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PubMed1989

[Clinical methods for evaluating infarct size and its anatomic correlations. A study conducted with 193 cases. II. Evaluation of infarct size by determining maximal creatine phosphokinase in serum. Enzimatico-anatomic correlations].

AIMS: To compare the infarct size calculated by the peak serum CK method with the anatomic infarct size in a population dying of acute myocardial infarction. CONCEPT AND PLACE OF THE STUDY: To use the method of peak serum CK in the assessment of infarct size, calculated by a method developed by the authors, in a population dying of acute myocardial infarction in a coronary care unit. METHODS: 193 patients who successively died with acute myocardial infarction entered the study. After establishing the exclusion criteria the anatomical infarct size was measured using the method developed by the authors of myocardial slices after fixation of the heart and by the peak CK method. The two methods were correlated using linear regression curves. RESULTS AND CONCLUSIONS: A global correlation between the two methods was found although wide scattered values were found. After dividing the population in several subgroups, the analysis showed that survival below 48 hours, death in left ventricular failure, inferior infarcts and reinfarction influenced negatively this correlation. The anatomical method showed its value for this kind of evaluation having always in mind its known limitations. The enzyme method looked less discriminating as peak CK, obtained by 12 h sampling will seldom reflect the peaks of CK liberation curve. As the study was applied to a population of patients dying of acute myocardial infarction its results cannot be applied without caution to a population of survivors. We anticipate that in such a population peak CK will have a better correlation with real CK peaks even with 12 hours sampling and therefore reflecting more accurately infarct size.

Autopsy↗
PubMed1988

Membrane-bound Na,K-ATPase: target size and radiation inactivation size of some of its enzymatic reactions.

Frozen samples of membrane-bound pig kidney Na,K-ATPase were subjected to target size analysis by radiation inactivation with 10-MeV electrons at -15 degrees C. The various properties investigated decreased monoexponentially with radiation dose, and the decay constants, gamma, were independent of the presence of other proteins and of sucrose concentrations above 0.25 M. The temperature factor was the same as described by others. Irradiation of four proteins of known molecular mass, m, showed that gamma for protein integrity was proportional to m with a proportionality factor about 20% higher than that conventionally used. By this standard curve, glucose-6-phosphate dehydrogenase activity used as internal standard gave a radiation inactivation size of 110 +/- 5 kDa, very close to m = 104-108 kDa for the dimer, as expected. For Na+/K+-transporting ATPase the following target sizes and radiation inactivation size values were very close to m = 112 kDa for the alpha-peptide: peptide integrity of alpha, 115 kDa; unmodified binding sites for ATP and vanadate, 108 kDa; K+-activated p-nitrophenylphosphatase activity, 106 kDa. There was thus no sign of dimerization of the alpha-peptide or involvement of the beta-peptide. In contrast, optimal Na+/K+-transporting ATPase activity had a radiation inactivation size = 189 +/- 7 kDa, and total nucleotide binding capacity corresponded to 72 +/- 3 kDa. These latter results will be extended and discussed in a forthcoming paper.

Animals↗
PubMed1982

A comparison of 15 year old children with excellent occlusion and with crowding of the teeth, Angle Class I malocclusion, in respect of face size and shape and tooth size.

The biological conflict that manifests itself in crowding of the teeth in man has fascinated orthodontists for generations. Correlations between tooth size and tooth arrangement can be shown, but such correlations tend to leave much unexplained in practical terms. The present report presents data from a preliminary examination of face size and shape and tooth size in boys and girls of 15-16 years, of which 47 had excellently arranged teeth and 91 showed crowding. Measurements were taken from lateral and posteroanterior cephalometric X-ray films and from dental casts. The statistical test used was the standard student t-test. Girls' faces were found to be on average significantly smaller than boys' whether the teeth were well arranged or were crowded. The comparisons of face size and shape of boys and girls with well arranged teeth with the faces of those with crowded teeth was less definite in its outcome. Girls' total tooth substance was on average significantly smaller than boys' whether the teeth were well arranged or crowded. Boys and girls with crowded teeth had a larger mean total tooth size than boys and girls with well arranged teeth.

Adolescent↗
PubMed1994

Serum cholesterol concentration of mice selected for litter size and its relationship to litter size and testis mass.

