SEARCH · PubMed Health

Results for “Intersectionality”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,387 records · Page 77Linked to original sources

PubMed1987

On the mechanism of amiloride-sensitive nonelectrogenic Na+-H+ exchange in cell membranes: Na+/H+ antiport or Na+/OH- symport?

The amiloride-sensitive and nonelectrogenic Na+-H+ exchange system of eucaryotic cells is currently a topic of great interest. The results of membrane transport in the presence of protons are shown to be similar in two cases: when H+ is transferred in one direction or OH- -in the opposite direction. Therefore, in principle Na+-H+ exchange can be performed by two different mechanisms: Na+/H+ antiport or Na+/OH- symport. However, the kinetic properties of these mechanisms turn out to be quite different. The present study analyses the simplest models of antiport and symport and delineates their important differences. For this purpose the Lineweaver-Burk plot presented as Na+ reverse flow entering a cell 1/JNa (or H+ leaving a cell) versus the reverse concentration of Na+ outside 1/[Na+]0 is most useful. If a series of lines with external pH as a parameter have a common point of intersection placed on the ordinate, it indicates the availability of Na+/H+ antiport. In case of Na+/OH- symport a point of intersection is shifted to the left of the ordinate axis. According to data available in the literature, Na+/H+ antiport manifests itself in dog kidney cells and in hamster lung fibroblasts. In the skeletal muscles of chicken and in rat thymus lymphocytes however, a Na+/OH- symport is apparently present.

Amiloride↗

PubMed1989

[The progress of the morphological research on the acupoint].

The morphological research of the acupoint began from 1977. The scholars have studied on three main works as following. 1) The sensory organs in the acupoint: The area of acupoint contains free nerve ending, Vater-Pacini corpuclese and muscular spindle. The nerve fibers are I, II, III types, the chief is II. 2) The segmental distributions of afferent neuronal fibers of the acupoint: The evidence of the experimental research has revealed that the fibers of mainly and essential acupoints are definite to be afferent segments. The fibers of the upper and lower limbs acupoints projected into III-IX lamina of the posterior horn of the spinal cord. 3) The mutual intersect in the dorsal ganglia between the segmental distributions of the afferent neurons of viscera and that of acupoints. It is proposed that the mutual intersect between the segmental distributions of the afferent neurons of viscera and that of the acupoints is probable the morphological foundation for the theory of somato-viscera.

Acupuncture Points↗

PubMed1989

A resolution restriction for Wolff's law of trabecular architecture.

A rigid constructionist view of Wolff's trajectorial theory of trabecular architecture, called the "orthodox theory," requires that the trabeculae of cancellous bone intersect at right angles exactly like the stress trajectories with which they are associated by the theory. It is well established that trabeculae do not always intersect at right angles. The author discusses the fallacy in the orthodox interpretation of Wolff's law, and suggests that a "resolution length restriction" be imposed on the trajectorial theory to avoid interpretations that lead to the fallacy.

Bone Development↗

PubMed1989

[Accommodation-convergence coupling using the stereomicroscope].

The term "instrument myopia" means an accommodative effort caused by the view into the microscope. This accommodation may be connected with the convergence position of the eye. Heterophoria should be developed if accommodation-induced convergence of the eyes does not harmonize with convergence of the ocular axes of a stereomicroscope. In 16 probands, an accommodation of 1.1 +/- 0.72 dpt and esophoria of +11.1 +/- 8.5 pdpt were measured at parallel ocular axes. The accommodation increased by 0.12 dpt/degree convergence with increasing convergence angle of the ocular axes. When the visual field was unrestricted, this line intersected the accommodation convergence line at 6.7 degrees. The esophoria decreased with increasing convergence angle and passed over to exophoria. At 8 degrees convergence, heterophoria amounted to -0.2 +/- 2.9 pdpt, and at 16 degrees exophoria was -12 +/- 9.5 pdpt. The minor degree of heterophoria and especially the very minor heterophoria at 8 degrees convergence support the view that the optimum convergence of the ocular axes is near where both accommodation convergence lines intersect.

