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1.
Transbound Emerg Dis ; 65(1): 221-231, 2018 Feb.
Article in English | MEDLINE | ID: mdl-28758346

ABSTRACT

Effective control and monitoring of foot-and-mouth disease (FMD) relies upon rapid and accurate disease confirmation. Currently, clinical samples are usually tested in reference laboratories using standardized assays recommended by The World Organisation for Animal Health (OIE). However, the requirements for prompt and serotype-specific diagnosis during FMD outbreaks, and the need to establish robust laboratory testing capacity in FMD-endemic countries have motivated the development of simple diagnostic platforms to support local decision-making. Using a portable thermocycler, the T-COR™ 8, this study describes the laboratory and field evaluation of a commercially available, lyophilized pan-serotype-specific real-time RT-PCR (rRT-PCR) assay and a newly available FMD virus (FMDV) typing assay (East Africa-specific for serotypes: O, A, Southern African Territories [SAT] 1 and 2). Analytical sensitivity, diagnostic sensitivity and specificity of the pan-serotype-specific lyophilized assay were comparable to that of an OIE-recommended laboratory-based rRT-PCR (determined using a panel of 57 FMDV-positive samples and six non-FMDV vesicular disease samples for differential diagnosis). The FMDV-typing assay was able to correctly identify the serotype of 33/36 FMDV-positive samples (no cross-reactivity between serotypes was evident). Furthermore, the assays were able to accurately detect and type FMDV RNA in multiple sample types, including epithelial tissue suspensions, serum, oesophageal-pharyngeal (OP) fluid and oral swabs, both with and without the use of nucleic acid extraction. When deployed in laboratory and field settings in Tanzania, Kenya and Ethiopia, both assays reliably detected and serotyped FMDV RNA in samples (n = 144) collected from pre-clinical, clinical and clinically recovered cattle. These data support the use of field-ready rRT-PCR platforms in endemic settings for simple, highly sensitive and rapid detection and/or characterization of FMDV.


Subject(s)
Cattle Diseases/diagnosis , Foot-and-Mouth Disease Virus/isolation & purification , Foot-and-Mouth Disease/diagnosis , Real-Time Polymerase Chain Reaction/veterinary , Africa, Eastern/epidemiology , Animals , Cattle , Cattle Diseases/epidemiology , Cattle Diseases/virology , Disease Outbreaks/veterinary , Foot-and-Mouth Disease/epidemiology , Foot-and-Mouth Disease/virology , Foot-and-Mouth Disease Virus/genetics , RNA, Viral/genetics , Sensitivity and Specificity , Serogroup , Serotyping/methods
2.
Parasitol Res ; 115(12): 4639-4648, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27630102

ABSTRACT

Gastrointestinal and pulmonary nematode infections are affecting the health and productivity of grazing cattle worldwide. To evaluate the effects of a single treatment with ivermectin long-acting injection (IVM LAI; IVOMEC® GOLD, Merial; 3.15 % ivermectin w/v) in first-grazing season cattle, two studies were conducted under continued stocking conditions for 84 or 100 days in Bavaria, Germany. Each study involved 68 naturally infected, approximately 4- to 6-month-old Brown Swiss bull calves. Animals were blocked based on pretreatment body weights. Within each block of four animals, animals were randomly assigned to treatments: one to saline (control) and three to IVM LAI. Treatments were injected at 1 mL/50 kg body weight subcutaneously in front of the shoulder. Animals in both studies were managed as one herd each grazing together. Cattle were weighed and fecal samples were collected pretreatment and at intervals thereafter for determination of weight gain and treatment efficacy, respectively. Fecal examination including composite fecal culture indicated the presence of nematodes of the genera Cooperia (dominating), Haemonchus, Nematodirus, Ostertagia, Strongyloides, Trichostrongylus, Trichuris, and Dictyocaulus, and Moniezia cestodes in the cattle. Following treatment, IVM LAI-treated cattle did not shed any Dictyocaulus larvae for 84 days while controls continued to pass larvae. Compared to the controls, IVM LAI-treated cattle had significantly (p < 0.01) lower strongylid egg counts at each occasion. Percentage reductions were ≥94 % up to 70 days after treatment and were ≥83.9 and 58.9 % at 84 and 100 days. Over the 84- or 100-day study periods, IVM LAI-treated cattle gained significantly more weight than the controls: 22.7 and 12.4 kg, respectively. The two studies demonstrated a high efficacy of IVM LAI against gastrointestinal and pulmonary nematode infections under field conditions in Germany which was associated with significant benefit as to weight gain.


