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At least 217 records · Page 12Linked to original sources
PubMed2005

Spatial control of protein within biomimetically nucleated mineral.

An ideal approach for bone tissue engineering allows for osteoconductivity, osteoinductivity, and cell transplantation. In this study, we examined coprecipitation and surface adsorption schemes with respect to their abilities to control the spatial quantity and localization of a model protein, bovine serum albumin (BSA), that is incorporated into a biomimetic apatite layer nucleated onto polylactic-co-glycolic acid (PLGA) films. Protein incorporation was characterized by determining protein: presence, quantity loaded, retention, effects on mineral morphology, and localization. FT-IR confirmed the presence of protein in all coprecipitation samples with stronger peaks in the coprecipitated samples compared to the surface adsorbed samples. Coprecipitation resulted in higher loading capacities and higher protein retention versus adsorption. Protein incorporation via coprecipitation changed the mineral morphology from sharp plate-like structures to more rounded structures, whereas, surface adsorption did not change mineral structure. By using confocal microscopy to examine the incorporation of fluorescently labeled proteins, spatial control over protein localization was exhibited. By controlling the loading quantity and localization of the model protein through the mineral thickness, a desired release profile can be achieved. A desired and effective delivery system of biological agents utilizing coprecipitation for bone regeneration can therefore be designed.

Adsorption↗
PubMed1993

Blinking, alpha brain waves and smoking in schizophrenia.

Blink rates (BR) and alpha brain waves were studied in 13 schizophrenic and 13 healthy smokers under conditions of smoking deprivation as well as smoking saturation and under different task conditions of smooth pursuit eye movements. Task conditions significantly changed BR and alpha power; smoking enhanced BR and alpha frequency, the latter effect being especially pronounced in schizophrenics for F3-F4 leadings. Concerning BR, groups differed significantly as long as smoking quantity was not statistically controlled. BR, alpha power and smoking quantity were consistently correlated above chance levels. Results are discussed with respect to the blink alpha neurocircuit model.

Adult↗
PubMedDate not supplied

Evaluation of inactivated influenza vaccines in market turkeys.

The potency and efficacy of an inactivated oil-emulsion influenza vaccine against infection, illness, and virus shed was studied in market turkeys. No undesirable local or systemic reactions occurred following vaccination. The vaccine induced measurable antibody to nucleocapsid and hemagglutinin antigens of the virus. Challenged unvaccinated controls experienced airsacculitis, but none of the vaccinates were affected. The percent of the birds shedding virus following intranasal challenge was lower in the vaccinated groups than in the controls, and the quantity of virus shed was also smaller in vaccinated groups than in the controls.

Animals↗
PubMedDate not supplied

Quantitative studies on the villi, trophoblast and intervillous pores of placentae from women with well-controlled diabetes mellitus.

Human placentae from well-controlled diabetic women were collected after 37 weeks of gestation and divided into three groups according to the duration and severity of diabetes mellitus established by White classification criteria. A fourth group of subjects served as matched controls. Various morphometric variables not estimated hitherto (including the star volumes of villous 'domains' and intervillous 'pores' and trophoblast surface denudation) were assessed stereologically. The aims were to test whether or not (1) control values of these structural quantities are preserved in well-controlled diabetes mellitus, and (2) differences occurred between alternative diabetic groups. Placental specimens were obtained by systematic random sampling procedures and paraffin sections were cut at random positions and orientations. Volume densities of peripheral (terminal+intermediate) villi and intervillous spaces were estimated by test point counting and multiplied by placental volumes in order to convert them into absolute volumes. Volume estimates were also obtained for trophoblast, syncytiotrophoblast nuclei and intervillous fibrin-type fibrinoid. Villous surface areas were estimated by intersection counting and the star volumes of villi and intervillous pores were obtained by measuring the lengths of point-sampled intercepts. Calculations were also made of the theoretical numbers of villous domains and intervillous pores and of the numbers of syncytiotrophoblast nuclei. No significant differences were detected between control and diabetic placentae, or between White classes, for any of the estimated quantities. It is concluded that normal values are preserved by good glycaemic control regardless of diabetic grouping.

Adult↗
PubMed1986

Hormonal modulation of the quantity and in situ activity of tyrosine hydroxylase in neurites of the median eminence.

