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PubMed2001

Use of SDS micelles to stabilize a ternary intermediate in the reaction of ferrioxamine B and 1,10-phenanthroline.

Spectrophotometric measurements of the reaction of ferrioxamine B (FeHDFB(+)) with 1,10-phenanthroline (phen) reveal the presence of a ternary intermediate complex in both aqueous solution and an aqueous solution of 0.16 M sodium dodecyl sulfate (SDS). The stoichiometry of the intermediate is Fe(H(2)DFB)(phen)(2+) on the basis of a Schwarzenbach analysis of spectrophotometric data obtained at variable pH and phen concentrations. The ternary complex formation constant for the reaction FeHDFB(+) + H(+) + phen right arrow over left arrow Fe(H(2)DFB)(phen)(2+) is log K = 6.96 in aqueous solution and log K = 8.64 in aqueous 0.16 M SDS. The enhanced stability of Fe(H(2)DFB)(phen)(2+) in micellar solution was analyzed in terms of the pseudophase ion-exchange (PPIE) model of micellar reactions. The association constants for the binding of each reactant to the micellar pseudophase were measured by ultrafiltration. According to PPIE model calculations, the enhanced stability of Fe(H(2)DFB)(phen)(2+) in micellar SDS arises from a proximity effect created by the high local concentrations of reactants in the micellar pseudophase. The calculations also indicate that an inhibitory medium or compartmentalization effect is operative since the observed micellar enhancement is much smaller than predicted by the PPIE model. The micellar stabilization of the Fe(H(2)DFB)(phen)(2+) intermediate and the overall conversion of FeHDFB(+) to Fe(phen)(3)(2+) are discussed as a possible model system for siderophore iron release in microbial organisms.

Cell Membrane↗
PubMed2001

Lead exposure in children living in a smelter community in region Lagunera, Mexico.

Industrial growth has created the potential for environmental problems in Mexico, since attention to environmental controls and urban planning has lagged behind the pace of industrialization. The aim of this cross-sectional study was to assess lead exposure in children aged 6-9 yr attending 3 primary schools and living in the vicinity of the largest smelter complex in Mexico. One of the schools is located 650 m distant from a smelter complex that includes a lead smelter (close school); the second is located 1750 m away from the complex and at the side of a heavy traffic road (intermediate school) in Torreon, Coahuila. The third school is located in Comez Palacio, Durango, 8100 m away from the smelter complex and distant from heavy vehicular traffic or industrial areas (remote school). Lead was measured in air, soil, dust, and well water. Lead in blood (PbB) was determined in 394 children attending the above mentioned schools. Determinations were performed by atomic absorption spectrometry. Diet, socioeconomic status, hygienic habits, and other variables were assessed by questionnaire. Median (range) PbB values were 7.8 microg/dl (3.54-29.61) in the remote school, 21.8 microg/dl (8.37-52.08) in the intermediate school and 27.6 microg/dl (7.37-58.53) in children attending the close school. The percentage of children with PbB > 15 microg/dl was 6.80%, 84.9%, and 92.1% respectively. In this order, the geometric means (range) of Pb concentrations in air were 2.5 microg/m3 (1.1-7.5), 5.8 microg/m3 (4.3-8.5), and 6.1 microg/m3 (1.6-14.9). The Pb concentrations in dust from playgrounds areas in the intermediate and close school settings ranged from 1,457 to 4,162.5 mg/kg. Pb concentrations in drinking water were less than 5 microg/L. Soil and dust ingestion and inhalation appear to be the main routes of exposure. Our results indicate that environmental contamination has resulted in an increased body burden of Pb, suggesting that children living in the vicinity of the smelter complex are at high risk for adverse effects of lead.

Air Pollutants, Occupational↗
PubMed1997

Intraspecific diversity of Schistosoma haematobium in west Africa: chronobiology of cercarial emergence.