Subject(s)
Cattle Diseases/drug therapy , Ivermectin/therapeutic use , Nematode Infections/veterinary , Animals , Cattle , Cattle Diseases/parasitology , Feces/parasitology , Germany , Larva/drug effects , Male , Nematoda/drug effects , Nematode Infections/drug therapy , Parasite Egg Count/veterinary , Seasons , Weight Gain
3.
Transbound Emerg Dis ; 63(5): e328-38, 2016 Oct.
Article in English | MEDLINE | ID: mdl-25488821

ABSTRACT

Influenza A virus (IAV) surveillance using pre-weaning oral fluid samples from litters of piglets was evaluated in four ˜12 500 sow and IAV-vaccinated, breeding herds. Oral fluid samples were collected from 600 litters and serum samples from their dams at weaning. Litter oral fluid samples were tested for IAV by virus isolation, quantitative reverse transcription-polymerase chain reaction (qRT-PCR), RT-PCR subtyping and sequencing. Commercial nucleoprotein (NP) enzyme-linked immunosorbent assay (ELISA) kits and NP isotype-specific assays (IgM, IgA and IgG) were used to characterize NP antibody in litter oral fluid and sow serum. All litter oral fluid specimens (n = 600) were negative by virus isolation. Twenty-five oral fluid samples (25/600 = 4.2%) were qRT-PCR positive based on screening (Laboratory 1) and confirmatory testing (Laboratory 2). No hemagglutinin (HA) and neuraminidase (NA) gene sequences were obtained, but matrix (M) gene sequences were obtained for all qRT-PCR-positive samples submitted for sequencing (n = 18). Genetic analysis revealed that all M genes sequences were identical (GenBank accession no. KF487544) and belonged to the triple reassortant influenza A virus M gene (TRIG M) previously identified in swine. The proportion of IgM- and IgA-positive samples was significantly higher in sow serum and litter oral fluid samples, respectively (P < 0.01). Consistent with the extensive use of IAV vaccine, no difference was detected in the proportion of IgG- and blocking ELISA-positive sow serum and litter oral fluids. This study supported the use of oral fluid sampling as a means of conducting IAV surveillance in pig populations and demonstrated the inapparent circulation of IAV in piglets. Future work on IAV oral fluid diagnostics should focus on improved procedures for virus isolation, subtyping and sequencing of HA and NA genes. The role of antibody in IAV surveillance remains to be elucidated, but longitudinal assessment of specific antibody has the potential to provide information regarding patterns of infection, vaccination status and herd immunity.


Subject(s)
Influenza A virus/isolation & purification , Mouth/metabolism , Mouth/virology , Swine Diseases/diagnosis , Weaning , Animals , Enzyme-Linked Immunosorbent Assay/veterinary , Swine/virology , Swine Diseases/epidemiology , United States/epidemiology
4.
Congenit Heart Dis ; 6(3): 266-8, 2011.
Article in English | MEDLINE | ID: mdl-21410652

ABSTRACT

Valve thrombosis is a potentially dangerous complication for right sided prosthetic valves in adults with congenital heart disease. Thrombolytic therapy is an important alternative to surgery and may be of benefit in patients with a history of multiple surgical interventions. We present two cases of successful thrombolytic therapy for right sided valve thrombosis in patients with congenital heart disease.


Subject(s)
Fibrinolytic Agents/administration & dosage , Heart Defects, Congenital/complications , Heart Valve Prosthesis Implantation/instrumentation , Heart Valve Prosthesis , Thrombolytic Therapy , Thrombosis/drug therapy , Tissue Plasminogen Activator/administration & dosage , Adult , Anticoagulants/therapeutic use , Female , Heart Defects, Congenital/surgery , Heart Valve Prosthesis Implantation/adverse effects , Humans , Male , Radiography, Interventional , Reoperation , Thrombosis/etiology , Treatment Outcome
5.
J Phys Chem A ; 113(23): 6437-45, 2009 Jun 11.
Article in English | MEDLINE | ID: mdl-19441808

ABSTRACT

We examine the photophysics of a colloidal suspension of C(60) particles in a micellar solution of Triton X-100 and water, prepared via a new synthesis which allows high-concentration suspensions. The particle sizes are characterized by transmission electron microscopy and dynamic light scattering and found to be somewhat polydisperse in the range of 10-100 nm. The suspension is characterized optically by UV-vis spectroscopy, femtosecond transient absorption spectroscopy, laser flash photolysis, and z-scan. The ground-state absorbance spectrum shows a broad absorbance feature centered near 450 nm which is indicative of colloidal C(60). The transient absorption dynamics, presented for the first time with femtosecond resolution, are very similar to that of thin films of C(60) and indicate a strong quenching of the singlet excited state on short time scales and evidence of little intersystem crossing to a triplet excited state. Laser flash photolysis reveals that a triplet excited-state absorption spectrum, which is essentially identical in shape to that of molecular C(60) solutions, does indeed arise, but with much lower magnitude and somewhat shorter lifetime. Z-scan analysis confirms that the optical response of this material is dominated by nonlinear scattering.