The role of ovarian hormones in the control of the quantity and activity of tyrosine hydroxylase (TyrOHase) in neurites of the median eminence of the rat was investigated. TyrOHase was quantified by an immunoblot assay using purified rat TyrOHase as the standard. Treatment of ovariectomized animals with progesterone, but not estradiol, resulted in a significant reduction in the amount of TyrOHase in the median eminence. The in situ activity of the enzyme was assayed by measuring the rate of synthesis of L-3,4-dihydroxyphenylalanine (dopa), and the results were expressed as mol of dopa per hr per mol of TyrOHase. In animals treated with both estradiol and progesterone for 3 days, the in situ activity of TyrOHase in the median eminence was 114 +/- 13.5 (mean +/- SEM) compared to 26 +/- 4.7 for the controls. Estradiol or progesterone alone was much less effective than was the combination of estradiol and progesterone. To ascertain whether the effect of estradiol and progesterone on TyrOHase activity was reflected in the secretion of dopamine into hypophyseal portal blood, ovariectomized rats were treated for 3 days with both estradiol and progesterone or with the solvent vehicle. The concentration of dopamine in portal plasma of the hormone-treated animals was 1.93 +/- 0.533 ng/ml compared to 0.34 +/- 0.094 ng/ml in vehicle-treated animals. We conclude that the quantity and in situ molar activity of TyrOHase in neurites of the median eminence as well as the secretion of dopamine from these neurites are modulated by the combined action of estradiol and progesterone.

Animals↗
PubMed2005

[Effects of expansion fashion and expansion quantity on retention of cement-expanded composite screw post].

OBJECTIVE: To study the effects of expansion fashion and expansion quantity on retention of cement-expanded composition screw post (CECSP). METHODS: Ninety simulated tooth roots made of polymethylmethacrylate were divided into ten groups, each fashion induded five groups. The expanded plastic sheath of tricuspid valve was made with the special separated valve device and cemented and tightened up into root with the screw post at the same time by ZPC. Then the root and screw post-core system was tested by the speed of 10 mm/min on the INSTRON 4302 and the retention force was recorded. RESULTS: It appeared that the difference between different expansion fashion and different expansion quantity were significantly (P < 0.05). The retention of expansion fashion one was significantly greater than those of fashion two. The retention was best when expansion quantity was within 10%. CONCLUSION: During clinic operation, we should apply definite fashion and control the expansion quantity within 10%, and the screw post should tighten up to the bottom of prepared root.

Bone Screws↗
PubMed1978

Control of somite number in normal and amputated mutant mouse embryos: an experimental and a theoretical analysis.

A regulation is shown for size and number of serially repeated axial structures, the somites, in a mammalian embryo. The mammalian embryo is normally inaccessible to operation at post-implantation stages. This problem is resolved by the quantitative analysis of somite size, number and development in a recessive mutant of the mouse, amputated, whose axial length is greatly reduced. The effect of the gene simulates an experiment ablating part of the embryonic tissue available for somitic segmentation. Regulation occurs at the time when the somite is first formed, by control of the quantity of cells included in each new somite. A model is devised for the control of somitic segmentation which explains most of the features observed and which can be simulated on a computer.

Amputation, Surgical↗
PubMed1987

Social interaction following severe closed head injury.

This paper describes research which sought to investigate and describe the interpersonal relationships and vulnerability to psychiatric disturbance in severely closed head injured subjects. The head injured subjects were severely injured, with mild or extremely severely injured individuals being excluded from this study. Self-report by the injured individual was compared with relatives' reports. Fifteen head injured people were individually matched with non-head injured people from the general population who acted as controls. Each subject nominated one 'close other' for comparative interview. The dependent variables included interpersonal relationships, non-psychotic psychiatric disturbance and behavioural change. The head injured group differed significantly from the control group in the quantity of interaction but not in the perceived quality of interaction. The groups differed significantly on behavioural change. No significant difference was found between responses given by the head injured and their 'close other' compared with the controls. Deficient quantity of interpersonal relationships and greater vulnerability to psychiatric disorders was shown in this sample. Further research on the assessment of long-term social outcome and psychiatric stability in the head injured could assist in the improved long-term rehabilitation of the survivors.

