated soil. The model is applied at a contaminated site located adjacent to the Göta Älv River that discharges into the Gothenburg estuary, in southwest Sweden. The results from the case study show that a contaminated runout deposit will likely cause contamination levels above EQSs in the near area for a long time and that it will take several years for the deposit to erode, with the greatest erosion at the beginning when water velocities are their highest above the deposit. A contaminated landslide runout deposit will thus act as a source of contamination to the downstream water system until all the contaminated deposit has been eroded away and the contaminants have been transported from the deposit to the river, and further to the river mouth - diluted but not necessarily negligible. Therefore, it is important to prevent landslides of contaminated soil or waste, and if such events were to occur, to remove the contaminated runout deposit as soon as possible.

Nest attendance during egg laying in pheasants.

As precocial bird species hatch synchronously, incubation during the egg-laying stage should be disadvantageous because it makes the embryos develop asynchronously. We established the patterns of nest attendance during egg laying and the start of incubation in ring-necked pheasants, Phasianus colchicus, and tested three hypotheses regarding the advantage of early incubation. To determine nest attendance, we measured egg temperatures in real pheasant nests. Females spent more time on the nest as laying progressed, with an average of 6.4 h at a clutch size of 10. At the start of incubation, nest attendance increased to over 20 h/day. On the day before full incubation, time spent on the nest was positively correlated with the female's condition and negatively with the number of breeding attempts she had already made that season. The hypothesis that an early start of incubation improves egg viability was rejected, as the predicted relationship between the number of eggs laid after the start of incubation and the number laid before the start of incubation was not significant. We also rejected the possibility that early incubation reduces the risk of nest parasitism, as it was negatively related to the number of females radiotracked around the nest. Our data supported the hypothesis that early incubation reduces the risk of nest predation by shortening the period of exposure, as the number of eggs laid after incubation started was positively related to the number of breeding attempts made by the female, and thus to the perceived predation risk, but was negatively related to the time of season. Copyright 1999 The Association for the Study of Animal Behaviour.

MHC genotype and male ornamentation: genetic evidence for the Hamilton-Zuk model.

The major histocompatibility complex (MHC) is an immunologically important cluster of highly variable genes that is known to affect fitness in domesticated mammals and birds. Spur length of male pheasants in southern Sweden correlates with male viability, female mate choice, and offspring survival rate. Here we show by genetic analyses that the MHC genotype is associated with variation in both male spur length and male viability. These are the first data that directly support a 'good genes' hypothesis by Hamilton and Zuk predicting that females discriminate among males on the basis of secondary sexual characters in order to pass on genes for disease resistance that improve fitness in their offspring.

Female choice selects for a viability-based male trait in pheasants.

Recent theory on sexual selection suggests that females in species without paternal care choose mates by their secondary sexual characters because these indicate genotypic quality which will be transmitted to the offspring. These ideas are not yet empirically supported as data quantifying the relationship between female mate choice and female reproductive success are lacking. Only in one case, in Colias butterflies, has it been demonstrated unequivocally that females choose 'good genotypes' as mates and there is only one study, on Drosophila, demonstrating that mate choice increases one component of offspring fitness. Spur length of male pheasants (Phasianus colchicus) correlates with various fitness-related properties. We here present the first experimental field data showing that female pheasants select mates on the basis of male spur length and that female mate choice correlates with female reproductive success.

Comparative evaluation of local hemostatic agents in experimental liver trauma: a study in the rat.

The efficacy of gelatin foam, oxidized regenerated cellulose, collagen fleece, and microcrystalline collagen as hemostatic agents was tested after standardized liver trauma in the rat. Experiments were divided into two series. In the first series all the above local hemostatic agents were tested on normal animals. Animals in which surgical gauze was applied to the traumatized surface served as controls. Nontreated animals bled profusely. Microcrystalline collagen and collagen fleece were more effective than gauze. In the second series collagen preparations were tested on animals with hemostatic disorders caused by administration of acetylsalicylic acid, ethanol intoxication, or infusion of bensylpenicillin. Collagen preparations were as effective as gauze in diminishing bleeding time and blood loss after liver trauma.

