Enhancement of bulk second-harmonic generation from silicon nitride films by material composition.

We present a comprehensive tensorial characterization of second-harmonic generation from silicon nitride films with varying compositions. The samples were fabricated using plasma-enhanced chemical vapor deposition, and the material composition was varied by the reactive gas mixture in the process. We found a six-fold enhancement between the lowest and highest second-order susceptibility, with the highest value of approximately 5 pm/V from the most silicon-rich sample. Moreover, the optical losses were found to be sufficiently small (below 6 dB/cm) for applications. The tensorial results show that all samples retain in-plane isotropy independent of the silicon content, highlighting the controllability of the fabrication process.

Brown adipose tissue triglyceride content is associated with decreased insulin sensitivity, independently of age and obesity.

The aim of the present study was to determine whether single-voxel proton magnetic resonance spectroscopy ((1)H-MRS) can non-invasively assess triglyceride content in both supraclavicular fat depots and subcutaneous white adipose tissue (WAT) to determine whether these measurements correlate to metabolic variables. A total of 25 healthy volunteers were studied using (18)F-fluorodeoxyglucose positron emission tomography (PET) and (15)O-H2O PET perfusion during cold exposure, and (1)H-MRS at ambient temperature. Image-guided biopsies were collected from nine volunteers. The supraclavicular triglyceride content determined by (1)H-MRS varied between 60 and 91% [mean ± standard deviation (s.d.) 77 ± 10%]. It correlated positively with body mass index, waist circumference, subcutaneous and visceral fat masses and 8-year diabetes risk based on the Framingham risk score and inversely with HDL cholesterol and insulin sensitivity (M-value; euglycaemic-hyperinsulinaemic clamp). Subcutaneous WAT had a significantly higher triglyceride content, 76-95% (mean ± s.d. 87 ± 5%; p = 0.0002). In conclusion, the triglyceride content in supraclavicular fat deposits measured by (1)H-MRS may be an independent marker of whole-body insulin sensitivity, independent of brown adipose tissue metabolic activation.

The use of balanced HES 130/0.42 during complex cardiac surgery; effect on blood coagulation and fluid balance: a randomized controlled trial.

INTRODUCTION: Colloids and crystalloid are used during cardiac surgery for priming of the cardiopulmonary bypass (CPB) circuit. Colloids may decrease postoperative fluid balance because of their high oncotic pressure and low risk of fluid extravasation. On the other hand, colloids have been shown to impair blood coagulation. MATERIALS AND METHODS: In a prospective, randomized, double-blinded study, 50 patients scheduled for coronary artery bypass grafting or a valve procedure were planned to be randomized to receive either balanced 6% HES130/0.42 or Ringer-acetate solution for CPB priming. Randomization was stopped prematurely after 35 randomized patients (19 in the HES and 16 in the Ringer groups) because of the published report where HES130/0.42 was associated with impaired renal function. Effects on haemostasis and fluid balance were investigated. RESULTS: The rotational thromboelastometry (ROTEM®) parameters and chest tube drainage on the first postoperative morning (1POM) were comparable between the groups (p>0.05). However, patients in the HES group needed more blood and blood product transfusions. The total volume administered into the CPB circuit was lower in the HES than in the Ringer (RIN) group, 2905±1049 mL versus 3973±1207 mL (p=0.011), but there was no statistically significant difference in total fluid balance on the 1POM (5086±1660 mL in the HES group versus 5850±1514 mL in the RIN group, respectively). CONCLUSIONS: After complex cardiac surgery, the use of balanced 6% HES130/0.42 solution for CPB circuit priming did not impair haemostasis measured by ROTEM®, but it increased the need for transfusions. Fluid balance after CPB was less positive in the HES group, but, on the 1POM, it was comparable between the groups.

Stroke volume-directed administration of hydroxyethyl starch or Ringer's acetate in sitting position during craniotomy.

