Ni0.4Cu0.2Zn0.4TbxFe2-xO4 nanospinel ferrites: Ultrasonic synthesis and physical properties

The Fe³⁺ ions were replace with Tb³⁺ ions as highly paramagnetic rare earth element within the structure of Ni_0.4Cu_0.2Zn_0.4Fe₂O₄ nano-spinel ferrites (NSFs). The structural, magnetic, spectroscopic and optic properties have been studied in details. All products have been synthesized via ultrasonic approach via Qsonica ultrasonic homogenizer, frequency: 20 kHz and power: 70 W for 60 min. No annealing or calcination process was applied for any product. The microstructural analysis of products has been done via X-ray powder diffractometry (XRD) which presented the cubic spinel structure with nanosized distribution of all. The cubic morphology of all products were confirmed by both HR-TEM and FE-SEM. Optical band gap (E_g) values were assessed by applying %DR (percent diffuse reflectance) analysis and Kubelka-Munk theory. The Tauc schemes showed that E_g values are in a narrow range (1.87-1.98 eV). The quadrupole splitting, line width, hyperfine magnetic field, isomer shift values and cation distribution have been determined from ⁵⁷Fe Mossbauer analysis. The magnetic properties of various nanoparticles have been obtained from VSM (vibration sample magnetometer) measurements at 10 and 300 K (RT). The magnetic results revealed superparamagnetic and soft ferromagnetic traits at 10 and 300 K, respectively. M_s (saturation magnetization) and M_r (remanence) initially increase with increasing Tb³⁺ substituting level up to x = 0.06 then diminish for further x values. H_c (coercivity) shows an opposite variation tendency of M_s and M_r. The observed magnetic traits are deeply discussed in relation with the structure, morphology, magnetic moments and cation distributions.

Sonochemical synthesis and physical properties of Co0.3Ni0.5Mn0.2EuxFe2-xO4 nano-spinel ferrites

Nanoparticles (NPs) of composition Co_0.3Ni_0.5Mn_0.2Eu_xFe_2-xO₄, where 0.00 ≤ x ≤ 0.10 (hereafter called CNMEuF) were synthesized by sonochemical approach using UZ SONOPULS HD 2070 ultrasonic homogenizer (frequency of 20 kHz and power of 70 W). As-synthesized samples were characterized thoroughly to determine the effects of europium ions (Eu³⁺) substitution on their structure, morphology and magnetic traits. Structural analyses of the synthesized NPs confirmed their high purity and crystalline cubic phases. Percent diffuse reflectance (%DR) data and Kubelka-Munk theory were exploited to evaluate the optical band gap energies of the studied CNMEuF NPs. Values of optical band gap energies obtained from the Tauc plots were observed in the range of 1.47-1.58 eV. The hysteresis loops (at room temperature and 10 K) of synthesized NPs were analyzed to determine their magnetic properties. These NPs disclosed superparamagnetic and hard ferrimagnetic character at room temperature and 10 K, respectively. With exception, the sample with x = 0.10 revealed soft ferrimagnetic behavior at 10 K. Eu³⁺ doping was shown to have significant influence on the structure and magnetic attributes of the proposed CNMEuF NPs. Values of various magnetic parameters of proposed compositions were reduced with the increase in Eu³⁺ dopant contents.

Structural, magnetic, optical properties and cation distribution of nanosized Co0.7Zn0.3TmxFe2-xO4 (0.0 ≤ x ≤ 0.04) spinel ferrites synthesized by ultrasonic irradiation

