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1.
Antioxid Redox Signal ; 38(4-6): 261-281, 2023 02.
Article in English | MEDLINE | ID: mdl-35950616

ABSTRACT

Aims: The objective of this study is to identify mechanisms for adipose stromal vascular fraction's (SVF) restorative effects on vasodilation in aging-induced coronary microvascular disease (CMD). We hypothesize that reactive oxygen species (ROS) diminish ß1-adrenergic receptor (ß1ADR)- and flow-mediated dilation (FMD) in coronary arterioles, reversible by SVF and adipose-derived stem cells (ADSCs). Results: SVF attenuates aging-induced chronic accumulation of ROS and pro-oxidant gene and protein expression with enhancement of antioxidant gene and protein expression and glutathione, but not nitric oxide. ADSCs attenuate hydrogen peroxide while restoring nitric oxide and glutathione. Mass spectrometry of SVF- and ADSC-conditioned media reveals abundant antioxidant proteins suggesting a paracrine mechanism. FMD and ß1ADR-mediated dilation diminished with aging, restored with SVF and ADSCs. FMD was restored by a switch in the acute signaling mediator from hydrogen peroxide in aging to peroxynitrite with SVF and ADSCs. Vasorelaxation to ß1ADR-agonism was mechanistically linked with hydrogen peroxide, nitric oxide, and glutathione. Exogenous ROS eliminates isoproterenol-mediated dilation in youth that is blocked by inhibition of pro-desensitization and internalization proteins while nitric oxide enhances isoproterenol-mediated dilation in aging. Innovation: We introduce a novel mechanism by which ROS impacts ß1ADR trafficking: the ROS/RNS-ß1ADR desensitization and internalization axis. Aging-induced ROS shunts ß1ADR from the plasma membrane into endosomes. SVF reduces oxidative burden, restoring functional ß1ADR. Conclusions: SVF (and ADSCs to a lesser extent) reduce oxidative stress, and restore flow- and ß1ADR-mediated vasodilation in aging. SVF represents a promising therapeutic strategy for CMD by addressing root cause of pathology; that is, oxidative stress-mediated hyperconstriction. Antioxid. Redox Signal. 38, 261-281.


Subject(s)
Stromal Vascular Fraction , Vasodilation , Reactive Oxygen Species/metabolism , Antioxidants/metabolism , Hydrogen Peroxide/pharmacology , Hydrogen Peroxide/metabolism , Isoproterenol/metabolism , Isoproterenol/pharmacology , Oxidative Stress , Oxidation-Reduction , Glutathione/metabolism , Adipose Tissue/metabolism
2.
Am Heart J ; 256: 37-50, 2023 02.
Article in English | MEDLINE | ID: mdl-36372247

ABSTRACT

BACKGROUND: Neighborhood disadvantage is associated with a higher risk of sudden cardiac death. However, autopsy findings have never been investigated in this context. Here, we sought to explore associations between neighborhood disadvantage and cardiovascular findings at autopsy in cases of sudden death in the State of Maryland. METHODS: State of Maryland investigation reports from 2,278 subjects within the CVPath Sudden Death Registry were screened for street addresses and 9-digit zip codes. Area deprivation index (ADI), used as metric for neighborhood disadvantage, was available for 1,464 subjects; 650 of whom self-identified as Black and 814 as White. The primary study outcome measurements were causes of death and gross and histopathologic findings of the heart. RESULTS: Subjects from most disadvantaged neighborhoods (i.e., ADI ≥ 8; n = 607) died at younger age compared with subjects from less disadvantaged neighborhoods (i.e., ADI ≤ 7; n = 857; 46.07 ± 14.10 vs 47.78 ± 13.86 years; P = 0.02) and were more likely Black or women. They were less likely to die from cardiac causes of death (61.8% vs 67.7%; P = 0.02) and had less severe atherosclerotic plaque features, including plaque burden, calcification, intraplaque hemorrhage, and thin-cap fibroatheromas. In addition, subjects from most disadvantaged neighborhoods had lower frequencies of plaque rupture (18.8% vs 25.1%, P = 0.004). However, these associations were omitted after adjustment for traditional risk factors and race. CONCLUSION: Neighborhood disadvantage did not associate with cause of death or coronary histopathology after adjustment for cardiovascular risk factors and race, implying that social determinants of health other than neighborhood disadvantage play a more prominent role in sudden cardiac death.


