Dynamics of cognitive change in HIV-infected individuals commencing three different initial antiretroviral regimens: a randomized, controlled study.

BACKGROUND: Improvements in neurocognitive (NC) function have been associated with commencing antiretroviral therapy in HIV-infected subjects. However, the dynamics of such improvements are poorly understood. METHODS: We assessed changes in NC function via a validated computerized battery (CogState™, Melbourne, Victoria, Australia) at baseline and after 24 and 48 weeks in a subset of therapy-naïve neuro-asymptomatic HIV-infected subjects, randomized to commence three different antiretroviral regimens. RESULTS: Of 28 subjects enrolled in the study, nine, eight and 11 were randomly allocated to commence tenofovir/emtricitabine with efavirenz (arm 1), atazanavir/ritonavir (arm 2) and zidovudine/abacavir (arm 3), respectively. Overall improvements in NC function were observed at week 24 and function continued to improve at week 48 (changes in z-score for overall cognitive global score of 0.16 and 0.18 at weeks 24 and 48, respectively). Within the NC speed domains, generally greater improvements were observed in arms 2 and 3, compared with arm 1 (changes in z-score for composite speed scores at weeks 24/48 of 0.16/0.16, -0.29/-0.24 and -0.15/-0.31 in arms 1, 2 and 3, respectively; P = 0.04 for change at week 48 in arm 3 versus arm 1). Finally, improvements in executive function occurred later (only observed at week 48) and were driven by improvements in arm 3 (z-score changes of 0.23, 0.06 and -0.78 in arms 1, 2 and 3, respectively; P = 0.02 for change in arm 3 versus arm 1). CONCLUSION: Improvements in NC function continue over the first year after initiating antiretroviral therapy in neuro-asymptomatic HIV-infected subjects.

[Imaging strategies for knee injuries]. / Bildgebungsstrategie bei Kniegelenkverletzungen.

Injuries of the knees are common. The Ottawa knee rule provides decisional support to determine whether radiographs are indicated or not. With the use of ultrasound it is possible to detect defects of the extensor ligaments and the anterior cruciate ligament. Furthermore, it is possible to detect indirect signs of an intra-articular fracture, e.g. lipohemarthrosis. In complex fractures, e.g. tibial plateau fractures, further diagnostic procedures with multislice computed tomography (CT) are needed for accurate classification and preoperative planning. Multislice CT with CT angiography enables three-dimensional reconstruction of the knee and non-invasive vascular imaging for detection of vascular injury. Magnetic resonance imaging (MRI) is the gold standard for detection of occult fractures and injuries of the ligaments and menisci. Higher field strengths can be used to improve the diagnostics of cartilage lesions. Virtual MR arthrography is superior to conventional MRI for detection of cartilage lesions especially after meniscus surgery.

[Laser ablation. Do we still need it?]. / Laserablation. Brauchen wir sie noch?

Laser ablation (LA) is momentarily the only invasive ablation procedure besides radiofrequency ablation (RFA) which can be performed entirely under magnetic resonance imaging (MRI) guidance. The long-term outcome and morbidity profiles are broadly identical for both modalities, excluding the RFA-specific prevalence for skin burns. The technical and logistic disadvantages of LA have been overcome since the introduction of miniaturized two-component applicators. The main advantage of LA is its superior MRI compatibility. Interference-free imaging during LA allows MR thermometric real-time therapy control without the need for RF filters. High-resolution thermometry in the target zone only makes sense without the extinction artifact of a metal probe and this condition is met only by the glass fibers of LA. An independent therapy monitoring is crucial in modern scenarios of oncologic quality management.

[Whole-body MRI in the study of health in Pomerania]. / Ganzkörper-MRT in der "Study of Health in Pomerania"

Population-based whole-body MRI examinations have been evaluated for the first time within the Study of Health in Pomerania (SHIP). This ongoing cohort study investigates associations of overweight (57.9% of the female and 74.1% of the male population) and obesity (25.1% and 26.0%, respectively) with cardiovascular and metabolic diseases in a population with decreased life expectancy compared to the total German average. Whole-body MRI offers the possibility to evaluate parameters, such as the amount of visceral and liver fat and can contribute to further conclusions on these common diseases.

Pharmacokinetic and Pharmacodynamic Comparison of Once-Daily Efavirenz (400 mg vs. 600 mg) in Treatment-Naïve HIV-Infected Patients: Results of the ENCORE1 Study.

