Sub-1.4 cm3 capsule for detecting labile inflammatory biomarkers in situ

Transient molecules in the gastrointestinal tract such as nitric oxide and hydrogen sulfide are key signals and mediators of inflammation. Owing to their highly reactive nature and extremely short lifetime in the body, these molecules are difficult to detect. Here we develop a miniaturized device that integrates genetically engineered probiotic biosensors with a custom-designed photodetector and readout chip to track these molecules in the gastrointestinal tract. Leveraging the molecular specificity of living sensors1, we genetically encoded bacteria to respond to inflammation-associated molecules by producing luminescence. Low-power electronic readout circuits2 integrated into the device convert the light emitted by the encapsulated bacteria to a wireless signal. We demonstrate in vivo biosensor monitoring in the gastrointestinal tract of small and large animal models and the integration of all components into a sub-1.4 cm3 form factor that is compatible with ingestion and capable of supporting wireless communication. With this device, diseases such as inflammatory bowel disease could be diagnosed earlier than is currently possible, and disease progression could be more accurately tracked. The wireless detection of short-lived, disease-associated molecules with our device could also support timely communication between patients and caregivers, as well as remote personalized care.

Pulse-shape discrimination against low-energy Ar-39 beta decays in liquid argon with 4.5 tonne-years of DEAP-3600 data

The DEAP-3600 detector searches for the scintillation signal from dark matter particles scattering on a 3.3 tonne liquid argon target. The largest background comes from 39 Ar beta decays and is suppressed using pulse-shape discrimination (PSD). We use two types of PSD estimator: the prompt-fraction, which considers the fraction of the scintillation signal in a narrow and a wide time window around the event peak, and the log-likelihood-ratio, which compares the observed photon arrival times to a signal and a background model. We furthermore use two algorithms to determine the number of photons detected at a given time: (1) simply dividing the charge of each PMT pulse by the mean single-photoelectron charge, and (2) a likelihood analysis that considers the probability to detect a certain number of photons at a given time, based on a model for the scintillation pulse shape and for afterpulsing in the light detectors. The prompt-fraction performs approximately as well as the log-likelihood-ratio PSD algorithm if the photon detection times are not biased by detector effects. We explain this result using a model for the information carried by scintillation photons as a function of the time when they are detected.

First Results from the DEAP-3600 Dark Matter Search with Argon at SNOLAB

This Letter reports the first results of a direct dark matter search with the DEAP-3600 single-phase liquid argon (LAr) detector. The experiment was performed 2 km underground at SNOLAB (Sudbury, Canada) utilizing a large target mass, with the LAr target contained in a spherical acrylic vessel of 3600 kg capacity. The LAr is viewed by an array of PMTs, which would register scintillation light produced by rare nuclear recoil signals induced by dark matter particle scattering. An analysis of 4.44 live days (fiducial exposure of 9.87 ton day) of data taken during the initial filling phase demonstrates the best electronic recoil rejection using pulse-shape discrimination in argon, with leakage <1.2×10^{-7} (90% C.L.) between 15 and 31  keV_{ee}. No candidate signal events are observed, which results in the leading limit on weakly interacting massive particle (WIMP)-nucleon spin-independent cross section on argon, <1.2×10^{-44}  cm^{2} for a 100  GeV/c^{2} WIMP mass (90% C.L.).

Search for low-mass weakly interacting massive particles using voltage-assisted calorimetric ionization detection in the SuperCDMS experiment

SuperCDMS is an experiment designed to directly detect weakly interacting massive particles (WIMPs), a favored candidate for dark matter ubiquitous in the Universe. In this Letter, we present WIMP-search results using a calorimetric technique we call CDMSlite, which relies on voltage-assisted Luke-Neganov amplification of the ionization energy deposited by particle interactions. The data were collected with a single 0.6 kg germanium detector running for ten live days at the Soudan Underground Laboratory. A low energy threshold of 170  eVee (electron equivalent) was obtained, which allows us to constrain new WIMP-nucleon spin-independent parameter space for WIMP masses below 6  GeV/c2.