Subject(s)
Plaque, Atherosclerotic , Residence Characteristics , Humans , Female , Autopsy , Risk Factors , Death, Sudden, Cardiac/epidemiology , Death, Sudden, Cardiac/etiology , Neighborhood Characteristics , Socioeconomic Factors
3.
Med J Armed Forces India ; 78(Suppl 1): S111-S115, 2022 Sep.
Article in English | MEDLINE | ID: mdl-36147434

ABSTRACT

Background: Millions of patients admitted globally in health care setups require insertion of peripheral intravascular catheter for intravenous drugs or fluid administration. However, if proper precautions are not followed during insertion, it results in significant morbidity. This study was designed to study the efficacy and safety of recommended Centre for Disease Control and Prevention (CDC) guidelines for peripheral intravascular catheter insertion practice and its comparison with a standard insertion protocol being followed and their outcome. Methods: Patients were randomized and catheter was inserted as recommended by CDC guideline (Group 1, n = 100) or followed standard defined steps during insertion (Group 2, n = 100). Results: Almost double the patients had occurrence of thrombophlebitis in Group 1 (p = 0.02). No difference observed between catheter needle size and infection rates (p = 0.3). Infection rate increased significantly if second attempt is taken for insertion. The time required to insert catheter following CDC recommended protocol is less than as by standard surgical complete asepsis cleaning protocol (86.03 vs 109.40 s) (p = 0.001). Study also observed that insertion at wrist joint leads to higher incidence of thrombophlebitis. During 0-24 h, 6% (12) insertions turned positive followed by a dip during 25-48 h, 2% (5) insertions. 80% (159) insertions did not develop thrombophlebitis at the end of 72 h. Conclusion: It is thus amply demonstrated that meticulous adherence to insertion procedure with asepsis plays an important role in decreasing intravascular catheter associated morbidity. Other parameters like needle gauge, sites of insertion, have little bearing. The time required in following standard aseptic technique is significantly more but keeping in view the benefit to the patient it is highly recommended.

4.
Am J Physiol Heart Circ Physiol ; 323(4): H749-H762, 2022 10 01.
Article in English | MEDLINE | ID: mdl-36018760

ABSTRACT

Aging is associated with blunted coronary microvascular vasodilatory function. Previously, systemically administered adipose stromal vascular fraction (SVF) therapy reversed aging-induced attenuation of ß1-adrenergic- and flow-mediated dilation dependent on reducing mitochondrial reactive oxygen species. We hypothesized that SVF-mediated recovery of microvascular dilatory function is dependent on recovery of mitochondrial function, specifically by reducing mitochondrial hyperfission. Female Fischer-344 rats were allocated into young control, old control, and old + SVF therapy groups. Pressure myography, immunofluorescent staining, Western blot analysis, and RNA sequencing were performed to determine coronary microvascular mitochondrial dynamics and function. Gene and protein expression of fission-mediator DRP-1 was enhanced with aging but reversed by SVF therapy. SVF facilitated an increase in fusion-mediator MFN-1 gene and protein expression. Mitochondrial morphology was characterized as rod-like and densely networked in young controls, isolated circular and punctate with aging, and less circularity with partially restored mitochondrial branch density with SVF therapy. Decreased mitochondrial membrane potential and ATP bioavailability in aged animals at baseline and during flow-mediated dilation were reversed by SVF and accompanied with enhanced oxygen consumption. Dilation to norepinephrine and flow in young controls were dependent on uninhibited mitochondrial fusion, whereas inhibiting fission did not restore aged microvessel response to norepinephrine or flow. SVF-mediated recovery of ß-adrenergic function was dependent on uninhibited mitochondrial fusion, whereas recovery of flow-mediated dilation was dependent on maintained mitochondrial fission. Impaired dilation in aging is mitigated by SVF therapy, which recovers mitochondrial function and fission/fusion balance.NEW & NOTEWORTHY We elucidated the consequences of aging on coronary microvascular mitochondrial health as well as SVF's ability to reverse these effects. Aging shifts gene/protein expression and mitochondrial morphology indicating hyperfission, alongside attenuated mitochondrial membrane potential and ATP bioavailability, all reversed using SVF therapy. Mitochondrial membrane potential and ATP levels correlated with vasodilatory efficiency. Mitochondrial dysfunction is a contributing pathological factor in aging that can be targeted by therapeutic SVF to preserve microvascular dilative function.