Daily efavirenz 400 mg (EFV400) was virologically noninferior to 600 mg (EFV600) at 48 weeks in treatment-naïve patients. We evaluated EFV400 and EFV600 pharmacokinetics (NONMEM v. 7.2), assessing patient demographics and genetic polymorphisms (CYP2B6, CYP2A6, CYP3A4, NR1I3) as covariates and explored relationships with efficacy (plasma HIV-RNA (pVL) <200 copies/mL) and safety outcomes at 48 weeks in 606 randomized ENCORE1 patients (female = 32%, African = 37%, Asian = 33%; EFV400 = 311, EFV600 = 295). CYP2B6 516G>T/983T>C/CYP2A6*9B/*17 and weight were associated with efavirenz CL/F. Exposure was significantly lower for EFV400 (geometric mean ratio, GMR; 90% confidence interval, CI: 0.73 (0.68-0.78)) but 97% (EFV400) and 98% (EFV600) of evaluable pVL was <200 copies/mL at 48 weeks (P = 0.802). Four of 20 patients with mid-dose concentrations <1.0 mg/L had pVL ≥200 copies/mL (EFV400 = 1; EFV600 = 3). Efavirenz exposure was similar between those with and without efavirenz-related side effects (GMR; 90% CI: 0.95 (0.88-1.02)). HIV suppression was comparable between doses despite significantly lower EFV400 exposure. Comprehensive evaluation of efavirenz pharmacokinetics/pharmacodynamics revealed important limitations in the accepted threshold concentration.

Histopathological correlation to MRI findings during and after laser-induced thermotherapy in a pig pancreas model.

RATIONALE AND OBJECTIVES: To investigate whether percutaneous laser-induced thermotherapy (LITT) with continuous magnetic resonance (MR) monitoring of thermal effects within the pancreas is feasible in a porcine model. METHODS: Laser applicators were placed in the pancreas of 15 female pigs. A temperature-sensitive (thermo--fast low-angle shot) sequence was used for continuous monitoring of thermal effects during LITT at 1.5 T. Follow-up MR images were acquired, the pigs were observed for 7 days, and then a pathological examination was performed after sacrifice. RESULTS: Continuous MR monitoring visualized thermal effects in pancreatic tissue and thermal damage of the spleen (n = 1), the left kidney (n = 1), and peripancreatic fat (n = 4) but missed the thermal damage of the duodenum (n = 2). Thermal-induced lesions (10--32-mm diameter) were clearly visualized on contrast-enhanced T1-weighted images. CONCLUSIONS: Laser-induced thermotherapy of pancreatic tissue was feasible in this porcine model, and online monitoring was practicable. Further studies are necessary to increase the accuracy of online MR imaging of thermal effects.

[Characterization of focal liver lesions with contrast-enhanced low MI real time ultrasound and SonoVue]. / Charakterisierung fokaler Leberläsionen mit kontrastmittelgestütztem "low MI real time" Ultraschall und SonoVue.

PURPOSE: SonoVue is a new microbubble ultrasound contrast agent that for the first time allows continuous real time examination during the different phases of contrast enhancement using low transmission power, expressed as mechanical index (MI). This study investigates whether low MI real time phase inversion imaging with SonoVue can improve the characterization of focal liver lesions in comparison to unenhanced sonography and power Doppler sonography. MATERIALS AND METHODS: Sixty-three patients with 35 malignant and 28 benign liver lesions were studied with unenhanced ultrasound (US) including B-mode and power Doppler, followed by contrast-enhanced al MI (0.1 - 0.3) real time phase inversion US during arterial, portal-venous and delayed liver phase (> 2 min after injection). Findings of the scans obtained before and after administration of contrast agent were compared with each other and with reference examinations (biopsy, MRI, CT or intraoperative US). RESULTS: The number of correctly diagnosed lesions increased from 41 (65%) without contrast agent to 58 (92%) with contrast agent (p < 0.001). The differentiation of malignant from benign lesions improved from 43 (68 %) to 60 (95 %, p < 0.001). After administration of the contrast agent, all 35 malignant lesions were correctly recognized and 3 of the 28 benign lesions were misclassified. All 27 metastases showed little or no enhancement on portal-venous and delayed phase imaging, independent of their arterial features. All 6 hepatocellular carcinomas (HCC) enhanced markedly during arterial phase and 5 showed less contrast uptake than normal liver in the late phase. Ten of 11 hemangioma displayed arterial peripheral nodular enhancement followed by progressive centripetal fill-in. Nine of 11 focal nodular hyperplasias (FNHs) showed profuse arterial enhancement (5 with a transient "spokewheel") and contrast uptake similar to normal liver thereafter. One FNH showed a subtle central scar. CONCLUSION: Low MI real time US with SonoVue markedly improves the characterization of focal hepatic lesions in comparison with unenhanced sonography.