This study expressed the influence of Tm substitution on the structural, optical and magnetic properties of Co-Zn spinel ferrites (Co_0.7Zn_0.3Tm_xFe_2-xO₄ (0.0 ≤ x ≤ 0.04)). The different compositions were synthesized by sonochemical method using Qsonica ultrasonic homogenizer, frequency: 20 kHz and power: 70 W for 60 min. XRD patterns proved the presence of single-phase spinel ferrites with crystallites size in the 8-10 nm range. Cation distribution approved the occupancy of octahedral (B) site by Tm. The morphology and the elements stoichiometry are obtainable through FE-SEM, EDX and elemental mapping. Optical band gap (E_g) values were estimated via DR % (percent diffuse reflectance) investigations and Kubelka-Munk theory. Tauc plots revealed that direct E_g values are ranging between 1.49 and 1.68 eV. The analyses of magnetization versus magnetic field, M(H), were performed. The following magnetic parameters like saturation magnetization M_s, squareness ratio (SQR = M_r/M_s), magnetic moment n_B, coercivity H_c and remanence M_r have been evaluated. M(H) curves revealed the superparamagnetic (SP) at RT and ferromagnetic property at 10 K. It was showed that the Tm³⁺ substitutions significantly affect the magnetic properties of host spinel ferrites. An increasing trend in the M_s, M_r, H_c, and n_B values was noticed for lower Tm³⁺ substitution content.

Do the trace elements play a role in the etiopathogenesis of developmental dysplasia of hip?

OBJECTIVE

Alterations in the connective tissue of the hip joint capsule and ligaments might account for the increased laxity seen in patients with developmental dysplasia of the hip. The tensile features of the connective tissue depend on collagen. A number of prior studies have noted the association between the trace elements and collagen biosynthesis. The aim of this research is to determine whether there exists an association between the trace elements and developmental dysplasia of the hip.

PATIENTS AND METHODS

This investigation included 27 patients with developmental dysplasia of the hip (18 females and nine males; mean age 24.3 ± 6.3 months, range 18–36 months) and 26 healthy controls (15 females and 11 males; mean age 23.8 ± 5.4 months, range 18-36 months). The levels of the serum trace elements in the groups were statistically compared.

RESULTS

The Cu levels of the patients with developmental dysplasia of hip were statistically higher than those of the control group (p<0.05). The Zn, Fe, Mg, and Mn levels of the patients with developmental dysplasia of hip were statistically lower than those of the control group (p<0.05).

CONCLUSIONS

We found an association between developmental dysplasia of the hip and the serum trace element levels. We, therefore, believe that the trace element levels may shed light on the etiopathogenesis of developmental dysplasia of the hip. This work should be supported by future studies concerning the causes of the alterations in the serum trace element levels seen in patients with developmental dysplasia of the hip.

Structural, optical and magnetic properties of Tm3+ substituted cobalt spinel ferrites synthesized via sonochemical approach

Co-Tm nano-spinel ferrite with chemical formula CoTm_xFe_2-xO₄ (0.0 ≤ x ≤ 0.08) NPs were prepared via sonochemical approach. X-ray powder diffraction patterns, microscopic images (SEM and TEM) and infrared spectra proved the formation of Co spinel ferrite. The effect of Tm³⁺ substituted on spinal structure was evaluated by lattice parameters, tetrahedral and octahedral bond length and cationic distribution. The band gap energy (Eg) of samples were estimated by performing UV-Vis percent diffuse reflectance (% DR) and applying the Kubelka-Munk theory. Eg values are in an interval between 1.33 eV and 1.64 eV. The analyses of magnetization were performed at room (300 K; RT) and low (10 K) temperatures. Different magnetic parameters including coercivity H_c, saturation magnetization M_s, remanence M_r, squareness ratio (SQR = M_r/M_s) and magnetic moment n_B were deduced and discussed. The results showed superparamagnetic (SPM) nature at RT for x = 0.00 and 0.02 samples. However, the other products exhibit ferromagnetic (FM) nature. At 10 K, all synthesized NPs display FM behavior. An amazing increase in the magnitudes of M_s, M_r and H_c was observed at 10 K in comparison to RT, which is principally due to the reduced thermal fluctuations of magnetic moments at lower temperatures. The Tm³⁺ substitution affects considerably the magnetizations data. An enhancement in the M_s, M_r, and n_B was detected on increasing the Tm³⁺ concentration. The SQR values at RT are found to be smaller than 0.5 postulating a single domain nature with uniaxial anisotropy for all produced ferrites. However, SQRs are in the range 0.66-0.76 at 10 K, suggesting the multi magnetic domain at low temperature, except the x = 0.02 product where the SQR = 0.47 indicating the single magnetic domain. The obtained magnetic results were investigated deeply with relation to structural and microstructural properties.