Silicon detector dark matter results from the final exposure of CDMS II

We report results of a search for weakly interacting massive particles (WIMPS) with the silicon detectors of the CDMS II experiment. This blind analysis of 140.2 kg day of data taken between July 2007 and September 2008 revealed three WIMP-candidate events with a surface-event background estimate of 0.41(-0.08)(+0.20)(stat)(-0.24)(+0.28)(syst). Other known backgrounds from neutrons and 206Pb are limited to <0.13 and <0.08 events at the 90% confidence level, respectively. The exposure of this analysis is equivalent to 23.4 kg day for a recoil energy range of 7-100 keV for a WIMP of mass 10  GeV/c2. The probability that the known backgrounds would produce three or more events in the signal region is 5.4%. A profile likelihood ratio test of the three events that includes the measured recoil energies gives a 0.19% probability for the known-background-only hypothesis when tested against the alternative WIMP+background hypothesis. The highest likelihood occurs for a WIMP mass of 8.6  GeV/c2 and WIMP-nucleon cross section of 1.9×10(-41)  cm2.

Vegetative storage proteins in overwintering storage organs of forage legumes: roles and regulation

In perennial forage legumes such as alfalfa (Medicago sativa L.) and white clover (Trifolium repens L.), vegetative storage proteins are extensively mobilized to meet the nitrogen requirements of new shoot growth in spring or after cutting in summer. The 32-kDa alfalfa storage protein possesses high homology with class III chitinases, belonging to a group of pathogenesis-related proteins that possess antifreeze protein properties in some species and exhibit chitinolytic activity in vitro. This protein and the corresponding mRNA accumulate in taproots of cold-hardy culti vars during acclimation for winter, and in response to short-day conditions in controlled environments. The 17.3-kDa storage protein of white clover possesses high homology with pathogenesis-related proteins and abscisic- acid-responsive proteins from several legume species and has characteristics common to stress-responsive proteins. Low temperature enhances accumulation of this 17.3-kDa protein and its corresponding transcript. Exogenous abscisic acid stimulates the accumulation of vegetative storage proteins and their transcripts in both legume species. These observations suggest that vegetative storage proteins do not exclusively serve as nitrogen reserves during specific phases of legume development, but may play important adaptive roles in plant protection against abiotic (low temperature) and biotic (pathogen attack) stresses.Key words: nitrogen reserves, vegetative storage proteins, regulation, cold tolerance, chitinase, pathogenesis-related proteins.

Proteolytic release and nuclear translocation of Notch-1 are induced by presenilin-1 and impaired by pathogenic presenilin-1 mutations

The Notch family of proteins consists of transmembrane receptors that play a critical role in the determination of cell fate. Genetic studies in Caenorhabditis elegans suggest that the presenilin proteins, which are associated with familial Alzheimer's disease, regulate Notch signaling. Here we show that proteolytic release of the Notch-1 intracellular domain (NICD), an essential step in the activation of Notch signaling, is markedly reduced in presenilin-1 (PS1)-deficient cells and is restored by PS1 expression. Nuclear translocation of the NICD is also markedly reduced in PS1-deficient cells, resulting in reduced transcriptional activation. Mutations in PS1 that are associated with familial Alzheimer's disease impair the ability of PS1 to induce proteolytic release of the NICD and nuclear translocation of the cleaved protein. These results suggest that PS1 plays a central role in the proteolytic activation of the Notch-1-signaling pathway and that this function is impaired by pathogenic PS1 mutations. Thus, dysregulation of proteolytic function may underlie the mechanism by which presenilin mutations cause Alzheimer's disease.

Differential accumulation of two glycine-rich proteins during cold-acclimation alfalfa

Two mRNAs, MsaCiA and MsaCiB, encoding for proteins harboring glycine-rich motifs, accumulate in alfalfa during cold acclimation. Fusion polypeptides containing the amino acid sequences deduced from these mRNAs were produced in Escherichia coli and used to raise antibodies. Each antibody cross-reacted specifically with soluble polypeptides, MSACIA-32 and MSACIB, respectively. These polypeptides were detectable only in crowns of cold-acclimated plants, even though MsaCiA mRNA accumulated in both crows and leaves during cold acclimation. The analysis of parietal proteins showed that several MSACIA-related proteins, with a molecular mass of 32, 41 and 68 kDa, did accumulate in leaf cell walls and one of 59 kDa crown cell walls. This diversity is most probably due to a tissue-specific maturation of MSACIA. A discrepancy was found between the time-course of accumulation of MSACIB and the one of the corresponding transcript. These results indicate that timing and localization of MSACIA and MSACIB expression are different, and suggest that this differential expression involves both transcriptional and post-transcriptional events. Comparisons made among six cultivars of contrasting freezing tolerance suggest that low tolerance could be explained by failure to accumulate proteins like MSACIA and MSACIB at a sufficient level.

