Exchange coupling in carboxylato-bridged dinuclear copper(II) compounds: a density functional study

A computational study of the exchange coupling is presented for a selected sample of carboxylato-bridged dinuclear copper(II) compounds. Model calculations have been used to examine the influence of several factors on the coupling constants: a) the electron-withdrawing power of the bridging ligands; b) the nature of the axial ligands; c) the number of bridging carboxylato groups; d) some structural distortions frequently found in this family of compounds; and e) the coordination mode of the carboxylato bridge. Coupling constants calculated for some complete structures, as determined by X-ray diffraction, are in excellent agreement with experimental data, confirming the ability of the computational strategy used in this work to predict the coupling constant for compounds for which experimental data are not yet available.

Heavy metal distribution and chemical speciation in tailings and soils around a Pb-Zn mine in Spain

Soil pollution by lead, zinc, cadmium and copper was characterized in the mine tailings and surrounding soils (arable and pasture lands) of an old Spanish Pb-Zn mine. Sixty soil samples were analyzed, determining the total metal concentration by acid digestion and the chemical fractionation of Pb and Zn by the modified BCR sequential extraction method. Samples belonging to mine waste areas showed the highest values, with mean concentrations of 28,453.50 mg kg(-1) for Pb, 7000.44 mg kg(-1) for Zn, 20.57 mg kg(-1) for Cd and 308.48 mg kg(-1) for Cu. High concentrations of Pb, Zn and Cd were found in many of the samples taken from surrounding arable and pasture lands, indicating a certain extent of spreading of heavy metal pollution. Acidic drainage and wind transport of dust were proposed as the main effects causing the dispersion of pollution. Sequential extraction showed that most of the Pb was associated with non-residual fractions, mainly in reducible form, in all the collected samples. Zn appeared mainly associated with the acid-extractable form in mine tailing samples, while the residual form was the predominant one in samples belonging to surrounding areas. Comparison of our results with several criteria reported in the literature for risk assessment in soils polluted by heavy metals showed the need to treat the mine tailings dumped in the mine area.

Oxidative stress at onset and in early stages of type 1 diabetes in children and adolescents

OBJECTIVE

In diabetes, the persistence of hyperglycemia has been reported to cause increased production of oxygen free radicals through glucose autooxidation and nonenzymatic glycation. The aim of this study was to determine whether oxidative cellular damage occurs at the clinical onset of diabetes and in later stages of the disease in young patients.

RESEARCH DESIGN AND METHODS

Indicative parameters of lipoperoxidation, protein oxidation, and changes in the status of antioxidant defense systems were evaluated in single blood samples from 54 diabetic children, adolescents, and young adults and 60 healthy age- and sex-matched control subjects.

RESULTS

Malondialdehyde and protein carbonyl group levels in plasma were progressively higher in diabetic children and adolescents than in control subjects (P < 0.0001). The highest erythrocyte superoxide dismutase (SOD) activity was found in diabetic children at onset of clinical diabetes. In diabetic adolescents, SOD was also significantly higher (P < 0.0001) than in control subjects. Erythrocyte glutathione peroxidase was significantly lower in diabetic children and adolescents compared with control subjects (P < 0.002). A significant decline in blood glutathione content at the recent onset of diabetes was found (P < 0.0001). Furthermore, our results demonstrated progressive glutathione depletion during diabetes evolution. The plasma alpha-tocopherol/total lipids ratio and beta-carotene levels during diabetes development (P < 0.001) were low.

CONCLUSIONS

This cross-sectional study in young diabetic patients showed that systemic oxidative stress is present upon early onset of type 1 diabetes and is increased by early adulthood. Decreased antioxidant defenses may increase the susceptibility of diabetic patients to oxidative injury. Appropriate support for enhancing antioxidant supply in these young diabetic patients may help prevent clinical complications during the course of the disease.

