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At least 325 records · Page 18Linked to original sources
PubMed1989

Influence of clenbuterol on mucociliary transport in healthy horses and horses with chronic obstructive pulmonary disease.

The mucociliary tracheal transport rate and clearance index were measured in 16 healthy horses and 16 horses suffering from chronic obstructive pulmonary disease. A marker, Indian ink in syrup, was placed in the mucus layer of the interior wall of the trachea, just in front of the carina, and its displacement was measured after 30 and 60 minutes. The same procedure was repeated 30 minutes after the intravenous administration of 0.8 microgram clenbuterol/kg bodyweight. In the diseased horses the mucociliary transport rate was significantly lower than in the healthy horses. After clenbuterol administration there was a significant increase in the transport rate and a similar increase in the clearance index. Sixty and 90 minutes after clenbuterol there was a significant increase of mucus secretion in both the healthy and diseased horses. Measurements in five healthy horses and five diseased horses on two different days gave similar results, showing that the technique provided reproducible data.

Animals↗
PubMed2003

Brain changes with aging: MR spectroscopy at supraventricular plane shows differences between women and men.

PURPOSE: To assess the effect of aging on the proportions of choline (Cho), creatine, and N-acetylaspartate (NAA) in the brains of elderly women and men. MATERIALS AND METHODS: A transverse plane above the ventricle of the brain was mapped with magnetic resonance spectroscopy. Examinations were performed in 1995-1996 with 271 healthy subjects (age range, 60-90 years; mean age, 73 years) and were repeated 4 years later (1999-2000). Student t tests were used for statistical analysis. RESULTS: Difference analysis of the changes in 4 years (paired data) reproduced the decrease in Cho in women only (2.9% per year, P <.001) that had been indicated with intersubject correlation analyses. Decreases in NAA, though significant in both men and women according to age correlation analyses (P <.01 for both), did not reach significance. The resulting sex difference in the Cho/NAA ratio at a mean age of 77 years, while not yet significant at a mean age of 73 years, was especially manifest in the posterior half of the plane analyzed. CONCLUSION: Increasing sex differences in Cho/NAA ratios in a supraventricular plane indicate that brain metabolite levels differ between women and men at advanced age.

Aged↗
PubMed2003

A model of graded calcium release and L-type Ca2+ channel inactivation in cardiac muscle.

We have developed a model of Ca(2+) handling in ferret ventricular myocytes. This model includes a novel L-type Ca(2+) channel, detailed intracellular Ca(2+) movements, and graded Ca(2+)-induced Ca(2+) release (CICR). The model successfully reproduces data from voltage-clamp experiments, including voltage- and time-dependent changes in intracellular Ca(2+) concentration ([Ca(2+)](i)), L-type Ca(2+) channel current (I(CaL)) inactivation and recovery kinetics, and Ca(2+) sparks. The development of graded CICR is critically dependent on spatial heterogeneity and the physical arrangement of calcium channels in opposition to ryanodine-sensitive release channels. The model contains spatially distinct subsystems representing the subsarcolemmal regions where the junctional sarcoplasmic reticulum (SR) abuts the T-tubular membrane and where the L-type Ca(2+) channels and SR ryanodine receptors (RyRs) are localized. There are eight different types of subsystems in our model, with between one and eight L-type Ca(2+) channels distributed binomially. This model exhibits graded CICR and provides a quantitative description of Ca(2+) dynamics not requiring Monte-Carlo simulations. Activation of RyRs and release of Ca(2+) from the SR depend critically on Ca(2+) entry through L-type Ca(2+) channels. In turn, Ca(2+) channel inactivation is critically dependent on the release of stored intracellular Ca(2+). Inactivation of I(CaL) depends on both transmembrane voltage and local [Ca(2+)](i) near the channel, which results in distinctive inactivation properties. The molecular mechanisms underlying many I(CaL) gating properties are unclear, but [Ca(2+)](i) dynamics clearly play a fundamental role.

Animals↗
PubMed2000

High hurdle of clinical trials to demonstrate efficacy of anticataractogenic drugs.

