Magnetic phase transition in a nanonetwork of solid 3He in aerogel.

When immersed in liquid 3He, the nanometer strands of aerogel are coated with a thin layer of solid 3He, forming a network of irregular nanotubes. Owing to its high purity and weak interactions, this system is ideal for studying fundamental processes. We report the first experiments on solid 3He in aerogel at ultralow temperatures, cooled by direct adiabatic demagnetization. Simultaneous nuclear magnetic susceptibility and heat capacity measurements indicate a magnetic phase transition.

Regional-scale assessment of soil salinity in the Red River Valley using multi-year MODIS EVI and NDVI.

The ability to inventory and map soil salinity at regional scales remains a significant challenge to scientists concerned with the salinization of agricultural soils throughout the world. Previous attempts to use satellite or aerial imagery to assess soil salinity have found limited success in part because of the inability of methods to isolate the effects of soil salinity on vegetative growth from other factors. This study evaluated the use of Moderate Resolution Imaging Spectroradiometer (MODIS) imagery in conjunction with directed soil sampling to assess and map soil salinity at a regional scale (i.e., 10-10(5) km(2)) in a parsimonious manner. Correlations with three soil salinity ground truth datasets differing in scale were made in Kittson County within the Red River Valley (RRV) of North Dakota and Minnesota, an area where soil salinity assessment is a top priority for the Natural Resource Conservation Service (NRCS). Multi-year MODIS imagery was used to mitigate the influence of temporally dynamic factors such as weather, pests, disease, and management influences. The average of the MODIS enhanced vegetation index (EVI) for a 7-yr period exhibited a strong relationship with soil salinity in all three datasets, and outperformed the normalized difference vegetation index (NDVI). One-third to one-half of the spatial variability in soil salinity could be captured by measuring average MODIS EVI and whether the land qualified for the Conservation Reserve Program (a USDA program that sets aside marginally productive land based on conservation principles). The approach has the practical simplicity to allow broad application in areas where limited resources are available for salinity assessment.

Spontaneous Remission of an Untreated, MYC and BCL2 Coexpressing, High-Grade B-Cell Lymphoma: A Case Report and Literature Review.

Non-Hodgkin lymphomas (NHL) are a heterogeneous group of hematologic malignancies typically treated with multiagent chemotherapy. Rarely, spontaneous remissions can be observed, particularly in more indolent subtypes. The prognosis of aggressive NHL can be predicted using clinical and histopathologic factors. In aggressive B-cell NHL, the importance of MYC and BCL2 proto-oncogene coexpression (as assessed by immunohistochemistry) and high-grade histologic features are particularly noteworthy. We report a unique case of spontaneous remission in a patient with an aggressive B-cell NHL which harbored high-risk histopathologic features, including MYC protein expression at 70-80%, BCL2 protein expression, and morphologic features suggestive of high-grade B-cell lymphoma, NOS (formerly B-cell lymphoma unclassifiable with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma [BCLU]). After undergoing a biopsy to confirm this diagnosis, he opted to forego curative-intent chemotherapy. The single, yet relatively large area of involvement noted on 18F-fluorodeoxyglucose positron emission tomography-computed tomography steadily resolved on subsequent follow-up studies. He remained without evidence of recurrence one year later, having never received treatment. This case emphasizes the potential for spontaneous remission in NHL and demonstrates that this phenomenon can be observed despite contemporary high-risk histopathologic features.

Photosynthetic phenological variation may promote coexistence among co-dominant tree species in a Madrean sky island mixed conifer forest.