Subject(s)
Adipose Tissue , Stromal Cells , Adenosine Triphosphate/metabolism , Adipose Tissue/metabolism , Adrenergic Agents , Animals , Female , Mitochondria , Norepinephrine/metabolism , Rats , Rats, Inbred F344 , Reactive Oxygen Species/metabolism , Stromal Cells/metabolism , Stromal Vascular Fraction
5.
J Feline Med Surg ; 22(4): 395-398, 2020 04.
Article in English | MEDLINE | ID: mdl-31084467

ABSTRACT

OBJECTIVES: Diagnosis of Platynosomum fastosum Kossack 1910, a liver fluke of cats, can be challenging, with infections potentially not identified depending on the fecal analysis method used. The aim of this study was to compare three methods for identification of P fastosum eggs in feces. METHODS: Feces from 50 cats with unknown infection status from a location endemic for P fastosum were analyzed. The methods used included double centrifugation with Sheather's sugar flotation solution (specific gravity 1.28); the Mini-Parasep (Apacor) flotation kit with ZnSO4 (specific gravity 1.20); and the Mini-Parasep sedimentation kit with Triton X/ethyl acetate solution. RESULTS: Thirty-four cats were identified as positive for P fastosum. Of these cats, 33 were identified with the double centrifugation method, 16 with the Mini-Parasep flotation kit and 11 with the Mini-Parasep sedimentation kit. Using the total number of samples identified as positive by at least one method as the true positive, the sensitivity of the methods was 97.1% for double centrifugation, 47.1% for the Mini-Parasep flotation kit and 32.4% for the Mini-Parasep sedimentation kit. Other parasite eggs (eg, Ancylostoma tubaeforme, Trichuris species and Toxocara cati) also were detected more frequently with the double centrifugation method. CONCLUSIONS AND RELEVANCE: Of the three methods tested, double centrifugation with Sheather's sugar flotation solution was the most effective in identifying cats with P fastosum and other helminth eggs in their feces. The lower specific gravity of the flotation solution in the Mini-Parasep flotation kit likely influenced the results. A primary drawback of the Mini-Parasep sedimentation kit was the amount of sediment. While more sediment was examined than recommended in the manufacturer's instructions, this was still only a small portion of the total sediment. In addition, reading the slides took longer than with the other methods.


Subject(s)
Cat Diseases/diagnosis , Dicrocoeliidae/isolation & purification , Feces/parasitology , Parasitology/methods , Trematode Infections , Animals , Cats , Trematode Infections/diagnosis , Trematode Infections/veterinary
6.
Mol Genet Metab ; 128(1-2): 137-143, 2019.
Article in English | MEDLINE | ID: mdl-31439511

ABSTRACT

Hereditary ß-mannosidosis causing progressive lysosomal neuropathy and other clinical signs, has been previously described in humans, Nubian goats, and Salers cattle. Here we report the clinicopathological, metabolic, and molecular genetic features of canine beta-mannosidase (MANBA, EC 3.2.1.25) deficiency. A 1-year-old male mix-breed dog from St. Kitts was presented with progressive stumbling, weakness, and regurgitation. Vacuolated lymphocytes were observed on the blood film. Postmortem findings included marked enlargement of nerves, megaesophagus, and internal hydrocephalus. Vacuolated macrophages, neurons, and secretory epithelial cells suggested an oligosaccharide storage disease. Plasma concentration of the ß-mannosidosis specific oligosaccharide was approximately 75 fold that of controls. The plasma beta-mannosidase activity was severely reduced to ~5% of controls; five other lysosomal acid hydrolase activities were increased or within their normal reference interval. Genomic sequencing of this dog's MANBA gene identified a homozygous exonic five bp tandem duplication in the penultimate exon of the MANBA gene (c.2377_2381dupTATCA) which results in a reading frame shift, altering the subsequent amino acid sequence and creating a premature stop codon. The truncated beta-mannosidase enzyme is expected to be dysfunctional. This enzyme deficiency causes the accumulation of un-degraded oligosaccharides in cells, which affect the myelination of the peripheral and central nervous systems. This insertion was not encountered in 121 and 80-screened samples from dogs on St. Kitts (all were homozygous for wild-type) and Philadelphia region (wild-type), respectively. In conclusion, canine ß-mannosidosis has similar clinicopathological features with some human patients, but milder signs than in ruminants and more severe than in knockout mice. Hence, dogs with ß-mannosidosis could become a valuable disease model for the human disease.