Cercarial emergence patterns were used to analyse the intraspecific variability within and between nine populations of Schistosoma haematobium collected along a transect line from the north to the South of the Ivory Coast (Africa) and using Bulinus truncatus or Bulinus globosus as intermediate snail hosts. Statistical comparison demonstrated the existence of a chronobiological polymorphism and the existence of three homogeneous groups of S. haematobium isolates with mean shedding times of the cercariae decreasing from the North to the South. The chronobiological variability observed was not correlated with the species of Bulinus (B. truncatus vs. B. globosus) implicated in the parasite transmission but with the climatic and vegetal features of the transmission area. S. haematobium from shaded sites of the forest zone (South) showed cercarial emergence patterns significantly earliest than that of S. haematobium from open sites of the savanna zone (North). Differences in sensitivity to light intensity could characterize the existence of eco-geographical races of S. haematobium one of the forest, the other from the savanna.

Animals↗
PubMed2000

Improving outcome over time of percutaneous coronary interventions in unstable angina.

OBJECTIVE: This study was performed to evaluate the recent changes in the outcome of coronary interventions in patients with unstable angina (UA). BACKGROUND: An early invasive strategy has not been shown to be superior to conservative treatment in patients with UA. Earlier studies had utilized older technology. Interventional approaches have changed in the recent past, but to our knowledge, no large studies have addressed the impact of these changes on the outcome of coronary interventions. METHODS: We analyzed the in-hospital and intermediate-term outcome in 7,632 patients with UA who underwent coronary interventions in the last two decades. The study population was divided into three groups: group 1, n = 2,209 who had coronary intervention from 1979 to 1989; group 2, n = 2,212 with interventions from 1990 to 1993; and group 3, n = 3,211 treated from 1994 to 1998. RESULTS: Group 2 and 3 patients were older and sicker compared with group 1 patients. The clinical success improved significantly in group 3 (94.1%) compared with group 2 (87%) and group 1 (76.5%) (p < 0.001). There was a significant reduction in in-hospital mortality, Q-wave myocardial infarction and need for emergency bypass surgery in group 3 compared with the earlier groups. One-year event-free survival was also significantly higher in the recent group compared with the earlier groups: 77% in group 3, 70% in group 2 and 74% in group 1 (p < 0.001). With the use of multivariate models to adjust for clinical and angiographic variables, treatment during the most recent era was found to be independently associated with improved in-hospital and intermediate-term outcomes. CONCLUSIONS: There has been significant improvement in the in-hospital and intermediate-term outcome of coronary interventions in patients with UA in recent years; newer trials comparing conservative and invasive strategies are therefore needed.

Aged↗
PubMedDate not supplied

Primary malignant rhabdoid tumor of the central nervous system.

Since the initial description of malignant rhabdoid tumor (MRT) of the kidney by Beckwith in 1978, MRTs have been established as a distinct clinicopathologic entity lacking nephrogenic and myogenic differentiation. MRTs are highly aggressive neoplasms with characteristic histopathologic, immunocytochemical, and ultrastructural features. Many reports have appeared documenting primary extrarenal rhabdoid tumors (ERRTs) occurring at diverse sites, including infratentorial and supratentorial compartments of the central nervous system (CNS). The authors report 2 cases of primary CNS-MRT in young male children (6.5 and 7 years of age) and review the literature on CNS-MRTs. Neuroimaging studies showed an inhomogeneous parasagittal mass in the left anterior parietal region involving the motor strip and attached to the lateral aspect of the superior sagittal sinus in one case, and a right parietal parasagittal tumor with a cystic component in the other case. Metastatic workup, including abdominal CT, was negative in both cases. Histologic examination of the resected tumors showed irregular clusters and nests of cells with variable desmoplasia in both cases. Large areas of tumor necrosis and apoptotic tumor cells were present. Prominent eosinophilic cytoplasmic inclusions and eccentric, indented nuclei with conspicuous nucleoli characterized many of the tumor cells. Diffuse strong vimentin reactivity and focal strong reaction for epithelial membrane antigen (EMA) were demonstrated. Cytogenetic analyses reported a normal male karyotype in one case and an abnormal male karyotype with loss of both normal copies of chromosome 22 and gain of one structurally rearranged chromosome 22 in the other case. Ultrastructural examination displayed tumor cells with avoid to indented nuclei, marginated chromatin, and prominent nucleoli. Intercellular junctions were not found. Masses of cytoplasmic intermediate filaments in a characteristic whorled configuration were present. CNS-MRTs are consistently vimentin positive (100%) and usually EMA positive (90%). Glial fibrillary acidic protein, neuron-specific enolase, and S-100 protein are variably expressed. Markers for myogenous differentiation are invariably absent. Ultrastructural characteristics include aggregates of intermediate filaments. Monosomy 22 occurs in some CNS rhabdoid tumors, while most renal rhabdoid tumors are cytogenetically normal with only isolated cases having del(13q), del(11p), del(22)(q11), and unbalanced reciprocal translocation involving chromosomes 8 and 22. The prognosis for CNS rhabdoid tumors is dismal and almost two-thirds of patients are dead of disease shortly after diagnosis; one-third have been reported to be alive with disease, but have been followed for only short periods; and a single patient is reported to be free of disease at 5 years.

