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PubMed1990

Dynamical behavior of middle ear: theoretical study corresponding to measurement results obtained by a newly developed measuring apparatus.

An attempt is made to develop a new measuring apparatus, and the dynamical characteristics of the middle ear of normal subjects and patients are measured with this apparatus. Applying the impedance theory of the tube to the external auditory canal, the aditus, and the tympanic and mastoid cavities, and applying the energy method to the eardrum and the ossicular chain, the equation of the middle ear, corresponding to the output of the apparatus and including the pressure difference effect upon the eardrum, is obtained. The numerical results are compared with the measurement results, and the effects of each part of the middle ear upon its dynamical characteristics are clarified. The great dependence of the dynamical characteristics of the middle ear upon the external auditory canal pressure is mainly caused by the pressure-dependent ossicular chain angular stiffness. The clearly different measurement results of the ossicular chain disorder patients from those of the normal subjects are obtainable by this apparatus, and these characteristics can be explained theoretically.

Acoustic Impedance Tests↗
PubMed2006

Assembly of the type III secretion apparatus of enteropathogenic Escherichia coli.

Enteropathogenic Escherichia coli (EPEC) secretes many Esps (E. coli-secreted proteins) and effectors via the type III secretion (TTS) system. We previously identified a novel needle complex (NC) composed of a basal body and a needle structure containing an expandable EspA sheath-like structure as a central part of the EPEC TTS apparatus. To further investigate the structure and protein components of the EPEC NC, we purified it in successive centrifugal steps. Finally, NCs with long EspA sheath-like structures could be separated from those with short needle structures on the basis of their densities. Although the highly purified NC appeared to lack an inner ring in the basal body, its core structure, composed of an outer ring and a central rod, was observed by transmission electron microscopy. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry, Western blot, and immunoelectron microscopic analyses revealed that EscC was a major protein component of the outer ring in the core basal body. To investigate the mechanisms of assembly of the basal body, interactions between the presumed components of the EPEC TTS apparatus were analyzed by a glutathione S-transferase pulldown assay. The EscC outer ring protein was associated with both the EscF needle protein and EscD, a presumed inner membrane protein. EscF was also associated with EscJ, a presumed inner ring protein. Furthermore, escC, escD, and escJ mutant strains were unable to produce the TTS apparatus, and thereby the secretion of the Esp proteins and Tir effector was abolished. These results indicate that EscC, EscD, and EscJ are required for the formation of the TTS apparatus.

Blotting, Western↗
PubMed1992

Congenital anomalies of the branchial apparatus: embryology and pathologic anatomy.

Various congenital anomalies of branchial origin are found in the neck region. Understanding the varied radiologic appearances of these anomalies is greatly aided by familiarity with their embryologic origins. By considering the anatomic location and radiologic appearance, the precise embryologic origin can be accurately predicted. Defects of the branchial apparatus include branchial, thymic, and parathyroid anomalies, which may manifest as cysts, sinuses, fistulas, and ectopic glands. The embryologic model is used to explain the origins of all branchial apparatus anomalies. The most accepted theory proposes that vestigial remnants result from incomplete obliteration of the branchial apparatus or buried cell rests, and, thus, if cells are trapped in the branchial apparatus during the embryologic stage, they can form branchial cysts later in life. By understanding the embryologic basis for these defects, the radiologist is better able to interpret the findings encountered with the various imaging modalities used in the evaluation of these anomalies.

Branchial Region↗
PubMed1981

A modified Van Slyke apparatus.

A modified micro-Van Slyke apparatus for analyzing gases in a 25- to 100-microliter sample of blood or other solutions is described. The method is based on the vacuum-extraction principle in which the gases are released for direct manometric measurement. A determination of total CO2 and total O2 content in blood can be completed in about 7 in. A commercial micro-Van Slyke apparatus (Thomas Magna-Matic manometer apparatus) requires 10-15 min for the same determination. The modified Van Slyke can be operated under field conditions without losing accuracy. The modified Van Slyke apparatus has greater reproducibility and accuracy than the commercial model.

Acid-Base Equilibrium↗
PubMed1986

Apparatus for long-term ventricular access in the awake canine.

