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At least 973 records · Page 54Linked to original sources

A novel nozzle for more efficient sperm orientation to improve sorting efficiency of X and Y chromosome-bearing sperm.

Efficient high-resolution detection of DNA for flow cytometric sorting of X and Y chromosome-bearing sperm is dependent on effectively orientating the sperm head to the laser beam in orthogonally configured flow systems. Normally, a beveled needle is required to enlarge the fraction of properly orientated sperm (flat side facing the laser beam). In this report, a modification to a standard jet-in-air nozzle for improved sperm orientation is presented. Inside the modified nozzle (novel nozzle), orientation forces are applied lower in the nozzle than in the current beveled injection needle system. The nozzle was tested with sperm heads from several species. This study shows that use of the nozzle to orientate cattle, swine, rabbit, mouse, and human sperm effectively improves the percentage of sperm that are properly oriented. The percentage of sperm heads oriented by use of the former system (beveled needle) ranges around 30% for most species. With the newly designed nozzle, that percentage ranges around 60%. At least a twofold increase in analysis is achieved. It was found that, unlike results with the beveled needle, the percentage of properly oriented sperm was independent of the sample rate. The introduced nozzle is a significant improvement over the beveled needle system for the analysis and sorting of sperm on the basis of DNA content. In addition to the improvement in sorted sperm production brought about by the novel nozzle when fitted to standard-speed cell sorters, it clearly also has significant potential for improving the efficiency of the Beltsville Sperm Sexing Technology for separating X and Y chromosome-bearing sperm when adapted to high-speed cell-sorting systems.

Animals↗

Devices for the treatment of diabetes: today.

Although single or multiple daily subcutaneous injections of insulin with syringes are the mainstay of insulin delivery techniques for the treatment of diabetes mellitus, several other methods are now available. The present paper will review the main problems occurring with the classical subcutaneous insulin therapy and the possible solutions given by the use of new devices, including more particularly insulin jet injectors, pens, and portable pumps. This review has to be considered as an introduction to the presentations of this symposium devoted to implantable pumps, glucose sensors, and artificial pancreas, respectively.

Diabetes Mellitus, Type 1↗

Mixing in the human carotid artery during carotid drug infusion studied with PET.

The safety and efficacy of drug infusion into the carotid artery require adequate mixing of the infused solution with carotid blood. Using positron emission tomography (PET), we studied the mixing of solutions infused into the human carotid artery in seven patients by analyzing the distribution of [15O]H2O infused into the carotid artery and by vein. At four infusion rates ranging from 0.5 to 10 ml/min, the variability in distribution averaged 16.5-17.8% among the pixels in a large volume of interest, without dependence on the infusion rate. The overall correlation between [15O]H2O influx with arterial infusion and [15O]H2O influx with venous injection was 0.78-0.82 at the four infusion rates, with no trend toward higher correlations at the faster infusion rates. The distribution into the anterior, middle, and posterior cerebral artery territories differed from distribution throughout the entire carotid territory by an average of 6.2-9.6% at the four infusion rates, with no trend toward smaller differences at the faster infusion rates. Infusions performed into a vinyl tube simulating the carotid artery indicated that at 0.5 ml/min, the velocity of fluid exiting the catheter makes no apparent contribution to mixing. We conclude that with infusions at the carotid bifurcation, mixing in the human carotid artery is complete or nearly complete over a wide range of infusion rates. The mixing appears to result from the patterns of blood flow within the artery, and not from jet effects at the catheter tip.

Adult↗

Lyophilized typhoid vaccine for intradermal use.

The prophylaxis of typhoid fever in Romania is usually achieved with fluid heat-killed phenolized vaccine. However the shelf life of this vaccine is only two years. The long term storage of an intradermal typhoid vaccine is made possible by lyophilization. A heat-inactivated bacterial suspension with a high concentration of organisms, at least 25 X 10(9) cells per ml, was freeze-dried at a temperature not higher than 30 degrees C. The final vaccine obtained had a residual moisture content of not more than 5%. Active and passive protection tests in mice, specific agglutinin production in humans and rabbits, the innocuity and the toxicity for mice, and the investigation of post-vaccinal adverse reactions in man, showed that the lyophilized typhoid vaccine could be stored at 4 degrees C for at least five years without loss of potency. Consequently, the vaccine may be stored without risk of deterioration for rapid emergency mass immunization with Jet-injector apparatus.

Animals↗

[Working conditions and complications during laryngomicroscopies under endotracheal ventilation via intubation tubes or injection ventilation].

