A tissue heat transfer model for relating dynamic skin temperature changes to physiological parameters

A physical and mathematical model of the superficial tissues of the body is presented which takes into account tissue physiology, structure and blood supply. The model relates transient temperature changes at the skin surface to underlying physiological parameters. The analysis is based on a one-dimensional finite difference version of the bioheat equation applied to a multi-layered model of the superficial 10 mm of body tissue. Application of the model to the volar forearm predicts that under steady-state conditions skin surface temperature is maintained primarily by heat transfer from tissues below 10 mm, to a lesser extent by perfusion and to a small extent by superficial tissue metabolism. Model predictions of the reheat curve following a 15 s cold challenge to the skin agree closely with preliminary experimental data provided by thermography. The model also provides a physical explanation for the shape of the skin temperature reheat curve. Calculations further suggest that transient skin surface temperature measurements can provide a better indication of dermal perfusion than static temperature measurements as the effects of variations in environmental conditions, deep tissue temperature and tissue metabolism can be reduced.

The switching of electron flux from the cyanide-insensitive oxidase to the cytochrome pathway in mung-bean (Phaseolus aureus L.) mitochondria

The activities of the mung-bean (Phaseolus aureus L.) mitochondrial cyanide-insensitive oxidase and cytochrome pathways have been measured simultaneously. The results show that electrons can be diverted both from the alternative pathway to the cytochrome pathway and from the cytochrome to the alternative pathway. The competition of the two pathways for the available electron flux is discussed.

Hormonal regulation of lipogenic enzymes in chick embryo hepatocytes in culture. Expression of the fatty acid synthase gene is regulated at both translational and pretranslational steps

Mechanisms involved in the multihormonal regulation of fatty acid synthase have been investigated by comparing levels of its mRNA with rates of enzyme synthesis in chick embryo hepatocytes in culture. Triiodothyronine or insulin caused about a 2.5-fold increase in the relative rate of synthesis of fatty acid synthase. Together, these hormones were synergistic, stimulating enzyme synthesis by nearly 40-fold (Fischer, P.W.F., and Goodridge, A.G. (1978) Arch. Biochem. Biophys. 190, 332-344). Addition of triiodothyronine stimulated increases in mRNA levels comparable to increases in enzyme synthesis whether insulin was present or not. Thus, triiodothyronine regulates fatty acid synthase primarily by controlling the amount of its mRNA. Addition of insulin, in the presence of triiodothyronine, stimulated enzyme synthesis by 14-fold and mRNA levels by only 2-fold. In the absence of triiodothyronine, insulin had no effect on mRNA levels. Thus, insulin has a major effect on the translation of fatty acid synthase mRNA. After the addition of triiodothyronine, fatty acid synthase mRNA accumulated with sigmoidal kinetics, approaching a new steady state about 48 h after the addition of hormone. Puromycin, an inhibitor of protein synthesis, blocked the effect of triiodothyronine. We suggest that the abundances of both fatty acid synthase and malic enzyme mRNAs are regulated by a common triiodothyronine-induced peptide intermediate which has a relatively long half-life. Glucagon caused an 80% decrease in the synthesis of fatty acid synthase (Fischer, P.W.F., and Goodridge, A.G. (1978) Arch. Biochem. Biophys. 190, 332-344) and a 60% decrease in the level of fatty acid synthase mRNA. Thus, glucagon regulates fatty acid synthase by controlling the concentration of its mRNA. The synthesis of malic enzyme also was inhibited by glucagon at a pretranslational step, but the inhibition was almost complete. Thus, despite coordinated regulation of the concentrations of these enzymes during starvation and refeeding, individual hormones sometimes regulate synthesis of the two enzymes at the same step and to about the same degree and sometimes at different steps or to very different degrees.