Etanercept restores vasocontractile sensitivity affected by mesenteric ischemia reperfusion

BACKGROUND

The aim of the study is to evaluate in vivo and in vitro effects of etanercept, a soluble tumor necrosis factor receptor, on the contractile responses of superior mesenteric artery in an experimental mesenteric ischemia and reperfusion model.

MATERIAL AND METHODS

After obtaining animal ethics committee approval, 24 Sprague-Dawley rats were allocated to three groups. Control group (Gr C, n = 6) underwent a sham operation, whereas ischemia/reperfusion and treatment groups underwent 90 min ischemia and 24-h reperfusion (Gr I/R, n = 12; Gr I/R+E, n = 6). The treatment group received 5 mg/kg etanercept intravenously at the beginning of reperfusion. At the end of reperfusion, all animals were sacrificed, and third branch of superior mesenteric artery was dissected for evaluation of contractile responses. In vitro effects of etanercept on vasocontractile responses were also evaluated. The excised ileums were analyzed under light microscope. Two-way analysis of variance following Bonferroni post hoc test was used for evaluation of contractile responses.

RESULTS

Endothelin-1 and phenylephrine-mediated vasocontractile sensitivity were found increased in Gr I/R when compared with Gr C. Both intravenous administration and organ bath incubation of etanercept decreased the sensitivity of contractile agents for Gr I/R. Mucosal injury, lamina propria disintegration, and denuded villous tips were observed in Gr I/R, whereas the epithelial injury and the subepithelial edema were found to be milder in Gr I/R+E.

CONCLUSIONS

Etanercept can be a promising agent in mesenteric ischemic reperfusion injury as it does not only inhibit inflammation by blocking tumor necrosis factor-α in circulation but also restores vascular contractility during reflow. These findings support an unexplained recuperative effect of drug beyond its anti-inflammatory effects.

Iatrogenic or fracture-related nerve injuries in supracondylar humerus fracture: is treatment necessary for nerve injury?

BACKGROUND

Supracondylar humerus fractures are very common types of elbow fractures in children between the ages of three and ten years. Totally displaced supracondylar humerus fractures can be associated with neurovascular injuries, and treatment can be complicated by iatrogenic neurovascular injury, compartment syndrome, malunion, and elbow stiffness.

AIM

The aim of this study was to describe the clinical outcome of nerve injuries associated with supracondylar humerus fractures in children observed over a period of seven years.

PATIENTS AND METHODS

Children with displaced supracondylar humerus fracture who were treated with closed reduction and percutaneous cross K-wire fixation were reviewed retrospectively at the Medical School Hospital of Yuzuncu Yil University from May 2004 to October 2012.

RESULTS

There were 91 patients available for follow-up. Nerve injury was observed in 11 (12.1%) of 91 patients with supracondylar humerus fractures. In 10 (90.1%) of these 11 cases, nerve functions recovered completely (excellent outcome) and in one (9.9%) case partial recovery was seen (good outcome).

CONCLUSIONS

Iatrogenic or fracture-related nerve injury in a supracondylar humerus fracture is a benign condition which may be resolved spontaneously and observation appears to be a good and valuable method for treatment of this complication.

Brucellosis as a trigger agent for Henoch-Schönlein purpura

Vasculitis in childhood is a result of a spectrum of causes ranging from idiopathic conditions with primary vessel inflammation to syndromes after exposure to recognized antigenic triggers, such as infectious agents and drugs causing hypersensitivity reactions. Henoch-Schönlein purpura (HSP) is the most common vasculitis of childhood. Although there is often a history of a recent or simultaneous upper respiratory tract infection, no consistent causative organism is found. We report an 11-year old boy with HSP and brucellosis and we speculated that brucellosis was the trigger agent for HSP (Ref. 13).