Subject(s)
Fullerenes/chemistry , Octoxynol/chemistry , Surface-Active Agents/chemistry , Water/chemistry , Absorption , Colloids , Lasers , Light , Microscopy, Electron, Transmission , Particle Size , Photolysis , Scattering, Radiation , Soot/chemistry , Suspensions , Time Factors
6.
Bioconjug Chem ; 19(7): 1423-9, 2008 Jul.
Article in English | MEDLINE | ID: mdl-18564869

ABSTRACT

Two types of 32 arm star polymers incorporating amphiphilic block copolymer arms have been synthesized and characterized. The first type, stPCL-PEG 32, is composed of a polyamidoamine (PAMAM) dendrimer as the core with radiating arms having poly(epsilon-caprolactone) (PCL) as an inner lipophilic block in the arm and poly(ethylene glycol) (PEG) as an outer hydrophilic block. The second type, stPLA-PEG 32, is similar but with poly(L-lactide) (PLA) as the inner lipophilic block. Characterization with SEC, (1)H NMR, FTIR, and DSC confirmed the structure of the polymers. Micelle formation by both star copolymers was studied by fluorescence spectroscopy. The stPCL-PEG 32 polymer exhibited unimolecular micelle behavior. It was capable of solubilizing hydrophobic molecules, such as pyrene, in aqueous solution, while not displaying a critical micelle concentration. In contrast, the association behavior of stPLA-PEG 32 in aqueous solution was characterized by an apparent critical micelle concentration of ca. 0.01 mg/mL. The hydrophobic anticancer drug etoposide can be encapsulated in the micelles formed from both polymers. Overall, the stPCL-PEG 32 polymer exhibited a higher etoposide loading capacity (up to 7.8 w/w % versus 4.3 w/w % for stPLA-PEG 32) as well as facile release kinetics and is more suitable as a potential drug delivery carrier.


Subject(s)
Drug Carriers/chemical synthesis , Ethylene Glycols/chemical synthesis , Polyesters/chemical synthesis , Polyethylene Glycols/chemical synthesis , Antineoplastic Agents/chemistry , Calorimetry, Differential Scanning , Drug Carriers/chemistry , Ethylene Glycols/chemistry , Etoposide/chemistry , Fluorescent Dyes/chemistry , Hydrophobic and Hydrophilic Interactions , Micelles , Polyesters/chemistry , Polyethylene Glycols/chemistry , Pyrenes/chemistry , Spectrometry, Fluorescence , Temperature
7.
J Urol ; 177(1): 258-61; discussion 261, 2007 Jan.
Article in English | MEDLINE | ID: mdl-17162058

ABSTRACT

PURPOSE: Sildenafil is the first member of a new class of oral drugs effective for erectile dysfunction. However, approximately 20% of patients complain about nasal congestion after sildenafil administration. MATERIALS AND METHODS: Because nasal airflow and olfaction are closely linked, the sense of smell was evaluated in 20 young, healthy volunteers after the administration of 50 and 100 mg sildenafil, and placebo in a double-blinded, crossover study. Olfactory function was evaluated using a standardized and validated test (Sniffin' Sticks). To investigate a possible impact of G-protein beta3 subunit C825T polymorphism on the effect of sildenafil on olfaction the genotype of all subjects was determined. RESULTS: The effect of sildenafil on olfaction was only present at a dose of 100 mg but not at a dose of 50 mg sildenafil. The genotypes TT, CC and TC of the G-protein beta3 C825T polymorphism had no impact on the change in olfactory function. CONCLUSIONS: Higher sildenafil doses may produce decreased olfactory sensitivity.


Subject(s)
Phosphodiesterase Inhibitors/pharmacology , Piperazines/pharmacology , Smell/drug effects , Cross-Over Studies , Double-Blind Method , Genotype , Heterotrimeric GTP-Binding Proteins/genetics , Humans , Male , Phosphodiesterase Inhibitors/administration & dosage , Piperazines/administration & dosage , Polymorphism, Genetic , Purines , Sildenafil Citrate , Sulfones
8.
J Neural Transm (Vienna) ; 114(2): 273-80, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17109073