Regulation of genes for enzymes involved in fatty acid synthesis

The levels of malic enzyme and fatty acid synthase are increased by feeding and decreased by starvation in liver in vivo and are increased by triiodothyronine and decreased by glucagon in hepatocytes in culture. Cloned malic enzyme and fatty acid synthase cDNAs are being used to analyze regulation of these unique genes. Dietary regulation of both enzymes occurs at pretranslational steps. Increased transcription and increased mRNA stability contribute about equally to a 20-fold increase in malic enzyme mRNA level when starved ducklings are refed. In contrast, a 10-fold increase in the level of fatty acid synthase mRNA is largely accounted for by increased transcription of this gene. In chick-embryo hepatocytes incubated in serum-free medium containing insulin, triiodothyronine causes a greater than 10-fold increase in levels of both malic enzyme and fatty acid synthase mRNAs. Kinetic and inhibitor experiments suggest a protein intermediate in the increases of malic enzyme and fatty acid synthase mRNAs caused by triiodothyronine. For malic enzyme, the stimulation by triiodothyronine is predominantly posttranscriptional. Glucagon decreases the level of malic enzyme mRNA by 90 to 95%, with regulation occurring at a posttranscriptional step. Inhibitor experiments suggest that stimulation of the degradation of malic enzyme mRNA is partially responsible. Glucagon inhibited fatty acid synthase mRNA level by less than 50%; the inhibited step has not been identified. Thus, the coordinated regulation of malic enzyme and fatty acid synthase proteins by nutritional state may involve different hormones regulating at different points. A surprisingly large component of the regulation is posttranscriptional.

Hormonal regulation of lipogenic enzymes in chick embryo hepatocytes in culture. Thyroid hormone and glucagon regulate malic enzyme mRNA level at post-transcriptional steps

Mechanisms involved in stimulation of the synthesis of malic enzyme by insulin and triiodothyronine and in inhibition of synthesis by glucagon have been investigated by assessing levels and rates of synthesis of malic enzyme mRNA in chick embryo hepatocytes in culture. Insulin alone had no effect on the level of malic enzyme mRNA, whereas triiodothyronine by itself caused a 7-fold increase. Insulin plus triiodothyronine caused an 11-fold increase. Glucagon caused a 93% decrease in the accumulation of malic enzyme mRNA caused by insulin plus triiodothyronine. Although the relative changes in mRNA level are smaller in magnitude, they are qualitatively similar to the effects of these hormones on synthesis of malic enzyme, suggesting that control is exerted primarily at pretranslational steps. After addition of triiodothyronine, malic enzyme mRNA accumulated with sigmoidal kinetics, approaching a new steady state at 36-48 h after adding hormone. Puromycin, an inhibitor of protein synthesis, blocked the effect of triiodothyronine if added 30 min prior to the hormone and inhibited further accumulation of malic enzyme mRNA if added 24 h after triiodothyronine. However, puromycin had no effect on the level of beta-tubulin mRNA (t1/2 = 3-5 h), suggesting that the effect of triiodothyronine on malic enzyme mRNA required synthesis of a peptide. Triiodothyronine increased transcription of the malic enzyme gene by 2-fold and level of its mRNA by 11-14-fold, indicating regulation is primarily at a post-transcriptional step. Glucagon caused malic enzyme mRNA to decay with a half-life of 1.5 h, whereas alpha-amanitin or actinomycin D, inhibitors of transcription, caused the mRNA to decay with a half-life of 8-11 h. The effect of glucagon was entirely post-transcriptional because the hormone had no effect on transcription. Taken together, these results suggest a model in which triiodothyronine regulates production of a peptide that stabilizes malic enzyme transcripts in the cytoplasm and/or nucleus. Glucagon may inhibit activity of the peptide induced by triiodothyronine.

Cadmium-binding proteins in the scallop Pecten maximus

Scallops, Pecten maximus, accumulate cadmium naturally in the digestive gland to a level of approximately 100 ppm wet weight. Of this cadmium, 60% was soluble and was composed of three weight classes as judged by Sephadex G-100 chromatography. Of the soluble cadmium, 60% was in the 55,000 molecular weight range and 20% each in an excluded fraction and a 10,000 molecular weight fraction. The 55,000 molecular weight fraction, after further purification, showed a maximum cadmium concentration of 1.4% by weight. The cadmium was thiolate bound but not as strongly bound as in the case of metallothionein. The 10,000 molecular weight fraction was a metallothionein-like protein.

The influence of the polyphenols of cider on plasmin and plasminogen activators

Preliminary findings suggested that the inhibitory activity on fibrinolysis produced by most varieties of cider is due to their content of polyphenols. In particular, the inhibitory activity co-eluted with the brown coloration on gel filtration, was removed by adsorption with polyvinylpyrrolidine, and was greatly reduced in a type of cider with a low concentration of phenolic compounds. The individual polyphenols of apple juice and ciders were examined for their ability to inhibit tissue activator, urokinase and plasmin. Neither phloridzin nor chlorogenic acid had any inhibitory activity at concentrations of 500 micrograms/ml while epicatechin had only a slight inhibitory effect at this concentration. The procyanidin fractions were markedly inhibitory on urokinase-induced clot lysis, the amidolytic activity of plasmin and on the fibrinolytic activities of plasmin, urokinase and tissue activator on fibrin plates: inhibition was noted at concentrations as low as 0.25 micrograms/ml. The order of inhibition was polymer greater than oligomer greater than trimer greater than dimer.