An apparatus is described that permits lateral ventricular cerebrospinal fluid (CSF) to be sampled or an infusion to be performed into the ventricular system in the awake canine. The device has been used in 25 dogs. CSF was sampled, and experiments involving infusions into the lateral ventricle were performed over a 6- to 24-mo period. The maximum frequency of ventricular cannulation using the apparatus was once per week. Complications occurred in 10 dogs, all of which were successfully treated, permitting experiments to continue. Three fatal complications included meningitis in one animal at 24 mo and seizures in two animals, causing death at 12 and 18 mo. Administration of peptides, bombesin, and somatostatin into the ventricular system was followed by prompt rises in bombesin and somatostatin radioimmunoactivity in the CSF. There were no parallel increases of these peptides in the peripheral blood levels up to 2 h after infusion. Peptides of this molecular weight infused with this apparatus do not seem to leak into peripheral blood. The apparatus permits repeated ventricular cannulation in the awake canine for sampling of CSF and administration of biological substances to determine specific central nervous system action.

Animals↗
PubMed2004

Response to CO2 in novice closed-circuit apparatus divers and after 1 year of active oxygen diving at shallow depths.

Elevated arterial Pco(2) (hypercapnia) has a major effect on central nervous system oxygen toxicity in diving with a closed-circuit breathing apparatus. The purpose of the present study was to follow up the ability of divers to detect CO(2) and to determine the CO(2) retention trait after 1 year of active oxygen diving with closed-circuit apparatus. Ventilatory and perceptual responses to variations in inspired CO(2) (range: 0-5.6 kPa, 0-42 Torr) during moderate exercise were assessed in Israeli Navy combat divers on active duty. Tests were carried out on 40 divers during the novice oxygen diving phase (ND) and the experienced oxygen diving phase. No significant changes were found between the two phases for the minimal mean inspired Pco(2) that could be detected. The mean (with SD in parentheses) end-tidal Pco(2) during exposure to an inspired Pco(2) of 5.6 kPa (42 Torr) was significantly higher in the novice diving phase than in the experienced diving phase [8.1 kPa (SD 0.7), 62 Torr (SD 5) and 7.8 kPa (SD 0.6), 59 Torr (SD 4), respectively; P < or = 0.001]. One year of shallow oxygen diving activity with a closed-circuit apparatus does not affect the ability to detect CO(2) nor does it lead to increased CO(2) retention; rather, it may even bring about a decrease in this trait. This finding suggests that acquiring experience in oxygen diving with a closed-circuit apparatus at shallow depths does not place the diver at a greater risk of central nervous system oxygen toxicity due to CO(2) retention.

Adult↗
PubMedDate not supplied

Ultrastructure of the vacuolar apparatus in the renal proximal tubule microinfused in vivo with the cytological stain light green.

To obtain insight into the basic mechanisms controlling endocytosis, we tested the effects of different perfusates containing the cytological stain light green on endocytosis and ultrastructure of the vacuolar apparatus in renal proximal tubule cells. Rat proximal tubules were microinfused in vivo for 2 min in the presence or absence of light green with the following solutions: (A) perfusates containing inorganic salts and (B) perfusates with organic components or protein. In other experiments, the tubules were first microinfused for 2 min with 0.9% NaCl in the presence or absence of light green, then 15 min later further microinfused with or without light green using either group A or B solutions in order to either aggravate or reverse possible changes. All infused tubules were fixed after 5 min with 1% glutaraldehyde and examined by electron microscopy. In tubules microinfused without light green, the endocytic vacuolar apparatus in the apical cytoplasm showed a normal ultrastructure. However, microinfusion of solutions containing light green in either inorganic salts or a low concentration of protein caused significant changes in the apical endocytic apparatus. Large endocytic vacuoles were absent, and invaginations and small endocytic vacuoles were decreased in frequency. On the other hand, the amount of dense apical tubules was significantly increased, and in some cells dense apical tubules had transformed into a cisternalike network. These changes were aggravated in tubules which received a second microinfusion of NaCl and reversed in tubules that received a second infusion of protein. Furthermore, in the tubules microinfused with light green using perfusates containing organic components or protein, the apical cytoplasm of proximal tubule cells showed an essentially normal endocytic apparatus. The present study demonstrates that microinfusion of renal proximal tubules with light green disrupted normal endocytic membrane trafficking and recycling. These changes could be prevented or reversed by microinfusion of solutions containing protein or organic components.