KEYWORDS

brucellosis, trigger agent, Henoch-Schönlein purpura, vasculitis, infectious agents, drug, hypersensitivity reactions, primary vessel inflammation.

Fabrication And Characterization of Thermoelectric Generators From SiGe Thin Films

Thermoelectric materials are being important due to their application in both thermoelectric power generation and microelectronic cooling. The thermoelectric power generations convert the heat change to electricity. The waste of heat could be useful if the thermoelectric power generation is applied. Effective thermoelectric materials have a low thermal conductivity and a high electrical conductivity. A high thermal conductivity causes too much heat leakage through heat conduction. The performance of the thermoelectric materials and devices is shown by a dimensionless figure of merit, ZT = S2σT/K, where S is the Seebeck coefficient, σ is the electrical conductivity, T is the absolute temperature and K is the thermal conductivity. ZT can be increased by increasing S, increasing σ, or decreasing K. In this study, we prepared thermoelectric generator devices of SiGe at the thickness of 112 nm using the ion beam assisted deposition (IBAD) system. Rutherford Backscattering Spectrometry (RBS) analysis was used for the elemental analysis. The 5 MeV Si ion bombardment was performed using the AAMU Pelletron ion beam accelerator to make quantum clusters in the film to decrease the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and electrical conductivity. To characterize the thermoelectric generator devices before and after Si ion bombardment we measured the cross plane Seebeck coefficient, electrical conductivity by Van der Pauw method, and thermal conductivity by 3w method for different fluences.

The changes in beta-adrenoceptor-mediated cardiac function in experimental hypothyroidism: the possible contribution of cardiac beta3-adrenoceptors

Thyroid hormone deficiency has been reported to decrease expression and function of both beta(1)- and beta(2)-adrenoceptor in different tissues including heart. The purpose of this study was to examine the possible contribution of beta(3)-adrenoceptors to cardiac dysfunction in hypothyroidism. In addition, effect of this pathology on beta(1)- and beta(2)-adrenoceptor was investigated. Hypothyroidism was induced by adding methimazole (300 mg/l) to drinking water of rats for 8 weeks. Cardiac hemodynamic parameters were measured in anesthetised rats in vivo. Responses to beta-adrenoceptor agonists were examined in rat papillary muscle in vitro. We also studied the effect of hypotyroidism on mRNA expression of beta-adrenoceptors, Gialpha, GRK, and eNOS in rat heart. All of the hemodynamic parameters (systolic, diastolic and mean arterial pressure, left ventricular pressure, heart rate, +dp/dt, and -dp/dt) were significantly reduced by the methimazole treatment. The negative inotropic effect elicited by BRL 37344 (a beta(3)-adrenoceptor preferential agonist) and positive inotropic effects produced by isoprenaline and noradrenaline, respectively, were significantly decreased in papillary muscle of hypothyroid rats as compared to those of controls. On the other hand, hypothyroidism resulted in increased cardiac beta(2)- and beta(3)-adrenoceptor, Gialpha(2), Gialpha(3), GRK3, and eNOS mRNA expressions. However, beta(1)-adrenoceptor and GRK2 mRNA expressions were not changed significantly in this pathology. These results show that mRNA expression of beta(3)-adrenoceptors as well as the signalling pathway components mediated through beta(3)-adrenoceptors are significantly increased in hypothyroid rat heart. Since we could not correlate these alternates with the decreased negative inotropic response mediated by this receptor subtype, it is not clear whether these changes are important for hypothyroid induced reduction in cardiac function.