Platelet antibodies of the IgM class in immune thrombocytopenic purpura

The clinical course and response to therapy of patients with immune thrombocytopenic purpura (ITP) are not completely determined by the level of IgG present on the platelet surface. It is possible that antibodies of other immunoglobulin classes also play a role in platelet destruction in some of these patients. Therefore, we studied 175 patients with ITP for the presence of IgM anti-platelet antibodies using radiolabeled polyclonal or monoclonal anti-IgM. We observed that 57% of patients with clinical ITP had increased levels of IgM on their platelets, compared with normal controls and patients with thrombocytopenia who did not have ITP (less than 10%), (P less than 0.01). We obtained similar results using either radiolabeled polyclonal or monoclonal anti-IgM, reagents whose integrity was first characterized using erythrocytes coated with defined amounts of IgM antibody. Among patients with increased platelet-IgM there was a significant correlation both with the presence of increased platelet-C3 as well as the amount of platelet-C3 (P less than 0.01, r = 0.53). We demonstrated the presence of warm-reacting IgM anti-platelet antibodies in the plasma of two of these patients who were further studied. The isolated IgM fraction from these two plasmas was able to activate complement and place 3H-C3 on normal platelets. These studies demonstrate the presence of warm-reacting IgM anti-platelet antibodies in some patients with ITP. They suggest that the binding of complement to platelets by IgM antibodies may initiate platelet clearance as well as enhance the effect of IgG antibodies in ITP.

Concentration-time course of niridazole and six metabolites in the serum of four Filipinos with Schistosoma japonicum infection

Niridazole and six of its metabolites have been quantitated by high-pressure liquid chromatography in sera of four male Filipino patients with mild Schistosoma japonicum infections given single oral doses of niridazole (15 mg/kg) on two occasions 10 days apart. Of the five oxidative metabolites measured, 4-hydroxyniridazole and 4-ketoniridazole achieved the highest concentrations, reaching peak values of 0.9 +/- 0.3 microgram/ml of serum (mean +/- S.D., n = 4) and 0.7 +/- 0.1 microgram/ml of serum within 1 to 4 hr. 4-Ketoniridazole achieved peak serum levels 1 hr after the other oxidative metabolites in three of four patients and was the predominant metabolite in the serum of all patients 6 to 10 hr after dosing. By 24 hr, both 4-ketoniridazole and 4-hydroxyniridazole had largely disappeared from the serum. Niridazole and three other oxidative metabolites, 4,5-dihydroxyniridazole, 5-hydroxyniridazole and 4,5-dehydroniridazole, appeared within 1 hr in serum but failed to exceed 0.4 microgram/ml; none of these compounds were detected in the 24-hr serum samples. The pharmacokinetic pattern of niridazole and the oxidative metabolites showed marked interindividual variation but was quite reproducible in the same individual studied 10 days later. 1-Thiocarbamoyl-2-imidazolidinone was analyzed in serum samples by a different high-pressure liquid chromatographic procedure. This reductive metabolite attained maximal levels of 50 to 150 ng/ml of serum 6 to 12 hr after drug administration and remained at 40% or more of its peak concentration even after 24 hr.(ABSTRACT TRUNCATED AT 250 WORDS)

Hope Index Scale: an instrument for the objective assessment of hope

Although many clinical observations suggest that Hope influences the onset, duration, prognosis, and recovery from mental and physical illnesses, a lack of direct scientific proof persists because no method exists for the objective assessment of hope. We have now constructed the Hope Index Scale, a testing instrument for the measurement of this rather elusive human attribute. Upon testing control and experimental subjects, it was found that score distribution on the Hope Index Scale correlates negatively with Beck's Hopelessness Scale (Pearson r = -.88, P <.001) and is independent of age, race, or sex. It is concluded that this tool can help identify individuals with varying degrees of psychosocial problems and that scores of 150 or below are indicative of pathologic hope deficit often associated with suicide.