ABSTRACT

The study was aimed at the evaluation of weight gain associated with atypical antipsychotics and its clinical risk factors in children and adolescents. Weight and body mass index (BMI) of initially hospitalised patients treated with clozapine (n = 15), olanzapine (n = 15), and risperidone (n = 15) were prospectively monitored on a weekly basis for the first 6 weeks. Different clinical risk factors were tested for their association with weight gain in the three groups. All three groups experienced significant weight gain between baseline and endpoint (p < 0.0001). For all weight measures, planned comparisons were all significant between olanzapine vs. clozapine and risperidone, respectively. Average weight gain was significantly higher for the olanzapine group (mean = 4.6 kg, SD = 1.9) than for the risperidone (mean = 2.8 kg, SD = 1.3) and clozapine (mean = 2.5 kg, SD = 2.9) groups. Olanzapine and risperidone, but not clozapine, caused a disproportionately higher weight gain in children and adolescents in comparison to adults.


Subject(s)
Antipsychotic Agents/adverse effects , Clozapine/adverse effects , Risperidone/adverse effects , Weight Gain/drug effects , Adolescent , Benzodiazepines/adverse effects , Body Weight/drug effects , Child , Female , Humans , Male , Mental Disorders/drug therapy , Olanzapine
9.
Bioconjug Chem ; 16(2): 397-405, 2005.
Article in English | MEDLINE | ID: mdl-15769095

ABSTRACT

A star polymer composed of amphiphilic block copolymer arms has been synthesized and characterized. The core of the star polymer is polyamidoamine (PAMAM) dendrimer, the inner block in the arm is lipophilic poly(epsilon-caprolactone) (PCL), and the outer block in the arm is hydrophilic poly(ethylene glycol) (PEG). The star-PCL polymer was synthesized first by ring-opening polymerization of epsilon-caprolactone with a PAMAM-OH dendrimer as initiator. The PEG polymer was then attached to the PCL terminus by an ester-forming reaction. Characterization with SEC, (1)H NMR, FTIR, TGA, and DSC confirmed the star structure of the polymers. The micelle formation of the star copolymer (star-PCL-PEG) was studied by fluorescence spectroscopy. Hydrophobic dyes and drugs can be encapsulated in the micelles. A loading capacity of up to 22% (w/w) was achieved with etoposide, a hydrophobic anticancer drug. A cytotoxicity assay demonstrated that the star-PCL-PEG copolymer is nontoxic in cell culture. This type of block copolymer can be used as a drug delivery carrier.


Subject(s)
Drug Carriers/chemistry , Polymers/chemical synthesis , Animals , Cell Line , Cell Survival , Etoposide/administration & dosage , Micelles , Molecular Conformation , Polyesters , Polyethylene Glycols , Polymers/chemistry , Polymers/therapeutic use , Spectrum Analysis , Surface-Active Agents , Swine
10.
Biosens Bioelectron ; 20(2): 276-83, 2004 Sep 15.
Article in English | MEDLINE | ID: mdl-15308232

ABSTRACT

Hydroquinone diphosphate (HQDP) was synthesized and compared to phenyl phosphate (PP) and 1-naphthyl phosphate (NP) as a substrate for alkaline phosphatase (AP) under electrochemical immunoassay (EIA) conditions. Voltammetric and amperometric experiments showed that electrochemical oxidation of hydroquinone (HQ), which is the AP hydrolysis product of HQDP, did not produce electrode passivation, even with repeated biosensor use. In contrast, phenol and 1-naphthol, the hydrolysis products of PP and NP, respectively, were shown to be irreversibly oxidized on the electrode surfaces, and produced rapid electrode passivation, resulting in complete loss of electrode signal. When employed as AP substrate in an iridium oxide based EIA, HQDP produced significantly larger amperometric responses (117 microA/cm2) compared to PP (31 microA/cm2) and NP (27 microA/cm2). The results presented in this paper show that HQDP is an attractive alternative to commonly used AP substrates such as NP and PP. The substrate shows excellent hydrolytic stability, produces larger amperometric responses (than PP or NP), and does not produce sensor passivation.


Subject(s)
Alkaline Phosphatase/analysis , Alkaline Phosphatase/chemistry , Electrochemistry/instrumentation , Electrodes , Hydroquinones/analysis , Hydroquinones/chemistry , Immunoassay/instrumentation , Immunoglobulin G/analysis , Organophosphates/analysis , Organophosphates/chemistry , Electrochemistry/methods , Enzyme Activation , Equipment Failure , Equipment Failure Analysis , Hydrolysis , Immunoassay/methods , Reproducibility of Results , Sensitivity and Specificity , Substrate Specificity
11.
Biosens Bioelectron ; 19(7): 693-9, 2004 Feb 15.
Article in English | MEDLINE | ID: mdl-14709387