Changes in ABA and gene expression in cold-acclimated sugar maple

To determine if cold acclimation of sugar maple (Acer saccharum Marsh.) is associated with specific changes in gene expression under natural hardening conditions, we compared bud and root translatable mRNAs of potted maple seedlings after cold acclimation under natural conditions and following spring dehardening. Cold-hardened roots and buds were sampled in January when tissues reached their maximum hardiness. Freezing tolerance, expressed as the lethal temperature for 50% of the tissues (LT(50)), was estimated at -17 degrees C for roots, and at lower than -36 degrees C for buds. Approximately ten transcripts were specifically synthesized in cold-acclimated buds, or were more abundant in cold-acclimated buds than in unhardened buds. Cold hardening was also associated with changes in translation. At least five translation products were more abundant in cold-acclimated buds and roots compared with unhardened tissues. Abscisic acid (ABA) concentration increased approximately tenfold in the xylem sap following winter acclimation, and the maximum concentration was reached just before maximal acclimation. We discuss the potential involvement of ABA in the observed modification of gene expression during cold hardening.

On the source of the oscillations observed during in vivo zinc phthalocyanine fluorescence pharmacokinetic measurements in mice

Surface-detected fluorescence spectroscopy can be used to monitor the pharmacokinetics of uptake and clearance of red-absorbing fluorophores such as zinc(II) phthalocyanine (ZnPc) in vivo. When this technique is applied to mice that have been fed on a normal chlorophyll-based diet, and particularly when measurements are performed in the abdominal region, oscillations are sometimes observed superimposed on the pharmacokinetic curve of the ZnPc. An oscillatory signal has also been observed arising from the abdominal region of control mice fed a normal diet but not injected with the ZnPc photosensitizer; this oscillatory component to the signal is reduced when mice are fed a chlorophyll-free diet. The oscillatory signal component has been attributed to fluorescence arising from chlorophyll derivatives (pheophorbide/pheophytin) contained in the rodent food, whose concentration in the measured abdominal region changes substantially with time, presumably due to digestive processes. Thus it is important to be aware of the possibility of such artifactual contributions to in vivo fluorescence pharmacokinetic measurements.

Effects of soil freezing and drought stress on abscisic acid content of sugar maple sap and leaves

In 1991 and 1992, mature maple trees (Acer saccharum Marsh.) were freeze-stressed or drought-stressed by preventing precipitation (snow or rain) from reaching the forest floor under selected trees. Lack of snow cover caused a decrease in soil temperature to well below 0 degrees C from December to April and a lowering of the soil water content to 10%. The abscisic acid (ABA) concentration in the spring sap of deep-soil frost-stressed trees was significantly higher than in control or drought-stressed trees. The increase in ABA concentration in the xylem sap in the spring of 1991 and 1992 preceded symptoms of canopy decline and a decrease in leaf area that were observed during the summers of 1991 and 1992. These results suggest a role for ABA in root-to-shoot communication in response to environmental stress. The largest differences in ABA concentration induced by the treatments was found in sap collected at the end of sap flow. The increase in ABA concentration in spring sap at the end of the sap flow could be used as an early indicator of stress suffered by trees during the winter. Not only did the increase in ABA concentration occur before any visible symptoms of tree decline appeared, but the trees that showed the most evident decline had the highest ABA concentrations in the spring sap. Leaf ABA concentration was not a good indicator of induced stress.

A cold-induced gene from Medicago sativa encodes a bimodular protein similar to developmentally regulated proteins

A new cold-regulated (COR) gene, msa CIC, was isolated by differential screening of a cDNA library from cold-acclimated crowns of alfalfa (Medicago sativa L. cv. Apica). Transcripts of msa CIC were not detectable in unacclimated alfalfa and accumulated to higher levels in cold-acclimated plants of the cold-tolerant cv. Apica than in those of the cold-sensitive cv. CUF-101. The DNA sequence analysis of a full-length cDNA clone revealed that msa CIC encodes for a putative protein (MSACIC) of 166 amino acids with distinct proline-rich and hydrophobic domains. Protein sequence comparisons indicated that MSACIC is similar to a group of bimodular proteins that are developmentally regulated in other plant species.