BACKGROUND: To determine the volumes required for stable haemodynamics and possible effects on the coagulation, we studied stroke volume (SV)-directed administration of hydroxyethyl starch (HES 130 kDa/0.4) and Ringer's acetate (RAC) in neurosurgical patients operated on in a sitting position. METHODS: Thirty craniotomy patients were randomised to receive either HES or RAC. Before positioning, SV, measured by arterial pressure waveform analysis, was maximised by boluses of fluid until SV did not increase more than 10%. SV was maintained by repeated administration of fluid. RAC 3 ml/kg/h was infused in both groups during surgery. RESULTS: Comparable haemodynamics were achieved with the mean [standard deviation (SD)] cumulative doses of HES or RAC 271 (47) or 264 (50) ml (P = 0.699) before the sitting position. Mean (SD) doses of HES or RAC at 30 min after the positioning were 343 (94) or 450 (156) ml (P = 0.036), and at the end of surgery 464 (284) or 707 (425) ml, respectively (P = 0.087). The intraoperative fluid balance was more positive in the RAC than in the HES group [P = 0.044, 95% confidence interval (CI) -978 to -14]. Cardiac and stroke volume indexes [CI and stroke volume index (SVI)] increased in the HES group (P < 0.05) but not in the RAC group [non significant (N.S.)]. Neither coagulation profile nor blood loss differed between the groups. CONCLUSION: Fluid filling with HES boluses resulted in a positive response in CI and SVI during the sitting position. The 34% smaller volume of HES than crystalloid and less positive fluid balance in the HES group might be important in craniotomy patients with decreased brain compliance.

Effects of combined balanced colloid and crystalloid on rotational thromboelastometry in vitro.

Our objective was to investigate the in vitro effects of a totally balanced fluid concept on whole blood coagulation. Venous blood from 12 healthy volunteers was diluted by 20% and 40% with a combination of an equal amount of colloid (balanced or unbalanced 6% HES 130/0.4, or 4% gelatin) and crystalloid (balanced or unbalanced Ringer's acetate). Blood samples were analyzed with rotational thromboelastometry (ROTEM®). The initiation of coagulation was delayed in all dilutions except for the 20 vol% gelatin-dilution. In the extrinsic activation test, maximum clot firmness was decreased and clot formation time prolonged after 40 vol% hemodilution with a balanced Ringer's/unbalanced HES combination, more than in the corresponding gelatin hemodilution. In the fibrin-based test, after both 20- and 40 vol% hemodilution with unbalanced Ringer's/gelatin solution, maximum clot firmness was significantly stronger than in the Ringer's/HES-combinations. The combination of balanced colloid and crystalloid has similar coagulation effects in vitro as their respective combination of unbalanced solutions.

Hydroxyethylstarch and gelatin solutions impair blood coagulation after cardiac surgery: a prospective randomized trial.

BACKGROUND: Colloids are often used after cardiac surgery as intravascular volume replacement therapy. Cardiac surgical patients have an increased risk of bleeding. Both hydroxyethylstarch (HES) and gelatin solutions impair haemostasis. We examined the impact and dose effect on coagulation of HES 130/0.4, gelatin, or Ringer's acetate solutions after cardiac surgery. METHODS: Forty-five patients received three boluses (each 7 ml kg(-1)) of either 6% HES 130/0.4, 4% gelatin, or Ringer's acetate solution after elective cardiac surgery. The infusion of study solution was continued in the dose 7 ml kg(-1) over the following 12 h. The total dose of study solution was 28 ml kg(-1). Hypovolaemia was treated with Ringer's acetate. Modified thromboelastometry was performed to detect coagulation disorders. RESULTS: Clot formation time was prolonged and clot strength decreased after infusion of 7, 14, and 21 ml kg(-1) of either colloid compared with the Ringer's acetate group. After infusion of 14 and 21 ml kg(-1) of Ringer's acetate, clot strength was slightly, but significantly, increased. On the first postoperative morning, clot strength was still decreased in the gelatin group in comparison with the Ringer's acetate group. Neither HES nor gelatin induced fibrinolysis. Chest tube drainage was comparable between all groups. CONCLUSIONS: Even a small dose of HES 130/0.4 or gelatin impaired clot strength after cardiac surgery in a dose-dependent fashion, but neither colloid increased blood loss.

Basal and cold-induced fatty acid uptake of human brown adipose tissue is impaired in obesity.

Fatty acids (FA) are important substrates for brown adipose tissue (BAT) metabolism, however, it remains unclear whether there exists a difference in FA metabolism of BAT between lean and obese healthy humans. In this study we evaluated supraclavicular BAT fatty acid uptake (FAU) along with blood perfusion in lean and obese subjects during cold exposure and at room temperature using positron emission tomography (PET)/computed tomography (CT). Additionally, tissue samples were taken from supraclavicular region (typical BAT region) from a subset of subjects to evaluate histological presence of BAT. Non-shivering cold stress elevated FAU and perfusion of BAT in lean, but not in obese subjects. Lean subjects had greater FAU in BAT compared to obese subjects during cold exposure and interestingly also at room temperature. The higher BAT FAU was related to younger age and several indicators of superior systemic metabolic health. The subjects who manifested BAT histologically had several folds higher BAT FAU compared to subjects with no such histological manifestation. Together, obese subjects have less active tissue in supraclavicular region both in basal and cold-activated state and the FA metabolism of BAT is blunted in obesity.