During a period of 7 years 693 laryngomicroscopies (LAR) were performed on 490 patients. General anaesthesia was given by 21 anaesthesists: 5 applied ventilation only through a conventional intubation tube. Of the remaining 16 anaesthesists, 8 constantly prefered, 4 used occasionally jet ventilation (JET), and 4 applied both methods alternatively. No rationale was found for this choice. Laryngomicroscopies were performed by 14 ENT surgeons. One case of subcutaneous emphysema and two of pneumothorax were obtained with JET, obviously because of inexperience and neglect of precautions. Two epidermoid carcinomas in the left posterior commissure escaped the primary LAR, most probably because of poor vision due to the intubation tube, and were found during subsequent procedures with JET. In spite of the risk of complications (mostly avoidable with care and increasing experience), the main advantage of JET is the better chance of revealing of carcinoma in an earlier phase, when it is more amenable to curative therapy. Therefore, we no longer recommend ventilation through an intubation tube for laryngomicroscopies, but prefer intratracheal jet-ventilation for this purpose.

Anesthesia↗

[High frequency jet ventilation in heated gas saturated in water vapor without a reserve of medical gas under pressure. An original method].

A prototype of high frequency jet ventilator is compared with a classic device: Gambro Soxijet ventilator. The advantages of the prototype are: no need of pressured medical gas; warming and saturated moisture of the gas. A powerful compressor (2 M3.H-1 flow--3 bar pressure) draws up the moistened and warmed gases and injects them into a double pneumatic capacity. The first capacity is pressure limited by a relief valve (3 bar). Exhausted gases flow back to the pump. A miniature pressure regulator, placed between the two capacities, rules the driving pressure. Gas mixture is injected through a solenoid valve controlled by an electronic twin-timer. Results of both devices are similar. However, our prototype seems to be very convenient for developing countries where medical gases under high pressure are not often available.

Developing Countries↗

Evaluation of alternative strategies for optimizing glycemia: progress to date.

Adequate control of blood sugar has been repeatedly shown to translate into reductions in diabetic complications. Although insulin therapy in patients with type 2 diabetes can achieve and maintain near-normal glycemic goals associated with reductions in microvascular and macrovascular end points, it is often reserved for the later stages of management of these patients because of real or perceived concerns; these include fear and anxiety about worsening diabetes, failure of self-management, loss of quality of life, the pain of self-injection, and the possibility of multiple daily injections. Risks of hypoglycemia, weight gain, and cardiovascular disease may be concerns of physicians, but these risks are either manageable or, in the case of cardiovascular disease, unfounded. Taken together, the barriers to insulin therapy frequently compel physicians to consider it a treatment of last resort. Some of the more common barriers have been addressed through device options such as insulin pens and jet injectors, which may improve convenience but do not alleviate pain and discomfort. Transdermal delivery options using iontophoresis or ultrasound are in early stages of development, but methods based on transmucosal delivery-including buccal, nasal, and pulmonary routes-are further advanced. In particular, recent evidence shows that pulmonary forms of insulin are as safe and effective as rapid-acting injected insulin, and are well accepted by patients even over long-term periods of use. These innovative delivery systems may help overcome the barriers to insulin use.

Administration, Inhalation↗

Beam-injection flame furnace AAS: comparison of different nozzle types for beam generation and application of sub-critical liquid carbon dioxide as carrier and gas pressure pump.

In beam injection flame furnace AAS (BIFF-AAS) the sample is introduced as a free-flying high-speed liquid beam into an AAS flame-heated nickel tube, resulting in a considerable improvement in the power of detection. For optimization of beam generation different nozzle types (smooth jet nozzles, turbulent working nozzles) have been compared at different pressures. It was found that the type of the nozzle hardly influences the analytical signal. However, the flow rates resulting from the different inner diameters of the nozzles and the applied pressures led to drastic changes in the analytical signal. For these investigations a recently developed 0.6 MPa (84 psig) diaphragm pump system was used. Furthermore, for the first time ever sub-critical liquid carbon dioxide has been used simultaneously as a liquid gas-pressure pump, as carrier in a flow-injection system (FIA), and for the beam generation. Transport of the carrier takes place as a result of the head pressure (6 MPa) of the liquid CO2 in the gas cylinder. For volatile elements (e.g. Cd, Hg, Pb, and Tl) detection limits between 0.2 microg L(-1) (Cd) and 28 microg L(-1) (Hg) were found, the standard deviation was from 0.6% to 3.2% depending on the element, concentration, and sample volume used. The use of liquid CO2 as a carrier in FIA systems opens up new possibilities for online sample pretreatment and trace preconcentration.

Journal Article↗

An improved method for the quantitation of flavonoids in Herba Leonuri by capillary electrophoresis.

