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At least 1,603 records · Page 89Linked to original sources
PubMed2000

Sevoflurane output from the Oxford Miniature Vaporizer in drawover mode.

The sevoflurane output from the Oxford Miniature Vaporizer (OMV) was measured in a series of bench tests in a drawover system. Using a range of settings on two OMVs in series, output ranged from 0.5 to 5.9% with a 600 ml tidal volume at a rate of 12 breaths/min produced by a Penlon Multivent. The OMVs' output was steady over 40 minutes. In tests with tidal volumes ranging from 300 ml to 1200 ml, the OMVs' output was lower at higher minute volumes. When continuous flow of carrier gas at 7.2 l/min was used, the output was lower than at the equivalent intermittent flow rate. Using two OMVs with a drawover system appears to be a feasible technique for the induction and maintenance of sevoflurane anaesthesia. Clinical tests of sevoflurane drawover anaesthesia are now required so that the advantages of sevoflurane can gain wider application in field and military anaesthesia.

Anesthesiology↗
PubMed2001

Sevoflurane drawover anaesthesia with two Oxford Miniature Vaporizers in series.

The output of sevoflurane from a drawover system utilizing two Oxford Miniature Vaporizers (OMVs) in series has been shown in bench-testing to be predictable. We have shown that adequate anaesthesia can be achieved with one vaporizer in most situations if an intravenous induction is used. Occasionally a second vaporizer is necessary to deepen the level of anaesthesia. For an inhalational technique to be successful it is necessary to use both vaporizers from the outset. Under these conditions, adequate operating conditions are easily produced. The method could be useful in field or military applications.

Anesthesiology↗
PubMed2003

Malignant granulosa-theca cell tumor in a two-year-old Miniature Horse.

A 2-year-old female Miniature Horse that presented with a history of progressive weight loss, depression, and diarrhea was diagnosed at necropsy with a highly malignant abdominal neoplasm involving the left ovary, kidneys, adrenal glands, intestines, and various abdominal and thoracic lymph nodes. Microscopic examination of these masses revealed large pleomorphic cells that stained positive for vimentin and inhibin and negative for epithelial membrane antigen and placental alkaline phosphatase. Ultrastructural examination of the cells revealed a high nucleocytoplasmic ratio and indented euchromatic nuclei with large nucleoli. Based on the gross, microscopic, immunohistochemical, and ultrastructural features, the neoplasm was identified as a malignant granulosa-theca cell tumor, a rare neoplasm in young horses.

Animals↗
PubMed2002

Binding of a Pleckstrin homology domain protein to phosphoinositide in membranes: a miniaturized FRET-based assay for drug screening.

Pleckstrin homology (PH) domains are present in key proteins involved in many vital cell processes. For example, the PH domain of Bruton's tyrosine kinase (Btk) binds to phosphatidylinositol triphosphate (PIP(3)) in the plasma membrane after stimulation of the B-cell receptor in B cells. Mutations in the Btk PH domain result in changes in its affinity for PIP(3), with higher binding leading to cell transformation in vitro and lower binding leading to antibody deficiencies in both humans and mice. We describe here a fluorescence resonance energy transfer (FRET)-based biochemical assay that directly monitors the interaction of a PH domain with PIP(3) at a membrane surface. We overexpressed a fusion protein consisting of an enhanced green fluorescent protein (GFP) and the N-terminal 170 amino acids of a Tec family kinase that contains its PH domain (PH170). Homogeneous unilamellar vesicles were made that contained PIP(3) and octadecylrhodamine (OR), a lipophilic FRET acceptor for GFP. After optimization of both protein and vesicle components, we found that binding of the GFP-PH170 protein to PIP3 in vesicles that contain OR results in about a 90% reduction of GFP fluorescence. Using this assay to screen 1440 compounds, we identified three that efficiently inhibited binding of GFP-PH170 to PIP(3) in vesicles. This biochemical assay readily miniaturized to 1.8-microl reaction volumes and was validated in a 3456-well screening format.

Agammaglobulinaemia Tyrosine Kinase↗
PubMed2004

Miniaturization of whole live cell-based GPCR assays using microdispensing and detection systems.

Cell-based beta-lactamase reporter gene assays designed to measure the functional responses of G-protein-coupled receptors (GPCRs) were miniaturized to less than 2 microL total assay volume in a 3456-well microplate. Studies were done to evaluate both receptor agonists and antagonists. The pharmacology of agonists and antagonists for target GPCRs originally developed in a 96-well format was recapitulated in a 3456-well microplate format without compromising data quality or EC(50)/IC(50) precision. These assays were employed in high-throughput screening campaigns, allowing the testing of more than 150,000 compounds in 8 h. The instrumentation used and practical aspects of the assay development are discussed.