Role of fibrinogen-, factor VIII- and XIII-mediated clot propagation in gelatin haemodilution.

BACKGROUND: Gelatin solution impairs coagulation. The mechanism of coagulopathy is incompletely defined. The purpose of this study was to evaluate the capacity of single coagulation factors to reverse gelatin-promoted whole-blood coagulation disorders in vitro. METHODS: Venous blood was withdrawn from 12 volunteers in a crossover study. Four percent succinylated gelatin was added to citrated whole-blood samples to make a 40 vol% end-concentration of gelatin. The baseline and 40 vol% samples, and samples with addition of fresh-frozen plasma (FFP), fibrinogen, coagulation factors XIII (FXIII) or VIII, together with the von Willebrand factor (FVIII+vWF), were analysed by thromboelastometry (ROTEM. Coagulation was initiated by tissue thromboplastin (ExTEM with and without cytochalasin to determine the functional component of fibrinogen (FibTEM. RESULTS: Initiation of coagulation and fibrin formation were delayed at 40 vol% gelatin dilution. At this stage, the median (25th-75th percentiles) maximum clot firmness (MCF) was 76.3 (65.9-80.0) and 32.5 (27.4-45.0)% of the pre-dilution value in ExTEM and FibTEM thromboelastometry, respectively. Coagulation time was corrected by addition of fibrinogen and FFP in ExTEM and FibTEM analysis, whereas FVIII or FXIII had minimal effects. MCF was partly restored only by FFP in ExTEM. In FibTEM analysis, MCF improved more by fibrinogen than by FVIII+VWF, FXIII or FFP. CONCLUSIONS: Gelatin-induced whole-blood coagulation disorder in vitro is mainly dependent on the initial fibrinogen-fibrin interaction. The proposed mechanism might suggest not to reverse gelatin coagulopathy solely by fibrinogen administration. The administration of FFP, a mixture of different coagulation factors, reversed the gelatin-induced in vitro coagulopathy the best.

Haemodynamics and acid-base equilibrium after cardiac surgery: comparison of rapidly degradable hydroxyethyl starch solutions and albumin.

BACKGROUND: Stable haemodynamics is often achieved by administration of colloids after cardiac surgery. We conducted a prospective, randomized, open-label study comparing haemodynamics and acid-base equilibrium after infusion of two rapidly degradable hydroxyethyl starch (HES) solutions or human albumin (HA) to cardiac surgical patients. MATERIALS AND METHODS: 45 patients received a predetermined fixed dose of 15 ml kg(-1) of either 6% HES (mW 130 kDa, n = 15), 6% HES (MW 200 kDa, n = 15) or 4% HA (MW 69 kDa, n = 15) after on-pump cardiac surgery. RESULTS: Left ventricular filling pressures assessed using pulmonary artery catheter responded similarly in all groups. mean (SD) cardiac index was higher in HES130 [3.5 l min(-1) m(-2) (0.7) ] and HES200 [3.5 l min(-1) m(-2) (0.5)] than in HA [2.8 l min(-1) m(-2) (0.6)] group after completion of infusion (P = 0.002) but no differences were detected at 2 and 18 hours. Oxygen delivery increased in both HES groups but not in HA group. After cessation of infusion base excess was the most negative in Ha group. At 2 hours mean (SD) base excess was higher in HES130 [0 (1.32)] than in HES200 [-1.32 (2.27) ] and HA [-2.3 (1.3)] group (P = 0.002, between the groups). CONCLUSIONS: We conclude that the effect of albumin on cardiac performance is inferior than that of HES130 or HES200 in early postoperative phase after cardiac surgery. HES130 induces no alterations in acid-base equilibrium whereas a negative base excess was observed after HA infusion.

A comparison of the haemodynamic effects of 4% succinylated gelatin, 6% hydroxyethyl starch (200/0.5) and 4% human albumin after cardiac surgery.