Emergency department echocardiography improves outcome in penetrating cardiac injury

STUDY OBJECTIVES

To determine the effect of immediate two-dimensional echocardiography on the time to diagnosis, survival rate, and neurologic outcome of patients with penetrating cardiac injury.

DESIGN

A ten-year retrospective review.

SETTING

Regional trauma center serving a population base of 1.25 million with 85,000 visits yearly.

TYPE OF PARTICIPANTS

All patients presenting to the emergency department with penetrating cardiac injury.

MEASUREMENTS AND MAIN RESULTS

The records of 49 patients with penetrating cardiac injury were reviewed. Of these, 28 received immediate two-dimensional echocardiography in the ED (echo group) and 21 did not (nonecho group). The probability of survival was derived using TRISS methodology. Differences between groups were determined using either the two sample t-test for parametric data or the Mann-Whitney test for nonparametric data. The overall probability of survival was 33.2%, and the actual survival rate was 81.6%. The probability of survival was 34.2% and 31.8% for the echo group and nonecho group, respectively. The actual survival was 100% in the echo group and 57.1% in the nonecho group. The average time to diagnosis and disposition for surgical intervention was 15.5 +/- 11.4 minutes for the echo group and 42.4 +/- 21.7 minutes for the nonecho group (P less than .001). The Glasgow Outcome Score was 5.0 for the echo group and 4.2 for the nonecho group (P = .007).

CONCLUSION

Since the introduction of immediate ED two-dimensional echocardiography, the time to diagnosis of penetrating cardiac injury has decreased and both the survival rate and neurologic outcome of survivors has improved.

Cricothyrotomy in the emergency department

Thirty-eight emergency cricothyrotomies were performed over a 3-year period. This was the first airway control maneuver attempted in 5 patients, 3 of whom had facial and/or neck injury, one apneic with upper airway hemorrhage, and one with aortobronchial fistula. The remaining 33 procedures were performed only after other airway management failed. Five indications were identified among these cases: 1) excessive emesis or hemorrhage (11), 2) possible cervical spine injury with airway compromise (9), 3) technical failure (7), 4) clenched teeth (5), and 5) masseter spasm following succinylcholine administration (1). Fourteen immediate complications occurred in 12 patients (32%). The most frequent was incorrect site of tracheostomy tube placement (5), with 4 of 5 misplaced through the thyrohyoid membrane. Others included execution time greater than 3 minutes (4), unsuccessful tracheostomy tube placement (3), and significant hemorrhage (2). Twelve of the 38 patients were long-term survivors. There was one long-term complication, a longitudinal fracture of the thyroid cartilage during forceful placement of an oversized tube (8 mm inner diameter) through the cricothyroid membrane. This required operative repair and left the patient with severe dysphonia.

Magnetic coupling in end-to-end azido-bridged copper and nickel binuclear complexes: a theoretical study

The influence of structural parameters on the exchange coupling J between metal atoms in end-to-end azido-bridged binuclear complexes of Cu(II) and Ni(II) has been studied by means of density functional calculations. For the case of double-bridged Cu(II) compounds, four ideal pentacoordinate models have been employed in which the coordination spheres of the two metal atoms are either a trigonal bipyramid or a square pyramid, connected through equatorial or axial bridges. The distortion from those ideal geometries along a Berry pathway has also been analyzed. For the hexacoordinate Ni(II) compounds, models with two or one bridging ligands have been studied. The effect of the bridging M-N-N bond angles on the exchange coupling has been analyzed for both the Cu(II) and Ni(II) complexes.