Across much of western North America, forests are predicted to experience a transition from snow- to rain-dominated precipitation regimes due to anthropogenic climate warming. Madrean sky island mixed conifer forests receive a large portion of their precipitation from summertime convective storms and may serve as a lens into the future for snow-dominated forests after prolonged warming. To better understand the linkage between physiological traits, climate variation, and the structure and function of mixed conifer forests, we measured leaf photosynthetic (A) responses to controlled variation in internal CO2 concentration (Ci) to quantify interspecific phenological variation in A/Ci-derived ecophysiological traits among ponderosa pine (Pinus ponderosa Lawson and C. Lawson), southwestern white pine (Pinus strobiformis Engelm.) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Species had similar, positive responses in net photosynthesis under ambient conditions (Anet) to the onset of summertime monsoonal precipitation, but during the cooler portions of the year P. ponderosa was able to maintain greater Anet than P. menziesii and P. strobiformis. Moreover, P. ponderosa had greater Anet in response to ephemerally favorable springtime conditions than either P. menziesii or P. strobiformis. Monsoonal precipitation was associated with a sharp rise in the maximum rates of electron transport (Jmax) and carboxylation (VCmax) in P. menziesii in comparison with P. ponderosa and P. strobiformis. In contrast, species shared similar low values of Jmax and VCmax in response to cool winter temperatures. Patterns of relative stomatal limitation followed predictions based on species' elevational distributions, reinforcing the role of stomatal behavior in maintaining hydraulic conductivity and shaping bioclimatic limits. Phenological variation in ecophysiologial traits among co-occurring tree species in a Madrean mixed conifer forest may promote temporal resource partitioning and thereby contribute to species' coexistence. Moreover, these results provide a physiological basis for predicting the ecological implications of North American mixed conifer forests currently transitioning from snow- to rain-dominated precipitation regimes.

Evaluation of allogeneic transplantation in first or later minimal residual disease - negative remission following adult-inspired therapy for acute lymphoblastic leukemia.

Comparisons without hematopoietic cell transplantation (HCT) to myeloablative (MAC) or reduced-intensity HCT (RIC) for adults with acute lymphoblastic leukemia (ALL) in first minimal-residual-disease negative remission (MRD(Neg) CR1) are limited. Further, the importance of MRD(Neg) following salvage therapy (MRD(Neg) CR2+) is unknown. We evaluated 89 patients in MRD(Neg) CR1 after adult-inspired treatment: 33 received MAC (12 Philadelphia chromosome [Ph]+), 17 received RIC (13 Ph+), and 39 Deferred HCT (3 Ph+). Three-year overall survival (OS) estimates for MAC, RIC, and Deferred HCT were 71%, 69%, and 68%, while 3-year event-free survival (EFS) estimates were 65%, 54%, and 28%, respectively. Further, HCT in MRD(Neg) CR1 performed similarly to MRD(Neg) CR2+: 3-year OS estimates were 70% and 69%, and 3-year EFS estimates were 62% and 62%, respectively. In conclusion, adults with ALL in MRD(Neg) CR1 following adult-inspired therapy had similar OS with or without HCT, and HCT in MRD(Neg) CR2 + can yield long-term survival.

The glucose-pH relationship in parapneumonic effusions.

Both a low pleural fluid glucose concentration and pleural fluid acidosis are markers of severe pleural inflammation, but the relationship between these phenomena has not been defined clearly. Therefore, we measured simultaneous pleural fluid glucose concentrations and pH in 25 consecutive parapneumonic pleural fluids. Seventeen effusions had a glucose concentration greater than 60 mg/dl (group 1, 126 +/- 7 mg/dl, mean +/- SEM), while eight had a pleural fluid glucose less than 60 mg/dl (group 2, 15 +/- 3 mg/dl, P less than .01). Pleural fluid pH was 7.35 +/- 0.03 in group 1 compared with 6.83 +/- 0.09 in group 2 (P less than .01). A significant correlation between pleural fluid glucose and pH was found (r = .81, P less than .01). Low-glucose, low-pH effusions were complicated (either loculated or empyemas). Uncomplicated effusions had glucose concentrations greater than 60 mg/dl and a pleural fluid pH greater than 7.30. The concomitant occurrence of low pleural fluid glucose and pH suggests that the mechanisms leading to these phenomena are interrelated.

Acid-base disturbances in the salicylate-intoxicated adult.

This study examined the acid-base disturbances in 67 adults with salicylate intoxication. On admission, 66 patients had an acid-base distrubance. In contract to previous suggestions, however, only 25% of the patients had simple respiratory alkalosis. Unlike salicylate intoxication in children, 33% of these adults with salicylate intoxication had ingested additional drugs. These additional drugs generally were CNS depressants and were important determinants of the variety of the acid-base disturbance. Those patients who ingested additional drugs had a significantly lower incidence of respiratory alkalosis (P less than .005) and a higher incidence of respiratory acidosis (P less than .005) and acidemia (P less than 0.25). The incidence of acidemia correlated with the presence of neurological symptoms.