Animals↗
PubMed1997

Is elastic energy storage of quantitative relevance for the functional morphology of the human locomotor apparatus?

Elastic storage of energy in the vertebrate locomotor apparatus is supposed to be an important functional factor in cyclic and acyclic movements. In terms of physics, for humans a proof for the occurrence and quantitative relevance of this phenomenon in vivo and under physiological conditions has been missing until now. In addition to the large amount of plausible, but inconclusive information about elasticity in humans and animals, we describe a simple experiment to prove the existence of quantitatively relevant elastic energy storage in the human locomotor apparatus. Ten volunteers (5 female, 5 male) each assumed a relaxed, upright posture on a steel platform. After the release of a support, the volunteers and the platform fell for a defined distance of 33 mm. Loaded with the volunteers, the platform fell significantly (p < 0.001) faster than predicted by the laws of stiff body mechanics (50 vs. 82 ms). For a minimum time of 50 ms, the human locomotor apparatus is able to support an average external power output of more than 400 W by means of an energy transfer of more than 20 J. During the fall, no EMG activities of the ankle flexors could be recorded. We conclude that the acceleration of the platform fall is induced by elastic elements serving as energy sources. Elastic energy storage is of quantitative relevance for the functional morphology and biomechanics of the human locomotor apparatus.

Adult↗
PubMed1993

Efficacy of pressure support in compensating for apparatus work.

Breathing through an endotracheal tube, connector, and ventilator demand valve imposes an added load on the respiratory muscles. As respiratory muscle fatigue is thought to be a frequent cause of ventilator dependence, we sought to examine the efficacy of five different ventilators in reducing this imposed work through the application of pressure support ventilation. Using a model of spontaneous breathing, we examined the apparatus work imposed by the Servo 900-C, Puritan Bennett 7200a, Engstrom Erica, Drager EV-A or Hamilton Veolar ventilators, a size 7.0 and 8.0 mm endotracheal tube, and inspiratory flow rates of 40 and 60 l/min. Pressure support of 0, 5, 10, 15, 20 and 30 cm H2O was tested at each experimental condition. Apparatus work was greater with increased inspiratory flow rate and decreased endotracheal tube size, and was lowest for the Servo 900-C and Puritan Bennett 7200a ventilators. Apparatus work fell in a curvilinear fashion when pressure support was applied, with no major difference noted between the five ventilators tested. At an inspiratory flow rate of 40 l/min, a pressure support of 5 and 8 cm H2O compensated for apparatus work through size 8.0 and 7.0 endotracheal tubes and the Servo 900-C and Puritan Bennett 7200a ventilators. However, the maximum negative pressure was greater for the Servo 900-C. The added work of breathing through endotracheal tubes and ventilator demand valves may be compensated for by the application of pressure support. The level of pressure support required depends on inspiratory flow rate, endotracheal tube size, and type of ventilator.

Equipment Design↗
PubMed2002

In vitro evaluation of dissolution behavior for a colon-specific drug delivery system (CODES) in multi-pH media using United States Pharmacopeia apparatus II and III.

United States Pharmacopeia dissolution apparatus II (paddle) and III (reciprocating cylinder) coupled with automatic sampling devices and software were used to develop a testing procedure for acquiring release profiles of colon-specific drug delivery system (CODES) drug formulations in multi-pH media using acetaminophen (APAP) as a model drug. System suitability was examined. Several important instrument parameters and formulation variables were evaluated. Release profiles in artificial gastric fluid (pH 1.2), intestinal fluid (pH 6.8), and pH 5.0 buffer were determined. As expected, the percent release of APAP from coated core tablets was highly pH dependent. A release profile exhibiting a negligible release in pH 1.2 and 6.8 buffers followed by a rapid release in pH 5.0 buffer was established. The drug release in pH 5.0 buffer increased significantly with the increase in the dip or paddle speed but was inversely related to the screen mesh observed at lower dip speeds. It was interesting to note that there was a close similarity (f2 = 80.6) between the release profiles at dip speed 5 dpm and paddle speed 100 rpm. In addition, the release rate was reduced significantly with the increase in acid-soluble Eudragit E coating levels, but lactulose loading showed only a negligible effect. In conclusion, the established reciprocating cylinder method at lower agitation rates can give release profiles equivalent to those for the paddle procedure for CODES drug pH-gradient release testing. Apparatus III was demonstrated to be more convenient and efficient than apparatus II by providing various programmable options in sampling times, agitation rates, and medium changes, which suggested that the apparatus III approach has better potential for in vitro evaluation of colon-specific drug delivery systems.

