Introducing Benzene-1,3,5-tri(dithiocarboxylate) as a Multidentate Linker in Coordination Chemistry

Benzene-1,3,5-tri(dithiocarboxylate) (BTDTC^3-), the sulfur-donor analogue of trimesate (BTC^3-, benzene-1,3,5-tricarboxylate), is introduced, and its potential as a multidentate, electronically bridging ligand in coordination chemistry is evaluated. For this, the sodium salt Na₃BTDTC has been synthesized, characterized, and compared with the sodium salt of the related ditopic benzene-1,4-di(dithiocarboxylate) (Na₂BDDTC). Single-crystal X-ray diffraction of the respective tetrahydrofuran (THF) solvates reveals that such multitopic aromatic dithiocarboxylate linkers can form both discrete metal complexes (Na₃BTDTC·9THF) and (two-dimensional) coordination polymers (Na₂BDDTC·4THF). Additionally, the versatile coordination behavior of the novel BTDTC^3- ligand is demonstrated by successful synthesis and characterization of trinuclear Cu(I) and hexanuclear Mo(II)₂ paddlewheel complexes. The electronic structure and molecular orbitals of both dithiocarboxylate ligands as well as their carboxylate counterparts are investigated by density functional theory computational methods. Electrochemical investigations suggest that BTDTC^3- enables electronic communication between the coordinated metal ions, rendering it a promising tritopic linker for functional coordination polymers.

Is the type of neuraxial anesthesia associated with adverse neonatal outcomes among patients with preeclampsia?

OBJECTIVE

Both preeclampsia and neuraxial anesthesia can alter placental perfusion, potentially affecting the neonatal status. The objective of our study is to quantify the association between type of neuraxial anesthetic and short-term neonatal morbidity among preeclamptic patients undergoing cesarean delivery.

METHODS

We performed a secondary analysis of a prospective observational cohort study. Women with singleton gestations and a diagnosis of preeclampsia who underwent cesarean delivery with neuraxial anesthesia were included in the analysis. Short-term neonatal morbidities, defined as neonatal intensive care unit (NICU) admission, arterial cord gas pH ≤7.2 and 5-minute Apgar <7, were compared based on type of neuraxial anesthetic.

RESULTS

A total of 4100 patients were included in the analysis, 1696 (41.4%) received spinal anesthesia 1848 (45.1%) received epidural anesthesia and 556 (13.5%) received a combined spinal-epidural (CSE). Antepartum and intrapartum characteristics significantly differed between the groups (p≤0.02). After adjusted analysis, spinal anesthesia was associated with reduced odds of NICU admission, compared with epidural or CSE (OR; 95% CI: 0.79; 0.63-0.98, 0.71; 0.53-0.94, respectively). Spinal anesthesia was also associated with lower odds of a 5-minute Apgar <7 compared with epidural anesthesia (OR 0.59; 95% CI; 0.43-0.83). We found no association between type of anesthesia and arterial cord pH ≤7.2. In stratiifed analysis by gestational age, no association between the type of neuraxial anesthesia and neonatal outcomes was noted among term infants, but associations persisted in preterm infants.

CONCLUSIONS

Among women with preeclampsia undergoing cesarean delivery, spinal anesthesia may be associated with reduced short-term neonatal morbidity in preterm infants, compared with epidural or CSE.

Non-Innocent Methylene Linker in Bridged Lewis Pair Initiators

Deprotonation usually occurs as an unwanted side reaction in the Lewis pair polymerization of Michael acceptors, for which the conjugated addition of the Lewis base to the acid-activated monomer is the commonly accepted initiation mechanism. This has also been reported for B-P-based bridged Lewis pairs (BLPs) that form macrocyclic addition products. We now show that the formerly unwanted deprotonation is the likely initiation pathway in the case of Al-P-based BLPs. In a detailed study of a series of Al-P-based BLPs, using a combination of single-crystal diffraction experiments (X-ray and neutron) and mechanistic investigations (experimental and computational), an active role of the methylene bridge was revealed, acting as a base towards the α-acidic monomers. Additionally, the polymerization studies proved a living behavior combined with significantly high activities, narrow molecular mass distributions, and the possibility of copolymerization.

A Novel Core Competencies-Based Academic Medicine Curriculum: Description and Preliminary Results

BACKGROUND

Physicians practice health care in a rapidly changing system that requires more than the delivery of safe and effective care. Modern physicians must also acquire skills beyond direct patient care. Residency programs must, therefore, prepare physicians to meet these demands by providing appropriate education and training.