[Laser-induced thermotherapy (LITT). Use of round and pointed laser applicator systems--initial results]. / Laserinduzierte interstitielle Thermotherapie (LITT). Anwendung runder und spitzer Laserapplikatorsysteme--erste Ergebnisse.

PURPOSE: To assess the advantages and disadvantages by using round and sharp laser application systems during laser-induced thermotherapy. METHOD: 6 in vitro examinations were performed and 12 patients with liver metastases of colorectal carcinoma were treated with laser-induced thermotherapy. All lesions were closely localised to the diaphragm, liver capsule and large intrahepatic vessels. Five patients were treated with the sharp and 7 patients with the round applicator system. After CT-guided insertion of the catheter system into the metastasis laser therapy was performed under MRI control (approx. 25 W, 20 min). RESULTS: Reduction of the distance between the laser applicator and rounded laser catheter tipp (approx. 0.5-1 cm) leads to better placement of the laser applicator in metastases located near the diaphragm, liver capsule and large intrahepatic vessels. Improved therapy results due to complete ablation of metastases were obtained. All patients treated with the round system had complete ablation of metastasis. In 3 of 5 patients treated with the sharp system, MRI control 2 days after therapy showed a residual tumour margin close to the diaphragm or to an intrahepatic vessel. DISCUSSION: Improved ablation can be obtained by closer placement of a round laser catheter in liver metastasis located near the diaphragm, liver capsule and large intrahepatic vessels.

[Color doppler ultrasonography in peripheral artery occlusive disease: continuous application of a signal enhancer]. / Farb-Doppler-Sonographie bei der peripheren arteriellen Verschlusskrankheit: Kontinuierliche Applikation eines Signalverstärkers.

PURPOSE: The effect of continuous infusion of a signal enhancer on the diagnostic efficacy of Doppler ultrasound in peripheral artery disease was evaluated. METHODS: 35 patients with peripheral artery disease were investigated by Doppler ultrasound before and during infusion of a signal enhancer (Levovist). Femoral and popliteal arteries were examined. Angiographic diagnoses included occlusions (24) and stenoses (22). They were compared to plain and enhanced Doppler findings. Artefacts and effects on signal intensity were evaluated. RESULTS: An increased Doppler signal was observed starting 1 min 35 s (mean) after begin of the infusion. It persisted for 11 min 46 s (mean). Signal enhanced studies provided less over- (0/1) and underestimation (3/5) of the findings and evaluation in the adductor channel was less compromised. Signal enhanced studies highlighted collaterals. CONCLUSION: Doppler ultrasound in patients with peripheral arterial disease is improved by continuous application of a signal enhancer.

[Blood flow quantification in hemodialysis shunts by phase contrast magnetic resonance angiography (PC-MRA) compared with duplex sonography]. / Flussquantifizierung in Hämodialyseshunts mittels Phasenkontrast-Magnetresonanzangiographie (PC-MRA) im Vergleich zur Duplex-sonographie.

PURPOSE: Aim of this study was to evaluate whether phase contrast MR angiography (PC-MRA) could provide additional functional information besides morphology in the assessment of haemodialysis fistulae. MATERIAL AND METHOD: Twenty-two patients (11 male, 11 female), aged 22-77 years, were examined. MR images were obtained with a 1.5 T Gyroscan ACS-NT (Philips, Best, Netherlands) using a high-resolution wrap-around coil. In addition to MRA blood-flow measurements were performed with a gradient-echo sequence (TR 14 ms, TE 5-5.5 ms, flip-angle 15 degrees, 6 mm slice thickness, retrospective gating, matrix 96:128) in the venous and arterial section of the fistulae. Doppler flow measurements were performed at the same position with a Sonoline Elegra (Siemens AG, Erlangen) using a 7.5 MHz transducer. RESULTS: Both methods of flow-volume measurements showed a good correlation (r = 0.94 in the arterial section, r = 0.90 in the venous section, p < 0.001). The average calculated blood flow was measured 11% (arterial section) and 12.8% (venous section) higher with Pulsed Waved Doppler as compared to PC-MRA. CONCLUSION: PC-MRA with a high-resolution wrap-around coil is a reliable method for measuring functional parameters like flow-volume and flow velocity in haemodialysis fistulae and a useful complement to the visualisation capabilities of MRA.