Defoliation levels of oriental spruce by Ips typographus (L.) in relation to elevation and exposure

A study concerning the effects of elevation and exposure of the spruce forests on defoliation levels of oriental spruce (Picea orientalis (L.) Link.) by Ips typographus L. was carried out during 2005 and 2006 in Artvin-Hatila National Park, Turkey Nine spruce stands were selected at 3 zones of elevations (1000-1350 m, 1350-1700 m and 1700-2000 m) and at different aspects to assess the role of elevation and exposure in the crown defoliation level and body length of beetles. Influence of bark thickness and trunk diameter at 1.3 m on the damage caused by the pest was investigated as well. The results of the study were as follows: (1) The mean defoliation level was highest at 1700-2000 m following by 1350-1700 m and 1000-1350 m. (2) The highest defoliation levels occurred on southern slopes following by eastern and northern slopes at 1700-2000 m. (3) No statistical differences were found in the mean bark thickness between tree defoliation levels 1, 2, 3 and 4. (4) Mean trunk diameters of dead trees (level 4) were significantly greater than those with defoliation levels 0, 1 and 2. (5) Mean body length of I. typographus at upper zones was significantly higher than those at middle and lower zones.

Role of Beta-3-Adrenoceptor in Catecholamine-Induced Relaxations in Gastric Fundus from Control and Diabetic Rats

The contribution of beta-adrenoceptor subtypes to the catecholamine-mediated relaxations in gastric fundus from control and streptozotocin (STZ)-induced diabetic rats were investigated. Isolated organ bath studies and molecular techniques were used to characterize the beta-adrenoceptor subtypes mediating relaxation of rat gastric fundus. Isoprenaline-mediated relaxation was not significantly changed by nadolol (beta(1)-/beta(2)-adrenoceptor antagonist; 1 micromol/l) but only shifted to the right by SR59230A (3-(2-ethylphenoxy)-1-[[(1S)-1,2,3,4-tetrahydronaphth-1-yl]amino]-(2S)-2-propanol oxalate salt, 0.1-1 micromol/l), a selective beta(3)-adrenoceptor antagonist, in a competitive manner. Relaxant responses to noradrenaline were antagonized in a concentration-dependent manner by SR59230A (0.1-1 micromol/l), but not by metoprolol (selective beta(1)-adrenoceptor antagonist; 0.1-1 micromol/l) and ICI-118551 (1-[2,3-(dihydro-7-methyl-1Hinden- 4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol hydrochloride, selective beta(2)-adrenoceptor antagonist; 0.1-1 micromol/l). SR59230A (1 micromol/l) also caused a significant rightward shift in fenoterol-induced relaxation while ICI-118551 (1 micromol/l) did not have any effect. Selective beta(3)-adrenoceptor agonist, BRL37344 ([4-[2-[[2-(3-chlorophenyl)-2-hydroxyethyl]amino]propyl]phenoxy]acetic acid), caused biphasic relaxation which was not affected by nadolol (1 micromol/l). SR59230A (1 micromol/l) abolished only the first phase of BRL37344 response. beta(1)-, beta(2)- and beta(3)-adrenoceptor mRNA expressions have been detected in a similar intensity in gastric fundus from control rats. Experimental diabetes caused a significant decrease in E(max) and pD(2) values of isoprenaline and noradrenaline. Diabetes also reduced E(max) but not pD(2) value of the first component of BRL37344-induced relaxation response. The band intensity of mRNA transcript of beta(3)-adrenoceptor was reduced in diabetics while no alteration has been found for beta(1)- and beta(2)-adrenoceptor mRNA transcripts between groups. These results show that functional beta-adrenoceptor subtype involved in catecholamine-mediated relaxations is beta(3)-adrenoceptor, and its function and mRNA expression are decreased in diabetes.