METHODS

We designed, implemented and assessed an academic medicine curriculum in the first post-graduate year. This curriculum provides comprehensive exposure to necessary non-patient contact related physician skills. Topics centered around four domains: critical appraisal of literature of literature, quality improvement, professional development, and teaching. Each of these domains is linked to the six core competencies established by the Accreditation Council for Graduate Medical Education's (ACGME). Instruction includes small-group learning sessions with additional time for self-directed online modules and a faculty-mentored quality improvement research project that is presented at a graduation symposium. All residents completed a survey evaluation of the curriculum before and after the course via open-ended questions and Likert responses (0-5). We assessed improvement in resident confidence with each curricular domain using mean Likert score change and 95% confidence intervals (CI).

RESULTS

Residents improved at all curricular domains measured. The most significant mean changes included confidence in: poster presentations (2.7; 95% CI: 1.9-3.5), plan-do-check-act cycle (2.5; 95% CI: 2.1-2.9), quality improvement projects (2.4; 95% CI: 1.9-2.9), and abstract presentation (2.3; 95% CI: 1.6-3.0).

CONCLUSIONS

We found that the academic medicine rotation (AMR) is feasible in a large academic setting. Furthermore, the AMR allows early exposure to and improvement in essential non-patient contact related physician skills required by the ACGME core competencies and assessed through the milestones.

Enhancement of anesthesiology in-training exam performance with institution of an academic improvement policy

BACKGROUND

Anesthesiology resident physicians across the United States complete an annual in-training examination (ITE). The ITE evaluates resident knowledge and provides personalized feedback to guide future study in low scoring sections(1). Performance on the ITE correlates with outcomes on the American Board of Anesthesiology (ABA) written board examination(2). Over the last several years, declining ITE scores were observed at the University of North Carolina (UNC). In response to this decline, our department reprioritized the ITE by instituting an academic improvement policy (AIP). The AIP employed both reward for satisfactory achievement and consequence for under-performance to elevate the ITE as a "high stakes" examination. Our hypothesis was that implementation of this AIP would improve ITE scores.

METHODS

ITE scores were compiled from 150 residents in the Department of Anesthesiology at UNC for graduating classes from 2004-2015. Data is presented as the number of residents scoring below the 20th percentile when compared to the national distribution before and after the AIP. In addition, average USMLE Step 1 three-digit scores for each graduating class were compared to average ITE percentile scores of the corresponding graduating class (USMLE does not provide percentile scores).

RESULTS

Between 2009 and 2013, the number of residents who scored below the 20th percentile on the ITE increased steadily to a peak of 10 in 2011. After implementation of the AIP in July 2011, there was an 80% decrease in those scoring below the 20th percentile, from 10 to 2 residents (p<0.05).

CONCLUSIONS

Anesthesiology resident ITE scores improved after implementation of an academic improvement policy.

Anaphylactoid reaction to intravenous sodium ferric gluconate complex during pregnancy

We report the first case of a severe anaphylactic or anaphylactoid reaction to sodium ferric gluconate complex in a pregnant patient. Sodium ferric gluconate complex is felt to be one of the safest forms of iron therapy during pregnancy. This case highlights the need for extreme caution and vigilance in pregnant patients receiving any type of parenteral iron therapy.

Characterization of a Plasmodium falciparum erythrocyte-binding protein paralogous to EBA-175

A member of a Plasmodium receptor family for erythrocyte invasion was identified on chromosome 13 from the Plasmodium falciparum genome sequence of the Sanger Centre (Cambridge, U.K.). The protein (named BAEBL) has homology to EBA-175, a P. falciparum receptor that binds specifically to sialic acid and the peptide backbone of glycophorin A on erythrocytes. Both EBA-175 and BAEBL localize to the micronemes, organelles at the invasive ends of the parasites that contain other members of the family. Like EBA-175, the erythrocyte receptor for BAEBL is destroyed by neuraminidase and trypsin, indicating that the erythrocyte receptor is a sialoglycoprotein. Its specificity, however, differs from that of EBA-175 in that BAEBL can bind to erythrocytes that lack glycophorin A, the receptor for EBA-175. It has reduced binding to erythrocytes with the Gerbich mutation found in another erythrocyte, sialoglycoprotein (glycophorin C/D). The interest in BAEBL's reduced binding to Gerbich erythrocytes derives from the high frequency of the Gerbich phenotype in some regions of Papua New Guinea where P. falciparum is hyperendemic.