Recently, the rapid progression of cataract surgical technique has led cataract patients in industrialized countries to ignore the possibilities of drug therapy. Globally, however, it will be impossible in the near future to treat cataract by surgery alone, mainly due to medicoeconomic reasons. Preventative measures must be sought. As one of the these measures, the development of anticataractogenic drugs has reemerged as a focus in the lens research field. Although clinical trials of newly developed drugs are absolutely necessary before they enter the market, they have been considered to be a rather easy task. However, in order to gain accurate and reproducible data from trials, the trial program must be carefully prepared. The numbers of participants to the trial, the selection criteria of the subjects, the objective judgment of cataractous changes, follow-up period, a high technical level for cataract documentation and image analysis are proposed. Although there still remain some difficulties concerning the methods for objective judgment, a scientifically acceptable examination must be conducted.

Animals↗
PubMed2001

Influence of body posture and gravitational forces on shear wave propagation in the skin.

The body posture and gravitational forces govern in part the intrinsic skin tensile strength because they influence the orientation of the dermal fibre networks. Our objective was to assess changes in shear wave propagation in the skin according to the body posture and orientation of the gravitational forces. The study was performed in 30 middle-aged women with a normal body mass index. The Reviscometer was used to assess the mechanical wave propagation on the volar forearm in extension or flexion. Similar measurements were made on the supra-areolar region of the breast when the trunk was in the horizontal or vertical position. Four measurements were made in each of 4 directions at given angles with regard to the body axis. The device gave reproducible data. Shear wave propagation was influenced by the body posture. The intra-individual variability in shear wave velocity according to the directions of measurements increased when the tissues were in a relaxed position. Skin tensile anisotropy increased in a relaxed body posture. Shear wave propagation may be a convenient non-invasive tool to better identify the natural skin tension lines in the skin, thus refining the orientation of incision during cutaneous surgery.

Adult↗
PubMedDate not supplied

EEMCO guidance for the measurement of skin microcirculation.

The blood supply to the skin is provided by a network of arterioles, capillaries and venules organized into a superficial and a deep plexus. The assessment of skin microcirculation is of valuable interest in cosmetology in the quantification of the sun protection factor, skin irritation and efficacy of antiredness treatments. Skin microcirculation can be measured by means of different techniques, based mainly on the quantification of optical and thermal properties of the skin which are modified by the amount of blood perfusion. Relevant and reproducible data can be obtained only through the understanding of the biophysical background of the technique(s) utilized. Standardization of measuring conditions and procedures is particularly required for blood flow assessment. In this paper, the advantages and disadvantages of the main techniques in use are discussed, and optimization of measurements for laser Doppler techniques is described.

Animals↗
PubMed1988

Effectiveness of enteric-coated preparations on nutritional parameters in cystic fibrosis. A long-term study.

To evaluate the effectiveness of enteric-coated pancreatic enzyme supplements in comparison to conventional preparations of ingested enzyme on growth and nutritional parameters of patients with cystic fibrosis, we conducted a long-term study involving 40 patients. The data reproduced here were recorded after 6 months of therapy with powder-containing capsules or with enteric-coated products. Fat absorption was estimated by measurement of steatorrhoea with the steatocrit method. All parameters studied improved after enteric-coated pancreatic enzyme therapy, with a statistically significant increase in weight, cholesterol and haemoglobin values. Furthermore, the number of patients with positive steatocrit test was lower after therapy with enteric-coated enzyme supplementation. These findings suggest that the enteric-coated product not only reduces steatorrhoea, but above all improves the nutritional parameters and growth of patients affected by cystic fibrosis.

Adolescent↗
PubMed1991

Flowcytometric measurement of the cell cycle of experimental tumors: some devices for accurate measurement of proliferative activity.

In this paper we present the cell cycle analysis using the latest flowcytometer, FACScan and dedicated softwares. Although the 5-bromodeoxyuridine (BrdU) and anti-BrdU method developed by Gratzner has become popular for analysis of cell kinetics, contaminating interstitial cells and cell doublets are still factors responsible for some mistakes in measuring the cell cycle accurately. These hampering cells were almost gated out on the catogram consisting of the forward scatter and DNA content (propidium iodide, PI). After that, the bivariate distribution of BrdU and PI according to the tumor growth showed reliable patterns. In LLC tumor the population, of which DNA content was compatible with S phase cells, was detected in the cytogram. Thus, the two-dimensional analysis of the cell cycle can demonstrate each population clearly. The results obtained from the BrdU method are more beneficial than autoradiography or microspectrophotometry, and reproducible data of the cell cycle parameters can be acquired with some devices described here.