Metabolic effects of glucose compared with invertose and a mixture of fructose, glucose and xylitol before and after moderate surgical trauma.

The metabolic and clinical effects of different isocaloric carbohydrate infusions were studied perioperatively in 54 female patients undergoing cholecystectomy. The patients were randomized to six treatment groups, who received infusions only postoperatively (group 1, 2 and 3) or pre- as well as postoperatively (group 4, 5 and 6). One litre was given during 8 h as a 12% infusion solution. Glucose (group 1 and 4) was compared to invertose (group 2 and 5) and to a mixture of fructose, glucose and xylitol 2:1:1 i.e. Triofusin (group 3 and 6). The glycogen content in liver biopsies, taken peroperatively, was significantly higher when infusions were given preoperatively. No significant differences were found between groups, when comparing the different carbohydrate infusions. A minor glucose intolerance was noticed postoperatively, especially in group 4, whereas no fructose or xylitol intolerance was seen. Lactataemia was insignificant and acid-base balance normal in all groups. Serum urea concentrations were lower when preoperative infusions were given but without differences between groups 4, 5 and 6. Electrolytes, creatinine, hemoglobin, hematocrite and liver function tests were unaltered and the clinical course was uncomplicated in all cases. No side effects were observed. It is concluded that the infusion of one litre 12% Triofusin can be used as effectively and safely as 12% glucose and invertose before and after moderate surgical trauma. But no obvious advantage with Triofusin was revealed.

Colloid-induced changes in bleeding following liver resection in the rat.

The effect of preoperative infusion of Ringer's solution, Ringer's acetate solution, dextran 70, dextran 40, degraded gelatin and hydroxyethyl starch on haemostasis after standardized liver resection was studied in the rat. Ringer's and Ringer's acetate solutions did not affect haemostasis more than expected from haemodilution. Dextrans, degraded gelatin and hydroxyethyl starch caused a significant increase in bleeding time and blood loss. APT time was significantly increased after infusion of hydroxyethyl starch. Dextran and hydroxyethyl starch impaired ADP- and collagen-induced aggregation. Platelet aggregation was not affected by the infusion of Ringer's solution or Ringer's acetate solution as compared to non-treated controls.

Single versus multiple dose doxycycline prophylaxis in elective colorectal surgery.

One hundred and two patients undergoing elective colorectal surgery were randomized in a prospective but "non-blind" way into two groups. The first group received 0.4 g of doxycycline preoperatively and the second group 0.2 g of doxycycline preoperatively and 0.1 g of doxycycline on the first, second and third postoperative day. All doxycycline was administered by intravenous infusion. The infection rate was 10% in the "one-dose" treatment group and 10% in the "four-dose" treatment group. It is thus concluded that 0.4 g of doxycycline preoperatively results in an acceptable rate of postoperative infections, which may be explained by the satisfactory concentration of doxycycline up till three days after administration. The advantage of "one-dose" treatment compared to "four-dose" treatment from practical and economical standpoints are obvious.

Impairment of primary hemostasis and platelet function after alcohol ingestion in man.

The effect of alcohol ingestion on primary hemostasis was investigated in fasting healthy humans. Primary hemostasis was measured with the template bleeding time and platelet aggregation assayed with the turbidometric method. Blood was collected to study coagulation and fibrinolysis. 1 h after ingestion of 2 ml/kg body weight of 40% alcohol the plasma alcohol concentration was 19.3 +/- 1.6 mmol/l. At this time there was a significant prolongation of the bleeding time accompanied by an impairment of platelet responsiveness to both collagen and ADP. A prolongation of the bleeding time and impairment of platelet function was also found 2 h after alcohol ingestion. Ingestion of this amount of alcohol did not affect parameters of coagulation or fibrinolysis. The data indicate that primary hemostasis is impaired in man after ingestion of moderate amounts of alcohol. This may explain the favorable effect of moderate alcohol consumption on ischemic heart disease but indicates an increased risk for patients with bleeding.

Acute alcohol intoxication and traumatic shock. An experimental study on circulating microaggregates and survival.