Thyrotoxicosis: comparison of effects of thyroid ablation and beta-adrenergic blockade on metabolic rate and ventilatory control.

To elucidate the role of the beta-sympathetic system in thyrotoxicosis (THY), we examined cardiac sensitivity to infused beta-agonist and compared the effect of beta-blockade with that of resolution of the hyperthyroid state. Beta-sympathetic (beta-SYM) sensitivity was measured as the heart rate response to isoproterenol in THY patients and in normal subjects. The patients with THY showed both lower threshold (P less than 0.05) and increased slope (P less than 0.05) of the heart rate-isoproterenol response, suggesting beta-SYM hypersensitivity. The beta-SYM like features of THY were measured in 7 patients before and 7 days after beta-SYM blockade with propranolol (mean dose 411 +/- 32 mg/day [SEM]) which was shown to block the heart rate response to isoproterenol. These results were compared with those in a similar group of thyrotoxic patients rendered euthyroid with 131I. During beta-SYM blockade, heart rate decreased from 101 +/- 6.3 to 78 +/- 4.6 (P less than 0.01), but the elevated metabolic rate (V02), resting ventilation (VE), and increased hypoxic and hypercapnic ventilatory responses were not significantly affected. In the group rendered euthyroid with 131I, heart rate decreased from 110 +/- 3.5 to 76 +/- 7.8 (P less than 0.02), but in contrast to the result of beta-SYM blockade, a 28% decrease in VO2 (P less than 0.01), 41% decrease in VE (P less than 0.05), a 38% decrease in hypercapnic ventilatory response (P less than 0.05), and a 66% decrease in hypoxic response (P less than 0.03) occurred. During THY, beta-SYM mechanisms are responsible for part of the tachycardia, but the metabolic and ventilatory abnormalities are not beta-SYM mediated.

Syndrome and pancreatic disease, subcutaneous fat necrosis and polyserositis. Case report and review of literature.

Immunologic evaluation of a patient with pancreatitis, subcutaneous fat necrosis, pleuritis, pericarditis and synovitis is presented. The previously recognized syndrome of pancreatic disease, subcutaneous fat necrosis and arthritis is reviewed. Based on analysis of all the cases described in the English language literature it is suggested that this syndrome be expanded to include polyserositis rather than arthritis alone. Although experimental and clinical evidence tends to implicate physiocochemical tissue injury by pancreatic lipase as the primary pathogenic mechanism in this syndrome, studies in our patient suggest the possible contribution of immune-mediated injury. Supporting data include eosinophilia, biopsy demonstration of vasculitis antedating the subcutaneous fat necrosis, immunofluorescent identification of immunoglobulin G (IgG) and C3 in the pleura, and reduced levels of total hemolytic complement in the serum, and pleural and pericardial effusions.

Improved porcine renal preservation with a simple extracellular solution--PBS140.

In this prospective randomized trial a porcine model of renal autotransplantation was used to compare quality of preservation, as reflected by detailed analysis of posttransplant renal function, following 24-hr cold storage in phosphate-buffered sucrose (PBS140), hyperosmolar citrate (HOC), and University of Wisconsin (UW) preservation solutions. There were 6 deaths with primary nonfunction: 3 of 5 HOC, 2 of 5 UW, but only 1 of 5 PBS140. Analysis of the whole group and separate analysis of the survivors demonstrated significantly better renal function following preservation with PBS140 when compared with both HOC and UW, with a lower peak serum creatinine (P = 0.02) and improved loop of Henle function (P = 0.02). The animals in the PBS140 group also demonstrated a more rapid return to normal creatinine, higher GFR, improved tubular function, and higher effective renal plasma flow, with figures approaching statistical significance (P = 0.06-0.07). The proposal of UW as a universal storage medium prompted this study, and its results suggest the need for a clinical comparison of renal preservation using UW and PBS140 in a prospective randomized trial.

Improved 72-hour renal preservation with phosphate-buffered sucrose.

The result of this study shows that a simple phosphate buffered sucrose solution (PBS) is better than hyperosmolar citrate (HOC) solution in the flush perfusion and hypothermic storage of canine kidneys for 72 hr prior to autotransplantation with immediate contralateral nephrectomy. The peroperative measurement of postreperfusion renal blood flow revealed a significant reduction after 60 min in kidneys preserved with HOC solution. All grafts and animals in the PBS group (5/5) survived with primary renal function compared with one in the HOC group (1/5), which functioned after a period of oliguria. The early serum creatinine and urea levels were significantly lower in the PBS group, with a return to normal range within two weeks. This is reflected in higher inulin clearances and a more rapid recovery of proximal tubular function in the PBS animals, which also demonstrated a more rapid return of loop function and the ability to concentrate urine.