Acetaminophen↗
PubMed2003

Simulating the hydrodynamic conditions in the United States Pharmacopeia paddle dissolution apparatus.

The objective of this work was to examine the feasibility of developing a high-performance computing software system to simulate the United States Pharmacopeia (USP) dissolution apparatus 2 (paddle apparatus) and thus aid in characterizing the fluid hydrodynamics in the method. The USP apparatus was modeled using the hydrodynamic package Fluent. The Gambit program was used to create a "wireframe" of the apparatus and generate the 3-dimensional grids for the computational fluid dynamics solver. The Fluent solver was run on an IBM RS/6000 SP distributed memory parallel processor system, using 8 processors. Configurations with and without a tablet present were developed and examined. Simulations for a liquid-filled vessel at a paddle speed of 50 rpm were generated. Large variations in fluid velocity magnitudes with position in the vessel were evident. Fluid velocity predictions were in good agreement with those previously published, using laser Doppler velocity measurements. A low-velocity domain was evident directly below the center of the rotating paddle. The model was extended to simulate the impact of the presence of a cylindrical tablet in the base of the dissolution vessel. The presence of the tablet complicated the local fluid flow, and large fluid shear rates were evident at the base of the compact. Fluid shear rates varied depending on the tablet surface and the location on the surface and were consistent with the reported asymmetrical dissolution of model tablets. The approach has the potential to explain the variable dissolution results reported and to aid in the design/prediction of optimal dissolution conditions for in vitro--in vivo correlations.

Chemistry, Pharmaceutical↗
PubMed1991

Monoclonal antibodies specific for rat relaxin. V. Passive immunization with monoclonal antibodies throughout the second half of pregnancy disrupts development of the mammary apparatus and, hence, lactational performance in rats.

There were two related objectives to this study. The first was to determine the influence of relaxin on development of the mammary apparatus (nipples and glands) during the second half of pregnancy. The second was to determine whether the relaxin-dependent development of the mammary apparatus was required for normal postpartum lactational performance. Both objectives were accomplished by neutralizing endogenous relaxin throughout the second half of pregnancy with a monoclonal antibody specific for rat relaxin (MCA1). MCA1 was administered iv to rats daily from days 12-22 of pregnancy. On day 22 the morphology of the mammary apparatus of MCA1-treated rats differed from that of controls; nipples were dramatically smaller, collagen fibers had significantly greater mean density and consistency, and elastin fibers had greater mean density, length, and interdigitation. In addition, the mean number of alveoli surrounding lactiferous ducts was significantly smaller in MCA1-treated rats than in controls. There were no differences between MCA1-treated rats and controls in the mean thickness of connective tissue surrounding ducts, the height or density of luminal cells lining lactiferous ducts, or the sizes of either adipocytes or arteries. To examine lactational performance, MCA1-treated and control rats were cesarean sectioned between 2100-2400 h on day 22 of pregnancy and given foster pups born of untreated intact donors. Although both MCA1-treated rats and control rats exhibited a high incidence of maternal behavior after cesarean delivery, mean pup weight and incidence of live pups declined markedly during days 1-5 of fosterage in MCA1-treated rats compared to controls. Furthermore, unlike controls, there was no observable postpartum nipple development in MCA1-treated rats by day 5 of fosterage. Mammary glands obtained from MCA1-treated rats on day 5 of fosterage had markedly lower mean weight than controls. This study demonstrates that passive immunization of endogenous relaxin throughout the second half of pregnancy disrupts development of the nipples and mammary glands in the rat. Moreover, it establishes that relaxin's effects on the development of the mammary apparatus during pregnancy are essential for growth and survival of the young during lactation.

Animals↗
PubMed1978

Isolated flagellar apparatus of Chlamydomonas: characterization of forward swimming and alteration of waveform and reversal of motion by calcium ions in vitro.