A capillary electrophoresis system coupled with wall-jet amperometric detection was used to determine five flavonoids (kaempferol, rutin, hyperoside, quercitrin, quercetin) in Herba Leonuri. Several important effect factors, such as the pH and concentration of running buffer, separation voltage, injection time, and detection potential, were investigated to acquire the optimum conditions. With 50 mmoL/L Na(2)B(4)O(7)-100 mmoL/L NaH(2)PO(4) buffer (pH=7.50) as the running buffer, the five flavonoids were baseline separated within 15 min in a 60 cm length capillary at a separation voltage of 15 kV. The relationship between peak currents and analyte concentrations was linear over about 2 orders of magnitude, with detection limits (S/N = 3) ranging from 0.03 to 0.08 microg/mL for all analytes. The use of this method for the quantitation of the above flavonoids present in the real sample of Herba Leonuri was reported.

Electrophoresis, Capillary↗

Clinical uses of high frequency jet ventilation in anaesthesia.

Since 1981, high frequency jet ventilation (HFJV) has been used in 300 patients undergoing surgery, most commonly during i.v. general anaesthesia for endoscopy and surgery of the airways: laryngoscopy, bronchoscopy, laryngeal microsurgery and laser surgery (more than 230 patients); repair of tracheal stenosis, tracheal sleeve pneumonectomy and tracheal sleeve lobectomy. HFJV was administered through a narrow injection catheter inserted in the airway, with a second rigid catheter positioned distally to the injector in the airway for gas sampling and measurement of airway pressure. In all subjects gas exchange was satisfactory, even during tracheoplasty and bronchoplasty.

Adolescent↗

Immunization without needles.

Most current immunization procedures make use of needles and syringes for vaccine administration. With the increase in the number of immunizations that children around the world routinely receive, health organizations are beginning to look for safer alternatives that reduce the risk of cross-contamination that arises from needle reuse. This article focuses on contemporary developments in needle-free methods of immunization, such as liquid-jet injectors, topical application to the skin, oral pills and nasal sprays.

Administration, Oral↗

[Non-variceal upper digestive hemorrhage: evaluation of endoscopic sclerosing treatment].

We appraise the efficacy of endoscopic injection treatment in 112 patients with gastroduodenal bleeding lesion versus 78 control patients (historical group), employing adrenaline (29 patients), absolute ethanol (52 patients) o adrenaline and ethanol (31 patients) as sclerosants. We observe in the treated group a diminution in rebleeding, lower transfusional blood needs and shorter hospital staying, with high stadistic significance versus the control group (p less than 0,001). Among treated patients the larger relapsing index (29.6%) was in patients treated with adrenaline injection only, against the group treated with ethanol or adrenaline and ethanol (10.2%) (p less than 0.05). The demand of surgical treatment was not significant between both groups, except in patients with actively jet bleeding, because urgent treatment was necessary in 37.5% of endoscopically treated patients versus 88.8% in not endoscopically treated. The mortality was similar in both groups.

Aged↗

[Color Doppler echocardiography].

Colour-coded doppler echocardiography uses a pulsed doppler shooting lines scanning system to perform a true real-time doppler angiography of intracradiac flows. Combined with ultrasonic imaging, it has proved irreplaceable for the diagnosis of leakages and for direct visualization of intracradiac shunts; by determining the anatomical location of the jet it facilitates an accurate pulsed and continuous Doppler study. Aortic leakages are best evaluated by measuring the jet at its point of origin. The quantification of moderate to medium leakages remains difficult since it depends on numerous factors and needs integration of other echocardiographic data. Echocardiographic contrast tests after intravenous injection of microbubbles diagnose the right-to-left shunts by the passage of contrast into the left cavities, and the left-to-right shunts by a washing image.

Echocardiography, Doppler↗

Liposome delivery of ciprofloxacin against intracellular Francisella tularensis infection.

The effect of liposome delivery on the controlled release and therapeutic efficacy of ciprofloxacin against intracellular Francisella tularensis infection in vivo was evaluated in this study. Ciprofloxacin was encapsulated in small unilamellar vesicles by a remote loading procedure using an ammonium sulfate gradient. This procedure produced uniform sized liposomes (100 nm) with an entrapment rate of 90+/-3.5%. Following administration of unencapsulated or liposome-encapsulated ciprofloxacin by intravenous injection or aerosol inhalation, levels of ciprofloxacin in sera, lungs, liver and spleen were determined using 14C-ciprofloxacin as radiotracer for ciprofloxacin. Intravenous injection of liposome-encapsulated ciprofloxacin resulted in higher serum levels of drug in serum, as well as increased drug retention in lungs, liver and spleen, compared to that of free encapsulated drug. Aerosol administration of liposome-encapsulated ciprofloxacin by jet nebulization resulted in significantly higher drug levels and prolonged drug retention in the lower respiratory tract compared to the free drug. Aerosol inhalation of liposome-encapsulated ciprofloxacin, given either prophylactically or therapeutically, provided complete protection to mice against a pulmonary lethal infection model of F. tularensis. In contrast, ciprofloxacin given in its free form, was ineffective. These results suggest that liposome encapsulation of ciprofloxacin enhances drug delivery to the primary site of infection and results in increasing therapeutic efficacy against F. tularensis.