The role of dorsal striatal GABA(A) receptors in dopamine agonist-induced behavior and neuropeptide gene expression

The purpose of this study was to investigate whether GABA(A) receptors in the dorsal striatum regulate basal or stimulant-induced behaviors. Correspondingly, the question of possible GABA(A) receptor control of neuropeptide mRNA expression in nigrostriatal neurons was addressed. The GABA(A) receptor antagonist, bicuculline, was unilaterally or bilaterally microinjected into the dorsal striatum of rats in a series of 3 studies. In the first study, unilateral administration of 10-50 ng/microliter of bicuculline did not alter behavior. However, 250 ng/microliter bicuculline produced motor dyskinesias and/or seizures. In the second study, 100 ng/microliter bicuculline administered unilaterally prior to saline or amphetamine treatment, produced mild twitching in 61% of rats but did not affect amphetamine (2.5 mg/kg, i.p.)-induced behavioral activity, specifically rearing and sniffing. In the third study, 75 ng/microliter of bicuculline was administered unilaterally or bilaterally into the striatum in two separate experiments. Administration of bicuculline either unilaterally or bilaterally produced mild transient twitching of the forelimbs but did not affect behaviors induced by the selective D(1) receptor agonist SKF-82958 (0.5 mg/kg, s.c.). Three hours after unilateral bicuculline administration, the brains were removed and processed for quantitative in situ hybridization. Bicuculline did not significantly affect the basal or SKF-82958-induced increase in preprodynorphin or substance P mRNA expression in striatonigral neurons on the side of injection. These data suggest that blockade of GABA(A) receptors in the dorsal striatum does not affect dopamine agonist-stimulated behaviors or neuropeptide mRNA expression in striatonigral neurons in the rat striatum.

Sarcomeric gene expression and contractility in myofibroblasts

Myofibroblasts are unusual cells that share morphological and functional features of muscle and nonmuscle cells. Such cells are thought to control liver blood flow and kidney glomerular filtration rate by having unique contractile properties. To determine how these cells achieve their contractile properties and their resemblance to muscle cells, we have characterized two myofibroblast cell lines. Here, we demonstrate that myofibroblast cell lines from kidney mesangial cells (BHK) and liver stellate cells activate extensive programs of muscle gene expression including a wide variety of muscle structural proteins. In BHK cells, six different striated myosin heavy chain isoforms and many thin filament proteins, including troponin T and tropomyosin are expressed. Liver stellate cells express a limited subset of the muscle thick filament proteins expressed in BHK cells. Although these cells are mitotically active and do not morphologically differentiate into myotubes, we show that MyoD and myogenin are expressed and functional in both cell types. Finally, these cells contract in response to endothelin-1 (ET-1); and we show that ET-1 treatment increases the expression of sarcomeric myosin.

Central hemodynamic effects of oxytocin and interaction with magnesium and pregnancy in the isolated perfused rat heart

OBJECTIVE

Our purpose was to determine the cardiac effects of oxytocin in the isolated perfused rat heart model and to see whether pregnancy or pharmacologic levels of magnesium modifies the hormone's action.

STUDY DESIGN

Hearts were excised from 30 female Sprague-Dawley rats (15 pregnant, 15 nonpregnant) and attached to a Langendorf's apparatus. Heart rate, left ventricular systolic pressure, and contractility were measured. Hearts were exposed serially to 2, 4, and 6 mU/ml concentrations of oxytocin. The experiment was repeated in 15 pregnant animals at a magnesium level of 5 mEq/L.

RESULTS

Hearts from pregnant rats had lower heart rates than did hearts from nonpregnant animals. Oxytocin exposure diminished heart rate but increased left ventricular systolic pressure and contractility in a dose-dependent manner. Pregnancy did not alter this response. Magnesium levels of 5 mEq/L reversed the effects of oxytocin on contractility and left ventricular systolic pressure.

CONCLUSION

Oxytocin is a negative chronotropic and positive inotropic agent in hearts from pregnant and nonpregnant rats. Magnesium reserves the positive inotropic effects of oxytocin.