Heat and cold shock protein synthesis in arctic and temperate strains of rhizobia

We compared heat shock proteins (HSPs) and cold shock proteins (CSPs) produced by different species of Rhizobium having different growth temperature ranges. Several HSPs and CSPs were induced when cells of three arctic (psychrotrophic) and three temperate (mesophilic) strains of rhizobia were shifted from their optimal growth temperatures (arctic, 25 degrees C; temperate, 30 degrees C) to shock temperatures outside their growth temperature ranges. At heat shock temperatures, three major HSPs of high molecular weight (106,900, 83,100, and 59,500) were present in all strains for all shock treatments (29, 32, 36.4, 38.4, 40.7, 41.4, and 46.4 degrees C), with the exception of temperate strains exposed to 46.4 degrees C, in which no protein synthesis was detected. Cell survival of arctic and temperate strains decreased markedly with the increase of shock temperature and was only 1% at 46.4 degrees C. Under cold shock conditions, five proteins (52.0, 38.0, 23.4, 22.7, and 11.1 kDa) were always present for all treatments (-2, -5, and -10 degrees C) in arctic strains. Among temperate strains, five CSPs (56.1, 37.1, 34.4, 17.3, and 11.1 kDa) were present at temperatures down to 0 degrees C. The 34.4- and the 11.1-kDa components were present in all temperate strains at -5 degrees C and in one strain at -10 degrees C. Survival of all strains decreased with cold shock temperatures but was always higher than 50%. These results show that rhizobia can synthesize proteins at temperatures not permissive for growth. In all shock treatments, no correspondence between the number of HSPs or CSPs produced and rhizobial survival was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Clearance times of porphyrin derivatives from mice as measured by in vivo fluorescence spectroscopy

The clearance times of 17 different porphyrin derivatives from SKH:HR-1 mice have been measured using the technique of in vivo fluorescence spectroscopy. This technique monitors the in vivo porphyrin fluorescence observed from the external skin surface. Most hydrophilic porphyrin derivatives show relatively short clearance times, in the order of 2.5-6 h. The dicarboxylic acid porphyrins, proto-, hydroxyethylvinyldeutero- and hematoporphyrin IX have clearance times of 7.8, 12.2 and 14.7 h respectively. The mixture hematoporphyrin derivative has an intermediate clearance time of 12.6 h. N-methylated porphyrins show clearance times in the vicinity of 15-22 h. Monoaspartyl chlorin e6 shows the longest clearance time of all porphyrin derivatives measured (30.3 h).

Effect of ABA on freezing resistance of Betula papyrifera and Alnus incana woody plant cell suspensions

Treatment of birch (Betula papyrifera Marsh) and alder (Alnus incana (L.) Moench) cell suspension cultures with ABA increased the freezing resistance of the cells. After 7 days of treatment with 10(-5) M ABA, birch cells grown at 23 and 4 degrees C attained an LT(50) of -16.9 and -14.1 degrees C, respectively, whereas control cells had an LT(50) of -9.1 degrees C. In alder cell suspensions, treatment with 10(-5) M ABA at 23 degrees C induced a small increase in freezing resistance from -7.3 to -10.8 degrees C. Exposure to 4 degrees C alone did not induce a significant increase in hardiness in birch cell suspensions. Addition of 10(-5) M ABA to the medium inhibited fresh weight increase over 10 days of 3-g inocula of birch and alder by 70 and 52%, respectively. With the same concentration of ABA in the medium we found different intracellular ABA concentrations in 3- and 6-g inocula. We conclude that the concentration of ABA in the medium does not reflect the intracellular concentration of tissue cultures, and that cultural conditions may influence ABA accumulation by cell cultures.

A comparison of fluorescence methods used in the pharmacokinetic studies of Zn(II)phthalocyanine in mice

The pharmacokinetics of Zn phthalocyanine (ZnPc) encapsulated in dipalmitoyl-phosphatidylcholine (DPPC) liposomes, injected intravenously in Skh:HR-1 nude mice, was monitored by two in vitro techniques and one in vivo technique, all based on fluorescence spectroscopy. The in vitro methods involve either fluorescence measurements on thin tissue sections or on extracts from these tissues. The in vivo method involves the fluorescence measurement at the skin surface. Both in vitro techniques gave similar results which are consistent with previous findings on the pharmacokinetic behavior of ZnPc. The liver and spleen showed rapid ZnPc concentration increases, reaching a maximum level in 30 min. or less post drug administration. Relatively little ZnPc was detected in the skin, fat or muscle, the maximum concentration occurring at 12 h. In vivo fluorescence reached a maximum intensity approx. 6 h post injection at the mid-chest analysis site and at 12 h in the thigh. The in vivo measurements at two different anatomical sites showed pharmacokinetic behavior that reflects an overall integrated fluorescence originating from several tissue sites.