Energy conservation by the plant mitochondrial cyanide-insensitive oxidase. Some additional evidence

Several measures of energy conservation, namely ADP/O ratio, P/O ratio, ATP/O ratio and phosphorylation detected by continuous assay with purified firefly luciferase and luciferin, all show phosphorylation can occur with mung-bean mitochondria at cyanide concentrations sufficient to inhibit the cytochrome oxidase system. Phosphorylation in the presence of cyanide is uncoupler- oligomycin- and salicylhydroxamate-sensitive. The participation of phosphorylation site 1 is excluded, phosphorylation being attributable to a single phosphorylation site associated with the cyanide-insensitive oxidase. The cyanide-insensitive oxidase has also been shown to support a variety of other energy-linked functions, namely, Ca2+ uptake, reversed electron transport and the maintenance of a membrane potential detected by the dye probes 8-anilinonaphthalene-1-sulphonate and safranine. High concentrations of cyanide have uncoupler-like activity, decreasing the ADP/O ratio and the t 1/2 for the decay of a pH pulse through the the mitochondrial membrane. This uncoupler-like effect is most marked with aged mitochondria. The observations of energy conservation attributable to the cyanide-insensitive oxidase are compared with other reports where it is concluded that the alternative oxidase is uncoupled.

Effects of the cyanine dye 3,3'-dipropylthiocarbocyanine on mitochondrial energy conservation

Mitochondrial respiration and oxidative phosphorylation were inhibited by the membrane potential probe 3,3'-dipropylthiocarbocyanine [diS-C3-(5)]. Evidence is presented that suggests that the dye acts as both an inhibitor of electron transport and an uncoupler of oxidative phosphorylation.

Cyanide-insensitive oxidation of ascorbate + NNN'N'-tetramethyl-p-phenylenediamine mixture by mung-bean (Phaseolus aureus) mitochondria. An energy-linked function

Freshly prepared washed or purified mung-bean (Phaseolus aureus) mitochondria utilize oxygen with ascorbate/tetramethyl-p-phenylenediamine mixture as electron donor in the presence of KCN. ATP control of the oxygen uptake can be observed with very fresh mitochondria. The electron flow, which is inhibited by antimycin A, salicylhydroxamic acid or octylguanidine, takes place by reversed electron transport through phosphorylation site II and thence to oxygen through the cyanide-insensitive pathway. Oligomycin and low concentrations of uncoupler partially inhibit the oxygen uptake in a manner similar to that observed for other energy-linked functions of plant mitochondria. An antimycin A-insensitive oxygen uptake occurs if high concentrations of uncoupler are used, indicating that the pathway of electron flow has been altered. The process of cyanide-insensitive ascorbate oxidation is self-starting, and, since it occurs in the presence of oligomycin, it is concluded that the reaction can be energized by a single energy-conservation site associated with the cyanide-insensitive oxidase pathway.

An estimation of the proton conductance of the inner membrane of turnip (Brassica napus L.) mitochondria

The permeability of the inner membrane of turnip mitochondria to H(+) and OH(-) ions has been investigated using an acid pulse technique. The rate of decay of a H(+) pulse across the inner membrane is exponential having first-order kinetics and gives t 1/2 values of approx 54 s at neutral pH and at 25° C. Valinomycin or 1799 alone have little effect on t 1/2 values, whereas in combination, values of <15 s are observed. Nigericin produces a similar effect. The effective proton conductance of the inner membrane near pH 7 at 25° C is 0.27 nmol H(+) min(-1) mg protein(-1) mV(-1). The results suggest that at neutral pH, the inner membrane of plant mitochondria is relatively impermeable to H(+) and OH(-) ions.

Sources of self-esteem and the person X situation controversy

This study investigated various sources of self-esteem contributing to a global measure of self-esteem. Self-esteem scores for 79 male and 56 female undergraduates on a sentence completion test were analyzed by content area and sources of self-esteem were found. As predicted, sex differences were found for major sources of self-esteem. Results were discussed in terms of the utility of the self-esteem construct in interactions of persons and situations.