Animals↗

[A comparison between high-frequency jet ventilation (HFJV) and conventional positive end-expiratory pressure ventilation (CPPV)--an experimental study on dogs with acute lung damage].

In a controlled study on 24 dogs with severe damage to the lungs HFJV was compared to CPPV on the basis of selected cardiorespiratory parameters. The pulmonary damage was produced by injection of oleic acid (OA) into the right atrium under conventional mechanical ventilation (IPPV). After the damage, the dogs were randomly allotted into one of two groups. Twelve dogs (group I) were ventilated for 5 hours with a PEEP of 10 cm H2O (1 kPA), 12 animals (group II) for 5 hours with HFJV. The oleic-acid-induced damage results in the known hypoxaemia with an increase in the intrapulmonary shunt. After changing to CPPV, the PaO2, which fell from 27.2 +/- 3 kPa to 10.8 +/- 2.9 kPa, rises to 20.3 +/- 7.7 kPa, but shows no further significant alteration until the end of the experiment. In contrast to the clearly improved oxygenation, essential cardiocirculatory parameters (CI, SVI, RVSWI, LVSWI, TCO2) are partially reduced by more than 50% of the initial values. PAP, PCWP, HR, TPR and PVR increase significantly, MAP remaining nearly unchanged. After changeover to HFJV, there is first a further fall of PaO2 from 11.1. +/- 3.0 kPa to 9.1 +/- 1.4 kPa following OA, then, however, until the end of the experiment, a continuous elevation to 15.6 +/- 2.4 kPa with a mean airway pressure that is by 75% lower. The haemodynamic parameters show no significant changes as compared to the initial values, overall, however, they lie significantly below or above those of group I. The results from our investigations allow to draw the conclusion that, despite haemodynamic advantages, HFJV in consequence of deterioration of the arterial oxygenation currently is no alternative superior to CPPV in ventilating the severely damaged lung.

Animals↗

Induction of lupus-related specific autoantibodies by non-specific inflammation caused by an intraperitoneal injection of n-hexadecane in BALB/c mice.

A single intraperitoneal (i.p.) injection of pristane, incomplete Freund's adjuvant (IFA), or the adjuvant oil squalene, but not high molecular weight medicinal mineral oils, induces lupus-related autoantibodies to nRNP/Sm and -Su in non-autoimmune strains of mice. This ability appears to be associated with the low molecular weight and adjuvanticity of hydrocarbon. n-Hexadecane (C(16)H(34)), which is present in petroleum, has adjuvant activity and induces arthritis in rodents like other lupus-inducing oils. In addition to dietary exposure to n-hexadecane in mineral oils, exposure also occurs via inhalation of oil mist, jet fuel, or diesel exhaust or by absorption through the skin. Since n-hexadecane is a low molecular weight adjuvant hydrocarbon oil similar to other lupus-inducing hydrocarbons, the present study examined whether it can also induce lupus-related autoantibodies in mice. Female BALB/cJ mice received a single i.p. injection of 0.5 ml of n-hexadecane, pristane, or saline (control). Pathology and serology (immunoglobulin levels, autoantibodies by immunofluorescence, immunoprecipitation, and ELISA) were examined 3 months later. Unexpectedly, all n-hexadecane-treated mice, but none in the other groups, developed inflammatory ascites within 2.5 months. n-Hexadecane induced hypergammaglobulinemia (IgG1, IgG2a), antinuclear (titer>1:160, 67%) and -cytoplasmic antibodies (58%) and autoantibodies to nRNP/Sm (25%), Su (33%), ssDNA (83%), and chromatin (100%). Therefore, non-specific inflammation caused by n-hexadecane resulted in the production of a limited set of specific autoantibodies. These previously unrecognized immunological effects of n-hexadecane may have implications in monitoring human exposure to hydrocarbons and in the pathogenesis of autoimmune diseases.

Alkanes↗

An electrochemical cell coupled with disposable screen-printed electrodes for use in flow injection analysis.

An electrochemical cell coupled with disposable screen-printed electrodes (SPEs) that is specifically designed for use in flow injection analysis (FIA) is described in this study. The cell is made of foldable polyoxymethylene (acetal) thick platelets with the bottom portion consisting of a cavity track to drag the SPEs in position and the top portion having predrilled T-like holes to arrange the Ag/AgCl reference electrode and stainless steel inlet & outlet. An "O ring" is suitably fixed on the top of the working electrode to form a thin-layer space where the electrochemical reaction can take place. Hydrodynamic characterization was validated by using a benchmark hexacyanoferrate redox couple. The results of practical analysis of glucose in human plasma clearly demonstrate the characteristics and applicability of the proposed wall-jet electrochemical cell in FIA.

Blood Glucose↗