Acoustic resistance of fatty tissue as an indicator of its functional activity

The measurements of acoustic resistance have been performed in normal and pathologically changed fatty tissue from various human organs. It has been shown that the pathological process in fatty tissue results in corresponding changes of the acoustic resistance. It has been also found that the fatty tissue demonstrates a more marked acoustic reactivity in response to the pathological process, as compared to the muscular and glandular tissue.     

The nature of sources of bioelectric and biomagnetic fields.

The goal of this paper is to examine the origins and relative importance of primary and secondary sources of electric and magnetic fields for excitable tissue. It is shown that for axonal and cardiac tissue a comparison of the relative field strength from both primary and secondary sources shows only the latter to be significant. Even if the divergence and curl of the primary source were independent (and hence were both needed to define the primary source), because the secondary sources all arise from the divergence of the primary source the magnetic field reflects the same source component as the electric field. As a consequence magnetic and electric fields arising from active tissue are strongly linked.     

Reduced noradrenaline turnover in brown adipose tissue of lactating rats

Brown adipose tissue properties as well as noradrenaline turnover in the tissue were determined in 15-day lactating rats and virgin controls. Brown adipose tissue thermogenic activity was reduced in lactating rats as shown by a decrease in weight, cytochrome oxidase activity and mitochondrial GDP-binding. The noradrenaline turnover rate was lower in brown adipose tissue from lactating rats. It is suggested that diminished sympathetic activity in brown adipose tissue may be a major cause of the reduced tissue thermogenic activity during lactation.     

X-ray fluorescence-based differentiation of neck tissues in a bovine model: Implications for potential intraoperative use

This study explores the possibility of using X-ray fluorescence (XRF)-based trace-element analysis for differentiation of various bovine neck tissues. It is motivated by the requirement for an intra-operative in-vivo method for identifying parathyroid glands, particularly beneficial in surgery in the central neck-compartment. Using a dedicated X-ray spectral analysis, we examined ex-vivo XRF spectra from various histologically verified fresh neck tissues from cow, which was chosen as the animal model; these tissues included fat, muscle, thyroid, parathyroid, lymph nodes, thymus and salivary gland. The data for six trace elements K, Fe, Zn, Br, Rb and I, provided the basis for tissue identification by using multi-parameter analysis of the recorded XRF spectra. It is shown that the combination of XRF signals from these elements is sufficient for a reliable tissue differentiation. The average total abundance of these trace elements was evaluated in each tissue type, including parathyroid and salivary gland for the first time. It is shown that some tissues can unequivocally be identified on the basis of the abundance of a single element, for example, iodine and zinc for the identification of thyroid gland and muscle, respectively.     

On the dependence of the elasticity and strength of cancellous bone on apparent density

This paper presents a statistical analysis of the pooled data from a number of previous experiments concerning the dependence of the Young's moduli and strength of cancellous bone tissue upon apparent density. The results show that both the Young's moduli and the strength are proportional to the square of apparent density of the tissue and are therefore proportional to one another. It is shown that the coefficient of proportionality is different for human and bovine tissue. It is concluded that the suggestion of Wolff (Das Gesetz der Transformation der Knochen, Hirschwald, Berlin, 1892) that compact bone tissue is simply more dense cancellous bone tissue is not an accurate statement when only the mechanical properties of these two tissues are considered. It is noted that estimates for the elastic modulus of the individual trabecula of human cancellous bone vary from 1 to 20 GPa and it is suggested that this question needs further study.     

Purification and characterization of a cell-surface lectin (Lectin II) from Agrobacterium radiobacter NCIM 2443

A lectin was isolated from Agrobacterium radiobacter cell surface and purified. It is a monomer of 40 kDa as shown by SDS-PAGE. The lectin has a pI of 9.15 and amino acid composition of the lectin shows that 44% of the amino acids are hydrophobic. The lectin agglutinates rabbit erythrocytes but does not agglutinate human erythrocytes. It does not show specificity for monosaccharides except for D-glucosamine. Fetuin and its N-linked glycopeptide also inhibit the activity of the lectin but greater inhibition is shown by locust bean gum and Nicotiana tobaccum (tobacco) tissue extracts.     

Orbital paecilomycosis due to Paecilomyces lilacinus (Thom) Samson

The first case of orbital paecilomycosis is described. Fungal hyphae were found in a KOH preparation of the granulomatous tissue, removed from the orbit, and also in histological sections. Culture of the tissue was positive for fungus which was resistant to cycloheximide (0.5 g/l). It was identified as Paecilomyces lilacinus (Thom) Samson (IMI 213487) and shown to be pathogenic for the rabbit cornea.     