ABSTRACT

Novel immunosensors based on antibodies immobilized in electrochemically grown iridium oxide (IrOx) thin film matrices have been developed. Antibody loading in the oxide was evaluated using a non-competitive electrochemical immunoassay for IgG. Anti-IgG loading in the oxide was found to be dependent on the concentration of anti-IgG present in the oxide growth step, with 400 microg/ml anti-IgG producing maximum amperometric responses. To study the potential analytical properties of the matrix, the dose-response behavior of the sensors was determined using optimized alkaline phosphatase-linked IgG immunoassay. Hydroquinone diphosphate (HQDP) was used as enzyme substrate and the oxidation of hydroquinone was detected amperometrically at +420 mV. The sensors displayed a linear dose-response behavior for IgG concentrations between 10 and 200 ng/ml, saturating above 600 ng/ml, and had a low detection limit of 8 ng/ml.Finally, the method was used to produce sensors containing immobilized anti-transferrin. Using a non-optimized electrochemical immunoassay for human transferrin (HT), dose-response behavior was observed for HT concentrations between 100 and 600 ng/ml.The results presented in this paper show that IrOx matrices represent a new method for immunosensor fabrication. The oxide acts as a hydrophilic, highly porous, three-dimensional matrix that can immobilize antibodies and retain their activity. The method is attractive because it offers the potential for high antibody loadings and is suitable for mass production of sensors in an easy and economical manner.


Subject(s)
Biosensing Techniques/instrumentation , Immunoassay/instrumentation , Immunoglobulin G/analysis , Iridium/chemistry , Transferrin/analysis , Adsorption , Animals , Antigen-Antibody Complex/analysis , Antigen-Antibody Complex/immunology , Biosensing Techniques/methods , Equipment Design , Equipment Failure Analysis , Humans , Immunoassay/methods , Immunoglobulin G/immunology , Rabbits , Reproducibility of Results , Sensitivity and Specificity , Transferrin/immunology
12.
Clin Physiol Funct Imaging ; 22(3): 206-9, 2002 May.
Article in English | MEDLINE | ID: mdl-12076347

ABSTRACT

Diabetic or other neuropathies can affect the autonomic innervations of vessels and heart. Using non-invasive and inexpensive autonomic tests, one can detect autonomic neuropathy. One of these tests is the inspiratory gasp response (IGR). It appears as a short reduction of skin blood volume (SBV) following deep inspiration (DI). Unfortunately, because of a high degree of variability of the study results, the clinical merits of this test have been questioned. However, there remains vagueness about underlying mechanisms or pitfalls. The aim of the study was to identify preceding vasoconstrictor episodes as putative pitfalls in assessing IGR. With regard to the hypothesis that a preceding vasoconstrictor episode may affect the amplitude of the following one, we investigated SBV in fingertips of 25 healthy test subjects (14 females, 11 males; mean age 24 years), using the photoplethysmographic technique. After adaptation to environmental conditions the subjects were instructed to perform five DI in various time lags (90, 30, 20 and 180 s). We found that the shorter the time interval to a preceding IGR, the lower the amplitude of the following IGR. After an interval of 180 s, the amplitude increased again. We conclude that this newly observed phenomenon might explain the contradictory results of the IGR test found in some earlier studies. We suppose that reduced IGR may depend on alterations in peripheral norepinephrinergic transmission processes (e.g. emptying of norepinephrine reservoirs). In clinical studies it should be ruled out that a diagnostically assessed IGR is influenced by a preceding vasoconstrictor episode.


Subject(s)
Respiratory Mechanics/physiology , Skin/blood supply , Vasoconstriction/physiology , Adult , Blood Pressure , Female , Heart Rate , Humans , Male , Microcirculation/physiology , Middle Aged , Photoplethysmography , Skin/innervation , Sympathetic Nervous System/physiology
13.
J Clin Anesth ; 13(5): 361-5, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11498317