Brain Neoplasms↗
PubMed2004

Screening for retinopathy of prematurity: is it painful?

BACKGROUND: Screening programmes for retinopathy of prematurity have shown to reduce unfavourable visual outcome and to be cost-effective. Following present recommendations, almost 1% of all newborn babies should therefore be screened and undergo at least one ophthalmologic examination. This is a skilled procedure that requires drug instillation and manipulation of the ocular globe with scleral indentation. The objective of this study is to describe the side effects of this ophthalmic exam with special focus on the occurrence of pain. METHODS: This was an observational study with a before-after analysis where all neonates undergoing an ophthalmologic exam during a 4-month period in a third level hospital were included. CRIES pain score was determined before the exam, 5 min after and 24 h after the screening manoeuvre. Blood pressure and pulse rate were determined in addition to the mentioned measurements 30 min after the ophthalmologic examination. Minimum oxygen saturation, apnoeas, gastrointestinal side effects (like vomiting and gastric aspirates), the need for respiratory assistance or for intensive care unit admission were recorded within 24 h before and after the procedure. RESULTS: 27 preterm neonates underwent an ophthalmologic examination and were included in the study. CRIES pain score was significantly higher 5 min after and 24 h after the screening procedure than before. This difference was also observed after stratification for birth weight and gestational age. No other study variable modified this time effect. No significant changes in blood pressure and pulse rate were shown after the ophthalmic exam. Vomiting was present in 4% of the newborns, gastric aspirates in 22% and apnoeas in 41% after the examination. Ten percent of the explored preterm babies needed increased respiratory assistance and 4% had to be transferred from the intermediate care unit to the intensive care because of severe apnoeas. COMMENTS: An increase in pain score was shown after retinopathy of prematurity screening examination. Physiologic variable changes do not last long enough to evaluate the impact of certain procedures. Multivariate pain scores (like CRIES) should be used in everyday practice. It seems that the ophthalmologic examination in preterm babies might be painful and further studies should identify the best strategy to prevent pain during the retinopathy of prematurity screening manoeuvre.

Apnea↗
PubMed1996

Identification of intermediate-risk prostate cancer patients treated with radiotherapy suitable for neoadjuvant hormone studies.

We undertook a retrospective review of patients presenting with apparently localised prostatic carcinoma to a single practitioner for consideration of radiation therapy to clarify the characteristics of those patients who might benefit from the use of neo-adjuvant androgen deprivation. Of 133 patients referred between January 1989 and June 1994, 85 were considered suitable for radical therapy, of whom 31 were treated with hormone therapy prior to radiotherapy, frequently on the basis of an elevated PSA. Increasing PSA levels (p = 0.0016) and Gleason grade (p = 0.026) were independent variables for relapse. It was possible to define three prognostic groups of patients, on the basis of initial PSA and Gleason grade. Those of intermediate risk (PSA < 10 micrograms/l, Gleason score 8-10; PSA 10-25 micrograms/l, Gleason 5-7 or 8-10; PSA > 25 micrograms/l, Gleason score 2-4) had a superior duration of disease-free survival if given initial hormone therapy. This group of patients is potentially the most likely to benefit from such an approach and should be enrolled in prospective randomised studies of neoadjuvant androgen deprivation.

Aged↗
PubMed2005

The US twin study of age-related macular degeneration: relative roles of genetic and environmental influences.