Increased intrapartum antibiotic administration associated with epidural analgesia in labor

To determine whether women who receive continuous epidural analgesia for labor and delivery are more likely to receive antibiotic therapy compared to those parturients who do not use epidural analgesia, a chart review was performed for 300 women 100 in each group using narcotics alone epidural alone, or parenteral narcotics followed by epidural analgesia. While only 2% of women with narcotics alone developed an intrapartum temperature > or = 37.8 degrees C, 16% and 24% of women with epidural use alone or in addition to narcotics did so, respectively. Antibiotic administration was increased among women utilizing epidural analgesia, exclusively or following parenteral narcotics. No parturient with culture or pathological evidence of chorioamnionitis had maternal temperature elevation as an isolated finding. A probable causal relationship between maternal temperature elevation and epidural use in labor is supported. Rather than treating all women with temperature elevations and epidurals for presumed chorioamnionitis, it is reasonable to target treatment to those with fetal tachycardia, meconium stained fluid, or abnormal amniotic fluid studies.

Central hemodynamic effects of recombinant human relaxin in the isolated, perfused rat heart model

OBJECTIVE

To determine the cardiac effects of relaxin in the isolated, perfused rat heart model, and to see if pregnancy modifies the hormone's actions.

METHODS

Hearts were excised from 18 female Sprague-Dawley rats (ten pregnant, eight nonpregnant) and attached to a Langendorff apparatus. Left ventricular systolic pressure, heart rate, and contractility were measured. Hearts were exposed serially to 0.5, 1.0, 2.0, 4.0, 8.0, and 16.0 ng/mL concentrations of recombinant human relaxin.

RESULTS

Hearts from pregnant rats had lower heart rates than those from nonpregnant animals. Relaxin increased heart rate, left ventricular systolic pressure, and contractility in a dose-dependent fashion. Pregnancy did not modify this response.

CONCLUSION

Recombinant human relaxin is a potent inotropic and chronotropic agent. The effects coupled with the physiologic increase of relaxin during human pregnancy indicate that relaxin may be involved in the cardiovascular changes of pregnancy.

Hyperthyroidism and seizures during pregnancy

Untreated hyperthyroidism during pregnancy is associated with increased maternal and perinatal morbidity. Some features of this disease simulate preeclampsia, which may encourage delivery of the fetus. We report a case of poorly controlled hyperthyroidism associated with generalized seizures, where patient management was directed at a diagnosis of preeclampsia-eclampsia. Although the presence of eclampsia and marked hyperthyroidism is very rare, this case illustrates the importance of aggressive medical management of hyperthyroidism. A 17-year-old gravida was diagnosed with hyperthyroidism at 15 weeks' gestation. At 26 weeks' gestation, she was admitted to the hospital after noting edema of the upper and lower extremities, nausea, vomiting, shortness of breath, and a cough. At admission, she was hypertensive, tachycardic, and dyspneic. The patient was believed to have preeclampsia with pulmonary edema complicated by hyperthyroidism. We initiated magnesium sulfate therapy and administered several bolus doses of hydralazine, with little effect on blood pressure. Oliguria was noted, and a pulmonary artery catheter was inserted. Hours later, generalized seizure activity occurred, and a decision was made for abdominal delivery. Postoperatively, cardiovascular function stabilized. On postoperative day 3, we received the results of the thyroid function tests obtained at admission, which suggested a markedly hyperthyroid condition. Untreated or poorly treated hyperthyroidism may present a clinical picture similar to preeclampsia. In our case, both disease processes coexisted in their severest forms. It is possible, although completely unproven, that a relationship exists between poorly controlled hyperthyroidism and preeclampsia-eclampsia. More importantly, accurate diagnosis of hyperthyroidism should lead to prompt medical or surgical management, thereby decreasing maternal and perinatal morbidity.