Adult↗
PubMed1990

Interleukin-2 production of T cells in atopic dermatitis.

Patients with atopic dermatitis (AD) were treated with Tranilast, Interleukin-2 (IL-2) (production of T cells in vitro) and blood histamine values, before and after Tranilast therapy, were measured, and the following results were obtained: 1) Compared with healthy controls, the IL-2 producing ability of T cells in patients with AD was increased. 2) After Tranilast therapy, IL-2 production of T cells in AD decreased in quantity to the control level. 3) Skin lesion severities of AD were correlated with the quantity of IL-2 production of T cells. 4) Serum histamine levels were not significantly different between AD patients and healthy controls, before or after Tranilast therapy.

Adult↗
PubMed1975

Toxic effects of a new boron containing heterocycle: 4,4,8,8-tetraethyl-3,3a,4,8-tetrahydro 3a,4a,4-diazabora-S-indacene.

LD50 values in mice for 4,4,8,8-tetraethyl-3,3a,4,8-tetrahydro-3a,4a,4-diazabora-S-indacene (Myborin) were determined by the ip, po, and sc routes. The LD50 value for ip was 69.5 mg/kg found by the method of Litchfield and Wilcoxon, with upper and lower confidence limits of 77.8 and 62.1 mg/kg. Oral and sc LD50's were approximated after the method of Deichmann and LeBlanc and were found to be 180 mg/kg (po) and 420 mg/kg (sc). Each of these values has a confidence range of +/- 30%. Myborin induced convulsions, hyperreflexia, and death accompanied by tetany when given by either the ip or oral routes. Moreover, Myborin induced porphyria in animals surviving for 24 hr after these routes of administration and in virtually all animals dosed sc. Death by the sc route is probably a result of acute porphyria. Hepatomegaly and skin photosensitivity were demonstrated to be profound. Boron levels in the livers of mice were determined colorimetrically 24 hr after ip injections of Myborin and in untreated control mice. The quantity of boron found in the experimental group was 15.46 mug/g wet liver as compared to 8.11 mug/g wet liver for controls (P less than 0.01). The difference corresponds to 23% of the injected quantity of boron.

Animals↗
PubMed1975

A critical evaluation of body weight loss following lateral hypothalamic lesions.

The possibility that factors in addition to motivational or psychomotor deficits contribute to body weight losses following lateral hypothalamic (LH) lesions was assessed in 2 experiments. Rats with LH lesions failed to gain weight when compared to sham-operated controls, when equal quantities of nutrients were given by intragastric feeding. They also lost weight more rapidly than controls under total starvation conditions regardless of whether food was present or absent in the G1 tract prior to surgery. These results could not be explained on the basis of differences in urine or fecal output or activity levels. An increase in core temperature was found in LH lesioned rats immediately following surgery and throughout the experimental period. These results suggest that lateral hypothalamic lesions induce a metabolic impairment.

Animals↗
PubMed1993

Simple method for production of internal control DNA for Mycobacterium tuberculosis polymerase chain reaction assays.

A simple method for the production of internal control DNA for two well-established Mycobacterium tuberculosis polymerase chain reaction assays is described. The internal controls were produced from Mycobacterium kansasii DNA with the same primers but at a lower annealing temperature than that used in the standard assays. In both assays, therefore, the internal control DNA has the same primer-binding sequences at the target DNA. One-microgram quantities of internal control DNA which was not contaminated with target DNA could easily be produced by this method. The inclusion of the internal control in the reaction mixture did not affect the efficiency of amplification of the target DNA. The method is simple and rapid and should be adaptable to most M. tuberculosis polymerase chain reaction assays.

DNA, Bacterial↗
PubMed1999

Fluxes and metabolic pools as model traits for quantitative genetics. I. The L-shaped distribution of gene effects.