BACKGROUND AND AIMS: The goal for volume replacement therapy is to maintain stable haemodynamics after cardiac surgery. We hypothesized that a short term infusion of hydroxyethyl starch results in better haemodynamic response than an infusion of lower molecular weight gelatin. MATERIAL AND METHODS: 45 patients received a predetermined fixed dose of 15 ml kg(-1) of either 4% succinylated gelatin (GEL) or 6% hydroxyethyl starch (HES) or 4% human albumin (HA) after cardiac surgery. RESULTS AND CONCLUSIONS: Pulmonary capillary wedge pressure was more increased in GEL and HES groups [mean (SD) 153% (54) and 168% (57) of pre-infusion value] than in HA group [122% (23)] (P = 0.031) after completion of infusion, but no differences in cardiac index (CI) and stroke volume index (SVI) were observed. At 2 and 18 hours after end of study infusions SVI was more increased in HES [143% (38) and 148% (41) of pre-infusion values] and HA [143% (35) and 163% (42) of pre-infusion values] groups than in GEL [116% (23) and 125% (30)] group (P = 0.047 at 2 hours and P = 0.033 at 18 hours). In early postoperative phase after cardiac surgery, HES and HA infusions improve haemodynamics more and longer period than GEL infusion.

Interplay between coagulation and inflammation in open and endovascular abdominal aortic aneurysm repair--impact of intra-aneurysmal thrombus.

AIMS: Our aim was to compare hemostatic and inflammatory mechanisms in abdominal aortic aneurysm (AAA) patients after open surgery (OPEN) and endovascular AAA repair (ENDO). SUBJECTS AND METHODS: From the 32 consecutive AAA patients recruited, 17 represented ENDO and 15 OPEN. The intra-aneurysmal thrombus was removed during OPEN, but stayed intact after ENDO. The preoperative volume of the intra-aneurysmal thrombus was calculated from computed tomography images. Markers of coagulation and inflammation were studied preoperatively, at one, two, three, four and seven days and at three months postoperatively. RESULTS: Preoperative upregulation of F 1+2, TAT and D-dimer was evident in both groups. The volume of intra-aneurysmal thrombus correlated with CRP (beta = 0.62, p = 0.001), IL-6 (beta = 0.60, p = 0.001) and PAI-1 ag (beta = 0.51, p = 0.007). Surgery further enhanced inflammation, coagulation and fibrinolysis. IL-6 increased in both groups, but the increases of CRP and PIIINP were higher in the OPEN group. Postoperative CRP correlated with the intra-aneurysmal thrombus volume in the ENDO group. At three months D-dimer (p < 0.05) was higher than preoperatively in the ENDO, in contrast to the OPEN group. CONCLUSION: Preoperatively both prothrombotic and fibrinolytic mechanisms are activated in patients with AAA. Intraluminal thrombus induces prothrombotic and inflammatory interactions, which persist after endovascular aortic aneurysm repair.

Red blood cell transfusions in patients undergoing lower extremity artery bypass surgery.

BACKGROUND AND AIMS: The purpose of this study was to search predictors of red blood cell transfusions in peripheral vascular surgical patients. MATERIAL AND METHODS: All the patients who undergone infrainguinal bypass surgery at Helsinki University Hospital in the year 2000 were included. Of 266 records 261 (98%) were available for data review. Multiple stepwise regression model was created to identify independent predictors of blood use. RESULTS AND CONCLUSIONS: 174 (67%) of the patients received red blood cell transfusion. The lowest measured mean (SD) haemoglobin was 94 (11) g/l intraoperatively and 92 (+/- 10) g/l on the first two postoperative days. The median (range) number of units was 3 (1-19). Multivariate analysis showed that high age (p = 0.019), small body surface area (p = 0.017), low preoperative haemoglobin (p < 0.001), blood loss (p < 0.001), long lasting surgery (p<0.001), reoperation (p=0.018), femoro-distal reconstruction (p=0.048) and chronic obstructive pulmonary disease (p = 0.023) increased the risk to receive red blood cell transfusion. The frequent use of antithrombotic medication (72% of the patients) did not significantly increase red blood cell administration. The generous use of red blood cells despite relative safe haemoglobin levels indicates a need for a standardized multidisciplinary transfusion strategy in this patient population. Otherwise, most of the predictors for red blood cell administration were nonmodifiable.

P Metabolism in the Bean-Rhizobium tropici Symbiosis.