Studies of electron transport in dry and imbibed peanut embryos

The respiration of isolated peanut (Arachis hypogea) embryos has been studied with dry and wet embryos and mitochondria prepared after various times of imbibition. Dry seeds respire slowly, apparently via a respiratory chain which is deficient in cytochrome c. Cytochrome c-deficient mitochondria have been prepared from the embryos up to 16 hours following imbibition. These mitochondria can metabolize reduced nicotinamide adenine dinucleotide and succinate, without respiratory control by ADP, but they do phosphorylate. Added cytochrome c increases both respiration and phosphorylation of these embryonic mitochondria. When growth starts, mitochondria appear which are similar to those isolated from other mature plant tissues; they have respiratory control and can actively metabolize succinate, malate, and reduced nicotinamide adenine dinucleotide. These latter mitochondria contain a concentration of cytochrome c comparable to that found in mitochondria isolated from other mature plant tissues. It is suggested that the earliest type of mitochondria may be required to control respiration in the dry and the recently wetted embryo.

Energy-linked Functions of Submitochondrial Particles Prepared from Mung Bean Mitochondria

Submitochondrial particles from mung bean mitochondria (Phaseolus aureus) are able to catalyze an energy-linked reduced nicotinamide adenine dinucleotide-nicotinamide adenine dinucleotide phosphate transhydrogenase reaction supported by ATP or by aerobically generated high energy intermediates. The energy transfer pathway appears to differ from that utilized for oxidative phosphorylation.Mung bean submitochondrial particles will also reduce nicotinamide adenine dinucleotide by reversed electron transport from succinate or ascorbate tetramethyl-p-phenylenediamine. The energy requirement can be met by ATP or by aerobically generated high energy intermediates.A scheme for the energy transduction pathway in mung beans is postulated from the effects of inhibitors and uncouplers of energy transfer on transhydrogenase and reversed electron transfer reactions.

Preparation and some properties of submitochondrial particles from tightly coupled mung bean mitochondria

Osmotic shock was found to be better than freezing and thawing, a French press, or sonic oscillation for the preparation of submitochondrial particles from mung bean (Phaseolus aureus) hypocotyl mitochondria. Particles prepared by osmotic shock rapidly oxidize reduced nicotinamide adenine dinucleotide and succinate, but they oxidize malate slowly. NADH oxidation was slightly stimulated by cytochrome c, ATP, and ADP; succinate oxidation was markedly increased by ATP, slightly by ADP and cytochrome c; and malate oxidation required the addition of NAD(+) NADH oxidation is inhibited weakly by amytal, completely by antimycin A and KCN, but not by rotenone. Chlorsuccinate, malonate, antimycin A, and KCN inhibit succinate oxidation. The action of antimycin A and KCN is incomplete, while chlorsuccinate and malonate were competitive inhibitors. Antimycin A combined stoichiometrically with particle protein in the ratio of 0.23 millimicromole per milligram of protein.Oligomycin and bis(hexafluoroacetonitryl) acetone, a potent uncoupler of oxidative phosphorylation, were without effect on oxygen uptake but did influence the ATP-stimulated onset of respiration when succinate was substrate. Fresh particles were markedly inhibited by oxtylguanidine, indicating energy conservation, but this inhibition decreased on storage of the particles.Spectra show the presence of cytochrome components the same as those of the intact mung bean mitochondrion, but present at higher concentrations. The molar concentrations of the particle cytochromes were two to three times those of the intact mitochondrion and the molar ratios were calculated as 0.9:1.0:1.0:2.8 for cytochromes a:b:c:flavoprotein, respectively.

Effects of guanidine inhibitors on mung bean mitochondria

The effects of phenylethylbiguanidide, decamethylenediguanidide, and octylguanidine have been studied with mung bean hypocotyl mitochondria (Phaseolus aureus var. Jumbo) supplied with malate, reduced nicotinamide adenine dinucleotide, succinate, or ascorbate-tetramethyl-p-phenylenediamine as substrates. The guanidines act as energy transfer inhibitors, all three inhibiting all three phosphorylation sites. Phenylethylbiguanidide causes only partial inhibition even at relatively high concentrations. Decamethylenediguanidide inhibits about 70% of the malate respiration, 55% of the succinate respiration, and 35% of the ascorbate-tetramethyl-p-phenylenediamine respiration.Octylguanidine inhibits all three phosphorylation sites and the cyanide-insensitive respiration, but to differing extents and at different concentrations. Both states 3 and 4 are inhibited by octylguanidine. Inhibition of state 4 is preceded by an uncoupling action at lower concentrations of inhibitor, while inhibition of state 3 is influenced by the state of the mitochondria when the inhibitor is added. Application of the guanidine to state 4 mitochondria is more effective than application to mitochondria already in state 3.