Cricothyrotomy in the emergency department revisited

Thirty-nine emergency cricothyrotomies were reviewed from the emergency department of Hennepin County Medical Center during the 4-year period ending December 1985. Due to technical changes in airway management and a desire to assess their impact, this experience was compared with a previously reported series of 38 emergency cricothyrotomies from the same department. Technical changes include the use of paralyzing agents, transtracheal needle ventilation, and the use of only vertical skin incisions and #4 Shiley tubes when cricothyrotomy is performed. The presenting problem, indications for cricothyrotomy and complications of the procedure were compared between the two series. Fewer cricothyrotomies were done as a fraction of total surgical and nonsurgical tracheal intubations in the present series (1.7%) compared to the previous series (2.7%). The complication rate decreased from 40% in the previous series to 23% in the present series. Incorrect site of tube placement (10%) and hemorrhage (8%) remain the two leading complications. However, the tube was in the trachea in all cases, and acceptable ventilation was achieved. No patient developed a clinically significant hematoma or hemorrhage from cricothyrotomy. It is concluded that our technical changes in airway management have helped to decrease both the relative frequency of cricothyrotomy and the complication rate.

Metabolism of bovine parathyroid hormone. Immunological and biological characteristics of fragments generated by liver perfusion

The metabolism of bovine parathyroid hormone (PTH) by the perfused rat liver was studied. Labeled hormone, with or without cold hormone, was infused into the circulating perfusion medium containing various calcium concentrations. Pefusate samples at various time periods after the introduction of PTH into the system were chromatographed on Bio-gel P-10; radioactivity and/or immunoreactivity were measured in eluted fractions. Before the perfusion, all immuno- and radioactivity eluted in a single peak, with an apparent mol wt of 9,500 (peak I). After perfusion for 15 min, two other peaks with approximate mol wt of 7,000 (peak II) and 3,500 (peak III) were discernible. Peak I contained both NH2-terminal and COOH-terminal immunoreactivity and was biologically active at all time periods tested. The relative contribution of NH2-terminal and COOH-terminal immunoreactivity to the total immunoreactivity remained constant in this peak throughout the perfusion. In every respect, peak I had the characteristics of intact hormone. At all times, peak II consisted of only COOH-terminal immunoreactivity and was biologically inactive. At early time periods, peak III contained predominantly NH2-terminal immunoreactivity and was biologically active. With time, the relative contribution of NH2-terminal immunoreactivity decreased strikingly while that of COOH-terminal immunoreactivity increased. The three peaks identified in these experiments were analogous in size, biological activity, and immunological characteristics to those we have previously described for fractionated human hyperparathyroid serum. The rate of metabolism of PTH appeared to be regulated by the calcium concentration in the medium. At a high concentration of calcium (greater than 11 mg/100 ml), PTH metabolism was greatly retarded. At a low concentration of calcium (smaller than 5 mg/100 ml), the rate of metabolism was greatly increased. The physiological significance of our observations on the metabolism of PTH by isolated perfused rat liver is not known. However, since such metabolism results in a biologically active fragment, it is suggested that metabolism of intact hormone may be required before full biological expression is possible.

Cord blood transplants supported by co-infusion of mobilized hematopoietic stem cells from a third-party donor

This open label clinical study provides updated evaluation of the strategy of single unit cord blood transplants (CBTs) with co-infusion of third-party donor (TPD) mobilized hematopoietic stem cells (MHSC). Fifty-five adults with high-risk hematological malignancies, median age 34 years (16-60 years) and weight 70 kg (43-95 kg), received CBTs (median 2.39 x 10(7) total nucleated cell (TNC) per kg and 0.11 x 10(6) CD34+ per kg) and TPD-MHSC (median 2.4 x 10(6) CD34+ per kg and 3.2 x 10(3) CD3+ per kg). Median time to ANC and to CB-ANC >0.5 x 10(9)/l as well as to full CB-chimerism was 10, 21 and 44 days, with maximum cumulative incidences (MCI) of 0.96, 0.95 and 0.91. Median time to unsupported platelets >20 x 10(9)/l was 32 days (MCI 0.78). MCI for grades I-IV and III-IV acute GVHD (aGVHD) were 0.62 and 0.11; 12 of 41 patients (29%) who are at risk developed chronic GVHD, becoming severely extensive in three patients. Relapses occurred in seven patients (MCI=0.17). The main causes of morbi-mortality were post-engraftment infections. CMV reactivations were the most frequent, their incidence declining after the fourth month. Five-year overall survival and disease-free survival (Kaplan-Meier) were 56 % and 47% (63% and 54% for patients <or=40 years). In conclusion, CBT with single units of relatively low cell content and 0-3 HLA mismatches is feasible as a first choice option for adult patients who lack a readily available adequate adult donor.