This study assessed the genetic relationship between litter size and serum cholesterol concentration and between litter size and testis mass in mice. Mice were from a long-term experiment in which selection had occurred for 21 generations in three replicated lines per criterion of selection (LS = selection to increase litter size based on number born; LC = unselected control). Thereafter, random mating within lines was practiced. Serum cholesterol concentrations were evaluated in female and male mice from two replicates at Generation 29 and one replicate at Generation 30. Body weights and blood samples were collected from primiparous females 8 d after weaning their pups. Data from males were collected as they came out of breeding cages. In addition, the testes were excised, stripped clean of connective tissue and the epididymides, and weighed. Means for body mass of females and males, serum cholesterol, number born, and testis mass were as follows: 35.2 vs 32.5 g (P < .09), 33.9 vs 30.7 g (P < .08), 117.5 vs 110.5 mg/dL (P < .08), 14.0 vs 10.3 pups (P < .04), and 126 vs 122 mg, respectively, for LS and LC. Serum cholesterol was greater in males than in females (133.3 vs 95.1 mg/dL; P < .001), but there was no interaction between sex and selection criterion. Serum cholesterol concentration was not correlated phenotypically to number born or body mass, but it had a small negative relationship with testis mass. Therefore, we concluded that selection for litter size tended to increase serum cholesterol in addition to the increase in number born but did not change testis mass.

Animals↗
PubMed2006

Size exclusion chromatography-multiangle laser light scattering analysis of hyaluronan size distributions made by membrane-bound hyaluronan synthase.

Size exclusion chromatography-multiangle laser light scattering (SEC-MALLS) analyses of Escherichia coli membranes expressing Streptococcus equisimilis hyaluronan synthase (seHAS) demonstrated an inherent artifact (10-100 MDa) that coeluted with hyaluronan (HA) and skewed the apparent weight-average mass of HA to erroneously high values. Briefly heating samples to 65-75 degrees C eliminated this artifact and increased the yield of recovered HA due to the release of HA chains that were attached to membrane-bound HAS. Inclusion of alkaline phosphatase, which removed uridine 5'-diphosphate (UDP) produced during the reaction, improved the linearity of HA synthesis-even at high substrate use. Surprisingly, the addition of EDTA, to chelate Mg(2+) ions, did not completely stop the HAS reaction at 30 degrees C or at 4 degrees C. The best conditions for stopping the reaction without altering SEC-MALLS profiles of the product HA were to chill samples on ice in the presence of both EDTA and UDP. Even with excess substrate, the maximum size of product HA decreased as the enzyme concentration increased. Therefore, the maximum HA size made by HAS was determined by extrapolation to zero enzyme concentration. Using the above conditions, membrane-bound seHAS synthesized a cohort of HA products that steadily increased in weight-average molar mass, reaching a final maximal steady-state size of 4 to 6 MDa within 2-4 h.

Cell Membrane↗
PubMed2004

In an Aboriginal birth cohort, only child size and not birth size, predicts insulin and glucose concentrations in childhood.

The objectives were to describe cross-sectional growth in 279 Australian Aboriginal children aged 8-14 years in order to test the hypothesis that birth size interacts with child size to predict glucose and insulin metabolism. Cross-sectional growth outcomes were described using standard deviation scores or z-scores for height for age (HAZ) and weight for age (WAZ) calculated from CDC 2000 reference values in Epi Info 2000. Interrelationships were examined using standard regression models with current height and weight and birth weight, ponderal index and birth weight below the 10th percentile for gestational age. All models were adjusted for gestational age, gender and chronological age. Growth outcomes were poor with negative mean z scores for height and weight. Children with a birth weight <10th percentile for gestational age were significantly smaller and lighter than those with a birth >/= 10th percentile for gestational age, indicating post-natal catch-up growth of small babies was unlikely. After adjustment for childhood size, there was no relationship between any birth measures and fasting glucose or insulin concentrations. Current child height and weight had positive relationships with both fasting insulin and glucose concentrations with a greater proportional change for insulin. For every increment of 1cm in height or 1 kg in weight, insulin concentrations rose 2% whereas glucose increased by only 0.2%. In this indigenous Australian cohort with poor post-natal growth, only current child size is related to measures of glucose and insulin metabolism.

Australia↗
PubMed2001

Modulation of aggression in male mice: influence of group size and cage size.