[Radiological-guided liver-port implantation: Evaluation, technical approach, interventional procedure and follow up]. / Radiologisch-interventionelle Leberportanlage: Evaluierung, Zugangswege, Intervention und Nachkontrolle.

UNLABELLED: Radiological-guided liver-port implantation: Evaluation, technical approach, interventional procedure and follow up. PURPOSE: Description of evaluation, technical approach, interventional procedure and follow up of radiological-guided liver-port implantation. METHOD: Percutaneous implantation of a liver-port system was performed in twelve patients through a transfemoral approach and in one patient via the superficial epigastric artery after surgical exploration. In four patients we used port systems which are accessible via ventral puncture. Strecker-port systems were implanted in the remaining nine patients. RESULTS: The liver-port implantation was technically successful in all cases. No dislocation of the distal catheter tip, no thrombosis of the hepatic or splenic artery, no leakage near connections of the catheters or connections of catheter and port system and no thrombosis of the femoral arteries were observed. Correction of a kink in the catheter was performed in one patient. Another patient showed prolonged healing of the subcutaneous pocket. CONCLUSIONS: Interventional liver-port implantation is a safe procedure and leads to good clinical results. From the view of the radiologist the Strecker-system shows a good performance. The approach via the superficial epigastric artery demands excellent interdisciplinary cooperation.

[Fusion of CT and PET data: methods and clinical relevance for planning laser-induced thermotherapy of liver metastases]. / Fusion von CT- und PET-Daten: Methode und klinische Bedeutung am Beispiel der Planung der laserinduzierten Thermotherapie von Lebermetastasen.

AIM: Catheter-placement in liver metastases is difficult when the lesions are not visible on plain images. We evaluated the use of image fusion using CT and PET data, providing information on anatomy and liver lesions, respectively. METHODS: Plain CT of the liver and whole body FDG-PET were performed in 28 patients with colorectal carcinoma in preparation for laser-induced thermotherapy. Fusions of image data and 2D-visualisation were performed and evaluated with regard to quality of the registration, number of detected lesions and influence of the procedure on laser-induced thermotherapy. Image fusion was performed using an algorithm which was developed by our group. RESULTS: 84 focal liver lesions were visible on CT, 107 on PET images. This means that CT guided catheter placement would have to be performed "blindly" in 23 lesions. In 6 patients previously unknown extra-hepatic tumor deposits were seen on PET images (local recurrence, 2 extrahepatic metastases, 2 second primaries). CONCLUSION: Hot spots from metastases, which are difficult to locate on PET images alone, may be identified on images generated by fusion of CT and PET data. These images facilitate an interventional approach to liver lesions which are not visible on plain CT. As PET allows for whole body screening, it helps identifying patients who would not profit from laser-induced thermotherapy.

Double contrast MRI of thermally ablated liver metastases.

PURPOSE: To investigate the ability of double contrast MRI (enhancement with iron oxide and gadopentetate dimeglumine) to increase the difference in contrast between various tissues after thermal ablation of liver metastases. MATERIALS AND METHODS: 12 patients were imaged after MR-guided laser-induced thermotherapy (LITT). Imaging was performed with a 1.5T MR system. Nonenhanced, iron oxide-enhanced and double contrast images were acquired using T (1)-weighted GRE and T (2)-weighted TSE sequences. Iron oxide imaging was performed 10 min after injection of 1.4 ml ferucarbotran (Resovist(R), Schering AG Berlin, Germany) and double contrast imaging 60 sec after the additional injection of 0.1 mmol/kg body weight gadopentetate dimeglumine (Magnevist(R), Schering AG Berlin, Germany). Qualitative and quantitative assessment was performed on induced necroses, residual or recurrent tumor tissue and metastatic tissue untreated at the time of the study. RESULTS: Iron oxide-enhanced T (1) GRE images demonstrated the highest contrast between ablated hyperintense tissue and iron accumulating and resultant hypointense liver parenchyma. Due to Gd enhancement, double contrast T (1)-weighted GRE images displayed the highest change in signal intensity in vital tumor tissue compared to ablated tissue and iron oxide accumulating liver parenchyma (p < 0.01). CONCLUSIONS: First observations indicate that LITT of hepatic metastases can be better followed with double contrast MRI, which displays increased contrast due to Gd enhancement of perfused tumor tissue and signal intensity loss in iron oxide accumulating hepatic parenchyma. Induced necrosis does not change its signal intensity at all after injection of iron oxide and Gd-containing contrast media.