The pH of sclerosing agents: a determinant of pleural symphysis.

The rate of success in producing pleural symphysis with intrapleural instillation of sclerosing agents has been variable. Differences in the designs of studies probably account for some of the variability, but the reasons for the remainder are not clear. Since a low pH of the pleural fluid is associated with pleural adhesions and loculations, the pH of the commonly used solutions of sclerosing agents was determined, both in their usual concentrations and when diluted with large quantities of exudative pleural fluid. The buffered solution of tetracycline hydrochloride had the most acidic pH (2.0) and showed little change when diluted by pleural fluid. A 0.5 percent solution of sodium hydroxide had the highest pH (13.0). The remainder of the sclerosing solutions showed a range of pH from 4.3 to 8.7. Experimental and clinical experience suggests that tetracycline consistently has the highest rate of success in producing pleural symphysis. It appears that when proper technique is employed, the pH of the solution of the sclerosing agent is an important determinant of the production of pleural symphysis.

Pleural fluid pH in parapneumonic effusions.

The pH and carbon dioxide tension were measured in 24 consecutive parapneumonic effusions, along with the leukocyte count, leukocytic differential count, and levels of glucose and protein. Three categories of parapneumonic effusions were characterized: (1) empyemas; (2) benign (nonloculated) effusions; and (3) loculated effusions. A pH greater than 7.30 was present in all ten benign effusions, and spontaneous resolution occurred in each case. All ten empyemas and the four loculated effusions had a pH less than 7.30. All four loculated effusions required drainage with a chest tube for resolution. The pH of the pleural fluid alone separated the empyemas and loculated effusions from benign effusions. The early separation of parapneumonic effusions on the basis of the pleural fluid appears useful. If the pH is greater than 7.30, a benign effusion is present, and spontaneous resolution is likely. If the pH is less than 7.30, loculation of the pleural space may occur regardless of whether the effusion fulfills the criteria for empyema.

Emergency room intubations--complications and survival.

Forty-three consecutive patients requiring endotracheal intubation in an emergency room were studied prospectively to define the complications associated with intubation and the survival of these patients, and to evaluate emergency room policies. The indications for intubation were acute respiratory failure (ARF) in 22 patients and cardiopulmonary arrest (CPA) in 21 patients. Thirty-eight complications occurred in 24 of the 43 patients. The department or level of training of the intubator did not affect the rate of complications. Furthermore, specific complications did not influence survival. Seventeen patients survived, all in the ARF group. Age less than 40 years and admission PaO2 greater than 40 mm Hg also were associated with increased survival. We conclude that the complication rate of emergency room intubations is high and would not appear to be lowered by limiting intubations to physicians from specific departments or with certain levels of training. The underlying diagnosis and condition on admission to the emergency room appear to be more important factors relating to survival than complications during intubation.

Bacteriologic and endotoxin analysis of salvaged blood used in autologous transfusions during cardiac operations.