Tissue specific distribution of sulfated mucopolysaccharides in mammals

A comparative study on the distribution of sulfated mucopolysaccharides in several tissues of five mammalian species is reported. It is shown that each tissue has a characteristic composition differing from each other regarding the relative amount, type and molecular size of chondroitin sulfate A/C, chondroitin sulfate B and heparan sulfate. It is also shown that the same tissue from different mammals has the same types and proportions of sulfated mucopolysaccharides, but with different molecular weights. Exception to this rule was observed for the distribution of heparin which was present only in a few tissues of the five mammals studied.The possible involvement of the sulfated mucopolysaccharides in cell recognition and/or adhesiveness is discussed in view of this characteristic distribution.     

Tissue specific distribution of sulfated mucopolysaccharides in mammals.

A comparative study on the distribution of sulfated mucopolysaccharides in several tissues of five mammalian species is reported. It is shown that each tissue has a characteristic composition differing from each other regarding the relative amount, type and molecular size of chondroitin sulfate A/C, chondroitin sulfate B and heparan sulfate. It is also shown that the same tissue from different mammals has the same types and proportions of sulfated mucopolysaccharides, but with different molecular weights. Exception to this rule was observed for the distribution of heparin which was present only in a few tissues of the five mammals studied. The possible involvement of the sulfated mucopolysaccharides in cell recognition and/or adhesiveness is discussed in view of this characteristic distribution.     

Mechanisms of pheromone inactivation in the gut of Periplaneta americana

The sex attractant of the cockroach, Periplaneta americana, has been shown in earlier work to be largely inactivated by dissected midgut from males and from mated females. It is only slightly inactivated by the midgut from virgin females. In this paper, the sex pheromone inactivating system is further studied and shown to be active in late instar larvae of both sexes. In the male this pheromone inactivation is inhibited by piperonyl butoxide, a microsomal oxidase inhibitor. This compound appears to act on the midgut tissue directly. In the mated female, piperonyl butoxide has little effect. When the pheromone inactivating capacity is partitioned into soluble and tissue components, it appears that the soluble component is most active in the male, whereas the tissue component is most active in the female. Evidence from heat inactivation, trichloracetic acid precipitation, and the use of soy bean trypsin inhibitor, as well as the time course of the reaction, suggest that the factor or factors inactivating pheromone are proteins, probably enzymes. Evidence that at least part of the pheromone inactivating capacity is due to microsomal oxidases is considered. It is also observed that both pheromone and piperonyl butoxide absorb to membranes.     

The Effect of Carbon Dioxide on the Absorption of Manganese by Root Tissues of Red Beet

The absorption of manganese by beetroot tissue is shown to bepartially inhibited by the presence of carbon dioxide. Preliminarytreatment of well-washed tissue slices with carbon dioxide alsoproduces, after placing them in manganese solutions, an inhibitionof absorption for a time similar to that shown by tissue sliceswhen first excised from stored roots. It is suggested that aninhibitory substance is formed in bulky storage roots and tubersby dark fixation of accumulated respiratory carbon dixoide.On cutting thin slices from such organs, the removal of inhibitormay take place by diffusion into water during washing, by reversalof the fixation reaction when the partial pressure of carbondioxide is reduced, and possibly also by oxidation to form asubstance capable of stimulating manganese absorption when sufficientlyhigh oxygen concentrations are available.     

Structural-reactive properties of interoceptors (intravital study)]

It has been shown that between living and surviving receptors of a central and local origin there is similarity in a number of morphological, reactive and tinctorial properties as well as in their response to tissue fixation. At the same time these structures possess a number of specific properties making them different from one another.     

A transient heating technique for the measurement of thermal properties of perfused biological tissue

Knowledge of tissue thermal transport properties is imperative for any therapeutic medical tool which employs the localized application of heat to perfused biological tissue. In this study, several techniques are proposed to measure local tissue thermal diffusion by heating with a focused ultrasound field. Transient as well as near steady-state heat inputs are discussed and examined for their suitability as a measurement technique for either tissue thermal diffusivity or perfusion rate. It is shown that steady-state methods are better suited for the measurement of perfusion; however the uncertainty in the perfusion measurement is directly related to knowledge of the tissue's intrinsic thermal diffusivity. Results are presented for a transient thermal pulse technique for the measurement of the thermal diffusivity of perfused and nonperfused tissues, in vitro and in vivo. Measurements conducted in plexiglas, animal muscle, kidney and brain concur with tabulated values and show a scatter from 5-15 percent from the mean; measurements made in perfused muscle and brain compare well with the nonperfused values. An estimate of the error introduced by the effect of perfusion shows that except for highly perfused kidney tissue the effect of perfusion is less than the experimental scatter. This validation of the tissue heat transfer model will allow its eventual extension to the simultaneous measurement of local tissue thermal diffusivity and perfusion.     