The effect of tissue and cellular pH on the selective biodistribution of porphyrin-type photochemotherapeutic agents: a volumetric titration study

Volumetric titration of aqueous solutions of haematoporphyrin IX (HP) yields two inflexion points, whereas four pK values can be obtained via mathematical fitting of the experimental data. Assignment of all pK protonation sites is made. A zwitterion is proposed as the neutral species of HP. Evaluation of the pK values of HP in the presence of sodium dodecyl sulphate (SDS) leads to a drastically altered ionic species distribution. On the basis of the distribution diagrams obtained, a pH-sensitive twofold mechanism is proposed for the selective biodistribution of porphyrin-type photochemotherapeutic agents, one involving tissue distribution and the other involving cell membrane penetration by the neutral zwitterion.

Value of plasma NH2-terminal fragment of pro-opiomelanocortin in marking human lung cancer in various clinical settings

Plasma concentration of amino-terminal segment of pro-opiomelanocortin (N-POMC) was measured by radioimmunoassay (RIA) in 144 patients with various forms of lung cancer during pneumonectomy, at different times of the day after being newly diagnosed and serially, throughout their treatment (surgery or chemotherapy) in order to assess its value as a biomarker in this disease. Normal volunteers, coal miners smoking but without known lung diseases, and the patients with diverse pulmonary disorders served as comparison groups. A significant transtumoral gradient of N-POMC was found at surgery in 15 of 57 (26%) patients. Subjects without lung afflictions had significantly lower N-POMC levels than patients with pulmonary diseases (benign or malignant) only when the blood was drawn before breakfast. Furthermore, fasting levels in all subgroups of patients were higher at any time of the day than nonfasting ones. Finally, N-POMC levels did not decrease significantly after successful treatment of lung cancer (by surgery or chemotherapy) but were markedly higher after relapse. These results suggest that N-POMC, despite the fact that it cannot be used to discriminate lung cancer patients from controls, is a biomarker which may predict relapse in patients successfully treated by chemotherapy for their pulmonary neoplasm.

Late thrombosis of saphenous vein coronary bypass grafts related to risk factors

In 72% of 143 patients undergoing a second coronary bypass grafting, mural or occlusive late thrombosis was observed histologically in 69% of 173 resected grafts. Late thrombosis was particularly prevalent in atherosclerotic grafts (80.2% vs. 40.4% in nonatherosclerotic grafts) and was always noted in 16 grafts with aneurysmal dilation. Multivariate analysis of risk factors contributing to late thrombosis indicated that graft atherosclerosis and smoking after graft surgery played important roles. Univariate analysis also showed significantly higher ratios of serum total cholesterol/HDL cholesterol and of serum LDL cholesterol/HDL cholesterol in patients whose grafts were affected by late thrombosis. To prevent late thrombosis of saphenous vein aortocoronary grafts, it appears reasonable that decreasing the ratios of total cholesterol/HDL cholesterol and of LDL cholesterol/HDL cholesterol, refraining from smoking, and controlling other risk factors for atherosclerosis should be advised.

Effects of Cold Hardening on the Regulation of Polyamine Levels in Wheat (Triticum aestivum L.) and Alfalfa (Medicago sativa L.)

When leaves of wheat (Triticum aestivum L.) are exposed to a cold hardening temperature, a major accumulation of putrescine (6-9 times) takes place. Spermidine accumulates to a lesser extent and, conversely, spermine decreases slightly. These variations are completely reversible when plants are returned to initial growing conditions. A similar response is obtained with crowns. During cold hardening, arginine decarboxylase activity remains near its initial level while a considerable loss of activity is observed in control plants. Ornithine decarboxylase and diamine oxidase activity levels are not substantially modified by the treatment. Alfalfa (Medicago sativa L.) also accumulates putrescine under low temperature stress, indicating that this phenomenon is not typical of cereals. The physiological significance of this accumulation of putrescine is still unexplained but the results obtained suggest the involvement of polyamines in the biochemical processes of cold hardening.