Adenocarcinoma↗
PubMed1998

Cardiac physiology in transgenic mice.

By use of gene targeting and/or transgenesis, it is now possible to make defined changes in genes whose functions underlie mammalian cardiovascular function. Because of technical and economic considerations, these experiments are largely confined to the mouse. Genetic modification of the loci responsible for aspects of cardiac development, differentiation, and function via gene targeting, as well as modulation of the cardiac protein complement using transgenesis, has begun to provide mouse models of cardiac hypertrophy, dilated cardiomyopathy, and hypertrophic cardiomyopathies. In order to use these animal models fully and explore their phenotypes at the whole organ and whole animal levels, the extension of cardiovascular physiological methodologies to the mouse is imperative. Techniques for exploring aspects of cardiovascular function are well developed for larger animal models, but their modification for the small size of the mouse heart and for the animal's rapid cardiac cycle has proven to be a formidable challenge, requiring the combined efforts of the molecular biology, physiology, and cardiology communities. We review here the ability of present-day technology to obtain reproducible data on murine cardiac function at the whole organ and animal levels.

Animals↗
PubMed2002

Internet-based home monitoring of pulmonary function after lung transplantation.

Home monitoring of spirometry has been advocated in lung transplant recipients for the early detection of acute infection and rejection of the allograft. We have developed a user-friendly, Internet-based telemonitoring system providing direct transmission of home spirometry to the hospital. In this prospective study, we assessed patient adherence with the monitoring, agreement between home and hospital spirometry, intrasubject coefficient of variation (CV) for FEV(1) and FEF(25-75), and sensitivity of these variables for the detection of acute complications. Twenty-two bilateral-lung and heart-lung transplant recipients were followed for a median of 473 d (range, 60-822), during which 13,833 measurements were obtained. Patient compliance was 55% for two measurements a day and 84% for one measurement a day. Agreement between home and hospital spirometry was within 4% for FEV(1) and 6% for FEF(25-75). Mean CV was 3.2% for FEV(1) and 7.5% for FEF(25-75). Using transbronchial lung biopsy and/or bronchoalveolar lavage as gold standards, the sensitivity of home spirometry was 63%, and 23% of true positives were detected by changes in FEF(25-75) alone. We conclude that home monitoring of pulmonary function in lung transplant recipients via the Internet is feasible and provides very reproducible data; yet it has only a mild sensitivity for the detection of acute allograft dysfunction.

Adult↗
PubMed1978

The noninvasive diagnosis of thrombophlebitis in the lower extremities: clinical value of plethysmography combined with augmentation methods and a new scoring system.

Venous impedance plethysmography and respiratory-compression Doppler augmentation responses have proved to be diagnostically valuable in suspected thrombophlebitis of the lower extremities. These noninvasive methods can provide quantitative and reproducible data on the basis of which the presence of increased deep venous resistance can be confirmed, suspected, or doubted. A new scoring system for the composite evaluation of data from 100 consecutive patients with possible thrombophlebitis, pulmonary embolism, or both, is presented. These procedures assume added importance in view of the diagnostic limitations, and even potential hazards, of other methods. These methods indluce lung scanning, radioactive fibrinogen scanning, venography, and pulmonary angiography. Serial studies can be performed with impunity for following highrisk patients and evaluating various therapeutic or prophylactic measures. The importance of monitoring the femoral-popliteal segment is emphasized, because of the greater propensity for massive pulmonary thromboembolism from thrombi in these veins than in the calf vessels. Clinical observations coupled with these studies underscore the fallacy of several widely-held diagnostic biases pertaining to deep venous thrombosis and pulmonary thromboembolism. The long-term followup of 12 patients in whom inferior vena cava unbrellas has been inserted for life-threatening pulmonary embolism is presented. The possible propensity to deep vein thrombosis from vitamin E therapy is raised.

Adult↗
PubMed1995

Transcutaneous bilirubinometry as a screening tool for neonatal jaundice.

