Differences In Tissue Composition Research Articles

Prostate tissue stiffness as measured with a resonance sensor system: a study on silicone and human prostate tissue in vitro

Prostate cancer is the most common form of cancer in men in Europe and in the USA. Some prostate tumours are stiffer than the surrounding normal tissue, and it could therefore be of interest to measure prostate tissue stiffness. Resonance sensor technology based on piezoelectric resonance detects variations in tissue stiffness due to a change in the resonance frequency. An impression-controlled resonance sensor system was used to detect stiffness in silicone rubber and in human prostate tissue in vitro using two parameters, both combinations of frequency change and force. Variations in silicone rubber stiffness due to the mixing ratio of the two components could be detected (p<0.05) using both parameters. Measurements on prostate tissue showed that there existed a statistically significant (MANOVA test, p<0.001) reproducible difference between tumour tissue (n=13) and normal healthy tissue (n=98) when studying a multivariate parameter set. Both the tumour tissue and normal tissue groups had variations within them, which were assumed to be related to differences in tissue composition. Other sources of error could be uneven surfaces and different levels of dehydration for the prostates. Our results indicated that the resonance sensor could be used to detect stiffness variations in silicone and in human prostate tissue in vitro. This is promising for the development of a future diagnostic tool for prostate cancer.

Seasonal study of the lipid composition in different tissues of the common octopus ( Octopus vulgaris )

Seasonal variation of octopus (Octopus vulgaris) lipid composition was investigated in four tissues: arm, mantle, ovary and digestive gland. A non-homogeneous fat distribution was observed, with the digestive gland exhibiting a higher (p <0.05) lipid content than the other tissues. The ovary showed a higher (p <0.05) fat content than both muscle tissues, reaching its highest (p <0.05) value in winter. Neutral lipids – free fatty acids (FFA), triacylglycerols, and sterols (ST) – exhibited their highest (p <0.05) concentrations in the digestive gland and their lowest (p <0.05) values in muscle tissues. The phospholipid (PL) content of the ovary was the highest (p <0.05) of all tissues analysed, with the PL content also being significantly (p <0.05) higher in the digestive gland than in arm and mantle. The concentrations of most lipid classes (FFA, PL and ST) exhibited a seasonal variation. The fatty acid composition showed a remarkable difference between the digestive gland and all other tissues analysed. Thus, the digestive gland exhibited higher (p <0.05) contents in monounsaturated fatty acids and also lower (p <0.05) contents in both saturated (SFA) and polyunsaturated (PUFA) fatty acids. The highest mean values in SFA and PUFA were observed in ovary and muscle tissues, respectively. A seasonal effect was observed for SFA and PUFA.

Lipid content and fatty acid distribution in tissues from Portuguese dogfish, leafscale gulper shark and black dogfish

The lipid characterization in tissues from the three deep-sea sharks leafscale gulper shark ( Centrophorus squamosus), Portuguese dogfish ( Centroscymnus coelolepis) and black dogfish ( Centrocyllium fabricii) captured at Hatton Bank in the North Atlantic were examined. The objective was to determine the lipid content and the fatty acid composition in different tissues. In addition, the fatty acid composition in tissues and species was compared. The tissues examined were pancreas, heart, kidney, stomach, spleen and liver. The lipid content was high in liver (40–50%) and ranged from 1% to 5% in the other tissues. The dominant fatty acids were C16:0, C18:1 (n-9), C18:1 (n-7) and C22:6 (n-3) in all tissues. All tissues had a high content of unsaturated fatty acids.

Comparison of the phospholipid and triacylglycerol fatty acid profile of rat serum, skeletal muscle and heart

Although several studies have analyzed the fatty acid profile of phospholipids (PL) and, to a lesser degree, triacylglycerols (TG) in one or more tissues concurrently, a systematic comparison of the fatty acid composition of different tissues and/or lipid classes is lacking. The purpose of the present study was to compare the fatty acid composition of major lipid classes (PL and TG) in the rat serum, soleus muscle, extensor digitorum longus muscle and the heart. Lipids were extracted from these tissues and analyzed by a combination of thin-layer chromatography and gas chromatography. We found many significant differences in various tissues and lipid classes. Serum had the most distinct fatty acid profile in PL but this "uniqueness" was less apparent in TG, where differences among tissues were in general less frequent than in PL. These two skeletal muscles exhibited similar fatty acid composition in both lipid classes despite their different muscle fiber type composition, denoting that fiber type is not a major determinant of the fatty acid composition of rat skeletal muscle. The fatty acid profile of heart PL was the most different from that of the other tissues examined. PL were rich in polyunsaturated fatty acids, whereas TG were rich in monounsaturated fatty acids. Although the reasons for the differences in fatty acid profile among the tissues examined are largely unknown, it is likely that these differences have an impact upon numerous biological functions.