The control of flagellar activity in the biflagellate green alga, Chlamydomonas reinhardtii was investigated by the in vitro reactivation of the isolated flagellar apparatus (the 2 flagella attached to their respective basal bodies plus accessory structures). The waveform and beat frequency of the isolated apparatus in the presence of 1 mM adenosine triphophate (ATP) were comparable to those recorded for living cells. Equimolar concentrations of adenosine diphosphate (ADP) could be substituted for ATP with little change in beat frequency and no apparent change in waveform, suggesting that the latter is converted to ATP by axonemal adenylate kinase. No reactivation occurred in adenosine monophosphate (AMP). But frequencies in cytidine, guanosine and uridine triphosphates (CTP, GTP and UTP) were approximately 10% that obtained in ATP. Reactivation was optimal over a broad pH range between pH 6.4 and pH 8.9 in both APT and ADP. Isolated flagellar apparatus could be induced to change from forward to reverse motion in vitro by manipulation of exogenous calcium ions. The 2 types of motion were directly comparable to recorded responses of living cells. Forward swimming occurred at levels of calcium below 10(-6)M, the isolated apparatus changing to backward motion above this level. Motility was inhibited at concentrations above 10(-3)M. The threshold for reversal of motion by calcium was lowered to 10(-7)M when the flagellar membranes were solubilized with detergent, indicating that the flagellar membranes are involved in the regulaion of the level of calcium within the axoneme. The reversal of motion by calcium was itself freely reversible. The relationship of these observations to the known tactic responses of Chlamydomonas is discussed.

Adenosine Triphosphate↗
PubMed1983

Ultrastructure and development of the flagellar apparatus and flagellar motion in the colonial graeen alga Astrephomene gubernaculifera.

Immediately following embryonic cleavage, the cells of Astrephomene have four equal-sized basal bodies, two of which are connected by a striated distal fibre and two striated proximal fibres. The four microtubular rootlets, which alternate between having 3/1 and 2 members, are arranged cruciately. The two basal bodies that are connected by the striated fibres then extend into flagella, while the two accessory basal bodies are now markedly shorter. At this stage the flagellar apparatus has 180 degrees rotational symmetry and is very similar to the flagellar apparatus of the unicellular Chlamydomonas and related algae. Development proceeds with a number of concurrent events. The basal bodies begin to separate at their proximal ends and become nearly parallel. Each striated proximal fibre detaches at one end from one of the basal bodies. Each half of the flagellar apparatus, which consists of a flagellum and attached basal body, an accessory basal body, two rootlets and a striated fibre (formerly one of the proximal striated fibres), rotates about 90 degrees, the two halves rotating in opposite directions. An electron-dense strut forms near one two-membered rootlet and grows past both basal bodies. During this time a fine, fibrous component appears between newly developed spade-like structures and associated amorphous material connected to each basal body. The basal bodies continue to separate as the distal fibre stretches and finally detaches from one of them. These processes result in the loss of the 180 degree rotational symmetry present in previous stages. Although the flagella continue to separate, there is no further reorganization of the components of the flagellar apparatus. In the mature cell of Astrephomene, the two flagella are inserted separately and are parallel. The four microtubular rootlets are no longer arranged cruciately. Three of the rootlets are nearly parallel, while the fourth is approximately perpendicular to the other three. A straited fibre connects each basal body to the underside of the strut. These fibres run in the direction of the effective stroke of the flagella and might be important either in anchoring the basal bodies or in the initiation of flagellar motion. Unlike the case in the unicellular Chlamydomonas, the two flagella beat in the same direction and in parallel planes. The flagella of a given cell may or may not beat in synchrony. The combination of this type of flagellar motion and the parallel, separate flagella appears to be suited to the motion of this colonial organism.

Chlorophyta↗
PubMed1993

[A method employing housing in a radial maze apparatus for estimating working memory in mice: effects of scopolamine and delay upon maze performance].

Male ddY mice were housed in a 4-, 6-, or 8-arm radial maze apparatus for 6 hr a day and then removed to a normal cage for fasting until the next day's trial. A water bottle was placed at the central platform. The end of each arm ran to the home cage through a guillotine door (G). Food was placed in the home cage. During the housing in the apparatus, one G was opened, and the remaining Gs were shut. The opened G was changed in random order during the housing period of 6 hr. At the beginning of the trial, all Gs were shut. The mouse was placed on the platform and was permitted to choose the arms until it chose all arms. When the mouse chose the last arm, the G was opened to allow stepping into the home cage. The mice housed in these apparatus learned to go to the home cage without entering already chosen arms within 4-6 days. Scopolamine (0.2 and 0.4 mg/kg, i.p.) impaired the maze performance. A 1- to 4-min delay impaired the performance slightly, but did not show any significant effect depending on the delay intervals. These results suggest that the apparatus is a useful and easy method for estimating working memory and the drug effects thereon in mice.