The fluxes through metabolic pathways can be considered as model quantitative traits, whose QTL are the polymorphic loci controlling the activity or quantity of the enzymes. Relying on metabolic control theory, we investigated the relationships between the variations of enzyme activity along metabolic pathways and the variations of the flux in a population with biallelic QTL. Two kinds of variations were taken into account, the variation of the average enzyme activity across the loci, and the variation of the activity of each enzyme of the pathway among the individuals of the population. We proposed analytical approximations for the flux mean and variance in the population as well as for the additive and dominance variances of the individual QTL. Monte Carlo simulations based on these approximations showed that an L-shaped distribution of the contributions of individual QTL to the flux variance (R(2)) is consistently expected in an F(2) progeny. This result could partly account for the classically observed L-shaped distribution of QTL effects for quantitative traits. The high correlation we found between R(2) value and flux control coefficients variance suggests that such a distribution is an intrinsic property of metabolic pathways due to the summation property of control coefficients.

Enzymes↗
PubMed1986

Effects of fluoride on protein secretion and removal during enamel development in the rat.

Enamel maturation consists of a loss of the early secreted matrix proteins and an increase in mineralization. This study investigated the changes in enamel proteins of the rat incisor, caused by the ingestion of fluoride at various stages of enamel formation. Rats were given 0, 10, 25, 50, or 100 ppm fluoride in drinking water for five weeks. Changes in the protein composition of the secretory, early-maturation, and late-maturation enamel were investigated by means of gel filtration chromatography and polyacrylamide gel electrophoresis. No differences were found between fluorosed and control enamel proteins in secretory enamel. In fluorosed early-maturation enamel, amelogenins were retained in larger quantities than in control enamel in animals ingesting 25 ppm fluoride or greater. At the late-maturation stage of enamel formation, only enamel from animals ingesting 100 ppm fluoride in drinking water contained more protein, when compared with control enamel. This study suggests that fluoride ingestion levels resulting in enamel fluorosis inhibit the mechanisms involved in the removal of proteins during enamel maturation.

Amelogenesis↗
PubMed1999

A theoretical analysis of preferred pedaling rate selection in endurance cycling.

One objective of this study was to investigate whether neuromuscular quantities were associated with preferred pedaling rate selection during submaximal steady-state cycling from a theoretical perspective using a musculoskeletal model with an optimal control analysis. Specific neuromuscular quantities of interest were the individual muscle activation, force, stress and endurance. To achieve this objective, a forward dynamic model of cycling and optimization framework were used to simulate pedaling at three different rates of 75, 90 and 105 rpm at 265 W. The pedaling simulations were produced by optimizing the individual muscle excitation timing and magnitude to reproduce experimentally collected data. The results from these pedaling simulations indicated that all neuromuscular quantities were minimized at 90 rpm when summed across muscles. In the context of endurance cycling, these results suggest that minimizing neuromuscular fatigue is an important mechanism in pedaling rate selection. A second objective was to determine whether any of these quantities could be used to predict the preferred pedaling rate. By using the quantities with the strongest quadratic trends as the performance criterion to be minimized in an optimal control analysis, these quantities were analyzed to assess whether they could be further minimized at 90 rpm and produce normal pedaling mechanics. The results showed that both the integrated muscle activation and average endurance summed across all muscles could be further minimized at 90 rpm indicating that these quantities cannot be used individually to predict preferred pedaling rates.

Adult↗
PubMed1993

Relationships among protein and albumin concentrations and oncotic pressure in nephrotic plasma.

We determined oncotic pressure (pi) by membrane osmometry and assayed total protein (TP) and albumin (Alb) concentrations in plasma of 102 nephrotic subjects and 27 healthy controls. All three quantities were markedly depressed in the nephrotic group. When plasma was serially diluted and concentrated, nephrotic but not control plasma also exhibited a highly variable change point in the nonlinear relationship between TP or Alb and pi. Absent a unique change point, we developed quadratic models which incorporated TP, Alb, and (TP x Alb) to prospectively predict pi in unperturbed plasma. The ability of the most successful quadratic model to predict pi in afferent or efferent arteriolar plasma was limited; the prediction errors reached 10 mmHg in nephrotic and 6 mmHg in control subjects. The nephrotic model coefficients also differed significantly from control and pointed to an important influence of nonalbumin proteins on pi in nephrotic plasma. Investigation of the intrinsic membrane properties of diseased glomerular capillary walls requires precise knowledge of pi. For this purpose we recommend that pi be directly determined by membrane osmometry rather than calculated from protein concentration(s).

Adolescent↗