Nodulated legumes require more P than legumes growing on mineral nitrogen, but little is known about the basis for the higher P requirement. Experiments were conducted to determine how Rhizobium tropici responds to P limitation and to understand how P is partitioned between the symbionts under conditions of adequate or limiting P. Free-living R. tropici responds to P stress by increasing P transport capacity and inducing both an acid and an alkaline phosphatase. This P-stress response occurs when the medium P concentration decreases below 1 [mu]M. Both P-stress-inducible phosphatases are found in bacteroids taken from plants growing with adequate P, suggesting that P levels in the symbiosome space is low enough to induce the expression of these enzymes. Bacteroid alkaline phosphatase-specific activity was highest during vegetative growth of the bean plant, but decreased approximately 75% during the host reproductive stages. In hydroponic experiments 32P-tracer studies showed that in vivo rates of P accumulation were significantly higher in bacteroids from P-limited plants compared with those from plants that had been supplied with adequate P. In contrast, label accumulation in leaves was greatest in plants grown with adequate P.

Albumin induced hypercoagulability does not reduce blood loss in patients undergoing total hip arthroplasty.

BACKGROUND AND AIMS: Albumin may enhance and hydroxyethyl starch (HES) may impair haemostasis. While the effects are also dependent on haemodilution we minimized it by early structured transfusion therapy, and compared albumin and HES regarding blood loss and coagulation parameters in hip arthroplasty patients. MATERIAL AND METHODS: 101 patients undergoing primary hip arthroplasty received in random order 4% albumin (n = 48) or HES (average Mw 120 kDa/molar substitution ratio 0.7, n = 53). The administration of colloid, red blood cell (RBC), fresh frozen plasma and platetet concentrates begun after a 6-8%, 12-16%, 60% and 100% blood loss of the patient's calculated blood volume respectively. Explanatory risk factors for blood loss were modelled by regression analysis. RESULTS AND CONCLUSIONS: Administration of albumin or HES 1200 ml (500-2000 and 500-1800) [median (range) respectively] did not affect blood loss. The vWF antigen was higher in the albumin group (p = 0.04) postoperatively. Haematocrit value, platelet count, bleeding time, prothrombin time value, activated thromboplastin time, FV activity and fibrinogen concentration were comparable between the groups. Long operation time was associated with great blood loss (p < 0.001). In hip arthroplasty patients with near normal levels of haematocrit albumin enhanced coagulation without altering blood loss.

Comprehensive FDTD modelling of photonic crystal waveguide components.

Planar photonic crystal waveguide structures have been modelled using the finite-difference-time-domain method and perfectly matched layers have been employed as boundary conditions. Comprehensive numerical calculations have been performed and compared to experimentally obtained transmission spectra for various photonic crystal waveguides. It is found that within the experimental fabrication tolerances the calculations correctly predict the measured transmission levels and other major transmission features.

Purification and some properties of inorganic pyrophosphatase from Streptococcus faecalis.

Inorganic pyrophosphatase [EC 3.6.1.1] from Streptococcus faecalis ATCC 8043 was purified to homogeneity as judged by slab gel electrophoresis in the presence and absence of sodium dodecyl sulfate. The purification consisted of the following steps: streptomycin sulfate precipitation, (NH4)2SO4 treatment in a Sepharose CL-4B column, DEAE-Sepharose CL-6B chromatography, gel filtration on Ultrogel AcA 34, and preparative slab gel electrophoresis. Gel filtration on Ultrogel AcA 34 was used to determine the molecular weight and slab gel electrophoresis in the presence of sodium dodecyl sulfate to study the subunit molecular weight. The enzyme appeared to be composed of four subunits with molecular weights of approximately 32,500. The molecular weight of the native enzyme was about 128,000. The enzyme catalyzed the hydrolysis of inorganic pyrophosphate, and no activity was found with a variety of other phosphate esters. The cation Mg2+ was required for maximum activity; Co2+ and Ca2+ supported 24% and 5.6% of the activity observed with Mg2+, respectively. 2,4,6-Trinitrobenzene sulfonic acid inhibited the reductants containing SH-groups activated the enzyme suggesting that lysine and cysteine have essential roles in the enzyme.

Haemostatic disturbances in burned patients during early excision and skin grafting.

Bleeding is a major problem during early excision of burned skin. Therefore, 13 severely burned adult patients operated on during the first week after the trauma were studied. Blood loss was replaced with crystalloids, colloids and packed red cell concentrates (PRC). After ten infused PRCs, four fresh frozen plasma (FFP) units were given and thereafter one FFP unit with one PRC unit. Arterial blood samples were drawn before anaesthesia (SO), during operation after every four units of PRC transfusion (S1-4), 4 h postoperatively (S5) and on the first postoperative morning (S6). Prothrombin time (%) and activated partial thromboplastin time (s) were abnormal before operation (median values 67%, range 22-99% and 44 s, range 30-86 s, respectively). Prothrombin time decreased during operation and reached the critical level for normal haemostasis at S2. Thrombelastography showed decreased clot formation rate and impaired fibrin platelet interaction peri- and postoperatively. Fibrinogen and factor VIII activity were high preoperatively (median 6.1 g/l and 253%) and the critical values for normal haemostasis were not reached. Burned patients have a consumption coagulopathy which, in combination with haemodilution during operation, results in a clinically significant deficiency of coagulation factors II, VII and X, in spite of reactive elevation of coagulation factor VIII and fibrinogen.