CONTEXT: Age-related macular degeneration (AMD) is the leading cause of irreversible blindness among older individuals in many parts of the world. The relative importance of genes and environment in the etiology of this major public health problem is not well understood. OBJECTIVE: To investigate the impact of genetic and environmental factors. PARTICIPANTS: Living twins in the National Academy of Sciences-National Research Council World War II Veteran Twin Registry born between 1917 and 1927. METHODS: Twins were surveyed for the known presence of macular degeneration. Enrolled twins underwent a standardized examination and fundus photography. Age-related macular degeneration evaluation was completed for 840 elderly male twins, 210 monozygotic and 181 dizygotic complete twin pairs, both concordant and discordant for presence or absence of AMD, and 58 singletons. A bivariate twin model incorporating initial screening ascertainment and age effects was employed to partition variation in liability to AMD and signs of maculopathy into additive genetic, common environment, and unique environment components. MAIN OUTCOME MEASURE: Heritability of AMD grade and signs of maculopathy based on clinical examination and fundus photographs. RESULTS: Of the 840 twins, 331 had no signs of maculopathy and 241 had early signs, while 162 had intermediate AMD and 106 had advanced AMD. Heritability (additive genetic) estimates were significant for overall AMD grade (0.46) and for intermediate (0.67) and advanced (0.71) AMD. Significant unique environmental proportions of variance were also observed for these AMD variables (0.37, 0.19, and 0.24, respectively). Shared or common environmental contributions were not significant (0.05-0.17). For specific macular drusen and retinal pigment epithelial characteristics, significant genetic (0.26-0.71) and unique environmental (0.28-0.64) proportions of variance were detected. CONCLUSIONS: Genetic factors play a substantial role in the etiology of AMD and associated macular characteristics, explaining 46% to 71% of the variation in the overall severity of the disease. Environmental factors unique to each twin also contribute to the occurrence of this disease. This quantification of relative genetic and environmental contributions to the development of AMD should guide future research on this important cause of blindness.

Aged↗
PubMed1985

Amphicrine cells, dysplasias, and neoplasias.

The existence of epithelial cells displaying synchronous features of exocrine and endocrine differentiation has been well established. Sporadic descriptions of neoplasms comprising or including such cells have also been recorded. The authors investigated eight carcinomas (lung, two; stomach, two; colon, one; appendix, one; esophagus, one; and pancreas, one). By conventional light microscopy, all eight neoplasms appeared as moderately to well-differentiated adenocarcinomas. Mucosubstance stains showed positive material within well-defined lumina and as intracytoplasmic droplets. Argyrophil stains were positive in seven of the eight neoplasms. The esophageal tumor was a predominantly solid carcinoma; it compromised small to intermediate cells with focal mucosubstance positivity and squamous pearls. By electron microscopy, all these carcinomas including cells displaying variable complements of neurosecretory granules, which were concentrated in the basal pole or in cytoplasmic processes. The granule population was often heterogeneous. The pancreatic carcinoma also showed typical zymogen granules. In all cases, many of the neoplastic cells had true lumina or intracytoplasmic lumina, as well as arrays of filaments; secretory granules were also observed in cells with true or intracytoplasmic lumina. Immunohistochemical studies revealed in all cases either serotonin or one of a spectrum of neuropeptides. Five tumors contained more than one immunoreactive material. The authors conclude that synchronous exocrine and endocrine differentiation may be comparatively frequent in a spectrum of tumors that may be properly termed "amphicrine" carcinomas. This demonstrable heterogeneity of malignant cell populations, however variably expressed, may prove to have considerable significance in the diagnosis and management of these neoplasms.

Adenocarcinoma↗
PubMed1990

Primary lymphoma of the central nervous system. An unresolved therapeutic problem.

From January 1979 to December 1987, 35 cases of primary central nervous system lymphoma (CNS-L) were treated. We recently reviewed these cases focusing on treatment results, treatment modalities, and radiotherapy (RT) or chemotherapy-radiotherapy (CT-RT). Variables such as age, risk factors, presenting symptoms, and histologic condition (all were high-grade or intermediate-grade non-Hodgkin's lymphomas [NHL]) and radiologic data were similar to those of series reported previously. The median survival time was 36 months (+/- 0.2 months) and the disease-free survival (DFS) time was 16 months (+/- 0.12 months). Twelve of 32 patients evaluable for treatment results experienced a recurrence (all but one occurred in the CNS). The DFS rate was 70% for the CT-RT group and 50% for the RT group (median follow-up time, 24 months). Therapeutic results in CNS-L are discussed with special emphasis on a putative role of CT in the management of this rare type of tumor.