Subject(s)
Dog Diseases/genetics , beta-Mannosidase/genetics , beta-Mannosidosis/genetics , beta-Mannosidosis/veterinary , Animals , Codon, Nonsense , DNA Mutational Analysis , Dog Diseases/diagnosis , Dog Diseases/enzymology , Dogs , Exons , Male , Mutation , beta-Mannosidosis/diagnosis
7.
Vet Clin Pathol ; 48(4): 620-623, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31228292

ABSTRACT

This case report describes a massive honey bee envenomation in a 14-month-old male Belgian Malinois dog from St. Kitts, West Indies. Acute and delayed onsets of hemolytic anemia, echinocytosis, spherocytosis, thrombocytopenia, hemoglobinemia, and hemoglobinuria developed following envenomation. The dog recovered after treatment with glucocorticoids and supportive therapy. Spherocytosis, hemolysis, and thrombocytopenia in patients with massive bee envenomation are likely due to the direct toxic effects of the primary components of bee venom, melittin and phospholipase A2 (PLA2 ). Mellitin causes hemolysis by forming large pores in erythrocytes resulting in leakage of hemoglobin and also causes spectrin stiffening and resultant echinocyte and spherocyte formation. Melittin also stimulates PLA2 , a hydrolase that causes echinocytosis and spherocytosis, in vivo and in vitro, and mitochondrial breakdown in platelets. However, delayed manifestations could be attributed to immune-mediated mechanisms from the generation of antibodies against damaged erythrocytes and platelet membrane proteins.


Subject(s)
Anemia, Hemolytic/veterinary , Bee Venoms/poisoning , Bees , Dog Diseases/etiology , Insect Bites and Stings/veterinary , Spherocytes , Thrombocytopenia/veterinary , Anemia, Hemolytic/etiology , Animals , Blood Cell Count/veterinary , Dogs , Insect Bites and Stings/complications , Male , Thrombocytopenia/etiology
8.
JFMS Open Rep ; 4(1): 2055116918782584, 2018.
Article in English | MEDLINE | ID: mdl-30202541

ABSTRACT

OBJECTIVES: For over two decades, feline trichomonosis caused by Tritrichomonas foetus has been recognized as a large-bowel protozoan disease of the domestic cat. It has a wide distribution, but no reports exist in the Caribbean. The objectives of this study were to detect the presence of T foetus and its prevalence in the domestic cat on St Kitts, West Indies. METHODS: A cross-sectional study was performed between September 2014 and December 2015. This study recruited 115 feral cats from a trap-neuter-return program and 37 owned cats treated as outpatients at the university veterinary clinic. Fresh feces were inoculated in InPouch culture medium, as per the manufacturer's instructions. In addition, PCR was performed using primers for T foetus. DNA extraction with amplification using primers of a Feliscatus NADH dehydrogenase subunit 6 was used as a housekeeping gene for quality control. RESULTS: Only two owned cats had reported diarrhea in the preceding 6 months. None of the 152 samples were positive on InPouch culture microscopic examination. Only 35/69 feral cat fecal DNA samples were positive for the housekeeping gene, of which none tested PCR positive for T foetus. CONCLUSIONS AND RELEVANCE: T foetus was not detected by culture and PCR in feral cats and owned cats on St Kitts. A high proportion of PCR inhibitors in the DNA samples using a commercial fecal DNA kit can lead to underestimating the prevalence, which should be taken into consideration when a survey on gastrointestinal pathogens depends exclusively on molecular detection.