ABSTRACT

STUDY OBJECTIVE: To investigate the influence of pneumoperitoneum (PP) and posture on respiratory compliance and ventilation pressures. DESIGN: Prospective, single blind trial. PATIENTS: 10 female ASA physical status I and II patients scheduled for elective gynecologic laparoscopy. SETTING: University medical center. INTERVENTIONS: Anesthesia was performed as total IV anesthesia (TIVA) with propofol, alfentanil, and atracurium. After induction of anesthesia and orotracheal intubation, the lungs were ventilated to maintain partial pressure of CO(2) (P(ET)CO(2)) of 30 +/- 3 mmHg. Ventilation was kept constant. As gas mixture oxygen and air 1:1 was used without positive end-expiratory pressure (PEEP). MEASUREMENTS: Measurements were taken before and after creation of pneumoperitoneum with an intraabdominal pressure (IAP) of 10 mmHg, of 15 mmHg in 20 degrees head-down tilt, then in 20 degrees head-up tilt, and after deflation of PP. We determined peak inspiratory pressure (PIP), mean airway pressure (mPaw), P(ET)CO(2), expiratory minute volume (V(E)), heart rate (HR), and systolic (SBP), diastolic (DBP), and mean arterial pressure (MAP). Respiratory system compliance (C(eff rs)) was calculated as quotient of tidal volume (V(T)) and PIP. MAIN RESULTS: After creation of PP (IAP 10 mmHg), there was a significant increase of median PIP (3 cmH(2)O), mPaw (1 cm H(2)O) and arterial pressure (BP), (MAP by 7 mmHg), C(eff rs) decreased by 6 mL. cm H(2)O(-1). Increase of IAP to 15 mmHg led to a further increase of PIP (2 cm H(2)O) and mPaw (1 cm H(2)O), and a further decrease of C(eff rs) by 5 mL cm H(2)O(-1); BP decreased (MAP by 5.5 mmHg). Head-up or head down positions showed no significant hemodynamic or pulmonary changes. P(ET)CO(2)increased from 29.5 to 36 mmHg at an IAP of 15 mmHg, but then no further changes were noticed. Five minutes after deflation of pneumoperitoneum all values returned to baseline levels. CONCLUSIONS: Creation of PP at an IAP of 15 mmHg reduced respiratory system compliance, and increased peak inspiratory and mean airway pressures, which quickly returned to normal values after deflation. Head-down or head-up position did not further alter those parameters.


Subject(s)
Lung Compliance/physiology , Pneumoperitoneum/physiopathology , Posture/physiology , Adult , Anesthesia, Intravenous , Blood Pressure/physiology , Female , Gynecologic Surgical Procedures , Heart Rate/physiology , Hemodynamics , Humans , Laparoscopy , Respiration, Artificial , Respiratory Mechanics/physiology
15.
IEEE Trans Neural Syst Rehabil Eng ; 9(1): 2-11, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11482359

ABSTRACT

Iridium oxide films formed by electrodeposition onto noniridium metal substrates are compared with activated iridium oxide films (AIROFs) as a low impedance, high charge capacity coating for neural stimulation and recording electrodes. The electrodeposited iridium oxide films (EIROFs) were deposited on Au, Pt, PtIr, and 316 LVM stainless steel substrates from a solution of IrCl4, oxalic acid, and K2CO3. A deposition protocol involving 50 potential sweeps at 50 mV/s between limits of 0.0 V and 0.55 V (versus Ag AgCl) followed by potential pulsing between the same limits produced adherent films with a charge storage capacity of >25 mC/cm2. Characterization by cyclic voltammetry and impedance spectroscopy revealed no differences in the electrochemical behavior of EIROF on non-Ir substrates and AIROF. The mechanical stability of the oxides was evaluated by ultrasonication in distilled water followed by dehydration and rehydration. Stability under charge injection was evaluated using 200 micros, 5.9 A/cm2 (1.2 mC/cm2) cathodal pulses. Loss of iridium oxide charge capacity was comparable for AIROFs and the EIROFs, ranging from 1% to 8% of the capacity immediately after activation or deposition. The EIROFs were deposited and evaluated on silicon microprobe electrodes and on metallized polyimide electrodes being developed for neural recording and stimulation applications.


Subject(s)
Electroplating , Iridium/physiology , Neural Conduction/physiology , Electric Capacitance , Electric Impedance , Electric Stimulation , Electrochemistry , Microelectrodes , Models, Neurological , Signal Transduction/physiology
16.
J Clin Anesth ; 13(4): 244-9, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11435046

