Custom, spray coated receive coils for magnetic resonance imaging.

We have developed a process for fabricating patient specific Magnetic Resonance Imaging (MRI) Radio-frequency (RF) receive coil arrays using additive manufacturing. Our process involves spray deposition of silver nanoparticle inks and dielectric materials onto 3D printed substrates to form high-quality resonant circuits. In this paper, we describe the material selection and characterization, process optimization, and design and testing of a prototype 4-channel neck array for carotid imaging. We show that sprayed polystyrene can form a low loss dielectric layer in a parallel plate capacitor. We also demonstrate that by using sprayed silver nanoparticle ink as conductive traces, our devices are still dominated by sample noise, rather than material losses. These results are critical for maintaining high Signal-to-Noise-Ratio (SNR) in clinical settings. Finally, our prototype patient specific coil array exhibits higher SNR (5 × in the periphery, 1.4 × in the center) than a commercially available array designed to fit the majority of subjects when tested on our custom neck phantom. 3D printed substrates ensure an optimum fit to complex body parts, improve diagnostic image quality, and enable reproducible placement on subjects.

Single nucleotide polymorphisms at heat shock protein 90 gene and their association with thermo-tolerance potential in selected indigenous Nigerian cattle.

Heat shock protein (HSP) 90 gene provides protection and adaptation to thermal assault and certain polymorphisms have been associated to heat tolerance in humans and animals. Single nucleotide polymorphisms (SNPs) of HSP 90 gene were used to evaluate the scientific basis of heat tolerance in four zebu breeds of Nigeria. The DNA was extracted from skin tissue of 90 adult bulls representing White Fulani (WF), Sokoto Gudali (SG), Red Bororo (RB), and Ambala (AM). The SNPs were determined in DNAs using PCR, sequencing, and visualization and bio-editing by chromatogram in SeqMan Ngen tool. Subsequently, respective genotypes were constructed and genotypic and allelic frequencies were computed. Also, body parameters related to heat stress (HS) including body temperature (BT), rectal temperature (RT), and respiratory rates (RR) were taken for each animal before biological sampling and heat tolerance coefficient (HTC) was calculated. We detected four SNPs distinct/specific for each breed as follows: change from thymine (T) to guanine (G) at position 116 (T116G) in RB, G to cytosine (C) at 220 (G220C) in SG, G to adenine (A) at two positions, 346 (G346A) and 390 (G390A) in AM and WF, respectively. Heterozygous SNPs showed significantly lower values (P < 0.0001) for BT, RT, RR, and HTC than homozygous genotypes at all positions. We hypothesize that animals with heterozygous SNPs in exon 3 of HSP 90 may be tolerant to HS. These SNPs can be used as bio-markers for screening large populations of cattle for tolerance to hot tropical conditions in Nigeria and other sub-humid places.

Heterocyclic homoprostanoid derivative attenuates monoarthritis in rats: An in vitro and in vivo preclinical paradigm.

From our lab, among the nineteen heterocyclic homoprostanoids (HHPs), three derivatives (compounds 3, 3b and 3c) exerted antioxidant and anti-inflammatory activity. Present study is an extension of the earlier work, and, is designed to establish their therapeutic potential in monoarthritis in rats. In addition, their possible mechanism of action would be investigated. A battery of in vitro tests such as lipopolysaccharide (LPS)-induced nitrite (NO)/reactive oxygen species (ROS) and NO/interleukin (IL)-6 generation in murine macrophages and whole blood (WhB), respectively were conducted. Later, in vitro cyclooxygenase (COX) enzyme inhibitory activity was also evaluated. All the tested compounds showed comparable efficacy against ROS and NO in LPS-stimulated murine macrophages. However, compound 3 did not exert inhibitory effect on LPS-induced NO/IL-6 generation in WhB assay. Compounds (3b and 3c) inhibited the NO generation in LPS-stimulated WhB. However, only compound 3b reversed the raised IL-6 levels in this assay. None of the test compounds inhibited COX iso-enzymes in the in vitro assay. All three HHPs showed comparable efficacy against carrageenan-induced paw inflammation. However, none of them exhibited any dose-dependent effect in this model. Based upon previous reports, compound 3c was explored against adjuvant-induced monoarthritis (AIA) in male Sprague-Dawley rats, where it exerted promising therapeutic effect. In addition to radiological and histological examinations of tibio-tarsal joint, various parameters such as chronic inflammation/pain, clinical score, interleukin (IL)-6 levels and complete blood cell profile were evaluated in AIA rats. Chronic treatment with 3c halted the disease progression in rats, improved the overall health of animals, as demonstrated by haematological, clinical scoring and joint examinations (radiological and histopathological). Inhibitory effect on elevated IL-6 in AIA rats suggested the possible mechanism of 3c on cytokine signalling. Overall, the study supports the anti-arthritic potential of compound 3c.