Adolescent↗
PubMed2002

Functional imaging of Langerhans cell histiocytosis by (111)In-DTPA-D-Phe(1)-octreotide scintigraphy.

BACKGROUND: Langerhans cell histiocytosis is a rare group of diseases of unknown pathogenesis, variable clinical presentation, and behavior. It encompasses highly aggressive, often fatal, and indolent diseases, with a variety of intermediate forms between the two extremes. Localization and monitoring of Langerhans cell histiocytosis deposits are based on the combined use of different imaging modalities, which include magnetic resonance, computed tomography, and nuclear medicine procedures. Somatostatin receptor scintigraphy recently has been used to image immune-mediated diseases with excellent results. METHODS: In this study, the authors have evaluated the potential role of somatostatin receptor scintigraphy by using (111)In-DTPA-D-Phe(1)-octreotide in a series of patients with Langerhans cell histiocytosis. Eight consecutive patients (2 males, 6 females; mean age, 43 years; age range, 29-60 years) with histologically proven Langerhans cell histiocytosis, in various phases of their disease, were imaged 24 hours after intravenous injection of 111-222 MBq of (111)In-DTPA-D-Phe(1)-octreotide, by using total body and spot view images. The objective of the study was to preliminarily evaluate this technique in the evaluation of Langerhans cell histiocytosis. RESULTS: Most Langerhans cell histiocytosis deposits were clearly documented by somatostatin receptor scintigraphy, independently from the anatomic location (i.e., skeleton, mucosae, soft tissue, etc.). The correlation between conventional imaging modalities and somatostatin receptor scintigraphy results was fairly good, though this was not considered a primary objective of the study. CONCLUSIONS: Among the various imaging modalities for Langerhans cell histiocytosis, somatostatin receptor scintigraphy is unique, because it accurately depicts the active sites of disease and thus can help in monitoring the response to treatment, together with conventional imaging modalities. Further studies are necessary to confirm the diagnostic value of this technique and clarify the biologic significance of the expression of somatostatin receptors in Langerhans cell histiocytosis.

Adult↗
PubMed1991

Light microscopic Golgi study of mitral/tufted cells in the accessory olfactory bulb of the adult rat.

Mitral/tufted cells (MTCs) of the accessory olfactory bulb (AOB) of adult rats were investigated light microscopically with the rapid Golgi method. The somata of the MTCs, appearing ovoid or triangular in shape, are distributed throughout the external plexiform layer. The soma size varies from small to large (12-26 microns). Apical dendrites originating from the soma enter the glomerular layer to provide branches that form the glomerular arbors. After making a glomerular arbor, some dendrites develop a second arbor (en passant and terminal arbors, respectively). The MTCs have a very diverse dendritic branching pattern and most have a variable number of glomerular arbors per cell (up to 6); we have tentatively classified the MTCs into simple, intermediate, and complex. Of the glomerular arbors, 80% have a diameter of less than 50 microns. The glomerular arbors have been classified as baskets (small spherical or ovoid) with short loopy processes; balls of yarn (large and nearly spherical) with loosely intermingled thick loops; and bushes (small to large and rather polymorphic) with irregular processes. The MTCs send dendritic arbors to terminate in one or more glomeruli where they are arranged in several different types of endings. Since it is generally believed that the dendrites of mitral and tufted cells of the main olfactory bulb terminate in only one glomerulus, the difference in the termination of the dendrites of the MTCs may represent a morphological characteristic that is relevant to the coding and/or integration of sensory information.

Animals↗
PubMed1998

A genetic and correlation analysis of liver cholesterol concentration in rat recombinant inbred strains fed a high cholesterol diet.

Liver cholesterol concentration in rats fed a high cholesterol diet, is under genetic control which is supported by significant differences observed among inbred strains. For instance, the Brown Norway (BN-Lx/Cub) rat developed a twofold higher liver cholesterol concentration than the spontaneously hypertensive rat (SHR/Ola). In the current study, we used 30 recombinant inbred (RI) strains, derived from BN-Lx and SHR progenitors, to locate quantitative trait loci (QTL) that are responsible for differences in liver cholesterol concentrations between the BN-Lx and SHR strains. The heritability of liver cholesterol was estimated to be 0.55 and a significant association was detected between concentration of liver cholesterol and the D10Cebrp1016s2 marker on chromosome 10 (lod score = 3.3); this putative QTL was responsible for nearly 64% of additive genetic variability and thus represents a major genetic determinant of liver cholesterol concentration. Liver cholesterol concentrations significantly correlated with intermediate density lipoprotein (IDL) cholesterol levels.