Autologous blood transfusion is a common method of reducing the need for heterologous blood transfusion during cardiac operations. Recently we investigated an outbreak of severe, nonsurgical postoperative bleeding among patients undergoing heart operations and receiving intraoperative transfusion of blood from a cell conservation device (Cell Saver System, Haemonetics Corp., Braintree, Mass.). As a result of this investigation, we conducted a prospective study to determine if bacterial or endotoxin contamination of the blood collected in the Cell Saver System and used for reinfusion during heart operations contributes to postoperative bleeding complications. Patients' blood samples were collected immediately before operation, at the end of cardiopulmonary bypass, 1 hour postoperatively, and from the Cell Saver System. All blood samples were cultured for bacteria, and all plasma samples were assayed for endotoxin. Preoperatively all patients having heart operations were without signs of infection, 33 of 37 blood cultures taken were negative, and none of the plasma samples had detectable endotoxin. After discontinuance of cardiopulmonary bypass but before delivery of blood from the Cell Saver System, bacteria and endotoxin were detected in 11 of 36 (30.6%) and five of 35 (14.3%) of the patients' blood samples, respectively. The blood aspirated from the open chest and collected by the Cell Saver System was culture positive in 30 of 31 (96.8%) samples, and seven of 29 (24.1%) contained endotoxin. One of 28 blood samples collected 1 hour postoperatively was culture positive, and five of 25 samples contained endotoxin. Of 61 total microorganisms isolated, 50 (82%) were coagulase-negative staphylococci, four (6.6%) aerobic diphtheroids, five (8.2%) anaerobic "diphtheroids" (Propionibacterium acnes), and two (3.2%) gram-negative bacilli. Plasma endotoxin concentrations ranged from 10 to 765 pg/ml. No signs of endotoxemia or unusual bleeding were observed intraoperatively or postoperatively in any of the 38 patients. Although blood collected in the Cell Saver System and used for reinfusion during heart operations often was contaminated with gram-positive bacterial commensals of the skin and low concentrations of endotoxin, no adverse effects were noted in the patients.

Toxicology of iohexol.

This review summarizes the biological profile of the nonionic contrast medium, iohexol, with particular emphasis on neurovascular and myelographic applications. Iohexol was compared with conventional ionic media and with newer nonionic agents in a variety of animal models. Studies of systemic toxicity (teratogenicity, mutagenicity, and embryotoxicity effects) and cerebrovascular effects (epileptogenicity and arachnoiditis potential) are reported. Results indicate that iohexol has a lower toxicity than ionic and other nonionic contrast media.

A comparison of CT-stereotaxic brain biopsy techniques.

The role that computed tomography plays in the stereotaxic biopsy of intracranial lesions is reviewed. The most useful techniques, apparatuses results, and complications are described. Major complications of the procedure are hemorrhage and edema. The risk of hemorrhage may be reduced by the use of angiography before stereotaxic procedures; the risk of edema may be reduced by using steroids. Design features of several representative systems are compared. Indications for this procedure are suggested.

Evidence for transventricular absorption in the hydrocephalic dog.

Hydrocephalus was induced in 10 mongrel dogs by injection of a silastic mixture into the basal cisterns. The posterior part of the left lateral ventricle was isolated from the remainder of the ventricular system by introducing Pantopaque into both lateral ventricles and the third ventricle with the animals in prone positions. Labeled albumin injected into the posterior part of the left lateral ventricle was shown to enter the blood stream before it was shown in the fourth ventricle or vallecula. This provides qualitative evidence of transventricular absorption.

Cranial and spinal cerebrospinal fluid absorption and the clearance of water-soluble myelographic contrast media. A review.

Following myelography, water-soluble contrast media are cleared from the subarachnoid space with the cerebrospinal fluid via the cranial and spinal absorption pathways. These cerebrospinal fluid absorption pathways are reviewed. The effects of removal of excessive quantities of cerebrospinal fluid, increased numbers of cells in the cerebrospinal fluid, and dehydration are discussed.

Evaluation of the integrity of the blood-brain barrier after meningeal trauma.

RATIONALE AND OBJECTIVES: The authors used magnetic resonance imaging (MRI) techniques to examine the effect of meningeal trauma produced by cisterna magna puncture on the integrity of the blood-cerebrospinal fluid barrier (BCB) in a rat model. METHODS: Intravenous gadolinium-DTPA (Gd-DTPA), a relaxation rate modifier which normally does not cross the BCB, was used as a probe to follow leakage of fluid across the BCB. After Gd-DTPA injection, cerebrospinal fluid (CSF) serial samples were obtained through the needle used to create the experimental trauma. These samples were subsequently examined in vitro by MRI to obtain their T1 relaxation rates and assayed by mass spectrometry for gadolinium and elemental iron concentrations. RESULTS: The iron levels reflected the severity of puncture-related subarachnoid hemorrhage. Rats with ongoing meningeal damage showed significantly higher CSF levels of gadolinium and significantly higher CSF T1 relaxation rates than controls at all samples times over 1 hour after the puncture. Blood in the CSF could not explain these changes because the CSF iron levels did not significantly differ from control levels. CONCLUSIONS: Intravenously administered Gd-DTPA can gain access to the subarachnoid space through minor defects in the BCB and cause significant increases in CSF T1 relaxation rates.