ABSTRACT

STUDY OBJECTIVE: To determine the hemodynamic effects of pneumoperitoneum and patient positioning during laparoscopic surgery of the lower abdomen. DESIGN: Prospective study. SETTING: University-affiliated medical center. PATIENTS: 10 ASA physical I and II female patients scheduled for laparoscopic surgery of the lower abdomen. INTERVENTIONS: Patients were anesthetized with propofol and an alfentanil infusion, then intubated, and normoventilated. MEASUREMENTS: After intubation, a transesophageal multiplane probe for measurements of right (RVESA) and left (LVESA) ventricular end-systolic and end-diastolic areas (RVEDA and LVEDA) and ejection fraction area (RVEFa, LVEFa) was introduced; heart rate (HR) and noninvasive blood pressure (BP) were recorded every minute. Ventilation was not changed during the measurements. A transvaginal ultrasound probe was inserted to measure the diameter of the common iliac vein. Measurements were performed 15 minutes after induction of anesthesia and while patients were in the supine position (P 0), 10 minutes after CO(2) insufflation to 10 mmHg IA pressure (P 10), 10 minutes after a further increase to 15 mmHg (P 15), 10 minutes after 20 degrees Trendelenburg (P 15 T), and 20 degrees reverse Trendelenburg positions (P 15 RT). Data are shown as medians, 25th to 75th percentiles, and comparisons between P 0, P 10, P 15, and P15 T were made with the Friedman test, followed by Wilcoxon test, when significant. Data at P 15 T, P 15 RT, and P 15 were compared using the Wilcoxon test, with a p-value < 0.05 regarded as significant. MAIN RESULTS: Pneumoperitoneum at 10 mmHg abdominal pressure caused a significant increase of LVESA by 78% (RVESA: 61%) and LVEDA by 48.5% (RVEDA: 45%). The diameter of the common iliac vein was decreased by 6%. A further increase of abdominal pressure to 15 mmHg led to an additional increase of 20% (LVESA) and 17% (LVEDA). Mean arterial pressure increased by a significant 7% at P 10, decreasing subsequently by 5% at P 15. The Trendelenburg position did not alter any hemodynamic findings. Reverse Trendelenburg position, however, caused a significant LVEDA-and RVEDA-decrease by 18% and 27%, respectively, and an increase in the diameter of the common iliac vein by 22%. The LVEFa and RVEFa decreased significantly after abdominal CO(2) insufflation by 18% each (P 10) without further change. CONCLUSIONS: The lithotomy position and subsequent pneumoperitoneum increased preload, probably as a result of blood shifting from the abdomen to the thorax by compression of splanchnic vessels caused by the pneumoperitoneum. Careful fluid management, maintaining low abdominal pressure, and use of the reverse Trendelenburg position are favored to prevent adverse hemodynamic effects in laparoscopic surgery.


Subject(s)
Abdomen/surgery , Head-Down Tilt/physiology , Laparoscopy , Pneumoperitoneum/physiopathology , Splanchnic Circulation/physiology , Adult , Anesthesia , Blood Pressure/physiology , Echocardiography, Transesophageal , Female , Heart Rate/physiology , Humans , Iliac Vein/diagnostic imaging , Iliac Vein/physiology , Male , Monitoring, Intraoperative , Pressure , Prospective Studies , Stroke Volume/physiology
17.
Zentralbl Chir ; 126(1): 75-9, 2001 Jan.
Article in German | MEDLINE | ID: mdl-11227301

ABSTRACT

AIM OF STUDY: The study investigates the haemodynamic effects of the varying intraabdominal pressures and patient positions during gynecological procedures employing pneumoperitoneum in lithotomy positions. METHODS: TEE was used to determine end-diastolic and end-systolic left ventricular surface areas and ejection fractions were calculated from these data. To evaluate intraabdominal volume shifts the diameter of the internal iliac vein was measured by mean of vaginal ultrasound. RESULTS: In the horizontal lithotomy position both LVEDA and LVESA increased when intraabdominal pressure increased by 10 and 15 mmHg, respectively. LVAEF significantly decreased when intraabdominal pressure increased by 15 mmHg. Also DVII decreased. In Trendelenburg position there was no change in LVEDA, LVESA, LVAEF and DVII. In Anti-Trendelenburg position LVEDA and LVESA decreased. However, LVAEF remained constant and DVII increased. CONCLUSION: The increase of the intraabdominal pressure in the lithotomy position results in an increase in intrathoracic volume and an decrease in LVAEF via elevation of the the lower extremities and compression of the splanchnic vessels. There are no changes in Trendelenburg position. However, in Anti-Trendelenburg position, gravity results in a decrease in intrathoracic blood volume. In the decreased, dilatated heart the increase in intrathoracic volume may increase myocardial wall tension and hence oxygen demand, ultimately leading to an acute heart failure. As a result laparoscopic procedures in horizontal lithotomy position should be avoided in patients with dilatative cardiomyopathy.


Subject(s)
Genital Diseases, Female/surgery , Hemodynamics/physiology , Laparoscopy , Pneumoperitoneum, Artificial , Adolescent , Adult , Aged , Blood Volume/physiology , Female , Heart Rate/physiology , Humans , Middle Aged , Risk Factors , Stroke Volume/physiology , Supine Position/physiology , Ventricular Function, Left/physiology
18.
Am J Manag Care ; 5(1): 37-43, 1999 Jan.
Article in English | MEDLINE | ID: mdl-10345965