Effects of poloxamer 188 in a rabbit model of hemorrhagic shock

Poloxamer 188 is a synthetic surfactant that reduces the viscosity of whole blood without hemodilution. It is postulated that poloxamer 188 would improve outcome if administered during retransfusion following hemorrhage. Rabbits were anesthetized and instrumented for 3 hours of hemodynamic monitoring. After stabilization, blood was withdrawn over a 5 minute period to reduce mean arterial pressure to 35 mmHg (4.7 kPa). Following a 60 minute shock period, animals were randomly assigned to 1 of 5 experimental groups (n = 8 in each): (1) Shock (no retransfusion); (2) Transfusion (retransfusion of autologous shed blood); (3) Volume (retransfusion with autologous blood and infusion of an additional volume of normal saline equivalent to the volume of poloxamer 188 given in the next 2 experimental groups); (4) Low and (5) High drug (i.v. bolus of 200 mg/kg of poloxamer 188 over 5 minutes at retransfusion, followed by a continuous infusion of poloxamer 188 at 50 mg/kg/hr in the Low drug group and 200 mg/kg/hr in the High drug group). All animals in a surgery Control group (n = 6) remained stable during the 3 hour monitoring period. In contrast, none of the animals in the Shock group remained alive, confirming this to be a relevant model of trauma and severe hemorrhagic shock. There were significantly more animals surviving at the end of the monitoring period in the two groups that received poloxamer 188 (numbers of animals alive after 3 hours = 7 of 8 in the High group and 6 of 8 in the Low group) compared to the Transfusion (4 of 8) and Volume (2 of 8) groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Headache after spinal anesthesia for cesarean section: a comparison of the 27-gauge Quincke and 24-gauge Sprotte needles

A high incidence of postdural puncture headache (PDPH) occurs after spinal anesthesia for cesarean section. To examine this problem, a study was conducted with the recently developed 24-gauge Sprotte and 27-gauge Quincke needles in patients undergoing elective and emergency cesarean section (n = 298). The needle to be used was assigned in a random manner: group I, 27-gauge Quincke (n = 147); group II, 24-gauge Sprotte (n = 151). During the postoperative period, patients were visited daily and asked specifically about the presence and severity of headache. The overall incidence of PDPH was 2% (n = 6), five in the Quincke group (3.5%) and one in the Sprotte group (0.7%). There was no significant difference in the incidence of PDPH between the two groups. Five headaches were classified as mild, and only one was moderate to severe. All headaches resolved quickly with conservative management and without blood patch. The authors conclude that the choice between a 27-gauge Quincke and a 24-gauge Sprotte needle does not influence the incidence of PDPH after spinal anesthesia for cesarean section.

Ductus-dependent fetal cardiac defects contraindicate indomethacin tocolysis

The hemodynamics of critical aortic stenosis in the fetus make it a ductus-dependent cardiac defect because the ductus arteriosus supplies blood not only to the descending aorta but also to the aortic arch and coronary vessels. In utero closure of the ductus arteriosus has been reported in association with tetralogy of Fallot, truncus arteriosus, maternal use of prostaglandin inhibitors, and as idiopathic events. This is the first report of a ductus-dependent congenital heart defect (critical aortic stenosis) where treatment with indomethacin, a prostaglandin synthetase inhibitor, precipitated premature closure of the ductus and hydrops fetalis. Review of reported cases of premature closure of the ductus show that acute, in utero closure of the ductus in a fetus with limited cardiopulmonary reserves has a worse prognosis than with previously reported cardiac anomalies. This study strongly supports published concerns of increased perinatal morbidity and mortality when fetuses are exposed to prostaglandin inhibitors in utero, and shows that ductus-dependent fetal cardiac defects are contraindications to the maternal use of prostaglandin inhibitors during pregnancy.

Effects of hemorrhagic shock and retransfusion on catalase and superoxide dismutase activities in rabbits

The effects of hemorrhagic shock and retransfusion on the activities of two endogenous antioxidant enzymes, catalase and superoxide dismutase, were studied in male New Zealand white rabbits. Following instrumentation and stabilization, blood was withdrawn to reduce mean arterial pressure to 35 mmHg (SHOCK). After 60 min of shock, the warmed autologous blood was infused and the animals were allowed to recover for an additional 30 min (RETRANS). CONTROL animals were instrumented but not bled or transfused. A 60 min period of hemorrhagic shock had no significant effect on tissue or plasma activities of catalase or superoxide dismutase. However, transfusion following hemorrhagic shock resulted in an increase in catalase activity of nearly two-fold in the liver and five-fold in the small intestine. In contrast, superoxide dismutase activity remained unchanged after retransfusion in other tissues and in plasma. These results indicate that superoxide dismutase and catalase activities may be preserved or even induced following transfusion for hemorrhagic shock.

Antepartum uterine relaxation with nitroglycerin at caesarean delivery

In this case report, NTG provided sufficient uterine relaxation to allow difficult twin extraction at Caesarean delivery. Administration of NTG in this situation was controversial, and if it had not been effective, time may have been lost before general anaesthesia could have been induced. Nitroglycerin merits further evaluation as an antepartum uterine relaxant, but the initial experience is encouraging.