Aggression in group-housed male mice is known to be influenced by both cage size and group size. However, the interdependency of these two parameters has not been studied yet. In this study, the level of aggression in groups of three, five, or eight male BALB/c mice housed in cages with a floor size of either 80 or 125 cm(2)/animal was estimated weekly after cage cleaning for a period of 14 weeks. Furthermore, urine corticosterone levels, food and water intake, body weight, and number of wounds were measured weekly. At the end of the experiment, tyrosine hydroxylase (TH) activity, testosterone levels, and weight of spleen, thymus, testes, and seminal vesicles were determined. Results indicate a moderate increase of intermale aggression in larger cages when compared to the smaller cages. Aggression in groups of eight animals was considerably higher than in groups of three animals. The increase of agonistic behavior was observed both in dominant and subordinate animals. Physiological parameters indicate differences in stress levels between dominant and subordinate animals. It is concluded that aggressive behavior in group-housed male BALB/c mice is best prevented by housing the animals in small groups of three to five animals, while decreasing floor size per animal may be used as a temporary solution to decrease high levels of aggression in an existing social group.

Aggression↗
PubMed2002

Why size matters: altering cell size.

Several genes involved in growth control have lately been demonstrated to exhibit more potent effects on cell size than on cell proliferation. Many of these genes direct protein and ribosomal synthesis, highlighting the interdependence between cell size and macromolecular content. The failure to maintain normal cell size when these genes are deregulated suggests that, in certain contexts, cell growth and division are not coupled or coordinated. Several physiological repercussions of altering cell size have been identified.

Animals↗
PubMed1994

Two-dimensional high-performance liquid chromatography using monodisperse polymer beads containing segregated chemistries prepared by pore size specific functionalization. Single-column combinations of size exclusion or ion exchange with reversed-phase chromatography.

Separation media for the complete separation of complex samples that require a combination of size exclusion or ion-exchange with reversed-phase chromatographic modes in a single column have been prepared from size monodisperse 10 microns poly(glycidyl methacrylate-co-ethylene dimethacrylate) beads using a pore size specific functionalization process. To achieve the first combination of chromatographic modes, the large pores of the beads were selectively hydrolyzed to diols using aqueous poly(styrenesulfonic acid), while highly hydrophobic octadecyl groups were introduced into the small pores by reaction of the remaining epoxide groups with octadecylamine. These beads provide excellent protein recoveries and may be used for the direct injection separation of samples containing both hydrophilic proteins and hydrophobic drugs. Beads containing diethylamino groups in the large pores and octadecyl functionalities in the small pores were also prepared by size-selective modification. A plot of log k' against ionic strength of the mobile phase for these beads shows the absence of hydrophobic interactions and documents the clean ion-exchange mechanism of protein separation. Examination of the small pores in both types of separation media confirmed that their hydrophobicity was sufficient to allow the separations of small molecules in reversed-phase mode. Column packed with these dual-chemistry beads exhibited high efficiencies and were used successfully for the separations of proteins and alkylbenzenes or drugs.

Animals↗
PubMed2006

Synthesis and characterization of new micrometer-sized radiopaque polymeric particles of narrow size distribution by a single-step swelling of uniform polystyrene template microspheres for X-ray imaging applications.

Radiopaque micron-sized non-cross-linked polystyrene/poly(2-methacryloyloxyethyl(2,3,5-triiodobenzoate)) particles of narrow size distribution were prepared by a single-step swelling of uniform polystyrene template microspheres with emulsion droplets of methylene chloride containing the initiator benzoyl peroxide and the iodinated monomer 2-methacryloyloxyethyl(2,3,5-triiodobenzoate), followed by the polymerization of the monomer within the swollen template particles at 73 degrees C. Radiopaque micron-sized uniform cross-linked polystyrene/poly(2-methacryloyloxyethyl(2,3,5-triiodobenzoate)-divinylbenzene) composite particles were prepared similarly with emulsion droplets of methylene chloride containing divinylbenzene, in addition to the initiator and the iodinated monomer. Radiopaque micron-sized uniform cross-linked poly(2-methacryloyloxyethyl(2,3,5-triiodobenzoate)-divinylbenzene) particles were formed by dissolving the template polystyrene polymer belonging to the former cross-linked composite particles. Characterization of these novel radiopaque polymeric particles was performed by methods such as FTIR, TGA, DSC, SEM, XPS, elemental analysis, and light microscopy. The influence of the weight ratio [2-methacryloyloxyethyl(2,3,5-triiodobenzoate)]/[polystyrene] and [2-methacryloyloxyethyl(2,3,5-triiodobenzoate)]/[divinylbenzene] on the bulk and surface properties of the non-cross-linked and cross-linked particles, respectively was elucidated. The radiopacity of these iodinated particles was demonstrated by an imaging technique based on X-ray absorption usually used in hospitals. These novel radiopaque particles may be used for different X-ray imaging needs, e.g., blood pool, body organs, embolization, dental composition, implants, protheses, and nanocomposites.