Between 25 and 50% of all term newborns develop clinical jaundice, and a serum bilirubin level above 260 microml/l (15 mg/dl) is found in 3% of normal term infants. In the United Kingdom many newborn infants with clinical jaundice have blood samples sent to biochemistry laboratories for assessment of the plasma bilirubin concentration. We planned to assess the cost in terms of finance, medical staff time, numbers of blood samples, and family delay in leaving hospital. We demonstrated that reflectance bilirubinometry is a reliable screening method for identifying which caucasian infants require to have plasma bilirubin concentrations measured in the laboratory. The Minolta Airshields transcutaneous bilirubinometer provided reproducible data, saved time and costs, and often spared infants a capillary or venous blood sample. The transcutaneous bilirubinometer provides a digital assessment of skin pigmentation by xenon reflectance. It has previously been shown to be possible to derive an estimate of plasma bilirubin from the number displayed by the meter and it is suggested as a method for identifying which infants need plasma bilirubin estimations.

Bilirubin↗
PubMedDate not supplied

The influence of functional knee bracing on the anterior cruciate ligament strain biomechanics in weightbearing and nonweightbearing knees.

Functional knee braces are commonly prescribed after anterior cruciate ligament injury or reconstruction; however, their ability to protect the ligament, or graft, remains unclear. Our objective was to evaluate the anterior cruciate ligament strain response in braced and unbraced knees during weightbearing and nonweightbearing in combination with three externally applied loads: 1) anterior-posterior shear forces, 2) internal-external torques, and 3) varus-valgus moments. The Legend brace was tested. All external loads were applied to the tibia with the knee flexed to 20 degrees. Reproducible data were obtained from 11 subjects. For anterior shear loads up to 130 N, the brace significantly reduced strain values compared with the unbraced knee during nonweightbearing and weightbearing conditions. For internal torques of the tibia (up to 9 N x m), strain in the braced knee was significantly less than in the unbraced knee when the knee was nonweightbearing only. The brace did not reduce strain values when the knee was subjected to external torques (9 N x m) or varus-valgus moments (10 N x m) in weightbearing and nonweightbearing knees. These data indicate that a functional knee brace can protect the anterior cruciate ligament during anterior-posterior shear loading in the nonweightbearing and weightbearing knee and during internal torques in the nonweightbearing knee.

Adult↗
PubMed2000

Reliability and running speed effects of in-shoe loading measurements during slow treadmill running.

In-shoe measurement systems allow the clinician and researcher to examine the loading parameters within the shoe. This study sought to investigate the test retest reliability and speed effects of in-shoe loading parameters using the Pedar System (Novel GMBH Munich) during slow treadmill running. The results indicated good to excellent test retest reliability between the two days test-Intraclass correlation coefficients (ICC's) ranged from 0.84-0.99 depending on the plantar region and variable analyzed. All plantar loading variables increased (peak pressure, peak pressure time impulse, peak force, and force time impulse) with the exception of contact area when treadmill running speed was increased from 2.24 m/s to 3.13 m/s. Results indicate that control of running speed is essential in obtaining reproducible data using this system to measure in-shoe loading data.

Adult↗
PubMed2026

Single-cell RNA sequencing reveals disease associated changes in brain endothelial cells in the 5XFAD mouse.

Vascular dysfunction is a key contributor to Alzheimer&#x2019;s disease (AD) pathology, where changes to the endothelium and its crucial role in maintaining blood-brain barrier (BBB) integrity have been of particular emphasis. The transgenic 5XFAD (5X Familial Alzheimer&#x2019;s Disease) mouse model, which exhibits AD-related amyloidosis through FAD associated mutations in amyloid precursor protein (APP) and presenilin-1 (PS1), has become a widely adopted preclinical model in AD-related research studies. The need for cross-study standardization, accessibility, and data reproducibility has led to the widespread implementation of the C57BL/6J genetic background for maintaining this model. However, its reliability for studying vascular dysfunction and BBB alterations has been questioned due to conflicting reports in the literature. This variation is often attributed to the previously documented protective nature of the C57BL/6J background and loss of genetic background diversity. Since prior studies have mostly relied on imaging or functional assays, we herein utilized single-cell RNA sequencing (scRNAseq) to investigate AD-related molecular changes to endothelial cell populations in the 5XFAD mouse model. To initially build this resource, we focused on 12-month-old male mice, which revealed differentially expressed genes between 5XFAD and wildtype animals that mapped to signaling pathways involved in DNA damage, immune reactivity, and inflammation, among others. Many of these transcriptomic changes were zonated along the arteriovenous axis and occurred in AD genome-wide association study (GWAS) risk-associated genes. Overall, we anticipate this resource will help clarify the use of the 5XFAD model for studying AD-associated vascular changes and provide the foundation for expanded molecular profiling of brain endothelial cells under AD-associated conditions.