Haloperidol for sedation of disruptive emergency patients

Agitated, threatening, or violent behavior often jeopardizes the patient with self-inflicted injury or delays medical evaluation and treatment. Patient cooperation with therapy can be achieved using haloperidol by the IM, IV, or oral route. The safety and efficacy of haloperidol in the emergency department setting was examined. Haloperidol was administered to 136 patients to control behavior. Eighty-eight received the drug in the ED; 18 of these 88 were critical patients receiving the drug during resuscitation. Forty-eight of the 136 were crisis intervention center patients. Ninety patients were acutely intoxicated with ethanol. Twenty-three patients had head trauma; 20 of these also were inebriated. Various other drugs were responsible for the behavior of 15 patients. Acute psychosis was involved in 40 cases. Thirty-one patients were thought to have a personality disorder. The route of administration of haloperidol was intramuscular in 110, IV in 19, and oral in seven patients. Disruptive behavior was alleviated within 30 minutes in 113 of 136 (83%) patients. Effect was judged suboptimal in 20 of 136 (15%), and no effect was noted in three of 136 (2%) patients. Four complications (3%) were noted, three minor and one more serious episode of hypotension in a critical patient. Haloperidol is a safe and efficacious drug for use with disruptive patients in the emergency setting. It is a useful tool for management of agitation of diverse etiologies.

Exchange coupling in cyano-bridged homodinuclear Cu(II) and Ni(II) complexes: synthesis, structure, magnetism, and density functional theoretical study

The synthesis and structural characterization of several new cyano-bridged copper(II) and nickel(II) homodinuclear complexes is presented. The measure of magnetic properties for these complexes is complemented with a computational study of the exchange coupling for several model structures representing this family of compounds. The influence of several factors on the coupling constant has been examined, coordination position occupied by the bridging ligand, distortions of the coordination environment, and relative disposition of the cyanide ion with respect to the M-M vector. Comparison of experimental and calculated coupling constants allows for the rationalization of the most relevant features of the exchange interaction between two identical metal ions through a cyano bridge.

Succinylcholine for endotracheal intubation

In the emergency department at Hennepin County Medical Center, succinylcholine has been used to assist difficult intubations since March 1, 1979. In this report, the first 48 cases are reviewed. In these 48 patients, complete relaxation allowing endotracheal intubation was achieved in 42. Forty of the 42 patients intubated suffered no adverse effects. One patient vomited, delaying intubation, and another developed transient asystole. Six of 48 patients were not successfully intubated after succinylcholine; five of these six subsequently required cricothyrotomy. Inadequate dose, improper technique of administration, foreign material obscuring airway, and idiosyncratic reactions were thought to be reasons for failure. When properly administered, succinylcholine can be used to facilitate difficult intubations in the emergency department with an acceptable incidence of adverse effects or failures.

Effects of acute alcohol intoxication on pituitary-gonadal axis hormones, pituitary-adrenal axis hormones, beta-endorphin and prolactin in human adults of both sexes