Animals↗
PubMed2001

Heterogeneous distribution of TT virus of distinct genotypes in multiple tissues from infected humans.

TT virus (TTV) DNA was quantitated in the serum and nine autopsy tissues (bone marrow, lymph node, muscle, thyroid gland, lung, liver, spleen, pancreas, and kidney) obtained from each of three TTV-infected subjects by real-time polymerase chain reaction (PCR), which can detect all TTV genotypes. TTV DNA was detected in all examined tissues, with the viral load being equal to or up to 300 times higher than that in the corresponding serum (2.1 x 10(5) to 5.3 x 10(7) copies/g vs 1.2-3.9 x 10(5) copies/ml). Generally, the TTV viral load was higher in the bone marrow, lung, spleen, and liver than in the other tissues, although it varied by individual. Restriction fragment length polymorphism (RFLP) analysis of the PCR-amplified TTV DNA of 3.3 kilobases (kb) revealed considerable differences among the TTVs in the serum and tissue specimens from each subject. Further, the 3.3-kb amplicons from the serum and tissue specimens from one subject were molecularly cloned, and 30 clones each from the serum and each tissue specimen were subjected to RFLP and sequence analysis (total, 300 clones): the TTV clones were classified into six genotypes including four novel genotypes. The genotypic variability was remarkable: each specimen had one to five TTV genotypes at different frequencies. TTV DNA in replicative intermediate forms and TTV mRNA were detectable in all tissues tested. These results indicate the broad, uneven distribution of TTV genotypes in tissues and suggest that viral replication takes place in multiple tissues at distinct levels in infected individuals.

Base Sequence↗
PubMed1985

Kinetics of (Na+ + K+)-ATPase: analysis of the influence of Na+ and K+ by steady-state kinetics.

The influence of Na+ and K+ on the steady-state kinetics at 37 degrees C of (Na+ + K+)-ATPase was investigated. From an analysis of the dependence of slopes and intercepts (from double-reciprocal plots or from Hanes plots) of the primary data on Na+ and K+ concentrations a detailed model for the interaction of the cations with the individual steps in the mechanism may be inferred and a set of intrinsic (i.e. cation independent) rate constants and cation dissociation constants are obtained. A comparison of the rate constants with those obtained from an analogous analysis of Na+-ATPase kinetics (preceding paper) provides evidence that the ATP hydrolysis proceeds through a series of intermediates, all of which are kinetically different from those responsible for the Na+-ATPase activity. The complete model for the enzyme thus involves two distinct, but doubly connected, hydrolysis cycles. The model derived for (Na+ + K+)-ATPase has the following properties: The empty, substrate free, enzyme form is the K+-bound form E2K. Na+ (Kd = 9 mM) and MgATP (Kd = 0.48 mM), in that order, must be bound to it in order to effect K+ release. Thus Na+ and K+ are simultaneously present on the enzyme in part of the reaction cycle. Each enzyme unit has three equivalent and independent Na+ sites. K+ binding to high-affinity sites (Kd = 1.4 mM) on the presumed phosphorylated intermediate is preceded by release of Na+ from low-affinity sites (Kd = 430 mM). The stoichiometry is variable, and may be Na:K:ATP = 3:2:1. To the extent that the transport properties of the enzyme are reflected in the kinetic ATPase model, these properties are in accord with one of the models shown by Sachs ((1980) J. Physiol. 302, 219-240) to give a quantitative fit of transport data for red blood cells.

Binding Sites↗
PubMed2005

Synthesis, structure determination, and spectroscopic/computational characterization of a series of Fe(II)-thiolate model complexes: implications for Fe-S bonding in superoxide reductases.