Nutrient Uptake among Subspecies of Cucurbita pepo L. Is Related to Exudation of Citric Acid

Exudation of organic acids by roots has been implicated in uptake of minerals from soil. Three cultivars within each of two subspecies of summer squash (Cucurbita pepo ssp. ovifera D. S. Decker var. ovifera and C. pepo ssp. pepo var. pepo) were grown in the field. Plants of ssp. pepo had higher concentrations of K, P, and Zn than those of ssp. ovifera. These same cultivars were grown under P sufficient and depleted conditions in hydroponics, to measure exudation of organic acids from roots. When grown in hydroponics, tissues of ssp. ovifera had similar or higher concentrations of nutrients than ssp. pepo. Therefore, differences in tissue composition of field-grown plants are likely due to differences in nutrient uptake ability, not inherent differences in tissue composition between subspecies. Phosphorus nutrition played a significant role in exudation of organic acids into the hydroponics solution. For both subspecies, P depletion resulted in exudation of more citric and succinic acid, and less oxalic and tartaric acid. Under P depletion, ssp. pepo exuded more citric acid than ssp. ovifera. When soil was eluted with solution containing root exudates, the exudates from ssp. pepo eluted more K, Mg, Fe, and Zn than did those from ssp. ovifera. Among subspecies of C. pepo, exudation of organic acids, particularly exudation of citric acid in response to P depletion, is associated with the plant's ability to accumulate more inorganic nutrients when grown in the field.

The infected liver: radiologic-pathologic correlation.

Recent technologic advances have significantly enhanced the role of imaging in the detection, characterization, and management of infectious diseases involving the liver. In addition, imaging-guided percutaneous drainage has greatly improved the clinical treatment of patients with focal liver abscess. Infectious liver diseases can be accurately evaluated with ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging. Characteristic changes in US echogenicity, CT attenuation, or MR imaging signal intensity and typical enhancement patterns can contribute to the diagnosis of specific infectious diseases, including abscesses, parasitic diseases, fungal diseases, granulomatous diseases, viral hepatitis, and other less common infections. CT is particularly helpful in revealing the presence of calcifications and gas and in detailing the enhancement pattern. The multiplanar capability of MR imaging and its sensitivity to small differences in tissue composition increase its specificity for certain hepatic infections, including hydatid cyst and candidiasis. Radiologic findings may be sufficient to obviate aspiration or histologic examination, although in most instances they are less specific. Nevertheless, imaging findings taken together with appropriate clinical information may provide the most likely diagnosis, even if biopsy is sometimes required for confirmation.

Comparative pharmacokinetics of oxytetracycline in eel and its fate in a closed aquatic environment

Oxytetracycline (OTC) has been widely used in eel culture as a therapeutic and prophylactic agent because of its broad-spectrum activity against gram-positive cocci and gram-negative bacilli. The oral dosage of OTC approved for the treatment of vibriosis, furunculosis, and red pest disease in fresh water eel is 50 mg/kg/day for 6–7 days in Japan. The comparative pharmacokinetics and bioavailability of OTC after administration in cultured eel and its fate in closed aquatic environments (pond water and pond sediment) were examined. The pharmacokinetics of the drug in eel after intravascular administration was described by a two-compartment model. Marked differences were observed with respect to absorption, distribution, and elimination of the drug when compared with the parameters described by two-compartment models for other fish species. These differences could be explained by differences in tissue composition, blood perfusion, and mode of life. In the case of oral administration, the pharmacokinetics of OTC in eel was described by a one-compartment model with first-order absorption. The bioavailability of OTC following oral administration to eel was calculated to be 0.69%. In the feeding study, the serum level of OTC increased gradually during medication, and the highest level (0.64 μg/ml) was reached 1 day after the last medication. Oxytetracycline was not detected at 7 days after the last medication. In the sediment, however, OTC was abundant during medication, decreased quickly after medication ceased, and was not detected at 27 days after the last medication. During medication, the levels of OTC in pond water were approximately constant (0.23–0.27 μg/ml), but 5 days after the last medication, OTC was not detected. Almost the entire drug (99.9%) was recovered from the pond water and the sediment after medication through the diet. Therefore, further studies are urgently needed to develop methods to increase the bioavailability and recovery of uneaten food and to prevent the leaching of the drug from food before the food is eaten.