- The effects of acute alcohol intoxication (AAI) on the pituitary-gonadal axis hormones, and the possible contribution of pituitary-adrenal axis hormones, beta-endorphin and prolactin to alcohol-induced dysfunction of pituitary-gonadal axis hormones were studied in adult men and women. Blood samples were drawn from adults of both sexes who arrived at the emergency department with evident behavioural symptoms of drunkenness (AAI) or from adult volunteers with nil consumption of alcohol (controls). Our results demonstrated that AAI produces a high increase in plasma prolactin, corticotropin (adrenocorticotropic hormone, ACTH), and cortisol in adults of both sexes, a decrease in luteinizing hormone levels only in men, an increase in dehydroepiandrosterone-sulphate (DHEAS) and a contradictory behaviour of testosterone according to gender, with increased plasma testosterone in women and a decrease in men. ACTH and prolactin correlated positively with cortisol, DHEAS and testosterone in women, which suggests that prolactin and ACTH could contribute to stimulated adrenal androgen production. In contrast, the decrease in testosterone and increase in beta-endorphin in men suggests that AAI could have an inhibitory effect on testicular testosterone, perhaps mediated by beta-endorphin. Our results suggest that the effect of alcohol on pituitary-gonadal axis hormones in humans could depend on the gender and degree of sexual maturity of the individual.

Neuromuscular blockade for critical patients in the emergency department

This retrospective study examines the indications and the effects of 119 doses of succinylcholine or pancuronium given in the emergency department during a 24-month period to patients considered to have immediately life-threatening emergencies. The most common indication for succinylcholine was to accomplish tracheal intubation (20 of 25 patients). Indications for pancuronium included computerized tomography of the head (60 of 94), control of agitation (40 of 94), facilitation of tracheal intubation (20 of 94), control of ventilation (12 of 94), and control of seizure unresponsive to anticonvulsants (4 of 94). Deterioration following succinylcholine occurred in three cases. These included two involving bradycardia and one involving ventricular tachycardia. Major complications following pancuronium included four incidences of ventricular arrhythmias. Intubation failure requiring surgical airway occurred in one patient given succinylcholine, two patients given pancuronium, and one patient who received both succinylcholine and pancuronium. Inadequate documentation of neurological examination prior to blockade was noted in six of 25 succinylcholine and nine of 94 pancuronium cases. Failure to sedate patients who might be aware of paralysis occurred in three of 25 succinylcholine and eight of 94 pancuronium uses. Neuromuscular blocking agents facilitate expeditious management of selected critical patients in the ED. Their prudent use requires anticipation of potential complications, preparation for surgical airway should intubation fail, documentation of physical examination before paralysis, and prior sedation when the patient responds to pain.

Use of atropine for brady-asystolic prehospital cardiac arrest

The efficacy of atropine in treating prehospital cardiac arrest patients developing asystole slow pulseless idioventricular rhythms (PIVR) was evaluated in a controlled, prospective study. Twenty-one prehospital cardiac-arrested patients developing asystole or PIVR (less than 40) were divided into atropine-treated or non-atropine (control) groups. Control group patients received treatment including bicarbonate, epinephrine, calcium, isoproterenol, dexamethasone, and transthoracic pacing. Atropine-treated patients received 1 mg atropine intravenously with a repeat dose at one minute if no rhythm change occurred. These patients then received the same therapy as the control group. In both groups, rhythm changes were treated as appropriate for the specific circumstances. No differences in mortality or effected rhythm changes were observed. Ten of the 11 controls and eight of 10 atropine patients developed rhythms other than asystole or PIVR less than 40. However, only two patients in each group were successfully resuscitated in the emergency department and only one control group patient was discharged alive. Our findings are not in agreement with those of previous authors who have advocated the use of atropine in cardiac arrest patients with these arrhythmias. We question the usefulness of atropine in this setting. More study is necessary in order to clearly define its role in the resuscitation of patients who have sustained brady-asystolic arrests.