The effects of chronic trimetazidine treatment on mechanical function and fatty acid oxidation in diabetic rat hearts

Clinical and experimental evidence suggest that increased rates of fatty acid oxidation in the myocardium result in impaired contractile function in both normal and diabetic hearts. Glucose utilization is decreased in type 1 diabetes, and fatty acid oxidation dominates for energy production at the expense of an increase in oxygen requirement. The objective of this study was to examine the effect of chronic treatment with trimetazidine (TMZ) on cardiac mechanical function and fatty acid oxidation in streptozocin (STZ)-diabetic rats. Spontaneously beating hearts from male Sprague–Dawley rats were subjected to a 60-minute aerobic perfusion period with a recirculating Krebs–Henseleit solution containing 11 mmol/L glucose, 100 μU/mL insulin, and 0.8 mmol/L palmitate prebound to 3% bovine serum albumin (BSA). Mechanical function of the hearts, as cardiac output × heart rate (in (mL/min)·(beats/min)·10–2), was deteriorated in diabetic (73 ± 4) and TMZ-treated diabetic (61 ± 7) groups compared with control (119 ± 3) and TMZ-treated controls (131 ± 6). TMZ treatment increased coronary flow in TMZ-treated control (23 ± 1 mL/min) hearts compared with untreated controls (18 ± 1 mL/min). The mRNA expression of 3-ketoacyl-CoA thiolase (3-KAT) was increased in diabetic hearts. The inhibitory effect of TMZ on fatty acid oxidation was not detected at 0.8 mmol/L palmitate in the perfusate. Addition of 1 μmol/L TMZ 30 min into the perfusion did not affect fatty acid oxidation rates, cardiac work, or coronary flow. Our results suggest that higher expression of 3-KAT in diabetic rats might require increased concentrations of TMZ for the inhibitory effect on fatty acid oxidation. A detailed kinetic analysis of 3-KAT using different concentrations of fatty acid will determine the fatty acid inhibitory concentration of TMZ in diabetic state where plasma fatty acid levels are increased.

The influence of diabetes on cardiac β-adrenoceptor subtypes

Despite the significant developments in the treatment of diabetes mellitus, diabetic patients still continue to suffer from cardiac complications. The increase of cardiac adrenergic drive may ultimately contribute to the development and progression of diabetic cardiomyopathy. beta-Adrenoceptors play an important role in the regulation of heart function. However, responsiveness of diabetic heart to beta-adrenoceptor agonist stimulation is diminished. The chronotropic responses mediated by beta(1)-subtype, which is mainly responsible for cardiac effects of catecholamines are decreased in the atria of diabetic rats. The expression of cardiac beta(1)-subtype is significantly decreased in diabetic rats as well. beta(2)-Adrenoceptors also increase cardiac function. Although the expression of this subtype is slightly decreased in diabetic rat hearts, beta(2)-mediated chronotropic responses are preserved. On the other hand, functional beta(3)-adrenoceptor subtype was characterized in human heart. Interestingly, stimulation of cardiac beta(3)-adrenoceptors, on the contrary of beta(1)- and beta(2)-subtypes, mediates negative inotropic effect in human ventricular muscle. Cardiac beta(3)-adrenoceptors are upregulated in experimental diabetes as well as in human heart failure. These findings suggest that each beta-adrenoceptor subtype may play an important role in the pathophysiology of diabetes-induced heart disease. However, it is still not known whether the changes in the expression and/or responsiveness of beta-adrenoceptors are adaptive or maladaptive. Therefore, this review outlines the potential roles of these receptor subtypes in cardiac pathologies of diabetes.

The comprehensive evaluation of temporomandibular disorders seen in rheumatoid arthritis

BACKGROUND

We studied clinical signs and symptoms of temporomandibular disorders and radiological changes in the temporomandibular joint from patients with rheumatoid arthritis (RA) compared to patients with myofascial pain dysfunction of the temporomandibular system and control patients to evaluate clinical and radiological relationships.

METHODS

A cross-sectional, controlled, clinical and radiological study was planned and 99 subjects (69 patients and 30 controls) were included in the study.