Absorptiometry, Photon↗
PubMed2001

Size matters: impact of item size and quantity on array choice by chimpanzees (Pan troglodytes).

The authors previously reported that chimpanzees (Pan troglodytes) showed a striking bias to select the larger of 2 candy arrays, despite a reversed reward contingency in which the animals received the smaller, nonselected array as a reward, except when Arabic numerals were used as stimuli. A perceptual or incentive-based interference occurred that was overcome by symbolic stimuli. The authors of the present study examined the impact of element size in choice arrays, using 1 to 5 large and small candies. Five test-sophisticated chimpanzees selected an array from the 2 presented during each trial. Their responses were not optimal, as animals generally selected arrays with larger total mass; thus, they received the smaller remaining array as a reward. When choice stimuli differed in size and quantity, element size was more heavily weighted, although choices reflected total candy mass. These results replicate previous findings showing chimpanzees' difficulties with quantity judgments under reverse reward contingencies and also show that individual item size exerts a more powerful interference effect.

Animals↗
PubMed2002

Determining particle size distributions in the inhalable size range for wood dust collected by air samplers.

In the absence of methods for determining particle size distributions in the inhalable size range with good discrimination, the samples collected by personal air sampling devices can only be characterized by their total mass. This parameter gives no information regarding the size distribution of the aerosol or the size-selection characteristics of different samplers in field use conditions. A method is described where the particles collected by a sampler are removed, suspended, and re-deposited on a mixed cellulose-ester filter, and examined by optical microscopy to determine particle aerodynamic diameters. This method is particularly appropriate to wood dust particles which are generally large and close to rectangular prisms in shape. Over 200 wood dust samples have been collected in three different wood-products industries, using the traditional closed-face polystyrene/acrylonitrile cassette, the Institute of Occupational Medicine inhalable sampler, and the Button sampler developed by the University of Cincinnati. A portion of these samples has been analyzed to determine the limitations of this method. Extensive quality control measures are being developed to improve the robustness of the procedure, and preliminary results suggest the method has an accuracy similar to that required of National Institute for Occupational Safety and Health (NIOSH) methods. The results should provide valuable insights into the collection characteristics of the samplers and the impact of these characteristics on comparison of sampler results to present and potential future limit values. The NIOSH Deep South Education and Research Center has a focus on research into hazards of the forestry and associated wood-products industry, and it is hoped to expand this activity in the future.

Air Movements↗
PubMed1985

The size illusion: visual and kinaesthetic information in size perception.

Earlier studies have shown the size of kinaesthetically presented two-dimensional movement patterns to be significantly overestimated. Whether this size overestimation is characteristic of the kinaesthetic system alone has not been established. Two experiments are reported which were designed to investigate size judgment made after kinaesthetic and visual pattern presentation and the effect of environmental cues on the perception of movement patterns. In experiment 1 patterns were presented kinaesthetically (experimenter guided hand movements around the outline of the pattern) or in combination with visual information given by a moving light (pinpoint light attached to the stylus which was moved around the pattern); visual and kinaesthetic cues were either congruent or conflicting with each other; and environmental cues were either present or absent. In experiment 2 static visual display was compared with visually traced pattern presentation, again with or without environmental cues. Overall the results showed that, regardless of experimental manipulation, in all cases where the information was given over time the subject perceived the pattern larger than reality. After static visual display, overestimation of size did not occur.

Adolescent↗
PubMedDate not supplied

Effects of meal size, meal type, body temperature, and body size on the specific dynamic action of the marine toad, Bufo marinus.

Specific dynamic action (SDA), the accumulated energy expended on all physiological processes associated with meal digestion, is strongly influenced by features of both the meal and the organism. We assessed the effects of meal size, meal type, body temperature, and body size on the postprandial metabolic response and calculated SDA of the marine toad, Bufo marinus. Peak postprandial rates of O(2) consumption (.V(O2)) and CO(2) production (.V(CO2)) and SDA increased with meal size (5%-20% of body mass). Postprandial metabolism was impacted by meal type; the digestion of hard-bodied superworms (Zophobas larva) and crickets was more costly than the digestion of soft-bodied earthworms and juvenile rats. An increase in body temperature (from 20 degrees to 35 degrees C) altered the postprandial metabolic profile, decreasing its duration and increasing its magnitude, but did not effect SDA, with the cost of meal digestion remaining constant across body temperatures. Allometric mass exponents were 0.69 for standard metabolic rate, 0.85 for peak postprandial .V(O2), and 1.02 for SDA; therefore, the factorial scope of peak postprandial .V(O2) increased with body mass. The mass of nutritive organs (stomach, liver, intestines, and kidneys) accounted for 38% and 20% of the variation in peak postprandial .V(O2) and SDA, respectively. Toads forced to exercise experienced 25-fold increases in .V(O2) much greater than the 5.5-fold increase experience during digestion. Controlling for meal size, meal type, and body temperature, the specific dynamic responses of B. marinus are similar to those of the congeneric Bufo alvarius, Bufo boreas, Bufo terrestris, and Bufo woodhouseii.