Predictive factors for mortality in patients with methicillin-resistant Staphylococcus aureus bloodstream infection: impact on outcome of host, microorganism and therapy

Mortality related to methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI) remains high, despite changes in the epidemiology. To analyze the current predictive factors for mortality we conducted a prospective study in a large cohort of patients with MRSA-BSI from 21 Spanish hospitals. Epidemiology, clinical data, therapy and outcome were recorded. All MRSA strains were analysed, including susceptibility to antibiotics and molecular characterization. Vancomycin MICs (V-MIC) were tested by the E-test and microdilution methods. Time until death was the dependent variable in a Cox regression analysis. Overall, 579 episodes were included. Acquisition was nosocomial in 59% and vascular catheter was the most frequent source (38%). A dominant PFGE genotype was found in 368 (67%) isolates, which belonged to Clonal Complex (CC)5 and carried SCCmecIV and agr2. Microdilution V-MIC50 and V-MIC90 were 0.7 and 1.0 mg/L, respectively. Initial therapy was appropriate in 66% of episodes. Overall mortality was observed in 179 (32%) episodes. The Cox-regression analysis identified age >70 years (HR 1.88), previous fatal disease (HR 2.16), Pitt score >1 (HR 3.45), high-risk source (HR 1.85) and inappropriate initial treatment (HR 1.39) as independent predictive factors for mortality. CC5 and CC22 (HR 0.52 and 0.45) were associated with significantly lower mortality rates than CC8. V-MIC ≥1.5 did not have a significant impact on mortality, regardless of the method used to assess it.

Effects of acute alcohol intoxication on pituitary-gonadal axis hormones, pituitary-adrenal axis hormones, beta-endorphin and prolactin in human adolescents of both sexes

Teenage drinking continues to be a major problem in industrialized countries, where almost 35% of alcohol drinkers are under 16 years old. In the present paper we studied the effects of acute alcohol intoxication (AAI) on the pituitary-gonadal (PG) axis hormones, and the possible contribution of pituitary-adrenal (PA) axis hormones, beta-endorphin (BEND), and prolactin (PRL) to the alcohol-induced dysfunction of PG axis hormones. Blood samples were drawn from adolescents that arrived at the emergency department with evident behavioral symptoms of drunkenness (AAI) or with nil consumption of alcohol (controls [C]). Our results demonstrated that AAI produces in adolescents a high increase in plasma PRL, ACTH, and cortisol (F), and a contradictory behavior of testosterone (T) according to gender: plasma T was increased in females and decreased in males. ACTH and PRL correlated positively with F, dehydroepiandrosterone-sulphate (DHEAS) and T in females, which suggests that PRL and ACTH could synergistically stimulate adrenal androgen production. In contrast, the decrease in T and increase in BEND in males suggests that AAI could have an inhibitory effect on testicular T, perhaps mediated by BEND. The hormones studied are involved in the development of secondary sexual characteristics and the growth axis during adolescence. The deleterious effects of alcohol abuse should be made known to adolescents and the appropriate authorities.

Comparison of single-dose meperidine, butorphanol, and dihydroergotamine in the treatment of vascular headache

We treated 64 emergency room patients with a primary vascular headache with dihydroergotamine (DHE), meperidine, or butorphanol. Post-treatment pain scores were lowest in the DHE group (p less than 0.01). Eight of 21 patients receiving DHE had greater than 90% reduction in pain compared with three of 19 patients receiving butorphanol and none of 22 receiving meperidine.

External rotation method of shoulder dislocation reduction

We used the external rotation method for reducing anterior shoulder dislocations on 85 consecutive patients seen in our emergency department during a one-year period. In relatively inexperienced hands, the external rotation method was successful on first attempt in 80% of cases. There were no complications attributable to the technique itself. We feel that it is a successful, easy, and atraumatic method of achieving reduction in both first occurrence and recurrent anterior shoulder dislocations.

Accidental hypothermia: core rewarming with partial bypass

Three patients with profound hypothermia were treated by rewarming on partial bypass. Two surivived and have normal mental and metabolic functions. The resuscitation of the hypothermic patient should be approached with enthusiasm since the outcome is often much better than expected from initial vital signs and neurologic examination. To avoid ventricular fibrillation the patient should be handled gently and an effort should be made to keep the patient well oxygenated and the pH normal. Blood gases should be measured often and corrected for temperature. The potassium concentration and hydration status of the patient should also be monitored closely. The rewarming of profoundly hypothermic patients can readily be accomplished with a pump oxygenator and heat exchanger. The indications for this method are not established from our small experience and the few cases reported in the literature. Certainly ventricular fibrillation is a compelling indication. Patients with frozen extremities might also benefit from this method since theoretically tissue salvage would be increased. Finally, those patients who do not respond rapidly to external rewarming may be at less risk of ventricular fibrillation if rewarmed on bypass.