Metabolic Changes in Excised Fruit Tissue. IV. Changes Occurring in Discs of Apple Peel During the Development of the Respiration Climacteric

It is shown that a sequential development of a series of enzyme systems occurs in the peel of the apple as the respiration climacteric develops in the whole fruit. The sequence of development of these systems, i.e. acetate incorporation into lipid, production of ethylene, incorporation of amino acid into protein and, finally, the decarboxylation of added malate (malate effect) is the same as that shown earlier for the short term (24 hr) aging of peel discs from pre-climacteric apples. As these systems appear in the initial discs from fruit passing through the climacteric they gradually cease to increase during the 24 hour aging period. Uptake studies show that none of the changes in these systems can be due solely to changes in the permeability of the tissue over the climacteric period. On the basis of these results it is tentatively suggested that the aging of discs from pre-climacteric tissue might provide a model system for a detailed study of the physiological and biochemical changes occurring during the climacteric of apple fruits.     

Contents of putrescine, spermidine and spermine in tissue of the human brain glial tumors

It is shown that in the tissue of the human brain glial tumours the content of putrescine depends on the degree of the tumour malignization. In malignant gliomas (glioblastomas), as compared to the benign (astrocytomas), the content of putrescine is significantly higher. The content of spermidine in glial tumours of a malignancy different degree is twice as high as the level of this polyamine in the brain grey matter, and it is twice as low as in the white matter. The content of spermine in the brain glial tumours does not differ essentially from its level in the brain tissue.     

Numerical simulation of systemic O2 and CO2 exchange in a hyperbaric environment

The process of gas exchange in systemic capillaries and its surrounding tissue is simulated numerically in a hyperbaric environment, taking into account the molecular diffusion, convection, saturation of haemoglobin with O2 and CO2, and the metabolic activity in the tissue. Krogh tissue-cylinder is used as a geometrical representation of the capillary-tissue system. The resulting system of non-linear governing equations together with the physiologically relevant boundary conditions is solved numerically. It is found that the concentration of oxygen decreases from the axis of the capillary to the tissue periphery whereas the concentration of carbon dioxide increases. It is shown that very little CO2 is transported radially. The location of the vulnerable region from the point of view of CO2 accumulation is found to be the rim (r = R2, z = L) situated at the periphery of the tissue near the venous end of the capillary. It is also found that accumulation of O2 decreases whereas that of CO2 increases in a hyperbaric environment. Finally, it is surmised that one of the reasons in causing discomfort among divers could be excessive accumulation of CO2 in the tissue.     

Rapid purification of tissue inhibitor of metalloproteinases from human plasma and identification as a gamma-serum protein.

A rapid method is described for the purification of human tissue inhibitor of metalloproteinases (TIMP) from plasma which involves immuno-affinity chromatography and gel filtration. The purified plasma inhibitor is immunologically identical with the TIMP previously purified from human amniotic fluid, human synovial fluid and human fibroblast culture medium. It is proposed that this inhibitor is identical with the plasma inhibitor previously named 'B1 anticollagenase', although the plasma inhibitor was shown to migrate as a gamma-serum component.     

Release of free fatty acids by the rat kidney.

The authors studied the release of free fatty acids (FFA) by the rat kidney cortex. They found that the kidney cortex released FFA into the incubation medium like adipose tissue. The presence of Ca2+ ions did not affect FFA release. Glucose significantly inhibited it. It was further shown that the kidney cortex is sensitive to the akipokinetic action of adrenaline and the antilipolytic action of insulin, in the same way as adipose tissue. It is concluded from the results that the kidney cortex has a lipolytic system which seems to be subject to higher hormonal regulatory mechanisms.     

Off-center spherical model for dosimetry calculations in chick brain tissue

This paper presents calculations for the electric field and absorbed power density distribution in chick brain tissue inside a test tube, using an off-center spherical model. It is shown that the off-center spherical model overcomes many of the limitations of the concentric spherical model, and permits a more realistic modeling of the brain tissue as it sits in the bottom of the test tube surrounded by buffer solution. The effect of the unequal amount of buffer solution above the upper and below the lower surfaces of the brain is analyzed. The field distribution is obtained in terms of a rapidly converging series of zonal harmonics. A method that permits the expansion of spherical harmonics about an off-center origin in terms of spherical harmonics at the origin is developed to calculate in closed form the electric field distribution. Numerical results are presented for the absorbed power density distribution at a carrier frequency of 147 MHz. It is shown that the absorbed power density increases toward the bottom of the brain surface. Scaling relations are developed by keeping the electric field intensity in the brain tissue the same at two different frequencies. Scaling relations inside, as well as outside, the brain surface are given. The scaling relation distribution is calculated as a function of position, and compared to the scaling relations obtained in the concentric spherical model. It is shown that the off-center spherical model yields scaling ratios in the brain tissue that lie between the extreme values predicted by the concentric and isolated spherical models.     

Fluorescence of acridine orange in the composition of blood and tissues

The interaction of acridine orange with blood albumins and tissue cells from different organs of white mouse has been studied by the spectral luminescence method. It was shown that acridine orange, by penetrating cells or organelles, is able to intercalate between base pairs in the DNA molecule. It was found that the application of acridine orange as a fluorescent probe can influence the metabolic activity of organs.