Preclinical efficacy of a gastro-sparing novel thiazolidin-4-one in alleviating secondary lesions of polyarthritis: A multi-parametric approach.

The promising role of thiazolidin-4-ones (TZOs) against inflammatory conditions has been reported. From our lab, one of the TZO derivatives, compound 4C, exerted anti-inflammatory potential via inhibition of locally released cytokines and prostaglandin. In continuance, a detailed study was undertaken for the preclinical profiling of this promising TZO derivative against polyarthritis in rats, along with assessment of risk associated with the treatment. Male Sprague-Dawley rats were used for the adjuvant-induced arthritis (AIA) model. Based on the development of secondary lesion, the animals were randomized into different treatment groups. To establish the efficacy of the test compound, parameters such as inflammation, pain, disease progression, cytokines and prostaglandin (PG)-E2 levels and complete blood cell profile were recorded along with radiological and histological examinations of joints. The study also focused on evaluating the side effect of test compound on gastric, liver, renal, blood and cardiovascular components. Compound 4C exerted promising therapeutic effect against secondary lesions in polyarthritis in rats. It limited the progression of chronic inflammation and associated pain in rats. Modulation of cytokine signalling and arachidonate metabolism by 4C was evident from inhibition of interleukin (IL)-6, tumor necrosis factor (TNF)-α and PGE2 generation in AIA rats. Comparatively, compound 4C was safer than diclofenac to cause gastric, liver, renal, blood and cardiovascular toxicities. These finding supports the efficacy and safety profile of 4C, a TZO derivative in limiting the progression of arthritis when administered orally.

Synthesis, characterization, and preclinical evaluation of new thiazolidin-4-ones substituted with p-chlorophenoxy acetic acid and clofibric acid against insulin resistance and metabolic disorder.

We synthesized twenty thiazolidin-4-one derivatives, which were then characterized by standard chromatographic and spectroscopic methods. From the in vitro glucose uptake assay, two compounds behaved as insulin sensitizers, where they enhanced glucose uptake in isolated rat diaphragm. In high-carbohydrate diet-induced insulin resistant mice, these two thiazolidin-4-ones attenuated hyperglycemia, hyperinsulinemia, hypertriglyceridemia, hypercholesterolemia, and glucose intolerance. They raised the plasma leptin but did not reverse the diabetes-induced hypoadiponectinemia. Additionally, compound 3a reduced adiposity. The test compounds were also able to reverse the disturbed liver antioxidant milieu. To conclude, these two novel thiazolidin-4-ones modulated multiple mechanisms involved in metabolic disorders, reversing insulin resistance and thus preventing the development of type-2 diabetes.

Remedial effects of novel 2,3-disubstituted thiazolidin-4-ones in chemical mediated inflammation.

Three thiazolidin-4-one derivatives were synthesized, purified and characterized by chromatographic and spectroscopic methods. In the in vitro assays, these compounds inhibited reactive oxygen species (ROS), nitrite and cytokine generation in RAW 264.7 murine macrophages and whole blood. These derivatives attenuated carrageenan-induced acute inflammation in rats. The most effective compound 4C possessed identical anti-inflammatory action at two doses (50 and 100 mg/kg). Further, the effect of compound 4C on locally induced inflammatory mediators was investigated in carrageenan-induced air pouch inflammation in rats. In this model, compound 4C inhibited the cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-6 (systemic and local). Additionally, compound 4C was able to reduce locally elevated prostaglandin-E2 (PGE2). Inhibition of leukocyte infiltration by compound 4C was correlated with reduced locally released myeloperoxidase (MPO). To conclude, compound 4C corrected the inflammatory condition by negative effect on cytokine (TNF-α, IL-6) network and prostaglandin-E2 generation.