Animals↗
PubMed1988

A new method for studying working memory by using the three-panel runway apparatus in rats.

We designed a new method for studying working memory, by using a repeated acquisition procedure in the three-panel runway apparatus. This apparatus is composed of a start box, a goal box and four consecutive choice points; each choice point consists of three panel gates. Male Wistar rats were trained with 6 consecutive trials (one session) per day. Each trial was performed every two minutes. In this apparatus, rats could pass through only one gate (correct gate) among three panel gates in the direction of the goal box and were given 100 mg food pellets as the positive reinforcement. The sequence of correct gate position in each rat was changed everyday, but not in each session. Error responses (pushing the incorrect gate) were gradually reduced as training was repeated, and the learning was established within 16 training sessions to achieve criterion performance. Intraperitoneal scopolamine and intrahippocampal ethylcholine aziridinium ion (AF64A) produced increases in both the number of errors and the latency in a dose-dependent manner. The increase in errors induced by AF64A did not return to the control level, though the prolonged latency returned to normal. As a conclusion, this experimental procedure using the three-panel runway apparatus would be a useful method for studying working memory, and its memory deficit is involved at least in the dysfunction of the cholinergic system in the hippocampus.

Animals↗
PubMed1990

Responses of female rhesus macaques to an environmental enrichment apparatus.

Environmental enrichment devices are a potential way to enhance psychological well-being in laboratory animals. The effects of such devices need to be systematically evaluated before they are recommended for widespread use. The purpose of this research was to monitor the behavioural and physiological responses of adult female rhesus macaques to a simple enrichment device. The apparatus consisted of a box attached to the monkey's home cage that contained a radio and a food dispenser, which could be controlled by the monkeys via contact detectors. Radio and food dispenser use were automatically recorded. Whole blood serotonin (WBS), plasma cortisol and abnormal behaviour were measured in 5 monkeys before, during and after a 20-week period in which the monkey's cages were equipped with the device. All monkeys used the device (3 of the 5 subjects earned an average of more than 200 food pellets per day). Mean plasma cortisol and whole blood serotonin did not differ across sampling times, suggesting that the apparatus had no effect on basal stress levels. There was an inverse relationship between apparatus use and cortisol levels in 76% of the samples, but only 3 of 17 coefficients were significant. There was a significant but small negative correlation between apparatus use and self-abusive behaviour. This enrichment device was readily used by adult rhesus monkeys and could be adapted for use in a wide variety of laboratory settings.

Animals↗
PubMed1996

Closed-circuit apparatus for specific inhalation challenges with an occupational agent, formaldehyde, in vapor form.

Specific inhalation challenges are an important tool for confirming occupational asthma. In recent years, we have described two closed-circuit apparatuses that allow exposure to stable and controlled concentrations of particles and isocyanate gases. More recently, we developed a similar apparatus that generates chemicals in vapor form. The aim of this work is to describe its performance in the specific case of formaldehyde. This instrument is made of four parts: a generator as such, an exposure chamber, a monitor, and an automated regulatory system. This apparatus was assessed in four subjects suspected of having formaldehyde-induced asthma or alveolitis. The concentrations of formaldehyde were increased from 0.5 to 1 mg/m3 to 3 mg/m3 keeping the concentration at a value of 3 mg/m3 or less (threshold limit value). The dispersion of obtained values by comparison with the median data (6 values) was as follows: maximum value, 12 to 84%; minimum value, 20 to 58%; interquartile range, 0.13 to 0.9 mg/m3. We observed that target concentrations took a few minutes to be reached, but, once they were obtained, delivered concentrations were stable. The new vapor-delivery apparatus allows us to obtain concentrations of formaldehyde that are close to target concentrations with an acceptable dispersion of values around target concentration. Its use should be extended to other chemicals besides formaldehyde.

Administration, Inhalation↗