[Laser-induced thermotherapy (LITT) of lung metastases: description of a miniaturized applicator, optimization, and initial treatment of patients]. / Laser-induzierte Thermotherapie (LITT) von Lungenmetastasen: Beschreibung eines miniaturisierten Applikators, Optimierung und erste Patientenbehandlungen.

PURPOSE: A thin-caliber applicator system was developed for introducing a laser fiber under CT guidance into lung metastases with only minimal complications. MATERIALS AND METHODS: A space-saving 5.5 French Teflon cannula with a titanium trocar and connectors for a laser light guide (2 or 3 cm Dornier Diffusor-Tip H-6111-T2 or H-6111-T3 coupled to a Dornier Medilas Fibertom 5100 laser, wavelength of 1064 nm) and a perfusion line for physiologic saline solution were developed. After puncture the laser Diffusor-Tip remains in the cannula and is cooled during its tissue passage by slowly flowing saline solution. The miniaturized applicator system (Monocath) was calibrated in nonperfused bovine liver for maximum energy supply and necessary flow of the cooling saline solution in reference to a commercially available 9 French laser catheter with an 11.5 French inducer sheath (Power-Applicator). The new applicator system was used for treating lung metastases in 10 patients over a period of 21 months. RESULTS: The size of heat coagulation in bovine liver was 24 +/- 2 ml using the miniaturized system with application of 15 W for 20 min and a saline flow of 0.75 ml/min, in comparison to a size of 29 +/- 7 ml for the commercial applicator (30 W, 20 min, 60 ml/min). All metastases could be safely approached with the miniaturized applicator, except for two metastatic lesions at the lung base in two patients. A minor pneumothorax developed in three patients and intrapulmonary bleeding in two. Contrast-enhanced CT demonstrated necrosis of the treated metastatic areas in 6 patients. Follow-up of three patients after 5, 6, and 8 months showed complete tumor regression with minimal scarring in one patient. CONCLUSION: The miniaturized applicator system enables the introduction of a laser fiber into pulmonary metastases with only minor complications. Complete ablation seems to be achievable in suitable patients with the applied laser energy and a slow cooling fluid flow rate.

[Technical success rate, peri-interventional complications and radiation exposure of the transarterial embolization for leiomyomas of the uterus]. / Technische Erfolgsrate, peri-interventionelle Komplikationen und Strahlenexposition der transarteriellen Embolisation bei Uterus myomatosus.

PURPOSE: To analyze the technical success rate, incidence and type of peri-interventional complications, and radiation exposure of uterine artery embolization (UAE) in symptomatic leiomyomas of the uterus. MATERIALS AND METHODS: This prospective study includes 75 patients consecutively treated with UAE from October 2000 through August 2002, with all interventions performed by the same radiologist. Technical success rate, interventional material, and incidence and type of peri-interventional complications (length of hospitalization) were recorded and categorized according to the definitions of the Society of Interventional Radiology (SIR). Fluoroscopy time (FT), dose-area product (DAP), and effective dose (ED) were determined for each intervention and the influence of the radiologist's experience on the radiation exposure analyzed. RESULTS: UAE was technically successful in 97.3 % of the cases. Peri-interventional complications occurred in 14.7 %. Four complications (5.3 %) were classified as major class C according to the SIR (post-embolization syndrome requiring prolonged drug treatment and hospitalization [n = 3] perforation of the uterine artery [n = 1]). None of the complications led to discontinuation of the intervention, subsequent surgical intervention, or permanent sequelae. FT decreased significantly (p < 0.05) until the 35th intervention. The median FT decreased from 18.8 min (13.4 - 28 min [25th to 75th percentile]) to 11.8 min (9.7 - 13.3 min [25th to 75th percentile]). The DAP decreased by 25.3 % to a median of 8.547 (6.527 - 11.590 cGy*cm (2) [25th to 75th percentile]). The median ED was 31.5 mSv from the 36th intervention onward. CONCLUSION: UAE has a high technical success rate with a low rate of peri-interventional complications. The study showed a statistically significant learning effect with a decrease in radiation exposure for the first 35 interventions. The effective dose of UAE is comparable to that of 1 to 2 small bowel enema.

Pulse wave numerical analysis.