Evidence-based assessment of antiosteoporotic activity of petroleum-ether extract of Cissus quadrangularis Linn. on ovariectomy-induced osteoporosis.

The increasing incidence of postmenopausal osteoporosis and its related fractures have become global health issues in the recent days. Postmenopausal osteoporosis is the most frequent metabolic bone disease; it is characterized by a rapid loss of mineralized bone tissue. Hormone replacement therapy has proven efficacious in preventing bone loss but not desirable to many women due to its side-effects. Therefore we are in need to search the natural compounds for a treatment of postmenopausal symptoms in women with no toxic effects. In the present study, we have evaluated the effect of petroleum-ether extract of Cissus quadrangularis Linn. (CQ), a plant used in folk medicine, on an osteoporotic rat model developed by ovariectomy. In this experiment, healthy female Wistar rats were divided into four groups of six animals each. Group 1 was sham operated. All the remaining groups were ovariectomized. Group 2 was fed with an equivolume of saline and served as ovariectomized control (OVX). Groups 3 and 4 were orally treated with raloxifene (5.4 mg/kg) and petroleum-ether extract of CQ (500 mg/kg), respectively, for 3 months. The findings were assessed on the basis of animal weight, morphology of femur, and histochemical localization of alkaline phosphatase (ALP) (an osteoblastic marker) and tartrate-resistant acid phosphatase (TRAP) (an osteoclastic marker) in upper end of femur. The study revealed for the first time that the petroleum-ether extract of CQ reduced bone loss, as evidenced by the weight gain in femur, and also reduced the osteoclastic activity there by facilitating bone formation when compared to the OVX group. The osteoclastic activity was confirmed by TRAP staining, and the bone formation was assessed by ALP staining in the femur sections. The color intensity of TRAP and ALP enzymes from the images were evaluated by image analysis software developed locally. The effect of CQ was found to be effective on both enzymes, and it might be a potential candidate for prevention and treatment of postmenopausal osteoporosis. The biological activity of CQ on bone may be attributed to the phytogenic steroids present in it.

Beta-oxidation of 5-hydroxydecanoate, a putative blocker of mitochondrial ATP-sensitive potassium channels.

5-Hydroxydecanoate (5-HD) inhibits ischaemic and pharmacological preconditioning of the heart. Since 5-HD is thought to inhibit specifically the putative mitochondrial ATP-sensitive K+ (KATP) channel, this channel has been inferred to be a mediator of preconditioning. However, it has recently been shown that 5-HD is a substrate for acyl-CoA synthetase, the mitochondrial enzyme which 'activates' fatty acids. Here, we tested whether activated 5-HD, 5-hydroxydecanoyl-CoA (5-HD-CoA), is a substrate for medium-chain acyl-CoA dehydrogenase (MCAD), the committed step of the mitochondrial beta-oxidation pathway. Using a molecular model, we predicted that the hydroxyl group on the acyl tail of 5-HD-CoA would not sterically hinder the active site of MCAD. Indeed, we found that 5-HD-CoA was a substrate for purified human liver MCAD with a Km of 12.8 +/- 0.6 microM and a kcat of 14.1 s-1. For comparison, with decanoyl-CoA (Km approximately 3 microM) as substrate, kcat was 6.4 s-1. 5-HD-CoA was also a substrate for purified pig kidney MCAD. We next tested whether the reaction product, 5-hydroxydecenoyl-CoA (5-HD-enoyl-CoA), was a substrate for enoyl-CoA hydratase, the second enzyme of the beta-oxidation pathway. Similar to decenoyl-CoA, purified 5-HD-enoyl-CoA was also a substrate for the hydratase reaction. In conclusion, we have shown that 5-HD is metabolised at least as far as the third enzyme of the beta-oxidation pathway. Our results open the possibility that beta-oxidation of 5-HD or metabolic intermediates of 5-HD may be responsible for the inhibitory effects of 5-HD on preconditioning of the heart.