Distinguishing and grading human gliomas by IR spectroscopy.

As a molecular probe of tissue composition, IR spectroscopy can potentially serve as an adjunct to histopathology in detecting and diagnosing disease. This study demonstrates that cancerous brain tissue (astrocytoma, glioblastoma) is distinguishable from control tissue on the basis of the IR spectra of thin tissue sections. It is further shown that the IR spectra of astrocytoma and glioblastoma affected tissue can be discriminated from one another, thus providing insight into the malignancy grade of the tissue. Both the spectra and the methods employed for their classification reveal characteristic differences in tissue composition. In particular, the nature and relative amounts of brain lipids, including both the gangliosides and phospholipids, appear to be altered in cancerous compared to control tissue. Using a genetic classification approach, classification success rates of up to 89% accuracy were obtained, depending on the number of regions included in the model. The diagnostic potential and practical applications of IR spectroscopy in brain tumor diagnosis are discussed.

Assessing heterogeneous distribution of blood flow and metabolism in the heart.

The literature is reviewed on methods to assess heterogeneity of blood flow, substrate uptake and oxidative end energy metabolism in the normal heart, and their interrelations. Even though the factors controlling matching on the regional level remain largely obscure, the evidence that heterogeneous blood flow partially correlates to indicators of metabolism in the normal heart is accumulating, particularly in face of a correlation between acetate metabolism indicative of regional O2 consumption to microsphere blood flow. Moreover, the partial matching cannot be explained by vascular anatomical differences from one region to the other, since, although fractal theory can partially describe the branching patterns of the coronaries, vasodilation is similar among regions upon metabolic stimulation of the heart. It is dissimilar among regions, so that blood flow is redistributed, upon maximum vasodilation with adenosine or hypoxia, denoting regionally different maximum vessel diameter and flow reserve. However, regionally differing tissue composition could also contribute somewhat to regional differences in (the need for) blood flow. It is still unknown, because of technical limitations, how the foregoing measures relate to regional work load.

Impact of starvation on survival, meat condition and metabolism ofChlamys farreri

The effects of 60-day starvation on survival rate, condition index (CI), changes of nutrient composition of different tissues, respiration and excretion of scallopChlamys farreri were studied in laboratory from Oct. 17 to Dec. 15, 1997. Two groups (control and starvation with 200 individuals each) were cultured in two 2 m3 tanks, with 31 to 32 salinity water at 17°C. Starvation effects were measured after 10, 20, 40 and 60 days. There was no mass mortality of scallops of the two tanks and survival rates of the control and starvation groups were 93.5% and 92.0%, respectively. Starvation had strong effect on the meat condition of the scallops, especially after 10 days; when relative lipid percentage dropped sharply while relative protein percentage increased. The impact of starvation on the oxygen consumption rate (OCR) and the ammonia-N excretion rate (AER) was obvious. The OCR increased rapidly after 10 days but decreased after 20 days. The AER increased after 10 days and 20 days, but decreased obviously from 20 to 40 days. The O∶N ratios varied to different degrees, and minimized after 20 days. The low O∶N ratios implied that the protein was the main material for the metabolism ofC. farreri.

Ultrasonic integrated backscatter coefficient profiling of human coronary arteries in vitro.

A theoretical formulation for the profile of the integrated backscatter coefficient (IBC) is derived. This new formulation is based on a theoretical treatment by Chen et al. [1]. It includes correction for the diffraction of the ultrasonic beam and correction for the non-ideal nature of the reference signal. The inclusion of these correction factors permits accurate quantitative profiling of the IBC over the transducer focal zone. Experimental measurements are first performed on well-calibrated vessel-equivalent phantom materials and subsequently on human coronary arteries in vitro. A spherically focused 50.0 MHz f/1.83 transducer is used. IBC profiles are shown for three samples that are representative of early, mid, and advanced atherosclerotic coronary disease. The IBC profiles clearly differentiate the arterial tissues. However, variation between samples with histologically confirmed intimal thickening (N = 24) was large. The mean IBC (+/- 1 standard deviation), in (Sr.mm)-1, for media, adventitia, and thickened intima were 3.86 x 10(-3), 1.53 x 10(-2), and 2.24 x 10(-2), respectively. The mean IBC of thickened intima is larger than previous measurements obtained from femoral arteries, and the mean IBC for media and adventitia layers are lower, reflecting differences in tissue composition between coronary and femoral vessels.