The general deterioration of the arterial system is well recognized but not easily measured. Leg pulse waves, generated by the electric impedance plethysmograph, would seem to be a promising method. This study is a mathematical analysis of these pulse waves from the legs. The data were taken from a previous study by the same authors. That study analyzed the pulse waves using a frequency analysis (Fourier) and a lumped component model of the circulatory system. Blood pressure became clinically very meaningful when a number could be assigned to it. This study is being done to determine if a numerical value could be assigned to different types of pulse waves. If this can be done it would furnish a new tool for analyzing the peripheral circulation and peripheral atherosclerosis. This would offer another method for analyzing therapeutic endeavors that affect the circulatory system. These pulse waves were from a rather homogeneous group of generally healthy white males. The subjects were arranged according to age: ages 5-11, ages 19-24, 36-45, ages 55-62, and ages 74-91. This present analysis involves an advanced mathematical analysis done by a computer. The first graph (4a)--sine amplitude vs age--showed a sloping line which intersects the abscissa at about age 100. The second graph (4b)--notch (of the downstroke of the pulse wave) vs age--showed a sloping line intersecting the age line at about age 100. Thus, these calculations suggest that the untreated circulatory system is programmed to have a functional death at about age 100. The two methods used, one involving mathematical calculations and one involving graphic measurements, showed that a number can be put on the pulse wave. The higher the number, theoretically the better the circulation. Then if a treatment scheme can substantially raise the patient's pulse wave number, it might be expected to increase the longevity of their circulatory system.

Forces dictating colloidal interactions between viruses and soil.

The fate and transport of viruses in soil and aquatic environments were studied with respect to the different forces involved in the process of sorption of these viruses on soil particles. In accordance with the classical DLVO theory, we have calculated the repulsive electrostatic forces and the attractive van der Waals forces. Bacteriophages have been used as model sorbates, while different clays have been used as model sorbents. The equations used for the determination of the change in free energy for the process (deltaG) takes into consideration the roughness of the sorbent surfaces. Results indicate that attractive van der Waals forces predominate the process of sorption of the selected bacteriophages on clays.

Long-term performance monitoring for a permeable reactive barrier at the U.S. Coast Guard Support Center, Elizabeth City, North Carolina.

A continuous hanging iron wall was installed in June, 1996, at the U. S. Coast Guard (USCG) Support Center near Elizabeth City, NC, United States, to treat overlapping plumes of chromate and chlorinated solvent compounds. The wall was emplaced using a continuous trenching machine whereby native soil and aquifer sediment was removed and the iron simultaneously emplaced in one continuous excavation and fill operation. To date, there have been seven rounds (November 1996, March 1997, June 1997, September 1997, December 1997, March 1998, and June 1998) of performance monitoring of the wall. At this time, this is the only full-scale continuous 'hanging' wall installed as a permeable reactive barrier to remediate both chlorinated solvent compounds and chromate in groundwater. Performance monitoring entails the following: sampling of 10-5 cm PVC compliance wells and 15 multi-level samplers for the following constituents: TCE, cis-dichloroethylene (c-DCE), vinyl chloride, ethane, ethene, acetylene, methane, major anions, metals, Cr(VI), Fe(II), total sulfides, dissolved H(2), Eh, pH, dissolved oxygen, specific conductance, alkalinity, and turbidity. Electrical conductivity profiles have been conducted using a Geoprobe to verify emplacement of the continuous wall as designed and to locate upgradient and downgradient wall interfaces for coring purposes. Coring has been conducted in November, 1996, in June and September, 1997, and March, 1998, to evaluate the rate of corrosion on the iron surfaces, precipitate buildup (particularly at the upgradient interface), and permeability changes due to wall emplacement. In addition to several continuous vertical cores, angled cores through the 0.6-m thick wall have been collected to capture upgradient and downgradient wall interfaces along approximate horizontal flow paths for mineralogic analyses.

Selenium levels of beef cattle in southeastern british columbia relative to supplementation and type of pasture.

Moderate to extremely low levels of selenium in hay were related to marginally deficient levels of selenium in sera from cattle in the Windermere Valley of southeastern British Columbia. Deficiency was most pronounced in cattle fed local hay during the winter or grazed on fertilized/irrigated pastures. Cattle on range had adequate levels of serum selenium. When sodium selenite was fed at 1.0 and 3.5 mg per head per day, serum selenium levels increased commensurate with the dose. Clinical observations indicated that a variety of clinical problems disappeared after injection or supplementation with selenium/vitamin E.