Accommodation, Ocular↗

PubMed1987

Biosynthesis and processing of class II histocompatibility antigens.

The class II major histocompatibility antigens at the cell surface exist as heterodimers of alpha and beta subunits. During biosynthesis, these subunits are associated with a third chain, the invariant (I) or I chain. Association with the I chain occurs early in biosynthesis in the rough endoplasmic reticulum and persists during transport through the Golgi apparatus. One of the two alpha subunit N-linked oligosaccharides and the single beta subunit N-linked oligosaccharide are converted to the complex form during Golgi transit. In the human system, both I chain N-linked oligosaccharides can also be processed to the complex form, and at least two O-linked oligosaccharides can be added to the I chain. At some point during transit to the cell surface, class II antigens associate with a proteoglycan bearing chondroitin sulfate side chains. Complexes containing alpha, beta and I chain subunits and the associated proteoglycan accumulate in human B-cell lines treated with the ionophore monensin, an inhibitor of Golgi transport, suggesting that this may be a biosynthetic intermediate in class II antigen transport and assembly. Prior to cell surface expression of class II antigens, the exocytic pathway which they follow intersects the endocytic route, followed by certain ligands internalized by receptor-mediated endocytosis. The I chain appears to dissociate from mature class II alpha, beta dimers prior to their cell surface expression but following the intersection of the exocytic and endocytic pathways.

Animals↗

PubMed1987

An analysis of ambulance accidents in Tennessee.

In an effort to improve our program for ambulance crash and related injury prevention, we analyzed 102 consecutive ambulance accidents. Incidents reported included those that resulted in human injury or in which property damage exceeded $200. Multiple logistic regression was used to determine the association between circumstances reported at the time of the accidents and the risk of injury. Twenty-nine accidents contributed to a total of 65 injured victims, with one death. The variable most strongly associated with the probability of an injury-accident was use of a passenger restraint device. Darkness and occurrence at an intersection were variables showing increased risk, but were not statistically significant. The interaction of variables did not have a combined influence on the incidence of injury. The mean delay to hospital care after an accident was 9.4 minutes. Based on our data, we conclude that passenger restraints for both ambulance attendants and passengers should be mandatory, and we suggest that traffic signals be strictly heeded at intersections and speed limits in urban settings be obeyed.

Accidents, Traffic↗

PubMed1986

[A new echocardiographic procedure for calculation of the accurate volume of the right atrium].

The right atrial (RA) volume can be determined angiographically from two perpendicular projections. Up to now volume calculations by means of two-dimensional echocardiography (2-DE) have only been attempted in a single plane, the apical four-chamber view. Our study reports a new method for RA volume calculation using two intersecting cross-sectional echocardiographic views. For this purpose silicone rubber casts of 20 human necropsy hearts were obtained and thin walled natural rubber moulds of the RA casts were prepared. Totally filled with and immersed in water, the mouls could be visualized in the apical four-chamber view and an additional echocardiographic plane, the latter corresponding to the subcostal view in vivo. In this view the vertical extension of RA could be estimated. Areas and length of RA were determined in the respective planes and RA volume was calculated by applying the formula: - Area X Length - to two intersecting planes. Finally, the latex moulds were filled with diluted contrast agent and the volume was determined angiographically using a biplane disc method. Real volume of RA was 112 +/- 23 ml (mean +/- 1 SD). Angiographically, an overestimation resulted: the calculated volume amounted to 119 +/- 24 ml, the mean difference was 7 +/- 2 ml (p less than 0.001). The regression equation was y = 1.04 X + 2.34, r = 0.995, SEE = 2.3 ml. Volume determination from the apical four-chamber view using a monoplane disc method resulted in a mean volume of 62 +/- 17 ml. The mean difference to the real RA volume was 50 +/- 17 ml, p less than 0.001.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1986

Photoreceptor latency: analysis and definition.