9.
Indian J Anaesth ; 61(10): 798-802, 2017 Oct.
Article in English | MEDLINE | ID: mdl-29242651

ABSTRACT

BACKGROUND AND AIMS: Sildenafil is known to reduce pulmonary artery pressure but its role in the perioperative period has not been well studied. We aimed to evaluate the efficacy of sildenafil in controlling post-operative pulmonary hypertension in children with pulmonary hypertension undergoing surgeries for correction of ventricular septal defect. METHODS: The patients were divided randomly into two groups of thirty each. Group 1 (placebo) received pre-operative placebo and post-operative sildenafil (0.5mg/kg every 6 hrs) while Group 2 (sildenafil) received pre- and post-operative sildenafil (0.5mg/kg every 6 hrs). RESULTS: In the Group 1, systolic pulmonary artery pressure reduced from 81.63 (±12.1) mmHg preoperatively to 79.26 (±11.29) mmHg pre-cardiopulmonary bypass (CPB) and 56.76 (±11) mmHg (with 10 minutes post-CPB), whereas in Group 2, it reduced from 83.3 (±12.1) before surgery to 68.9 (±11.3) mmHg pre-CPB and after CPB, to 42.2 (±7.6) mmHg (P = 0.001). The mean pulmonary artery pressure decreased from 60.63 (±10.5) mmHg to 42.13 (±8.3) mmHg in the Group 1 whereas it reduced from 54.36 (±10) mmHg to 31.36 (±6.5) mmHg in Group 2 (P = 0.001). The reductions in pulmonary artery/aortic ratio and Intensive Care Unit stay were statistically significant No adverse effects were recorded. CONCLUSION: The use of perioperative sildenafil has a statistically significant reduction in the mean pulmonary artery pressure without any adverse effects.

10.
JMM Case Rep ; 4(10): e005120, 2017 Oct.
Article in English | MEDLINE | ID: mdl-29188067

ABSTRACT

Introduction. Leptospirosis is a zoonotic bacterial disease of global distribution affecting humans and animals. The initial phase of leptospirosis resembles many other febrile illness and due to its broad and biphasic clinical manifestations, selection and implementation of appropriate diagnostic tests can be challenging. Case presentation. This report describes a case investigation of a 14 weeks old male, orphan puppy, presented with generalised jaundice, anemia, weakness, and anorexia. Clinical abnormalities included the evidence of renal and hepatic failure. Antemortem and postmortem diagnostic investigations were conducted to identify the cause of illness. PCR testing and culture of blood was positive for Leptospira sp. Necropsy followed by histopathology evaluation revealed lesions compatible with liver and kidney damage consisting of marked diffuse hepatocellular dissociation, acute renal tubular necrosis, and mild interstitial nephritis. Conclusion. Multiple diagnostic techniques including bacterial isolation confirmed Leptospira infection in this puppy. Whole genome sequencing and analysis identified the Leptospira sp. isolated from this puppy as Leptospira interrogans serovar Copenhageni. To our knowledge, this case report describes the first isolation of Leptospira from Saint Kitts. This case highlights the usefulness of including multiple diagnostic tests for the diagnosis and epidemiological investigation of Leptospira infection. Accurate diagnosis followed by timely intervention can prevent case fatality and mortality in infected patients.

11.
Virus Res ; 240: 154-160, 2017 08 15.
Article in English | MEDLINE | ID: mdl-28847699

ABSTRACT

Although canine parvovirus (CPV) and canine enteric coronavirus (CCoV) are important enteric pathogens of dogs and have been studied extensively in different parts of the world, there are no reports on these viruses from the Caribbean region. During 2015-2016, a total of 104 diarrheic fecal samples were collected from puppies and adult dogs, with or without hemorrhagic gastroenteritis, on the Caribbean island of St. Kitts (KNA). By PCR, 25 (24%, n=104) samples tested positive for CPV. Based on analysis of the complete deduced VP2 amino acid sequences, 20 of the KNA CPV strains were assigned to new CPV-2a (also designated as CPV-2a-297A). On the other hand, the VP2 genes of the remaining 5 strains were partially characterized, or could not be sequenced. New CPV-2a was the predominant CPV variant in St. Kitts, contrasting the molecular epidemiology of CPV variants reported in most studies from nearby North and South American countries. By RT-PCR, CCoVs were detected in 5 samples (4.8%, n=104). Based on analysis of partial M-protein gene, the KNA CCoV strains were assigned to CCoV-I genotype, and were closely related to CCoV-I strains from Brazil. To our knowledge, this is the first report on detection and genetic diversity of CPV and CCoV in dogs from the Caribbean region, and underscores the importance of similar studies in the other Caribbean islands.