The reaction to a standardized soft tissue trauma was investigated in pigs pretreated with gastric administration of saline or 40% ethanol. Circulating microaggregates in vena cava, vena portae and aorta were determined with screen filtration pressure (SFP). Using Swan-Ganz thermistor catheters changes in central hemodynamics were recorded. 1 min after trauma, pulmonary capillary wedge pressure (PCW) increased over pretrauma values in alcohol-intoxicated pigs while cardiac output (CO) and mean arterial pressure (MAP) decreased. In control animals, CO and MAP were reduced. 30 min after trauma the control animals had restored their circulatory parameters while intoxicated animals had not. SFP increased in alcohol-intoxicated animals before trauma and more so after trauma except for in aorta. The standardized trauma was nonlethal to control animals while 6 out of 7 pigs, pretreated with alcohol, died within 65 min of the trauma. The data indicate that alcohol intoxication decreases survival after traumatic shock and that alcohol and trauma induced a significant increase in circulating microaggregates.

The effect of intraperitoneal fluid on the prevention of small intestinal obstruction after appendicectomy. Preliminary results.

In 173 patients (study group), undergoing appendicectomy because of suspected acute appendicitis, normal saline solution, in the amount of 10 ml per 1000 g of patient weight, was injected into the peritoneal cavity before closing the incision. A control group of patients undergoing appendicectomy was selected, matched for age and sex. The mean observation period was five years for both groups. One of the patients in the study group and two patients in the control group developed small intestinal obstruction due to adhesions which led to relaparotomy. The difference was not statistically significant. Because of the rarity of this complication after appendicectomy (1-2%) and the long elapse of time reported from the appendicectomy to the development of the small intestinal obstruction due to adhesions, the group of 173 patients in too small and the observation period of five years too short to enable a conclusion to be made so far. Further follow-up of the patients in this study and a further investigation is necessary.

Effects of ethanol on platelet aggregation: an in vitro study.

Alcohol ingestion results in the formation of circulating microaggregates in the pig. To investigate the underlying mechanism, the effects of alcohol on platelet aggregation using a Born-aggregometer, was investigated. After incubating unstirred platelet rich plasma (PRP) with moderate concentrations of alcohol (175 mmol/l) the aggregation induced by collagen was reduced. This was probably due to platelet refractoriness caused by platelet ADP release. We could also demonstrate that high concentrations of alcohol (630 mmol/l) caused platelet release in stirred PRP. Release of ADP from red cells, after incubating unstirred whole blood with low concentrations of alcohol (17 mmol/l), was the probable explanation to the observed platelet refractoriness to ADP and collagen. Alcohol causing release of ADP from red cells is likely the cause of platelet aggregation in circulating blood and is probably the mechanism in formation of circulating platelet aggregates after alcohol ingestion.

Acute portal hypertension after gastric administration of ethanol in the pig.

A single gastric administration of 15 ml/kg of 40% ethanol to anesthetized pigs resulted in an increased portal venous blood pressure which increased with increasing blood alcohol levels. For the first 2 h there was no significant alteration in liver blood flow, but 3 h after the administration of ethanol, when portal blood pressure reached its highest values, liver blood flow had decreased. This was probably caused by increased hepatic vascular resistance as shown in electron thin-section phase-contrast microscopy which at this time showed marked hepatocyte swelling, narrowing of the sinusoids and platelet aggregates in small portal branches.

Effect of acute ethanol intoxication on primary haemostasis, coagulation factors and fibrinolytic activity.

The effect of ethanol intoxication on haemostasis was studied by transection of mesenteric microvessels and liver resection in the rat. Plasma concentrations of alcohol were within the range of those found in ethanol intoxication in man. Bleeding time and blood loss were increased 1 h after ethanol administration, regardless of the utilized technique. A significant positive correlation existed between bleeding time following liver resection and bleeding time after simultaneous transection of a mesenteric arteriole and venule. Coagulation mechanisms, assayed by whole blood clotting time, APT time, one-stage prothrombin time, recalcification time, thrombin time, Owren's P & P test and determination of plasma factor V and fibrinogen levels, were not significantly changed in ethanol-intoxicated animals. Administration of alcohol did not affect fibrinolytic activity, while it inhibited significantly ADP and collagen-induced platelet aggregation in the rat.