Animals↗
PubMed1991

Nondeformable red blood cells do not interfere with uteroplacental blood flow in the awake, late-pregnant guinea pig.

The fractional entrapment of rigidified [relative to control (labeled)] red cells after the intravascular bolus injection of a cocktail of these cells, and the concomitantly induced changes in cardiac output and its distribution (microspheres) were studied in 14 awake, late-pregnant guinea pigs. In a preceding validation study in eight nonpregnant guinea pigs, it was demonstrated that with this technique reproducible data could be generated on the fractional entrapment of rigidified red cells in all organs in this species except for lungs, liver, and spleen. In response to a bolus injection with rigidified and control red cells, only the brain showed preferential entrapment of rigidified red cells, together with a small but consistent increase in blood flow. In other organs (lungs, liver, and spleen excluded), neither preferential entrapment of rigidified red blood cells nor a consistent change in blood flow could be demonstrated. The results of our study suggest that circulating nondeformable red cells have no measurable adverse effect on the perfusion of the nondiseased hemochorial placenta in the awake, late-pregnant guinea pig. This does not exclude the possibility that rigidified red cells may increase the resistance to flow in a microcirculation that has been pathologically changed by some underlying disease.

Animals↗
PubMed2004

The development of a method to measure head acceleration and motion in high-impact crashes.

OBJECTIVE: To establish a mechanism to obtain precise measurements of the accelerations of the head in the high-speed racing environment and during crash impacts. The long-term goal is to apply this system to the assessment of head injury in automobile racing drivers and then in participants in other helmeted sports. METHODS: A multidisciplinary team conceptualized, designed, and successfully tested a triaxial accelerometer system capable of measuring head acceleration and motion in high-impact crashes. The system has been implemented successfully in the professional racing environment. RESULTS: Accurate and reproducible data have been obtained from the accelerometer system in tests on manikins and cadavers and in actual racing events. The system has been implemented in two professional racing series in 2003. Information gained from the accelerometer system is currently being entered into a database. Eventually, the data should aid in the development of improved cockpit head protection in racing cars. Improved helmet design not only in motor sports but also in other helmeted sports should benefit from the data collected. These data will also aid the development of improved head injury protection in military aircraft and passenger vehicles. CONCLUSION: Although there has been a significant decrease in the overall rate of injury during the past 25 years, head injury remains a serious safety concern in motor sports and the greatest cause of death. Sports-related head injuries are also of great concern because repeated mild head injury has become an important health issue with potential long-term disability. True human tolerance to brain injury has yet to be established. Our scientific knowledge of brain injury is currently based on results derived from manikin, cadaver, and human volunteer testing, along with animal and computer models. The racing environment represents a venue to ethically measure and evaluate the forces involved in human brain injury.

Acceleration↗
PubMed1981

Phagocytosis by macrophages. II. The dissociation of the attachment and ingestion steps.

The phagocytic process of mouse peritoneal macrophages was dissociated, using bovine serum albumin (BSA)-coated particles containing spin-labelled cholestanone, into 2 steps: attachment of particles to the cell surface and ingestion of the particles into the cytoplasm. The number of particles was estimated from electron spin resonance (e.s.r.) measurements. The particles ingested into the cytoplasm were distinguished from those attached to the cell surface by treatment with a membrane-impermeable reducing agent, ascorbate. The validity of the assay method was tested under various conditions. The measurements provided accurate and reproducible data. The phagocytic reaction was followed as a function of time and the rate constants for the attachment and ingestion steps were obtained from the initial phase. Both steps were highly dependent on temperature. Divalent cations in the incubation medium were essential for the attachment step but apparently had no effect on the ingestion step. The metabolic inhibitors, KCN and 2-deoxyglucose, inhibited both steps. Cytochalasin B inhibited both steps, while colchicine inhibited only the attachment step but apparently had no effect on the ingestion step.

Animals↗