The cytolysis of human neuroblastoma cells by a natural IgM 'antibody'-complement system in pregnancy serum

Cell lines from 26 human cancers were studied for cytotoxicity when treated with normal pregnancy serum. Cytotoxicity manifested by cell death and cytolysis, occurred in 4 of 8 neuroblastomas studied: SK-N-SH, NGP, LAN-5, and IMR-32. In NGP and SK-N-SH, evidence is presented showing that the cytotoxicity resulted from the cell-surface binding of a natural IgM 'antibody', which sensitized the neuroblastoma cells to the lytic action of complement (C). This system may be involved in a cytolytic form of spontaneous regression of neuroblastoma.

Isolation of a natural cytotoxic IgM "antibody" in human serum sensitizing L cells to complement

An IgM fraction of human serum was isolated and purified. A portion of this fraction firmly attaches to L cells' surfaces, which sensitizes these cells to the lytic action of low concentrations of serum C. It contains the natural cytotoxic "antibody" to L cells.

Natural cytotoxicity of human serum. A natural IgM 'antibody' sensitizes transformed murine cells to the lytic action of complement

The natural cytotoxicity of human serum on murine L cells, EA and Sa 180 cells is expressed as a rapid cytolysis at 37 degrees C. This cytotoxic system is analyzed as to its active constituents and their functional relationships. Ultrastructural studies indicate that cell injury and death are initiated within 10 min by membrane disruption. A trypan blue assay for cell death was used to study serum toxicity in individual normal healthy adults, pregnant females and newborn infants. Pregnancy sera, particularly in the 2nd and 3rd trimesters, were consistently more toxic than male serum or nonpregnant females. Cord serum was typically nontoxic. Pools of normal fresh pregnancy serum were used for immunochemical analysis of the cytotoxic activity. By a variety of immunologic and immunochemical techniques it was shown that the cytotoxicity was, in part, due to the combined action of alternative and classical pathways of complement, the former being more prominent. The lytic action of complement was shown to be greatly amplified by the prior adsorption of IgM on the target cells' surface. This IgM is a critical determinant of the cytotoxic reaction. It probably contains a natural 'antibody' to cell surface antigen(s), whose combination activates both pathways of C.

Implantation of balloon-expandable intravascular grafts by catheterization in pulmonary arteries and systemic veins

The purpose of this investigation was to evaluate the efficacy and safety of implanting expandable intravascular stents in pulmonary arteries and systemic veins. Twenty-seven balloon-expandable grafts were placed in 13 mongrel dogs under anesthesia. A long sheath was introduced over a wire and catheter or dilator into the pulmonary artery or target vein. A collapsed stainless steel expandable mesh stent was placed over the balloon of an angioplasty catheter. The catheter with the mounted stent was advanced through the sheath. The stent expanded to the diameter of the balloon as the balloon was inflated, and remained expanded as the balloon was deflated. The stent was expanded further with a larger balloon in 11 instances. Eleven stents were placed successfully in pulmonary arteries (out of thirteen attempted), and 11 of 14 were installed in tributaries of the precava or postcava. Three inadvertent embolizations of the devices occurred. All three devices that embolized lodged in the pulmonary arteries and did not obstruct flow. Seven dogs were recatheterized at intervals ranging from 56 to 278 days. Twelve stents were patent and nonobstructive, and two were malpositioned, one of which was obstructed. Three animals were killed 2 months (two dogs) and 9 months (one dog) after the implantations. The stents (four in the pulmonary arteries and two in veins) were completely covered with neointima and were patent, without thrombosis. These stents hold promise for definitive dilation of congenital or postoperative vessel stenoses.

Strain-induced anisotropy measurement in oxide films grown on silicon

A multiangle single-wavelength ellipsometric method has been applied to the evaluation of anisotropy and stress in SiO(2) films grown on silicon substrate. The method is nondestructive, and it does not require a priori knowledge of the dielectric functions of the oxide layer. A novel theoretical anisotropic multiple-layer program is used to calculate the Fresnel reflection coefficients at various angles of incidence; and an iterative least-squares algorithm compares the theoretical calculations to the experimental data. The data-fitting process yields the index, the thickness, and the anisotropy of the oxide layer and also the index and thickness of the SiO(x) transition layer.