Suprahyoid pharyngotomy for base of tongue carcinoma.

Carcinoma of the tongue remain one of the greatest management challenges for the head and neck surgeon because of the adverse effects of treatment on oral and pharyngeal function. In early carcinoma of the base of tongue however, the prognosis is encouraging and function of swallowing and speech is preserved despite surgery. Suprahyoid pharyngotomy is one of the surgical approaches advocated for resection of base of tongue tumours with primary anastomosis.

Beyond the proton abstracting role of Glu-376 in medium-chain acyl-CoA dehydrogenase: influence of Glu-376-->Gln substitution on ligand binding and catalysis.

The active site residue, Glu-376, of medium-chain acyl-CoA dehydrogenase (MCAD) has been known to abstract the alpha-proton from acyl-CoA substrates during the course of the reductive half-reaction. The site-specific mutation of Glu-376-->Gln(E376Q) slows down the octanoyl-CoA-dependent reductive half-reaction of the enzyme by about 5 orders of magnitude due to impairment in the proton-transfer step. To test whether the carboxyl group of Glu-376 exclusively serves as the active site base (for abstracting the alpha-proton) during the enzyme catalysis, we undertook a detailed kinetic investigation of the enzyme-ligand interaction and enzyme catalysis, utilizing octanoyl-CoA/octenoyl-CoA as a physiological substrate/product pair and the wild-type and E376Q mutant enzymes as the catalysts. The transient kinetic data revealed that the E376Q mutation not only impaired the rate of octanoyl-CoA-dependent reduction of the enzyme-bound FAD, but also impaired the association and dissociation rates for the binding of the reaction product, octenoyl-CoA. Besides, the E376Q mutation correspondingly impaired the kinetic profiles for the quenching of the intrinsic protein fluorescence during the course of the above diverse (i.e., "chemistry" versus "physical interaction") processes. A cumulative account of the experimental data led to the suggestion that the carboxyl group of Glu-376 of MCAD is intimately involved in modulating the microscopic environment (protein conformation) of the enzyme's active site during the course of ligand binding and catalysis. Arguments are presented that the electrostatic interactions among Glu-376, FAD, and CoA-ligands are responsible for structuring the enzyme's active site cavity in the ground and transition states of the enzyme during the above physicochemical processes.

Influence of Glu-376 --> Gln mutation on enthalpy and heat capacity changes for the binding of slightly altered ligands to medium chain acyl-CoA dehydrogenase.