Subject(s)
Coronavirus Infections/veterinary , Coronavirus, Canine/isolation & purification , Diarrhea/veterinary , Dog Diseases/virology , Parvoviridae Infections/veterinary , Parvovirus, Canine/isolation & purification , Animals , Coronavirus Infections/virology , Coronavirus, Canine/classification , Coronavirus, Canine/genetics , Diarrhea/virology , Dogs , Feces/virology , Genetic Variation , Genotype , Parvoviridae Infections/virology , Parvovirus, Canine/classification , Parvovirus, Canine/genetics , Phylogeny , Viral Proteins/genetics , West Indies
12.
Infect Genet Evol ; 54: 200-204, 2017 10.
Article in English | MEDLINE | ID: mdl-28688978

ABSTRACT

We report here molecular characterization of complete genomic segment-2 of picobirnavirus (PBV) strains PBV/Cat/KNA/K40/2014 and PBV/Dog/KNA/RVC7/2015 detected in a cat (Felis catus) and a dog (Canis lupus familiaris), respectively, on the Caribbean island of St. Kitts. To obtain the full-length nucleotide (nt) sequence of gene segment-2 of the canine and feline PBV strains, the 5'- and 3'- portions of gene segment-2 containing an overlapping region were amplified using a non-specific primer-based amplification method with modifications. The complete gene segment-2 of feline PBV strain K40 and canine PBV strain RVC7 was 1784nt and 1689nt long, respectively, and encoded a putative RNA-dependent RNA polymerase (RdRp) of 534 amino acid (aa) and 531 aa, respectively. The complete gene segment-2 of strains K40 and RVC7 exhibited a high degree of genetic diversity between themselves, and with those of PBVs from other host species. On the other hand, both the canine and feline PBV strains retained the 5'- and 3'- end nucleotide sequences and the three domains of putative RdRp that are conserved in PBVs. To our knowledge, this is the first report on molecular characterization of complete gene segment-2 of PBV strains detected in cats and dogs, allowing us to study the features of putative RdRps of PBVs in these host species, and providing important insights into the genetic makeup and evolution of feline and canine PBV strains. PBVs were detected for the first time in cats and dogs from the Caribbean region.


Subject(s)
Cat Diseases/virology , Dog Diseases/virology , Genome, Viral , Picobirnavirus/genetics , RNA Virus Infections/veterinary , Amino Acid Sequence , Animals , Cats , Dogs , Genomics/methods , Phylogeny , RNA, Viral , Sequence Analysis, DNA
14.
J Anaesthesiol Clin Pharmacol ; 30(4): 472-80, 2014 10.
Article in English | MEDLINE | ID: mdl-25425769

ABSTRACT

Hydroxyethyl starch (HES) family has been one of the cornerstones in fluid management for over four decades. Recent evidence from clinical studies and meta-analyses has raised few concerns about the safety of these fluids, especially in certain subpopulations of patients. High-quality clinical trials and meta-analyses have emphasized nephrotoxic effects, increased risk of bleeding, and a trend toward higher mortality in these patients after the use of HES solutions. Scientific evidence was derived from international guidelines, aggregated research literature, and opinion-based evidence was obtained from surveys and other activities (e.g., internet postings). On critical analysis of the current data available, it can be summarized that further large scale trials are still indicated before HES can be discarded.