Animals↗
PubMed1982

Using miniature osmotic infusion pumps to maintain tritiated thymidine exposure to cells in culture.

To provide a constant level of tracer doses of tritiated thymidine to cultured cells during continuous infusion, miniature osmotic infusion pumps were used to provide replacement thymidine. By determining the loss of isotope from the media during nonreplacement, the rate of constant infusion replacement to maintain thymidine levels was calculated. The replacement rates were similar for the three cell lines examined and allowed a standard osmotic pump infusion.

Cell Line↗
PubMed2004

Perfusion-assisted beating heart support with a miniature extracorporeal circuit and leukocyte filtration: a 58-year-old patient with severe COPD.

Patients with severe chronic obstructive pulmonary disease (COPD) impose a significant risk for postoperative morbidity and mortality requiring cardiovascular surgical intervention and the use of extracorporeal circulation. Recently, we treated a 58-year-old male with acute coronary syndrome complicated with recurrent ventricular arrhythmia, hypoxemia secondary to severe COPD and resolving pneumonia, who required urgent coronary revascularization. A novel operative strategy was used that included beating heart bypass grafting with cardiac decompression and support with a miniature perfusion circuit, kinetic-assisted venous return, rapid autologous priming and leukocyte filtration. The combination of multiple modalities was chosen because the patient was in a pre-existing inflammatory condition and had severe COPD. We herein report our perioperative clinical experience with this patient and the use of multiple modalities for extracorporeal perfusion therapy in managing this challenging case. We believe that, based upon his clinical course of ventilation time (17.4 hours) and postoperative length of hospital stay (5 days), this high risk patient demonstrated a positive clinical outcome as a result of these techniques.

Cardiopulmonary Bypass↗
PubMed2003

Miniature, low-dose, intrauterine drug-delivery systems.

The safety of systemically administered sex steroids continues to be a major focus of researchers. The negative results of the Women's Health Initiative study (WHI), and follow-up reports published in JAMA, evaluating the safety of estro-progestogen in postmenopausal women, elicited an unprecedented reaction in the press by women and doctors alike. From these publications, it is clear that research should focus on new progestogens and on alternative administration routes to minimize adverse drug effects. One approach to the improvement of safety, efficacy, and acceptability of steroid hormones, including patient compliance, is to develop long-acting implantable methods that deliver the lowest possible dose to the key target tissues. This therapeutic concept of "minimal intervention" has been known for several decades, but the practical applications of the method were lacking. Intrauterine drug-delivery systems can be developed to achieve minimal intervention fertility control without influencing normal ovarian function and/or causing adverse hormonal effects. With hormone replacement therapy in postmenopausal women, research suggests that progestogens delivered directly to the uterine mucosa could reduce side effects and minimize reversal of the beneficial effect of estrogens. Various "frameless" and "framed" intrauterine systems are currently being clinically evaluated. They are less troublesome than the available intrauterine systems and could therefore be suitable for use in the majority of women for contraception and treatment purposes (e.g., menorrhagia, hormone replacement). These systems require a single short office procedure, and have a low morbidity, which is undeniably linked with more invasive methods and systemic hormonal contraceptives. Due to the technological progress miniature, low-dose, long-term intrauterine drug-delivery systems offer enhanced effectiveness, reduced side effects, and optimal user compliance. Although there is minimal absorption in the systemic circulation, they deserve the status of a locally acting method that should be regarded as fundamentally advantageous, if effective, to systemically applied medications that may have potentially inherent ill side effects.

Adult↗
PubMed1982

Utilization of intravenously administered glucose-oligosaccharides in growing miniature pigs.

The ability of intravenously administered glucose or glucose oligosaccharides to supply 12% of the energy requirement of the growing miniature pig was determined. All pigs were fed a stock diet from days 5-28 of life, and a central venous catheter was inserted at 29 days. For the next 30 days, all pigs were fed both enterally and parenterally. Positive control pigs were fed the stock diet with infusions of an isotonic balanced electrolyte solution. Negative control and test animals were fed a diet containing cellulose to replace 12% of energy. Negative control animals received the balanced electrolyte solution intravenously, while test animals received either intravenous glucose of glucose oligosaccharides at levels providing 12% of energy. Carbohydrate utilization was measured by urinary loss of carbohydrate, as well as by growth and body composition. Chemical analyses of the urine indicated utilization of both glucose and glucose oligosaccharides. Glucose oligosaccharides were utilized less well (85%) than glucose (greater than or equal to 99%). No statistically significant differences in weight gain were noted between groups, although weight gain in negative control animals and those animals infused with glucose oligosaccharide solutions were lower than those in the other groups. Body fat analyses also indicated that glucose oligosaccharide solutions were less effective than glucose as an energy source.