Effects of nonsteroidal anti-inflammatory drugs on hemostasis in patients with aneurysmal subarachnoid hemorrhage.

Platelet function is impaired by nonsteroidal anti-inflammatory drugs (NSAIDs) with prominent anti-inflammatory properties. Their safety in patients undergoing intracranial surgery is under debate. Patients with aneurysmal subarachnoid hemorrhage (SAH) were randomized to receive either ketoprofen, 100 mg, three times a day (ketoprofen group, n = 9) or a weak NSAID, acetaminophen, 1 g, three times a day (acetaminophen group, n = 9) starting immediately after the diagnosis of aneurysmal SAH. Treatment was continued for 3 days postoperatively. Test blood samples were taken before treatment and surgery as well as on the first, third, and fifth postoperative mornings. Maximal platelet aggregation induced by 6 microM of adenosine diphosphate decreased after administration of ketoprofen. Aggregation was lower (P < .05) in the ketoprofen group than in the acetaminophen group just before surgery and on the third postoperative day. In contrast, maximal platelet aggregation increased in the acetaminophen group on the third postoperative day as compared with the pretreatment platelet aggregation results (P < .05). One patient in the ketoprofen group developed a postoperative intracranial hematoma. Coagulation (prothrombin time [PT], activated partial thromboplastin time [APPT], fibrinogen concentration, and antithrombin III [AT III]) was comparable between the two groups. Ketoprofen but not acetaminophen impaired platelet function in patients with SAH. If ketoprofen is used before surgery on cerebral artery aneurysms, it may pose an additional risk factor for hemorrhage.

Endovascular vs open AAA repair: similar effects on renal proximal tubular function.

AIM: To compare the effect of open and endovascular repair on renal function. MATERIALS AND METHODS: In a prospective, non-randomized study twenty-four abdominal aortic aneurysms (AAA) treatable with either method were repaired, 15 using endovascular device (ENDO group) and nine with open surgery with infrarenal aortic cross-clamping (OPEN group). All the patients had standardised general anaesthesia, intravascular fluid therapy and monitoring. Renal function tests and cardiovascular measurements were performed at predetermined intervals. RESULTS: N-acetyl-beta-D-glucosaminidase indexed to urinary creatinine (U-NAG/crea), a sensitive marker of renal proximal tubular damage, increased similarly in both groups at the end of surgery (two-way ANOVA, p < 0.05). No patient developed clinical renal impairment, on the contrary, creatinine clearance was increased, serum cystatin C (a sensitive marker of renal glomerular filtration) and serum creatinine concentration decreased at 24 hours postoperatively (Wilcoxon paired test, p < 0.05). Intraoperative blood loss and the amount of administered crystalloids were higher in the OPEN than in the ENDO group (Mann-Whitney U-test, p < 0.05). The cardiovascular measurements were comparable between the groups. The mean (SD) amount of radio-contrast media given was 3.1 (1.1) ml/kg in the ENDO group. CONCLUSIONS: Our results indicate that endovascular AAA repair does not protect renal proximal tubular function. A temporary renal tubular dysfunction was found both in open and in endovascular AAA repair which did not lead to permanent changes in renal function.

Suicides among university students in Finland.

This study is part of a nationwide research project dealing with all suicides in Finland. It includes all suicides among university students during the 1-year period from April 1, 1987, to March 31, 1988. Ten students (6 men and 4 women) committed suicide during the period studied. The observed suicide rates per 100,000 students per year were 13.8 (95% CI = 5.1-30.1) for men and 9.0 (95% CI = 2.4-22.8) for women. The difference between the observed and expected suicide rate for men (13.8 v 47.7, standard mortality rate [SMR] = 29) was statistically significant. For women (9.0 v 8.3, SMR = 108), the difference was not statistically significant. Most of the suicides had experienced serious difficulties since early childhood, including narcissistic problems, difficulties in human relations, severe depressive periods, previous suicidal behavior, and alcohol problems; they had also had earlier psychiatric treatment.