Growth and tissue composition as a function of feeding history in juvenile cephalopods.

We present the results of a series of experiments that examined the effect of feeding history on the growth and tissue composition of juveniles of two tropical cephalopods; the squid Sepioteuthis lessoniana and the cuttlefish Sepia elliptica. Juveniles were reared in individual containers for between 35 and 42 days at different ration levels, three ration levels for the squid and two levels for the cuttlefish. Although differences in ration were sufficient to cause different growth rates, both in body length and mass, the effects on tissue composition were less definitive. Sepioteuthis juveniles on the highest rations had higher concentrations of water, but no difference in lipid, carbohydrate or protein when compared with their lower ration siblings. In the case of juvenile cuttlefish no difference in tissue composition was detected between the two ration levels. RNA:protein ratios were also determined for the juveniles to provide an estimate of instantaneous growth. A significant correlation was found between body size and RNA:protein ratio in the squid; those juveniles that ate more had higher RNA:protein ratios than lower ration individuals. Significantly, the juvenile cuttlefish showed no relationship between growth rate and RNA:protein ratios, which means that we are unable to use this measure to estimate the growth rates of wild individuals. In conclusion, ration level did affect growth rates and food availability is an important factor in modifying growth rates of wild individuals. However, we could not find, at the individual level, an index or measure that could be used to explain the variability of observed differences in growth rates as a function of nutritional history.

Allometric differences between current-year shoots and large branches of deciduous broad-leaved tree species.

Current-year shoots are mostly made of primary tissues, whereas first-order branches comprise mainly secondary tissues. Differences in tissue composition of these units reflect differences in functional design. We compared the allometry of current-year shoots and first-order branches in eight deciduous broad-leaved tree species and examined the functional differences underlying the design of current-year shoots and first-order branches. Allometric relationships of first-order branches tended to be compatible with predictions of the pipe model and elastic similarity model. That is, allometric constants of the relationships between leaf mass and stem diameter at the branch base and between stem diameter and stem mass were 2.0 and 0.33-0.38, respectively, indicating that the functional regulation of stem form of first-order branches can be predicted by the two models. However, allometric relationships of current-year shoots were not compatible with the predictions of the pipe and elastic similarity models. Thus, the allometric constant of the relationship between leaf mass and stem diameter at the base of current-year shoots was larger than 2.0, and the allometric constant of the relationship between stem length and stem diameter of shoots was larger than 1.0 in all species examined. However, current-year shoots had an allometric constant of leaf mass against stem length that was less than 1.0, suggesting a functional demand on shoot design to reduce self-shading. Also, allometric constants of stem length against stem diameter at the shoot base were larger in monopodial species than in sympodial species, whereas allometric constants of leaf mass per shoot against stem length were smaller in monopodial species than in sympodial species. We propose that the allometries of current-year shoots reflect their function as disposable units for temporary leaf arrangement.

Effect of Dietary Hydrogenated Fish Oil on the Plasma Lipoprotein Profile and on the Fatty Acid Composition of Different Tissues of the Rat

Dietary fatty acids are actively incorporated into membrane lipids, and fat intake can modify the composition and the biochemical activity of cellular membranes and the pattern of plasma lipoproteins. Industrial hydrogenation of polyunsaturated oils leads to the formation of isomeric trans fatty acids which are incorporated into cellular membranes when they are present in the diet. The trans fatty acid amount present in hydrogenated oils depends on the degree of hydrogenation, being high for partially hydrogenated oils and low for highly hydrogenated oils. Hydrogenated fish oil is widely used in some countries for the production of margarine and industrial fats. This study compares the fatty acid composition of plasma, erythrocytes, subcutaneous adipose tissue, and hepatic microsomal membranes and the plasma lipoprotein profile after feeding rats with a synthetic diet containing either fish oil, partially hydrogenated fish oil, or highly hydrogenated fish oil. It is observed that the tissue content of monounsaturated fatty acids increases and that the content of polyunsaturated fatty acids decreases after an increase of the degree of hydrogenation of the dietary fat. Tissues from animals fed partially hydrogenated fish oil show significant amounts of trans fatty acids only. The plasma triacylglyceride composition and the lipoprotein profile are also altered by the degree of hydrogenation of the dietary fat. Triacylglycerides decrease after highly hydrogenated fat feeding only. Total cholesterol and low-density lipoprotein cholesterol are significantly increased after partially hydrogenated fat feeding. Although no direct evidence is presented, this effect may be attributable to the high content of trans isomers of this dietary fat which nutritionally may behave as saturated fatty acids.