Animals↗
PubMed1989

Microanalysis of hormone responsive ovarian interstitial gland cells in miniature culture.

Small cell aggregates of functional interstitial tissue were isolated from ovaries of 21- to 24-day-old rats, and their biochemical properties were studied in miniature cultures of 500-4000 cells. The isolated interstitial cells expressed high amounts of the mitochondrial cholesterol side-chain cleavage cytochrome P-450, visualized by immunofluorescent staining. Freshly isolated cells also expressed high activities of 17 alpha-hydroxylase and 17:20-lyase, which were assayed by TLC analysis of [3H]progesterone metabolites. The TLC technique revealed the immediate conversion of progesterone to 5 alpha-reduced progestins. Consequently, no aromatizable androgens were produced but, accumulation of androsterone resulted instead from the direct action of 17 alpha-hydroxylase on 3 alpha-hydroxy-5 alpha-pregnane-20-one (pregnanolone). Both the immunoreactive levels of cholesterol side-chain cleavage cytochrome P-450 and the rate of the 17:20-lyase activity declined rapidly during culture. However, addition of LH to the medium restored both enzymes, indicating the presence of functional LH receptors. The latter were also demonstrable by their ability to evoke cAMP formation in response to LH, but not to FSH. The activity of 5 alpha-reductase in the interstitial cells was much higher (3-fold) than its activity in the granulosa cells. Unlike 17:20 lyase, the activity of 5 alpha-reductase did not decay in culture, nor was it affected by LH. We thus established a novel and sensitive experimental method to isolate and study a minute population of ovarian cells which, unlike the follicular granulosa and theca cells, are enigmatically differentiated at the early stages of ovarian development.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1989

The temperature dependence of the time course of growth and decay of miniature end-plate currents in carp extraocular muscle following thermal acclimation.

1. The effect of temperature (5-35 degrees C) on the decay and growth phases of miniature end-plate currents (MEPCs) was investigated in extraocular muscle from freshwater carp acclimated to either high (28 degrees C) or low (8 degrees C) temperature. 2. The temperature dependence of the time constant of decay (TD) was found to follow an Arrhenius relationship; the relationship between logTD and reciprocal of absolute temperature (1/K) being linear in both groups. The TD of MEPCs recorded from cold-acclimated carp was not statistically significant from that of the warm group. 3. TD was moderately temperature-dependent. Regression gave a Q10 of 1.78 for the warm-acclimated carp, corresponding to an activation energy, Ea, of 41.15 +/- 2.17 kJ mol-1. For the cold-acclimated carp, the Q10 was 1.79, and Ea was 41.43 +/- 2.46 kJ mol-1. 4. Growth time (TG) was less susceptible than TD to temperature change. The relationship between growth time (taken as the time for MEPCs to rise from 20 to 80% of maximum) and temperature was linear for the cold-acclimated group, with a Q10 of 1.34 and Ea of 20.94 +/- 4.75 kJ mol-1. The data for the warm group, were, in contrast, best fitted by two linear regressions meeting at 15.1 degrees C. At temperatures below 15.1 degrees C Q10 was 3.16 and Ea was 82.20 +/- 15.47 kJ mol-1; above 15 degrees C, Q10 was 1.22 and Ea was 14.15 +/- 12.24 kJ mol-1. 5. The acetylcholinesterase inhibitor neostigmine increased TD by approximately twofold and raised TG to approximately 1.4 times control values. These effects were observed across the temperature range scanned for both groups. 6. The results are discussed with reference to the documented effects of temperature and temperature acclimation on membrane lipids and proteins.

Acclimatization↗
PubMed1994

THERMAL ACCLIMATION, NEUROMUSCULAR SYNAPTIC DELAY AND MINIATURE END-PLATE CURRENT DECAY IN THE FROG RANA TEMPORARIA

1. The effects of 1 or 2­3 weeks of acclimation to 4 °C and 24 °C of overwintering grass frogs (Rana temporaria) on the synaptic delay and on the time constant of the decay phase (tau) of miniature end-plate currents (MEPCs) in the neuromuscular junction of sartorius muscle were studied. In order to equalize the possible effects of differential starvation, the animals were usually cross-acclimated to the two temperatures. 2. Synaptic delay was not affected by temperature acclimation but was slightly prolonged by the more profound starvation at the higher temperature when the cross-acclimation procedure was not used. The average Q10 of synaptic delay between 4 and 24 °C was 2.60 and of minimum synaptic delays, 2.64. The corresponding values for apparent activation energy (Ea) were 65.79 and 66.48 kJ mol-1. 3. The time constant of the decay phase of MEPCs was not affected by temperature acclimation. The average Q10 between 4 and 24 °C was 2.27. The corresponding Ea value was 56.02 kJ mol-1. 4. The function of peripheral neuromuscular synapses is well regulated and changes in its time relationships do not appear to be involved in the thermal acclimation of frogs.