First evidence of light-induced spin transition in molybdenum(IV)

Photo-induced spin transition in a molybdenum-zinc complex has been evidenced and fully characterized by Squid magnetometry and several spectroscopies performed under irradiation (IR, EPR, etc.). The phenomenon has been confirmed by X-ray diffraction and DFT calculations yielding a Light-Induced Excited Spin State Trapping Effect (LIESST) on a 4d transition metal ion.

Copper(II) complexes with 4-amino-N-[4,6-dimethyl-2-pyrimidinyl]benzenesulfonamide. Synthesis, crystal structure, magnetic properties, EPR, and theoretical studies of a novel mixed mu-carboxylato, NCN-bridged dinuclear copper compound

New Cu(II) complexes of sulfamethazine (4-amino-N-[4,6-dimethyl-2-pyrimidinyl]benzenesulfonamide, HL) [Cu(2)(CH(3)COO)(2)(L)(2)].2dmf (1) and ([Cu(L)(2)].2H(2)O)(infinity) (2) were prepared and structurally characterized. Compound 1 crystallizes in the monoclinic system, space group P2(1)/n, with a = 8.9486(9) A, b = 15.0956(12) A, c = 16.542(3) A, beta = 105.584(15) degrees, and Z = 2. Compound 2 crystallizes in the monoclinic system, space group P2(1)/c, with a = 13.8097(8) A, b = 14.5765(4) A, c = 13.7853(15) A, beta = 96.033(9) degrees, and Z = 1. In compound 1 two copper ions are linked by two syn-syn acetates and two nonlinear NCN bridging groups pertaining to the deprotonated sulfamethazine ligands. Each copper center presents a nearly square planar geometry. Magnetic susceptibility data for 1 show a strong antiferromagnetic coupling with 2J = -216.7 cm(-)(1). The EPR spectra at the X- and Q-band frequencies present the signals corresponding to the dinuclear entity, being the zero-field splitting parameter, D = 0.265 cm(-)(1). The antiferromagnetic exchange coupling is discussed using DFT calculations on some model compounds with NCN bridging ligands and also on model structures with mixed mu-acetato and NCN bridges. The copper in the polymeric compound 2 is five coordinate. The CuN(5) chromophore has a highly distorted square pyramidal geometry with small axial N-Cu-N angles of 65.53(14) and 59.90(13) degrees. In the structure a sulfamethazinate anion binds to one copper through the sulfonamido and pyrimidine N atoms and to an adjacent copper via the amino N atom.

Effects of CRH and ACTH administration on plasma and brain neurosteroid levels

The 3alpha-hydroxy ring A-reduced metabolite of progesterone, 3alpha-hydroxy-5alpha-pregnan-20-one (allopregnanolone) is among the most potent known ligands of the gamma aminobutyric acid (GABA) receptor, designated GABA-A, in the central nervous system. We determined by RIA serum levels of progesterone (PROG), 5-alpha-dihidroprogesterone (DHP) and allopregnanolone in male and female rats after corticotropin releasing hormone (CRH) and adrenocorticotropin hormone (ACTH) administration. Allopregnanolone was undetectable in plasma and brain of control males but detectable in plasma and brain of males injected with CRH and ACTH and of control and similarly treated females. Allopregnanolone increased in the plasma and brain after CRH and ACTH administration in all cases. The data demonstrate that the administration of CRH plus ACTH results in a rapid increase of the neuroactive steroid allopregnanolone in the brain of males and females to levels known to modulate GABA-A receptor function. Thus, stress could regulate neurosteroid biosynthesis via the hormones ACTH and CRH.