Latency as a time difference between the stimulating light-pulse and the recorded potential response was studied with intracellular recording techniques on blowfly (Calliphora) visual receptors. Latency was shown to be a meaningful parameter in analysing the information content of the recorded receptor potential responses by comparing latency vs. amplitude functions using different intensities of stimulating light, stimulating angles of the incident light, ambient temperatures, and flies of different developmental stages. The maximum amplitude of the response is not sufficient to describe stimulus-response functions. With the help of the linear correlation analysis the most useful latency criterion among three widely used latency parameters (viz. the amplitude threshold (1 mV), the visual estimation (detectable voltage) and the maximum slope intersection with the base-line) was investigated. These were studied by correlating them with other commonly used response parameters. An arbitrarily chosen latency parameter that shows the lowest correlation coefficient is considered to contain more additional information from the photoreceptor voltage response than a latency parameter with high correlation. According to our analysis the most useful latency determination is proposed to be the time from the stimulus onset to the intersection of the maximum tangent at the base line, a criterion which also allows one to use concepts derived from systems analysis. The concept of latency is discussed and a definition proposed in the light of this and other recent findings.

Animals↗

PubMed1971

Evaluation of enterovirus immune horse serum pools for identification of virus field strains.

Immune horse sera to 42 enterovirus immunotypes were pooled according to the Lim Benyesh-Melnick and the "intersecting serum" schemes. Each serum was diluted in the pools to contain 50 antibody units. After it was established that the pools correctly neutralized prototype virus strains, they were evaluated in tests against 273 enterovirus field strains representing most of the viral types included in the pools. With test virus doses of 10-100 TCD(50), most of the poliovirus and coxsackievirus field strains were correctly identified in both schemes, but a number of the echoviruses were neutralized by heterotypic pools, particularly in the Lim Benyesh-Melnick scheme. However, at higher test virus doses of 320-3200 TCD(50), little heterotypic neutralization occurred in either scheme, and 93-94% of the virus field strains were correctly identified in each scheme. With these larger virus doses, breakthrough tended to occur in homologous pools by the 7th day, but rarely by the 5th day. Since the Lim Benyesh-Melnick pool scheme employs 8 pools as compared with 13 for the intersecting serum scheme, and since the two schemes were equally satisfactory for identifying virus field strains at test virus doses of 320-3200 TCD(50), immune horse sera will be pooled by the former scheme, thus utilizing fewer pools, for distribution to qualified viral diagnostic laboratories.

Animals↗

PubMedDate not supplied

[Description of the ratios between metabolite concentrations in a polyenzyme system].

It was demonstrated that the relations between substrate and product concentrations for a reaction catalyzed by michaelian enzyme incorporated in a multienzyme system can be graphically represented by a diverging set of straight lines intersecting in one point, the flux velocity being treated as a parameter. A competitive inhibitor shifts the intersection point along the line of equilibrium state. The relations between the concentrations of more than two reagents are represented by a set of equivelocity surfaces. The relations between substrate and product concentrations for a kinetically cooperative reaction conforming to the graphical representation by the second--order curves were analyzed. The stability criterion was obtained for a multienzyme system with the first enzyme allosterically regulated by products of subsequent reactions.

Allosteric Regulation↗

PubMed1982

Application of quantitative stereology to the evaluation of enzyme-altered foci in rat liver.

The mathematical science of quantitative stereology has established relationships for the quantitation of elements in three-dimensional space from observations on two-dimensional planes. This report describes the utilization and importance of such mathematical relationships for the quantitative analysis of focal hepatic lesions in terms relative to the volume of the liver. Three examples are utilized to demonstrate the utility of such calculations in the three-dimensional quantitation of hepatic focal lesions. The first is that of a computer-simulated experiment based on defined hypothetical situations. The simulations demonstrate the applicability of the computations described in this report to the evaluation of two-dimensional data from typical animal experiments. The other two examples are taken from actual experiments and involve the transplantation of hepatic cell populations into the liver suitably prepared hosts and the quantitation of altered foci produced by initiation with diethylnitrosamine-partial hepatectomy followed by promotion with phenobarbital. The quantitation of altered foci by means of a two-dimensional analysis (simple enumeration of focal intersections/area of tissue section) is proportional to the quantitation of foci per volume of liver provided that the mean diameter of the foci for each treatment is sufficiently uniform, as exemplified in the text by the transplantation experiment. When such mean diameters are unequal as in the diethylnitrosamine-phenobarbital experiment described herein, quantitation from three-dimensional analysis gives significantly different results as compared with enumeration of focal intersections on two-dimensional areas. These studies clearly demonstrate that the frequency and size of foci intersections viewed on two-dimensional tissue sections do not necessarily reflect the number of size of foci in the three-dimensional tissue. Only by quantitating the number and size of the foci in relation to the three-dimensional volume of the tissue can one determine the validity of the proportionality of data from two-dimensional measurements to the total number of foci per volume of tissue. Such a conclusion has important implications for quantitative studies on hepatocarcinogenesis as well as for the enumeration of premalignant lesions which occur during the natural history of carcinogenesis in any solid tissue.