Journal Article↗
PubMed1997

A prototype model for renal vasculature and its application in haemodialyser miniaturization.

At present, little information and few models are available to describe either renal haemodynamics or the structure of the kidney. By modelling renal haemodynamics, more information about flow behaviour and efficiency can be obtained, thus leading to the modelling of the human kidney and enabling comparisons with dialysis haemodynamics to be made. This paper examines a prototype model of renal vasculature and remarks upon comparisons drawn from data from human kidneys, as an introduction to those interested in replicating the functions of the kidney by using a miniature haemodialyser.

Equipment Design↗
PubMed1982

Oxygen consumption in treadmill-exercised Yucatan miniature swine.

Oxygen consumption was measured in Yucatan miniature swine during various intensities of treadmill exercise. Nine animals were evaluated at rest and at various treadmill velocities ranging from 2.5-4.5 mph. Oxygen consumption was linearly related to treadmill speed during sub-maximal exercise work loads (r = 0.92, P less than 0.01). Maximal oxygen consumption was also determined in two groups of animals. In one group (N = 6) the highest attainable oxygen consumption was 24.0 +/- 1.31 ml . min-1 . kg-1. In the second group (N = 9) an electric prod was utilized to encourage the animals to run. Their maximal oxygen consumptions ranged from 33.9-51.1 ml . min-1 . kg-1 with a mean of 41.7 +/- 1.8 ml . min-1 . kg-1. These data indicated that Yucatan swine have a relatively low aerobic capacity compared to the rat or dog, but their oxygen consumptions are similar to that observed in untrained man.

Animals↗
PubMed2004

Design, setup and first results of a miniaturized time-of-flight mass spectrometer with a simple reflector of a new design.

A new kind of reflector with only one element has been constructed and used in a miniaturized time-of- flight mass spectrometer. Details from the simulation of the instrument with SIMION and its design are presented and discussed. The instrumental setup is displayed and some first results from measurements are presented. Laser- generated electron ionization (LEI) and resonance-enhanced multi-photon ionization (REMPI) are used for ion production. While both methods yield good mass spectra, the mass resolving power of the instrument is different for both methods. The results of the measurements are compared and discussed with respect to the design. It is found that the resolution of the new instrument is satisfactory for mass spectrometric measurements of small molecules and not limited by the reflector.

Journal Article↗
PubMed2003

A miniature self-inflating bag-mask ventilator for rats.

Respiratory depression and apnoea during anaesthesia may lead to hypoxia and myocardial ischaemia. A self-inflating miniature bag-mask device was assembled combining characteristics from the Ambu-bag and the Kuhn-system. This bag-mask device permitted ventilation during anaesthesia-induced apnoea in rats until a safe airway by tracheotomy was achieved.

Anesthesia, General↗
PubMed1996

Radiation properties of a miniature X-ray device for radiosurgery.

An alternative technology for performing interstitial intracranial radiosurgery is presented. Treatments are performed intraoperatively using a stereotactically mounted, miniature X-ray device. A concentrated, spherical pattern of X-rays is generated about the tip of a needle-like probe, which is inserted into the site of the lesion allowing the absorbed dose to healthy tissue to be minimized. A description of the device is given and results of investigations into the operating characteristics discussed.

Equipment Design↗
PubMed2003

Genomic structure of the NtPDR1 gene, harboring the two miniature inverted-repeat transposable elements, NtToya1 and NtStowaway101.

Here we report the genomic structure including the promoter sequence and coding region of NtPDR1 (Nicotiana tabacum Pleiotropic Drug Resistance 1), which is an elicitor-responsive gene encoding an ATP binding cassette (ABC) transporter that might be involved in the defense response in tobacco, as we reported recently. The NtPDR1 gene consists of 20 exons and 19 introns. Among the introns, the first and fifth are much larger than the others and harbor typical miniature inverted-repeat transposable elements (MITEs). One of the MITE elements in the first intron, termed NtToya1, belongs to the Toya family that was recently described in rice, while the other element in the fifth intron, termed NtStowaway101, shows high homology with the Stowaway elements of the IS630-Tc1-mariner family. Many of the genes we found to harbor Toya and Stowaway elements in Nicotiana species by BLAST search are also involved in stress responses or plant-pathogen interactions. The existence of putative cis-elements (a GCC box, three W boxes, and several JA-responsive elements) in the promoter region supports our previous finding that this gene is strongly inducible by elicitation and methyljasmonate, and that this ABC transporter might be essential for plant defense responses. Furthermore, Southern blot analysis and PCR amplification of the introns harboring the MITE-like elements from genomic DNA of three Nicotiana species suggests that NtPDR1 originated from N. sylvestris.

Base Sequence↗