15.
Inorg Chem ; 53(19): 10276-82, 2014 Oct 06.
Article in English | MEDLINE | ID: mdl-25208010

ABSTRACT

The chemistry of the hydrotris(mercaptobenzothiazolyl)borate anion (Tbz) with metal salts (HgI2, SbI3, BiI3, CoCl2) is reported in an attempt to probe the stability of the of Tbz ligand once coordinated to hard and soft metals. Complexes of Tbz with bismuth, containing the [Bi(Tbz)I3](-) anion, are stable, but with the other metals this is not the case. Although simple complexes such as [Hg(Tbz)I] and [E(Tbz)I3](-) (E = Sb, Bi) can be isolated from the reaction mixtures, subsequent reactions lead to ligand modification or decomposition. In the presence of mercury and antimony we observe the formation of a hitherto unseen cationic pentacyclic heterocycle. With cobalt we observe a small quantity of a product which suggests a more complete decomposition. A simple benzothiazole (bz) adduct [Co(bz)2Cl2] has been identified, in which the Tbz ligand has disintegrated and the parent heterocycle, mercaptobenzothiazole, has been desulfurized. A rationale for these observations is given.

16.
Acta Crystallogr C Struct Chem ; 70(Pt 5): 421-7, 2014 May.
Article in English | MEDLINE | ID: mdl-24816005

ABSTRACT

Reported here are the single-crystal X-ray structure analyses of bis-µ-methanol-κ(4)O:O-bis{[hydrotris(3-phenyl-2-sulfanylidene-2,3-dihydro-1H-1,3-imidazol-1-yl)borato-κ(3)H,S,S'](methanol-κO)sodium(I)}, [Na2(C27H22BN6S3)2(CH4O)4] (NaTm(Ph)), bis-µ-methanol-κ(4)O:O-bis{[hydrotris(3-isopropyl-2-sulfanylidene-2,3-dihydro-1H-1,3-imidazol-1-yl)borato-κ(3)H,S,S'](methanol-κO)sodium(I)}-diethyl ether-methanol (1/0.3333/0.0833), [Na2(C18H28BN6S3)2(CH4O)4]·0.3333C4H10O·0.0833CH3OH (NaTm(iPr)), and a novel anhydrous form of sodium hydrotris(methylthioimidazolyl)borate, poly[[µ-hydrotris(3-methyl-2-sulfanylidene-2,3-dihydro-1H-1,3-imidazol-1-yl)borato]sodium(I)], [Na(C12H16BN6S3)] ([NaTm(Me)]n). NaTm(iPr) and NaTm(Ph) have similar dimeric molecular structures with κ(3)H,S,S'-bonding, but they differ in that NaTm(Ph) is crystallographically centrosymmetric (Z' = 0.5) while NaTm(iPr) contains one crystallographically centrosymmetric dimer and one dimer positioned on a general position (Z' = 1.5). [NaTm(Me)]n is a one-dimensional coordination polymer that extends along the a direction and which contains a hitherto unseen side-on η(2)-C=S-to-Na bond type. An overview of the structural preferences of alkali metal soft scorpionate complexes is presented. This analysis suggests that these thione-based ligands will continue to be a rich source of interesting alkali metal motifs worthy of isolation and characterization.

17.
Chemistry ; 19(40): 13561-8, 2013 Sep 27.
Article in English | MEDLINE | ID: mdl-23943587

ABSTRACT

Soft scorpionates have thus far been seen mainly as a family of ligands. Their chemistry is extended here to the production of novel cationic macrocycles using dihaloalkanes. By replacing the dihaloalkanes with mild oxidising agents (NO(+), I2) we obtain two unique polycyclic heterocycles. The mechanism which leads to the formation of these polycyclic heterocycles is investigated using ab initio DFT calculations.

18.
Chemistry ; 19(7): 2487-95, 2013 Feb 11.
Article in English | MEDLINE | ID: mdl-23297136

ABSTRACT

The alkylation reactions of soft scorpionates are reported. The hydrotris(S-alkyl-methimazolyl)borate dications (alkyl = methyl, allyl, benzyl), which were prepared by the reaction of Tm(Me) anion and primary alkyl halides, have been isolated and structurally characterised. The reaction is, however, not universally successful. DFT analysis of these alkylation reactions (C=S versus B-H alkylation) indicates that the observed outcome is driven by kinetic factors. Extending the study to incorporate alternative imine thiones (mercaptobenzothiazole, bz; thiazoline, tz) led to the structural characterisation of di[aquo-µ-aquohydrotris(mercaptobenzothiazolyl)boratosodium], which contains sodium atoms in the κ(3)-S,S,S coordination mode. Alkylation of Na[Tbz] and Na[tzTtz] leads to decomposition resulting in the formation of the simple S-alkylated heterocycles. The analysis of the species involved in these reactions shows an inherent weakness in the B-N bond in soft scorpionates, which has implications for their use in more advanced chemistry.