RESULTS

Twenty-three patients with RA (69.7 per cent) had painful temporomandibular joint. Fifty-five per cent had myofascial pain dysfunction according to the research diagnostic criteria for temporomandibular disorders (TMD). Nearly all of our patients with RA (93.9 per cent) had symptoms, and almost all of them had positive findings of TMD in high resolution computed tomography. Condylar head resorption, joint space narrowing and degeneration were statistically more prominent features in patients with rheumatoid arthritis compared with controls (p < 0.05). The pain score on active palpation correlated with the number of the mandibular subchondral cysts on high resolution computed tomography (r = 0.6, p < 0.05).

CONCLUSION

Although the myofascial pain of the temporomandibular system is an important cause of pain in rheumatoid arthritis, prospective controlled studies are needed to develop effective therapeutic strategies for these patients.

Thinning effects on production, root biomass and some soil properties in a young oriental beech stand in Artvin, Turkey

In this study, three thinning treatments were applied on a 0.54 ha young oriental beech (Fagus orientalis Lipsky) stand (25-30 years old) in Karadag, Artvin in the fall of 1999. The treatments were: (1) no thinning, (2) light thinning, and (3) heavy thinning. Prior to thinning, the stand averaged 15000 trees ha(-1) and 40.0 m2 ha(-1) of basal area, with an average mean diameter of 5 cm. Thinning reduced stand basal areas to about 31.1 and 24.9 m2 ha(-1) for the light and heavy thinning treatments, respectively. After 3-years, diameter increment was the highest in heavily thinned stand and the lowest in unthinned stand. The increment in stand basal area was about 10, 18 and 27% in the unthinned, lightly thinned, and heavily thinned stands, respectively. Fine root biomass significantly decreased with thinning and thinning had no significant effects on soil pH and soil organic matter content.

Diabetes decreases mRNA levels of calcium-release channels in human atrial appendage

Patients with chronic diabetes mellitus usually develop reductions in rate and force of cardiac contractions. Since calcium-release channels (ryanodine receptors (RyRs) and inositol 1,4,5-trisphosphate receptors (IP(3)Rs)) play integral roles in effecting these processes, we rationalize that alterations in their expression may underlie these defects. To test this hypothesis, right atrial appendages were obtained from diabetic (65.0 +/- 4.5 years) and nondiabetic (56.2 +/- 2.6 years) patients undergoing coronary arterial by-pass grafting and reverse transcription-polymerase chain reactions were used to compare steady state levels of mRNA encoding the three major isoforms of RyRs and IP(3)Rs. In this study we did not detect either RyR1 or RyR3 in human atrial appendage. When compared with nondiabetic patients, mRNA encoding RyR2 from diabetic patients decreased by 74.2 +/- 6.2% (p < 0.01). Diabetes also significantly decreased steady-state levels of mRNA encoding the IP(3)Rs in human atrial appendage. IP(3)R1 decreased by 24.2 +/- 4.6%, IP(3)R2 decreased by 63.0 +/- 4.6% and IP(3)R3 decreased by 55.5 +/- 6.5%. Since a reduction in steady-state mRNA is usually indicative of a decrease in protein levels, these data suggest that the decrease in chronotropy and inotropy seen in chronic diabetic patients may be due in part to a decrease in expression of calcium-release channels.

Thermal, vibrational and EPR studies of Cu(II) bromide bis(p-methylaniline) and bis(m-methylaniline) complexes

[CuBr(2)(pMA)(2)] and [CuBr(2)(mMA)(2)] complexes (pMA: p-methylaniline, mMA: m-methylaniline) have been prepared and characterized by elemental analyses, thermogravimetric analyses, magnetic moment measurements, and IR, Raman and EPR spectroscopic studies. Coordination effects on the vibrational spectra of the ligands have been investigated. The room temperature EPR spectra of the complexes and their simulated spectra are also discussed in detail. The vibrational and EPR spectral studies suggest that the coordination sphere around Cu(II) consist of a distorted tetragonal structure.