An examination of the role of the digestive gland of two loliginid squids, with respect to lipid: storage or excretion?

The role of the digestive gland, with respect to non-structural lipid, was examined using proximal analysis, histochemistry and quantitative histological techniques in the tropical loliginid squids Sepioteuthis lessoniana (Lesson) and Photololigo sp. The digestive gland of both species was characterized by large and numerous lipid droplets in the apical portion of the digestive cells and very few in the basal portion. The apical lipid droplets were released into the lumen of the gland and subsequently rapidly removed. Despite the numerous large apical lipid droplets, the lipid concentration in the digestive glands of S. lessoniana and Photololigo sp. was lower than that reported for most squid species. There was no relationship between lipid concentration and stage of digestion, suggesting that lipid is not stored in the gland after a meal. There was also no relationship between lipid concentration and the sex of an individual or stage of reproductive maturity, suggesting that these squids are not storing lipid in the digestive gland for use in fuelling reproductive maturation or providing an energy source for oocytes. I believe this study is the first to combine proximal analysis and quantitative histological techniques to examine the role of the squid digestive gland with respect to non-structural lipids. The results indicate that the digestive gland of these tropical loliginid squids is excreting, not storing, excess dietary lipid.

Anatomical and histological factors affecting the ruminal degradation of stem tissues in Bothriochloa species

Anatomical and histological features affecting the degradation of stem tissues by ruminal microorganisms were examined in ‘Caucasian’, ‘Ganada,’ and ‘WW-Spar’ Old World bluestem grasses (Bothriochloa spp.). Tissue degradation and/or staining results revealed variation among cultivars in the degree of lignification of parenchyma, sclerenchyma, and epidermal cells. In both immature and mature stems, parenchyma and sclerenchyma cell degradation by microorganisms was rapid and extensive for Ganada as compared with Caucasian and WW-Spar. In general, Caucasian tissues were more resistant to degradation than WW-Spar. There also were differences in tissue composition and degradation as a result of stem maturity. Increased lignification in parenchyma cells was primarily responsible for a decreased rate and extent of degradation in older stem portions. The major difference in tissue composition among cultivars was found in older stems; WW-Spar had more vascular and less parenchyma tissues than Caucasian and Ganada. However, Caucasian had a greater percentage of xylem-metaxylem complex tissues than the other two cultivars. The amount of lignified tissues did not seem to be related strongly with rate and extent of tissue degradation. Instead, the data suggest that our previously reported differences in digestibility among the three Old World bluestem grasses could be attributed to differences in the degradation of their individual tissue types. Fungal attachment was greatest on mature tissues, hence, the rate and extent of degradation of lignified tissues may be associated with the colonization of fungi in mature stems. Also, there was minimal colonization of fungi on immature tissues suggesting that their degradation was primarily affected by enzymatic or direct involvement of bacteria.

EFFECT OF GENDER ON FOREARM MUSCLE METABOLISM 535

To address whether significant gender differences exist for glucose and protein metabolism in human forearm, we compared foream blood flow, glucose, lactate and phenylalanine balances, oxygen uptake and the rates of protein synthesis and degradation between postabsorptive men (n=40) and women (n=36).Table To address whether these differences might result from male/female differences in muscle mass, forearm composition was measured (MRI × 16 cuts) and muscle mass estimated from a reconstructed 3D image in 17(8male/9female) subjects. In women the% of forearm composed of adipose was greater and% muscle mass less than men. In these subjects, neither the balances for glucose, phenylalanine and oxygen nor rates of protein synthesis or degradation differed between males and females when expressed per 100ml muscle. Table Conclusion: Cross sex comparisons of metabolic variables must accommodate differences in tissue composition. These data suggest that once corrected for muscle mass there may be no gender difference in forearm muscle metabolism of glucose, protein, or oxygen.