Animals↗

PubMed1983

Gyrase . DNA complexes visualized as looped structures by electron microscopy.

Gyrase bound to duplex DNA in the absence of ATP is seen by electron microscopy as a nearly spherical particle frequently located at the intersection of two duplex DNA strands. Such looped structures with gyrase situated at the base of the loops are observed with both linear and circular DNA substrates, and two or three individual DNA molecules bound to the same protein are also seen at high DNA concentrations. Addition of the nonhydrolyzable beta,gamma-imido analog of ATP to the gyrase . DNA reaction mixture prior to sample fixation for microscopy reduces the frequency of gyrase molecules found at DNA intersections. Looped structures similar to those of the gyrase . DNA complex are also seen with the complex of DNA and the A subunit of gyrase. When negatively supercoiled DNA which has been partially relaxed by gyrase in the absence of ATP is fixed for electron microscopic examination, intermediate forms are observed that contain both supercoiled and relaxed loops in a single DNA molecule, with the enzyme located at the common base of the loops. These results suggest that gyrase possesses multiple DNA-binding sites, a feature which allows the enzyme to hold DNA in constrained loops. The relation of these observations to the mechanism of gyrase action is discussed.

Base Composition↗

PubMed1983

A new plot for multiple enzyme inhibition.

A new graphical method is described for analyzing the results of multiple inhibition experiments. It is applicable to either single- or multi-substrate enzyme systems obeying Michaelis-Menten kinetics and is valid irrespective of the type of inhibition (competitive, noncompetitive, uncompetitive, mixed). According to this method, mutually exclusive inhibitor binding gives rise to lines that converge on the vertical axis, whereas mutually nonexclusive inhibitors yield lines that intersect to the left of the vertical axis. It has been pointed out that the inhibitor interaction factor can be determined directly from multiple inhibition experiments only if at least one of the inhibitors is noncompetitive. When this is the case, the present plot provides a very simple way of determining the inhibitor interaction factor from the coordinates of the intersection point.

Alcohol Dehydrogenase↗

PubMed1984

Collison 6-jet nebulizer: choice for the certification test of the class II biological safety cabinet.

Three types of nebulizers, one plastic, one glass and Collison 6-jet nebulizers were tested, to select an appropriate nebulizer for the certification of the class II biological safety cabinets (BSC). Performance of the plastic and glass refluxing nebulizers were found to be both inconsistent from one to another, and not provide reproducible results. The Collison nebulizers, on the other hand, showed little variations and provided reproducible results. In addition, the Collison nebulizer generated constant spray volume when the fluid level in the reservoir was varied. To determine optimum discharge velocity of the Collison nebulizer, nebulizers with an outlet diameter of 10, 12, 14, 16 and 18 mm were tested. For the personnel protection test, the main stream of aerosol sprayed from the Collison nebulizer with 14 mm outlet internal diameter hit the intersection of the test cylinder and the front opening. Each nebulizer with an outlet diameter of 12 to 16 mm located at the level of lower edge of the front window delivered aerosols more efficiently at the intersection than when located at 14 inches above the work surface. The aerosol from the 10 or 18 mm diameter nebulizers showed an inappropriate distribution. For the product protection test, the nebulizer with 14 mm outlet diameter showed the best distribution pattern around the test cylinder. In the cross contamination test, this nebulizer outperformed the 10 or 18 mm for class II BSC's without side wall effect. According to these results, the Collison nebulizer with 14 mm of internal diameter nozzle was found appropriate for the biological certification tests of the class II BSC. Exception was the cross contamination test of class II BSC with a side air intake between the internal side wall and the work surface, in which the nebulizer with 10 mm nozzle was the choice.