Laser Raman spectra of calf thymus chromatin and its constituents

Extensive Raman measurements have been made on calf thymus chromatin, core chromatin, the (H3,H4)/DNA complex, and isolated DNA. The results indicate that the alpha-helical content of the nucleosomal histones gradually increases as they form the heterocomplexes that lead to the formation of the octameric nucleosome core. The secondary structure of the latter is not modified as it binds to DNA. The spectra indicate that the DNA essentially retains its B conformation in nucleosomes, although slight changes probably occur in the ribose-phosphate backbone. No specific interactions between the nucleosomal histones and DNA can be established from the spectra, but histone H1 possibly interacts selectively with the thymine bases.

Polyamines in Acanthamoeba castellanii: presence of an unusually high, osmotically sensitive pool of 1,3-diaminopropane

High (15-25 mM) concentrations of 1,3-diaminopropane, a normally minor derivative of polyamine metabolism, have been observed in vegetative cells of Acanthamoeba castellanii. Trace amounts of a putative polyamine, which chromatographically behaved like norspermidine, were also found. The size of the intracellular pool of 1,3-diaminopropane was inversely related to the ambient osmolality and to the free amino acid levels during osmotic shock experiments. Due to its high concentration in A. castellanii, this diamine may be operative in ionic regulation during environmental stress. 1,3-diaminopropane may substitute for putrescine, a common diamine which was undetectable in A. castellanii.

Histone synthesis by lymphocytes in G0 and G1

Peripheral blood lymphocytes are a naturally occurring population of G0 cells which can be activated in vitro to grow and divide. Upon activation with phytohemagglutinin (PHA), they enter G1 and, after a 24-h lag, begin DNA replication (S phase). Using radioisotope labeling and gel electrophoresis of acid-soluble chromatin proteins, we investigated histone synthesis in G0, G1, and S phase cultures of human and pig lymphocytes. In G0 and G1 cultures, which have less than 0.1% S phase cells, all five histones are synthesized and are incorporated into chromatin in equimolar amounts. In G0 lymphocytes histone synthesis accounts for at least 6% of nuclear protein radioactivity, and the rate of synthesis is about 2-3% of that of S phase lymphocytes. In contrast to histone synthesis by S phase cultures, G0 and G1 histone synthesis was completely resistant to treatment with hydroxyurea.

Changes in protein and RNA during asexual differentiation of Physarum polycephalum

Some of the events during the growth and asexual differentiation of Physarum polycephalum amoebae are described. Encysted amoebae contain low levels of protein and RNA. When these cells are mixed with bacteria and inoculated onto agar plates, there is an increase in cellular RNA content followed by an increase in protein content. The cellular RNA and protein contents of all strains tested decrease during the subsequent cell divisions. In nondifferentiating cells (strain Cl at 30 degrees C and strain LU648), RNA and protein contents continue to decrease, and the cell eventually encyst. In the asexually differentiating strain Cl grown at 26 degrees C, the cellular RNA and protein contents stop decreasing and begin to increase when the first amoebae become committed to form plasmodia. At early stages of differentiation a new 36,000 molecular weight polypeptide appears. In fully formed plasmodia another polypeptide of 38,000 molecular is observed. These two plasmodial-specific polypeptides are among the most abundant plasmodial proteins.

Isolation and characterization of histones and other acid-soluble chromosomal proteins from Physarum polycephalum

Chromosomal basic proteins were isolated from amoebal and plasmodial stages of the acellular slime mold Physarum polycephalum. Polyacrylamide electrophoresis on high resolution acid-urea gels separated the five histone fractions in the sequence H1, H2A, H2B, H3, and H4. Under these electrophoretic conditions Physarum histones migrated more like plant (rye) than animal (calf) histones. Furthermore, Physarum histones H1, H2A, and H2B have higher molecular weights on sodium dodecyl sulfate (SDS) gels than the corresponding calf fractions. No differences were detected between amoebal and plasmodial histones on either acid-urea or SDS-polyacrylamide gel electrophoresis. Amoebal basic proteins were fractionated by exclusion chromatography. The five histone fractions plus another major acid-soluble chromosomal protein (AS) were isolated. The Physarum core histones had amino acid compositions more closely resembling those of the calf core histones than of rye, yeast, or Dictyostelium. Although generally similar in composition to the plant and animal H1 histones, the Physarum H1 had a lower lysine content. The AS protein was extracted with 5% perchloric acid or 0.5 M NaCl, migrated between histones H3 and H4 on acid-urea polyacrylamide gels, and had an apparent molecular weight of 15 900 on SDS gels. It may be related to a protein migrating near H1. Both somewhat resembled the high mobility group proteins in amino acid composition.