A combined synthetic/spectroscopic/computational approach has been employed to prepare and characterize a series of Fe(II)-thiolate complexes that model the square-pyramidal [Fe(II)(N(His))(4)(S(Cys))] structure of the reduced active site of superoxide reductases (SORs), a class of enzymes that detoxify superoxide in air-sensitive organisms. The high-spin (S = 2) Fe(II) complexes [(Me(4)cyclam)Fe(SC(6)H(4)-p-OMe)]OTf (2) and [FeL]PF(6) (3) (where Me(4)cyclam = 1,4,8,11-tetramethylcyclam and L is the pentadentate monoanion of 1-thioethyl-4,8,11-trimethylcyclam) were synthesized and subjected to structural, magnetic, and electrochemical characterization. X-ray crystallographic studies confirm that 2 and 3 possess an N(4)S donor set similar to that found for the SOR active site and reveal molecular geometries intermediate between square pyramidal and trigonal bipyramidal for both complexes. Electronic absorption, magnetic circular dichroism (MCD), and variable-temperature variable-field MCD (VTVH-MCD) spectroscopies were utilized, in conjunction with density functional theory (DFT) and semiemperical INDO/S-CI calculations, to probe the ground and excited states of complexes 2 and 3, as well as the previously reported Fe(II) SOR model [(L(8)py(2))Fe(SC(6)H(4)-p-Me)]BF(4) (1) (where L(8)py(2) is a tetradentate pyridyl-appended diazacyclooctane macrocycle). These studies allow for a detailed interpretation of the S-->Fe(II) charge transfer transitions observed in the absorption and MCD spectra of complexes 1-3 and provide significant insights into the nature of Fe(II)-S bonding in complexes with axial thiolate ligation. Of the three models investigated, complex 3 exhibits an absorption spectrum that is particularly similar to the one reported for the reduced SOR enzyme (SOR(red)), suggesting that this model accurately mimics key elements of the electronic structure of the enzyme active site; namely, highly covalent Fe-S pi- and sigma-interactions. These spectral similarities are shown to arise from the fact that 3 contains an alkyl thiolate tethered to the equatorial cyclam ring, resulting in a thiolate orientation that is very similar to the one adopted by the Cys residue in the SOR(red) active site. Possible implications of our results with respect to the electronic structure and reactivity of SOR(red) are discussed.

Binding Sites↗
PubMed1993

Exploring a psychotherapeutic change sequence: relating process to intersessional and posttreatment outcome.

Process was related to intermediate and posttreatment outcomes for 34 patients undergoing multimodal group therapy. Exploratory time series analysis suggested that process variable effects differed with the phase of the therapy. It appeared that an emotionally warm bond occurred between patient and therapist in the sessions prior to therapist-rated improvement. A patient rating of insight followed in subsequent sessions. A negative feedback loop between patient symptom levels and therapist negative patient-directed feelings was demonstrated. Patient dysphoria in later therapy sessions seemed to reflect an earlier therapeutic failure. Ego strength directly exerted its positive influence on outcome in later sessions. The relation between in-therapy process trends and overall outcome supported these findings.

Adult↗
PubMed1998

Smoking, lipoproteins and coronary heart disease risk. Data from the Münster Heart Study (PROCAM).

AIMS: The mechanism of the increase in coronary heart disease risk associated with smoking is unclear, but may partly be due to smoking-related changes in intermediate risk factors such as lipid levels, fibrinogen and blood pressure. We therefore examined the distribution of these variables among smokers and non-smokers in the Münster Heart Study. METHODS: 20696 men, aged 41.7+/-2.7 years (mean +/- SD) and 10212 women, aged 37.0+/-2.6 years, were enrolled between 1978 and 1995. Thirty-two percent of women and 36% of men smoked. Compared to non-smokers, mean levels of low density lipoprotein cholesterol, total cholesterol, triglycerides and fibrinogen were increased, respectively, by 1.4%, 0.9%, 15% and 12.1% in male and by 2.0%, 5.5%, 12% and 3.4% in female smokers. Mean high density lipoprotein cholesterol levels, body mass index and blood pressure were reduced, respectively, by 6.4%, 3.8%, and 2% in male, and by 6.7% 1.2% and 2% in female smokers. In the subgroup of 4639 men aged 40 to 65 with 8 years of follow-up, the coronary event rate (definite myocardial infarction, sudden cardiac death) in cigarette smokers was more than twice that of non-smokers with otherwise identical risk factors. CONCLUSION: In the Münster Heart Study, smoking was associated with adverse changes in lipids (of greater magnitude in women), and fibrinogen (of greater magnitude in men). However, these changes explained only a small part of the smoking-related increase in coronary heart disease risk.

Adult↗