ABSTRACT

OBJECTIVE: To do an analysis of patients with a primary diagnosis of congestive heart failure at discharge before (n = 407) and after (n = 347) the implementation of a comprehensive inpatient and outpatient congestive heart failure program consistent with the guidelines of the Agency for Health Care Policy and Research. STUDY DESIGN: A retrospective analysis of the impact of the congestive heart failure program on length of stay, admission and readmission rates, and costs to both patient and provider. The program, which used a multidisciplinary team approach, included an intensive education program focusing on diet, compliance, and symptom recognition, as well as the use of outpatient infusions. It also incorporated aggressive pharmacologic treatment for patients with advanced congestive heart failure. RESULTS: Our analysis revealed significant decreases in length of stay, admission and readmission rates, and costs to the patient and provider (P < or = .05). The mean cost per admission decreased 17% ($1118), and a substantial 77% ($718,468) net reduction in nonreimbursed (lost) hospital revenue was noted. CONCLUSION: A multidisciplinary, comprehensive congestive heart failure program can improve patient care in a community-hospital setting while significantly reducing costs to both the patient and the institution.


Subject(s)
Cardiology Service, Hospital/standards , Critical Pathways , Heart Failure/therapy , Hospitals, Community/standards , Cardiology Service, Hospital/economics , Cardiology Service, Hospital/organization & administration , Heart Failure/economics , Hospital Costs/statistics & numerical data , Hospitals, Community/economics , Hospitals, Community/organization & administration , Humans , Illinois , Length of Stay/statistics & numerical data , Outcome Assessment, Health Care , Patient Admission/statistics & numerical data , Patient Care Team , Patient Education as Topic , Retrospective Studies
19.
Stroke ; 27(4): 691-4, 1996 Apr.
Article in English | MEDLINE | ID: mdl-8614932

ABSTRACT

BACKGROUND AND PURPOSE: Identification of cardioembolic stroke is often limited by the difficulties involved in the detection of thrombi or the risk factors for thrombus formation. Patients in sinus rhythm with nondiagnostic transthoracic echocardiogram (TTE) and without carotid artery stenosis represent a subset in whom diagnostic recommendations are lacking. The aim of this study was to determine the value of transesophageal echocardiography (TEE) for diagnosis and therapy in this population. METHODS: Thirty patients with the characteristics described above were studied prospectively with the use of blood analysis, TTE, TEE, and Holter monitoring (in patients with atrial thrombus). RESULTS: TTE was abnormal in 16 of 30 patients, but no embolic source was identified. TEE disclosed left atrial appendage thrombus in 3 of 30 patients, atrial septal aneurysm in 2 of 30 patients, patent foramen ovale in 7 of 30 patients, and aortic plaques in 19 of 30 patients. The Tee resulted in a change of therapy in 3 of the 30 patients studied. CONCLUSION: This study demonstrates that TEE is a helpful diagnostic tool in delineating the risk of cardioembolic stroke and demonstrates significant pathology even in a subset of patients deemed to be at low risk. This additional new information led to a substantial change in therapy in 3 of 30 patients.


Subject(s)
Coronary Aneurysm/diagnostic imaging , Echocardiography, Transesophageal , Intracranial Embolism and Thrombosis/diagnostic imaging , Ischemic Attack, Transient/diagnostic imaging , Adult , Aged , Aged, 80 and over , Carotid Stenosis/diagnostic imaging , Coronary Aneurysm/epidemiology , Female , Humans , Hypertension , Intracranial Embolism and Thrombosis/epidemiology , Intracranial Embolism and Thrombosis/etiology , Ischemic Attack, Transient/etiology , Ischemic Attack, Transient/physiopathology , Male , Middle Aged , Predictive Value of Tests , Prospective Studies , Risk Factors
20.
Anal Chem ; 66(8): 1269-73, 1994 Apr 15.
Article in English | MEDLINE | ID: mdl-8210043

ABSTRACT

Increased restrictions on the enantiomeric purity of pharmaceuticals underscore the need for improved analytical techniques to quantitate chiral purity. The method of scattered circularly polarized Raman optical activity (SCP ROA) is examined as a potentially useful analytical technique. Preliminary studies revealed SCP ROA measurements were reproducible to within current experimental noise limits and displayed the expected linear decrease in SCP ROA with increasing racemization of the enantiomeric mixtures. Minimal interference in SCP ROA signal was observed when either an achiral or another chiral entity was present in a mixture. The advantages of spectral subtraction techniques were demonstrated for separation of SCP ROA signals when multiple chiral entities are present. SCP ROA has been shown to be capable of quantitative analysis and is capable of simultaneous identification of multiple enantiomeric species. This is significant since traditional optical activity measurements, such as polarimetry and circular dichroism, are of limited value on mixtures where the impurities are not quantitatively defined.


Subject(s)
Stereoisomerism , Spectrum Analysis, Raman
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