We showed that the alpha-CH(2) --> NH substitution in octanoyl-CoA alters the ground and transition state energies for the binding of the CoA ligands to medium-chain acyl-CoA dehydrogenase (MCAD), and such an effect is caused by a small electrostatic difference between the ligands. To ascertain the extent that the electrostatic contribution of the ligand structure and/or the enzyme site environment modulates the thermodynamics of the enzyme-ligand interaction, we undertook comparative microcalorimetric studies for the binding of 2-azaoctanoyl-CoA (alpha-CH(2) --> NH substituted octanoyl-CoA) and octenoyl-CoA to the wild-type and Glu-376 --> Gln mutant enzymes. The experimental data revealed that both enthalpy (DeltaH degrees ) and heat capacity changes (DeltaC(p) degrees ) for the binding of 2-azaoctanoyl-CoA (DeltaH degrees (298) = -21.7 +/- 0.8 kcal/mole, DeltaC(p) degrees = -0.627 +/- 0.04 kcal/mole/K) to the wild-type MCAD were more negative than those obtained for the binding of octenoyl-CoA (DeltaH degrees (298) = -17.2 +/- 1.6 kcal/mole, DeltaC(p) degrees = -0.526 +/- 0.03 kcal/mole/K). Of these, the decrease in the magnitude of DeltaC(p) degrees for the binding of 2-azaoctanoyl-CoA (vis-à-vis octenoyl-CoA) to the enzyme was unexpected, because the former ligand could be envisaged to be more polar than the latter. To our further surprise, the ligand-dependent discrimination in the above parameters was completely abolished on Glu-376 --> Gln mutation of the enzyme. Both DeltaH degrees and DeltaC(p) degrees values for the binding of 2-azaoctanoyl-CoA (DeltaH degrees (298) = -13.3 +/- 0.6 kcal/mole, DeltaC(p) degrees = -0.511 +/- 0.03 kcal/mole/K) to the E376Q mutant enzyme were found to be correspondingly identical to those obtained for the binding of octenoyl-CoA (DeltaH degrees (298) = -13.2 +/- 0.6 kcal/mole, DeltaC(p) degrees = -0.520 +/- 0.02 kcal/mole/K). However, in neither case could the experimentally determined DeltaC(p) degrees values be predicted on the basis of the changes in the water accessible surface areas of the enzyme and ligand species. Arguments are presented that the origin of the above thermodynamic differences lies in solvent reorganization and water-mediated electrostatic interaction between ligands and enzyme site groups, and such interactions are intrinsic to the molecular basis of the enzyme-ligand complementarity.

Influence of alpha-CH-->NH substitution in C8-CoA on the kinetics of association and dissociation of ligands with medium chain acyl-CoA dehydrogenase.

We previously reported that the kinetic profiles for the association and dissociation of functionally diverse C(8)-CoA-ligands, viz., octanoyl-CoA (substrate), octenoyl-CoA (product), and octynoyl-CoA (inactivator) with medium chain acyl-CoA dehydrogenase (MCAD), were essentially identical, suggesting that the protein conformational changes played an essential role during ligand binding and/or catalysis [Peterson, K. L., Sergienko, E. E., Wu, Y., Kumar, N. R., Strauss, A. W., Oleson, A. E., Muhonen, W. W., Shabb, J. B., and Srivastava, D. K. (1995) Biochemisry 34, 14942-14953]. To ascertain the structural basis of the above similarity, we investigated the kinetics of association and dissociation of alpha-CH-->NH-substituted C(8)-CoA, namely, 2-azaoctanoyl-CoA, with the recombinant form of human liver MCAD. The rapid-scanning and single wavelength stopped-flow data for the binding of 2-azaoctanoyl-CoA to MCAD revealed that the overall interaction proceeds via two steps. The first (fast) step involves the formation of an enzyme-ligand collision complex (with a dissociation constant of K(c)), followed by a slow isomerization step (with forward and reverse rate constants of k(f) and k(r), respectively) with concomitant changes in the electronic structure of the enzyme-bound FAD. Since the latter step involves a concurrent change in the enzyme's tryptophan fluorescence, it is suggested that the isomerization step is coupled to the changes in the protein conformation. Although the overall binding affinity (K(d)) of the enzyme-2-azaoctanoyl-CoA complex is similar to that of the enzyme-octenoyl-CoA complex, their microscopic equilibria within the collision and isomerized complexes show an opposite relationship. These results coupled with the isothermal titration microcalorimetric studies lead to the suggestion that the electrostatic interaction within the enzyme site phase modulates the microscopic steps, as well as their corresponding ground and transition states, during the course of the enzyme-ligand interaction.

Purification and characterization of the recombinant form of Acyl CoA oxidase 3 from the yeast Yarrowia lipolytica.