Aerosols↗

PubMed1978

[Study of the Wirsung duct by echography (author's transl)].

With the usual echographic technics, the Wirsung duct, when dilated can be only episodically seen: the seesaw motion of the transducer produces some undesirable echoes, which rub out the lumen of the Wirsung duct. In order to obtain steadily pictures of the dilated Wirsung duct, the transducer must be used with a sweep motion in only one direction, while a positive pressure is exerted on the epigastrium. When transversally intersected, the Wirsung duct appears spindle shaped; it can be displayed on a rather good length. When sagittaly intersected, it presents, itself like a curved shaped picture, 4 mm to 2 cm in diameter, empty of echoes, in the center of the pancreatic section. The Wirsung duct, with the former technics, had been displayed 20 times in 140 cases of chronic pancreatitis; whe have found it in 4 cases in our 10 last cases of chronic pancreatitis. These case have been verified by endoscopic Wirsungography.

Chronic Disease↗

PubMed1983

3-D envisioning by real time perpendicular bi-plane echocardiography (simultaneous multifrequency ultrasonography-III).

Simultaneous dual B-modes, the tomographic plane of which can be moved freely keeping the intersecting angle always perpendicular, was devised and based on simultaneous multifrequency ultrasonography (Miwa, et al, 1981). Dual probes, the ends of which are linked by two arms and three nodes with potentiometers are used to display the intersecting line on the both B-mode images by computation. Both images can be displayed together on one CRT, or separately on the different CRTs. This has proved to be a great help for understanding the 3-D structure of heart. Quantitative dimension and displacement speed measurement of 3-D structure of heart such as myocardium thickness, inner diameter of ventricle, and their changing speed, can be performed very exactly at the accurate three dimensional orientation to the heart. We have also recognized that measuring beam for M-mode must be guided to an exact orientation by this technology. Otherwise, unexpected error has been introduced very usually, if guided only by conventional single B-mode due to lack of information of three dimensional incident angle to the wall, valve,..

Biophysical Phenomena↗

PubMed1983

Functional studies in 79-year-olds. III. Walking performance and climbing capacity.

Walking speed and the ability to climbing steps were studied in a subsample of 112 women and 93 men of the longitudinal population study "70-year-old people in Göteborg", in order to evaluate the functional capacity of the lower extremities. No women or men of this age achieved, when walking comfortably, a speed of maximum 1.4 m/s which is recommended in Sweden as a norm for pedestrians at signalized intersections. At their maximum walking speed only 32% of the women and 72% of the men reached 1.4 m/s. In comfortable walking women on an average used 78% and men 70% of their maximal walking speed. All subjects could climb up and down a 20 cm step when using a handrail. Less than half of the women but almost all the men were able to climb up and down a 50 cm high step using a handrail. Subjects having handicap transport service choose significantly lower walking speed than the rest of the subjects. Correlations were found between step test results and walking speed. It is concluded that both traffic vehicles and the rythm at signalized intersections are not in accordance with the functional capacity of older persons.

Aged↗

PubMed1983

[Microcirculation of the lungs in histamine administration after vagotomy].

Intravital microscopy was used to study the microcirculatory bed of the lungs during application of histamine after righthand vagotomy. It was discovered that responses occurring at that level during histamine application after intersection of the right vagus were not equivalent to those when the biologically active substance was used in intact animals. Application of histamine without intersection of the nerve was characterized by aggravation of microcirculatory disorders in the lungs as the drug concentration was raised. The reverse was observed in cases where histamine was applied after righthand vagotomy. In this case the most significant alterations in the microcirculatory bed were recorded after local use of low doses of histamine. Besides, the duration of their occurrence was more prolonged as compared to that seen during histamine application in intact animals.

Animals↗