Subject(s)
Alkylating Agents/chemistry , Borates/chemistry , Thiones/chemistry , Alkylation , Kinetics , Molecular Structure
19.
Asian Cardiovasc Thorac Ann ; 13(4): 316-20, 2005 Dec.
Article in English | MEDLINE | ID: mdl-16304217

ABSTRACT

Between February and September 2003, 136 (5.3%) of 2,558 patients undergoing cardiac surgery were supported with intra-aortic balloon counterpulsation. There were 71 infected (group 1) and 65 noninfected (group 2) patients. Risk factors for nosocomial infections were identified by univariate and multivariate analysis. On univariate analysis, significant risk factors were operation time, balloon pump duration, ventilation hours, duration of central venous catheter placement, amount of blood transfused, left ventricular ejection fraction<30%, intra- and/or postoperative intra-aortic balloon counterpulsation, surgery under cardiopulmonary bypass, combined procedures, re-exploration, and Acute Physiology And Chronic Health Evaluation (APACHE) II score. On multivariate analysis, ventilation hours and amount of blood transfused were independently associated with group 1. Respiratory tract infections were common in the balloon counterpulsation population (41.1%). Mortality was significantly higher in patients needing balloon pump support (19.9%) compared to controls (1.1%), but it was similar in groups 1 and 2. Recognition of risk factors for postoperative infection in patients undergoing cardiovascular surgical procedures with intra-aortic balloon counterpulsation may help to improve their prognosis and allow more organized surveillance.


Subject(s)
Cross Infection/epidemiology , Cross Infection/etiology , Intra-Aortic Balloon Pumping/adverse effects , Aged , Analysis of Variance , Candidiasis/epidemiology , Candidiasis/etiology , Cardiac Surgical Procedures/methods , Case-Control Studies , Cross Infection/microbiology , Female , Humans , Intensive Care Units , Length of Stay , Male , Middle Aged , Prospective Studies , Pseudomonas Infections/epidemiology , Pseudomonas Infections/etiology , Respiratory Tract Infections/epidemiology , Respiratory Tract Infections/etiology , Risk Factors , Staphylococcal Infections/epidemiology , Staphylococcal Infections/etiology , Surgical Wound Infection/epidemiology , Surgical Wound Infection/etiology , Survival Rate , Treatment Outcome , Urinary Tract Infections/epidemiology , Urinary Tract Infections/etiology
20.
Vet Microbiol ; 94(2): 131-41, 2003 Jul 01.
Article in English | MEDLINE | ID: mdl-12781481

ABSTRACT

The role of indirect binding of host proteins through glycosaminoglycans (GAGs) on adherence and internalization of Streptococcus uberis to bovine mammary epithelial cells was evaluated. Preincubation of S. uberis with GAGs followed by incubation with fetal bovine serum (FBS), bovine milk or milk proteins resulted in greater adherence to and internalization of S. uberis into mammary epithelial cells than observed in untreated controls. Highest values were detected, when final incubation was done with milk. Greater adherence to and internalization into mammary epithelial cells were observed when heparin sulfate (HEP) and milk were used compared with any other GAG and FBS. When individual milk proteins were used, greatest adherence and internalization were observed when S. uberis strains were pretreated with HEP followed by treatment with beta-casein. The findings of this study illustrate a pathogenic strategy of S. uberis that may occur during the very early stages of infection.


Subject(s)
Glycosaminoglycans/metabolism , Heparin/analogs & derivatives , Mastitis, Bovine/etiology , Milk Proteins/metabolism , Streptococcal Infections/veterinary , Streptococcus/pathogenicity , Animals , Bacterial Adhesion/physiology , Cattle , Enzyme-Linked Immunosorbent Assay/veterinary , Female , Heparin/metabolism , Mammary Glands, Animal/microbiology , Mastitis, Bovine/microbiology , Milk/microbiology , Milk/physiology , Proteoglycans/metabolism , Streptococcal Infections/etiology , Streptococcal Infections/microbiology , Streptococcus/physiology
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