In vitro effect of ethanol on ADP and collagen-induced platelet aggregation.

Platelet aggregation was measured by Born's method. Plasma from Sprague-Dawley rats and inbred albino rabbits was used. 20% ethanol in 0.9% (w/v) NaCl was added to plasma at final concentrations of 56.5 mM, 85.9 mM 171.5 mM and 343.1 mM or to whole blood at final concentrations of 8.7 mM, 17.4 mM, 52.5 mM, 171.5 mM and 343.1 mM. Experiments using 0.9% NaCl volumes equivalent to the added ethanol volume were also conducted. Dose-response aggregation tests showed that a decrease in ADP- and collagen-induced aggregation existed when ethanol was mixed with rat or rabbit blood prior to the preparation of platelet-rich plasma. There was no effect on ADP-induced platelet aggregation when ethanol was mixed with rat or rabbit plasma. Collagen-induced aggregation was impaired only in rat plasma when ethanol concentration reached 343.1 mM. These results suggested that ethanol modified platelet function possibly via red cells.

Defects in hemostasis produced by antibiotics. An in vivo study in the rat.

The effect of preoperative infusion of benzylpenicillin, carbenicillin, ampicillin, chloramphenicol and doxycycline on hemostasis after standardized liver resection was studied in the rat. Plasma levels of each antibiotic were within the range of those found after administration of therapeutic doses in man. Bleeding time was prolonged and blood loss was increased in all cases of antibiotic administration compared with controls. APT time after liver resection was prolonged in the carbenicillin- and chloramphenicol-treated groups. Platelet function, assayed by ADP- and collagen-induced platelet aggregation was impaired in benzylpenicillin-, carbenicillin- and chloramphenicol-treated animals.

Increased bleeding during liver resection in ethanol-intoxicated rats.

The effect of ethanol intoxication on hemostasis after liver resection was studied in the rat. Plasma levels of ethanol were within the range of those found in ethanol intoxication in man. Bleeding time and blood loss were significantly increased, whereas hemoglobin and hematocrit values were decreased after resection in intoxicated animals compared to controls. APT-times and platelet counts did not differ significantly between the two groups of rats. ADP- and collagen-induced platelet aggregation was slightly inhibited one hour after ethanol administration in non-operated animals. A decrease in pH, such as observed in intoxicated animals, did not affect hemostasis. Distribution of cardiac output was significantly altered ethanol intoxication. Renal blood flow was increased by 54%, blood flow in the hepatic artery by 40% and in the portal vein by 47%.

Circulating microaggregates after gastric administration of ethanol in the pig.

Earlier in vitro experiments have shown microaggregate formation in pig and rabbit blood after addition of ethanol. In this study ethanol was given to pigs resulting in ethanol concentrations of 30-40 mmol/l 2-4 h after administration. As would be expected ethanol concentration was higher in the portal vein than in the hepatic vein, caval vein or aorta. Microaggregates in circulating blood were measured with screen filtration pressure (SFP). SFP rose to more than double the initial value in ethanol-intoxicated pigs whereas it remained unchanged in controls. The ethanol-intoxicated pigs developed hemoconcentration and metabolic acidosis. Our results indicate that microaggregates probably made up of aggregated platelets are formed in pig blood during acute ethanol intoxication.

Trauma an acetylsalicylic acid-induced changes in hemostasis during liver resection in the rat.

The effect of acetylsalicylic acid and bilateral femoral crush fractures on hemostasis after liver resection was studied in the rat. Serum salicylate levels were dose-dependent and similar in traumatized and non-traumatized animals. Bleeding time was significantly shortened and blood loss significantly decreased after bilateral femoral crush fractures. Both these values were significantly increased in salicylate pretreated animals compared to controls. Combination of bilateral femoral crush fractures and administration of 0.7 mg/100 g b.w. acetylsalicylic acid after bilateral femoral crush fractures increased blood loss significantly. Normal APT times indicated that the intrinsic coagulation system was not affected. ADP- and collagen-induced platelet aggregation was diminished in all animals as compared to controls.