Animals↗
PubMed2002

Size analysis of a pressurized metered dose inhaler-delivered solution formulation by an Aerosizer-LD time-of-flight aerosol particle size spectrometer.

In a previous study, an Aerosizer-LD time-of-flight (TOF) aerosol spectrometer was shown to underestimate significantly the aerodynamic size of airborne particles produced following actuation of a suspension-based formulation delivered from a pressurized metered-dose inhaler (pMDI) via a nonelectrostatic valved holding chamber (VHC). It was postulated that the nonspecific nature of the particle detection system in terms of chemical composition was responsible for the inclusion of smaller non-drug-containing excipient particles in the measured size distribution data from this analyzer. This limitation may not apply to certain solution formulations in which the only particles remaining after the evaporation of propellant and volatile excipient (solubilizer) are composed of pure drug substance. Such a formulation (QVAR, HFA-formulated beclomethasone di-propionate [BDP]) has recently become available, and the present investigation was therefore designed to test this hypothesis. Aerosizer-LD measured mass-weighted size distribution data for QVAR had a mass median aerodynamic diameter (MMAD) close to 1.1 microm, very similar to published data for this parameter, based on measurement of the aerosol by cascade impactor followed by drug-specific assay. However, the Aerosizer-LD underestimated the spread of the size distribution significantly. The causes are believed to be a combination of two separate effects: (1) lack of sensitivity of the particle detection system to particles finer than about 0.7 microm aerodynamic diameter and (2) preferential removal of particles larger than the MMAD, either by evaporation of residual solvent (ethanol) or by inertial/gravitational deposition in the sampling arrangement upstream of the measurement zone.

Aerosols↗
PubMed1979

Effect of drug content and drug particle size on the change in particle size during tablet compression.

Three size fractions for each of three poorly soluble drugs were compressed into 10 mm diameter tablets of four different dilution ratios. The compression was carried out on a physical testing instrument at four compression levels of 49.0, 98.1, 196.2 and 294.3 MN m-2. The effect of drug content and drug particle size on the change in particle size during tableting was examined by the determination of the dissolution rate for disintegrated tablets. A linear relation was obtained when plotting 1n(T80%) versus drug content. There was a critical particle size where the phenomena of cleavage and bonding during tableting balanced each other, but this varied with drug content.

Chemistry, Pharmaceutical↗
PubMed2000

Nucleotypic effects without nuclei: genome size and erythrocyte size in mammals.

Previously reported haploid genome sizes (C-values) and erythrocyte sizes (measured as mean dry diameters) were compared for 67 species of mammals representing 31 families and 16 orders. Measurements on erythrocytes of four species of bats were also included in the study. Erythrocyte size was significantly positively correlated with genome size at each of the specific, generic, familial, and ordinal levels, with the relationship becoming much stronger following the exclusion of the order Artiodactyla, a group unique among mammals in terms of red blood cell morphology. Physiologically, these results are relevant in light of the known relationship between C-value and mass-corrected metabolic rate in homeotherms. In evolutionary terms, they provide insights into the constraints on genome expansion among mammals and are therefore of interest in attempts to solve the long-standing C-value enigma (also known as the C-value paradox).

Animals↗
PubMed1996

Estimations of average particle sizes and size distributions of commercially available human-insulin aqueous suspensions using laser-light diffraction spectroscopy.

The average diameter and size distribution of particles in commercially available isophane-insulin and zinc-insulin aqueous suspensions (11 products) were examined using laser-light diffraction spectroscopy (LLDS). Wide variation was observed between products in volume-weighted and number-weighted average diameters. The particles in the insulin aqueous suspensions were found to be mono-dispersed within relatively narrow size distributions. Sonication for a short time led to a downshift in the apparent average diameter, which was most remarkable with isophane-insulin aqueous suspensions. This could be ascribed to dispersion of aggregated needle-like crystals and/or crystal breakage. In the case of biphasic isophane-insulin aqueous suspensions, the average size as well as the size distribution shifted toward the smaller end of the scale with decrease in the isophane content.

Humans↗