The Acyl CoA dependent oxidase 3 (Aox3p) from the yeast Yarrowia lipolytica, expressed in Escherichia coli, as an active protein with a 6 His tag at its N-terminal region has been purified to electrophoretic homogeneity. The purified enzyme exhibits a specific activity of 1.95 microM/min/mg using hexanoyl-CoA as substrate, and it remains active for at least 1 month upon storage at -30 degrees C in the presence of 35% (V/V) glycerol. The pH and temperature optima of the enzyme are 7.4 and 28-38 degrees C, respectively. Aox3p catalyzes the oxidation of both aliphatic acyl-CoA substrates of different chain lengths (e.g., hexanoyl-CoA, decanoyl-CoA, myristyl-CoA) as well as of the aromatic/heterocyclic ring-substituted chromogenic substrates, such as furylpropionyl-CoA. Of the above substrates, the efficiency of the enzyme, as judged by its kcat to Km ratio, exhibits the following order: decanoyl CoA > myristyl CoA > hexanoyl CoA > furyl-propionyl-CoA (FPCoA). Phenol, which is normally used in the coupled assay system for monitoring the H2O2 formation, functions as both an activator (at low concentrations) and a competitive inhibitor (at high concentrations) with respect to acyl-CoA substrates. The magnitude of activation and inhibition of the enzyme is dependent on the nature of the acyl-CoA substrates.

Cerebral blood flow velocity during repeatedly induced ventricular fibrillation.

STUDY OBJECTIVE: To investigate the effect of induced ventricular fibrillation and defibrillation on cerebral blood flow (CBF) was investigated using a transcranial Doppler. DESIGN: Prospective clinical study. SETTING: University hospital. PATIENTS: 12 ASA physical status III and IV patients who underwent implantable cardioverter defibrillator placement during general anesthesia. INTERVENTIONS: Cerebral blood flow velocity was measured repeatedly during induced ventricular fibrillation and subsequent defibrillation. MEASUREMENTS AND MAIN RESULTS: The mean flow velocity in the middle cerebral artery was measured using a transcranial Doppler. The mean flow velocities decreased significantly immediately after ventricular fibrillation was induced, but they returned to preventricular fibrillation levels immediately after successful defibrillation. Repeatedly induced ventricular fibrillations have no cumulative detrimental effect on the CBF velocity. CONCLUSIONS: Repetitively induced ventricular fibrillation and defibrillation during the insertion of implantable cardioverter defibrillator did not show any detrimental changes in CBF. Transcranial Doppler may be a more sensitive device than other currently available cerebral monitors to detect changes in cerebral circulation during a brief episode of ventricular fibrillation and defibrillation.

Inhibition of acyl-CoA oxidase by phenol and its implication in measurement of the enzyme activity via the peroxidase-coupled assay system.

Yeast (Candida tropicalis) acyl-CoA oxidase catalyzes the oxidation of a variety of acyl-CoA substrates to their corresponding alpha-beta enoyl-CoA products, with concomitant reduction of the buffer-dissolved O2 to H2O2. By utilizing indolepropionyl-CoA as a chromogenic substrate, we could measure the enzyme activity either directly by monitoring formation of the reaction product indoleacryloyl-CoA (lambda(max) = 367 nm) or indirectly by measuring the formation of H2O2 via the oxidative-coupled assay system, involving 4-aminoantipyrine, phenol, and horseradish peroxidase. We compared the rates of the enzyme catalysis by the above two methods. The experimental data revealed that the rate measured via the direct method was about twofold higher than that measured by the coupled-assay system. The above difference was found to be due to the inhibition of the enzyme by phenol, one of the reagents of the coupled assay system. The inhibitory role of phenol is not unique for indolepropionyl-CoA as substrate, but is also evident with aliphatic acyl-CoA substrates of varied chain lengths. Since the magnitude of inhibition is dependent on the nature of the acyl-CoA substrate, it is suggested that the coupled-reaction conditions must be carefully standardized with individual substrates. Some tips on standardizing the reaction conditions for quantitative measurement of the acyl-CoA oxidase-catalyzed reaction are offered.

Minocycline in the treatment of lymphogranuloma venereum.

In a study of 80 cases of lymphogranuloma venereum (LGV), minocycline hydrochloride (Minocin) was found to be an effective drug in the treatment of all stages of LGV, including complicated ones. In late cases adjuvant treatment was used in addition to the antibiotic. Healing time in uncomplicated cases was less than 10 days. In complicated cases, both early and late, healing took about 2 to 3 weeks. Reactions to the drug were not significant.