The responses of alpine grassland to four seasons of CO 2 enrichment: a synthesis

Alpine grassland at 2 470 m altitude in the Swiss Central alps was exposed to elevated CO 2 by using open top chambers (16 ambient, 16 elevated CO 2). Some plots received mineral fertilizer at a rate of N-deposition commonly measured in low altitude parts of Europe. Here we present a summary of results and data from the final harvest. Above-ground biomass measured after the completion of growth in the fourth season of treatment was not affected by CO 2 enrichment as was found by previous biometric estimates, but mean below-ground biomass was slightly stimulated (+ 12%, n.s.). In contrast, net CO 2 uptake per unit land area was strongly stimulated by CO 2 enrichment at the beginning of the experiment, and during the early part of each season. However, the CO 2 stimulation decreased during the later part of each growing season. By year four, also mid-season differences in CO 2 uptake per unit land area had disappeared. Neither microbial biomass, soil respiration in the laboratory, nor in situ land-area-based CO 2 evolution during the 10 week growing season increased under elevated CO 2. The total biomass N-pool and free soil nitrate and ammonium (capture by ion exchange resin bags) remained unaffected, whereas leaf nitrogen concentration was reduced and nonstructural carbohydrate concentration increased under elevated CO 2 in forbs. These differences in tissue composition largely disappeared during senescence and litter formation. Despite low CO 2 responsiveness at ecosystem level, species responses differed in terms of nitrogen, carbohydrates, tillering and flowering, suggesting the possibility for long-term changes in community structure. Addition of NPK equivalent to 40 kg N ha −1 a −1 had massive effects on all plant traits studied, but did not enable stimulated growth under CO 2 enrichment. However, when fertilizer and CO 2 enrichment were provided jointly, soil microbes were stimulated, indicating a co-limitation by carbon and nutrients (most likely nitrogen). Since responses to elevated CO 2 were absent in both warm and cold growing seasons, we conclude that this late successional plant community is carbon saturated at current atmospheric CO 2 concentrations for reasons not directly related to nutrient supply and climate. Perhaps, contrary to our expectation, evolutionary adjustments of this “old” ecosystem to the life conditions at high altitudes caused carbon to become a surplus resource today.

Correlations between parameters in pressure-flow analysis and histological compositions in prostate in patients with benign prostatic hyperplasia.

To investigate whether the differences in histological composition would be responsible for the grade of bladder outlet obstruction evaluated by pressure-flow (P-F) study and that increase in some histological components would result in increased degree of the obstruction, we evaluated relationships between morphometic data and results of P-F study. All prostate specimens with benign prostatic hyperplasia (BPH), obtained from 18 patients undergoing transurethral resection of the prostate, were analyzed by quantitative morphometry. Preoperatively each patient underwent P-F study. Stroma comprised the greater part of prostate (73%). Of all histological elements, fibrous tissue was the largest (48%). The relative and total volume of respective components showed no correlationships with parameters in P-F study. The differences in tissue composition did not affect the outcome of urodynamics. This result was the same even in a smooth muscle-rich subgroup. Also, in view of how small or large fibrous tissue and glandular elements were, no significant correlationships could be pointed out. The degree of infravesical obstruction and the outcome of P-F study cannot be explained by histological composition alone.

Comparative Mathematical Analyses of Freezing in Lung and Solid Tissue

In contrast to most organs of the body, the lung is composed 80% of air and 20% of tissue. Because freezing of the lung is fundamental to cryomicroscopy, cryopreservation, and cryosurgery, mathematical analyses of freezing in lung and solid tissue were performed to determine differences in freezing behavior resulting from differences in tissue composition. A comparison of the cooling rates of these tissues is presented. At the microscopic level ultrarapid solidification is more rapid in the subpleural region of the lung than in the same region of solid tissue. In this region, the air insulates the lung tissue and prevents transfer of heat from surrounding regions. Cooling rates on the order of 10 6 K/s can be achieved in the pleura and outermost alveolar wall because their aggregate thickness is less than 5 μm in the rat. At the macroscopic level and after steady state freezing has occurred, one-dimensional analyses show that freezing front propagation in the lung and solid tissue differs by less than 10%. This occurs even though the lung is less conductive than solid tissue; however, by having less heat storage capacity, the thermal diffusive property of lung is similar to that of solid tissue.