Application of differential spectra in the ultraviolet-visible region to study the formation of amphotericin B-sterol complexes

The extent of complex formation between the polyene antibiotic, amphotericin B, and cholesterol or ergosterol was investigated and a method for a quantitative measurement of the complex formation was developed. The effect of experimental conditions on the magnitude of the amphotericin B-sterol interaction and on the selectivity of this interaction showed that there was only a narrow range of solvent composition in which the differential selectivity of amphotericin B towards these two sterols could be observed.

Optical simulation for a fixed spherical solar collector

To calculate the absorber dimensions for a fixed spherical solar collector, an optical simulation of the raytracing type is proposed. The physical quantities, which have an effect upon these dimensions, are described as well as the measurement methods. Once the dimensions are determined, the incident flux on the absorber surface can be calculated by the same program in terms of different zenith distances. These calculations can be checked by comparing the calculated flux on the surface of the absorber with the measured flux at different points along the absorber aimed at the full moon instead of at the sun. Through the data obtained from the measurements, fluctuating points of high flux and permanent zones which receive double and triple reflection rays have been studied.

Lidocaine plasma concentrations during and after endoscopic procedures

Plasma lidocaine concentrations were intermittently measured in 8 upper gastrointestinal endoscopy and 12 bronchoscopy patients. The highest individual concentration was 0.98 microgram/ml in the upper gastrointestinal endoscopy patients and 3.79 microgram/ml in the bronchoscopy patients. Highest concentrations were reached at 15 minutes in the gastrointestinal endoscopy patients and at 30 or 60 minutes in the bronchoscopy patients. Thus, since lidocaine does not produce toxic effects at concentrations inferior to 6 microgram/ml, doses of this topical anaesthetic up to 16 mg/kg can be safely given during endoscopic procedures to patients with normal hepatic and cardiovascular functions. However, patients with liver metastases should be considered at high risk even if their liver function tests are normal. Patients at high risk of developing lidocaine toxicity should receive lower doses and be closely watched for at least 60 minutes after the end of the procedure.

Effect of inhibition of DNA synthesis on histone synthesis and deposition

We have reinvestigated the degree of coupling between DNA and histone synthesis in mammalian cells. In at least one cell line (HTC cells), the coupling is not nearly as tight as had previously been inferred from experiments with HeLa cells. The site of deposition of such histones which continue to be made in the presence of sufficient hydroxyurea to depress DNA synthesis almost totally has been studied. Deposition seems to be on material which absorbs at 260 nm. This material is not a part of the bulk chromatin and binds histone in a relatively tight manner. The possible role of such a material in histone synthesis and deposition is discussed.

Comparative study of rye and thymus histones: amino acid analysis and tryptic fingerprinting

Amino acid composition and tryptic fingerprints of rye (Secal cereale) H1, H2B (PH1), and H2A(PHII) histones indicate the presence of major differences between these and the corresponding calf or rabbit fractions. In addition to variations for other amino acids, fraction H1 from rye contains twice as much arginine as the corresponding animal fraction; the plant H2B (PHI) and H2A (PHII) histones show lysine to arginine ratios greater than those of their animal counterparts. The tryptic maps of the same proteins appear to differ between plants and animals by the number and the general pattern of the peptides, as well as by the quantity and distribution of the arginine-containing peptides. Such results suggest the presence of differences in the primary structure of the calf and rye lysine-rich and moderately lysine-rich histones. Furthermore, the possibility is ruled out that each of these plant histones consists of an animal-like protein with an additional segment of 20--30 amino acid residues. On the other hand, the rye and calf arginine-rich fractions H3 and H4 show similar amino acid compositions and tryptic peptides maps.

Vertical fracture dislocation of the tarsal navicular

An isolated vertical fracture dislocation of the left tarsal navicular with some comminution was successfully treated with open reduction and internal fixation with a screw. The surgical treatment is described, and early mobilization strongly recommended.