The influence of cold insoluble globulin on platelet morphological response to substrata

Light microscopic studies have been carried out on the attachment and morphological responses of washed human platelets in serum-free medium to fibrinogen-coated, collagen-coated and uncoated tissue culture plastic substrata. Platelets were observed to attach to the substratum, extend filipodia and undergo spreading. Subsequently, lysis of platelets occurred. On uncoated tissue culture plastic substrata, the addition of cold insoluble globulin to the incubations had no effect on the above morphological changes. On the other hand, on the protein coated substrata, there was very little platelet spreading or lysis without the addition of cold insoluble globulin.     

Isolation and preliminary characterization of temperature-sensitive mutants of poliovirus type 1.

We isolated six temperature-sensitive mutants of poliovirus type 1 (Mahoney) by hydroxylamine mutagenesis and replica plating at 31, 33 (permissive), and 39 degrees C (restrictive). One of these mutants, designated tsB9, was chosen for more detailed examination. tsB9 accumulated 25% of the wild-type amount of virus-specific RNA at the restrictive temperature. We found that tsB9 was not able to synthesize mature, 35S single-stranded RNA at the restrictive temperature. In spite of the absence of significant RNA synthesis, tsB9 retained the ability to inhibit host protein synthesis during infection at 39 degrees C at about the same rate as wild-type virus.     

Measurement of mucosal blood flow in the canine intestine with laser doppler velocimetry

Laser Doppler velocimetry is a technique for continuous estimation of changing blood flow in the surface of a tissue and does not require invasion of the circulation. This technique is based upon the Doppler principle that a shift in the frequency of an electromagnetic wave emitted or reflected from a moving object is proportional to the velocity of the object. The capacity of Laser Doppler velocimetry to estimate changes in intestinal mucosal blood flow was tested in a canine free flow preparation. In anesthetized dogs in which a segment of ileum was isolated, simultaneous measurements of instantaneous changes in total blood flow (measured with the electromagnetic blood flow meter) and instantaneous changes in presumed mucosal blood flow (using laser Doppler velocimetry) were obtained. Determinations were made during conditions of rest, prostacyclin induced vasodilation and norepinephrine induced vasoconstriction. Changes in laser Doppler velocimeter readings were qualitatively similar to and temporally related to changes in total blood flow to the gut segment during administration of the vasoactive drugs. The magnitude and direction of changes with the two measurements were significantly correlated. Stabilizing the laser probe on the mucosal surface to ensure reproducible readings proved technically difficult. Pharmacologically induced changes in laser Doppler velocimeter estimated changes in flow were more readily correlated with changes in electromagnetic flow meter readings than were control values obtained with the two methods.     

Sacculatane diterpenoids from axenic cultures of the liverwort Fossombronia wondraczekii

Five new sacculatane diterpenoids, 17,18-epoxy-7-sacculaten-12,11-olide, 7,17-sacculatadien-11,12-olide, 11beta,12-epoxy-7,17-sacculatadien-11alpha-ol, 1beta-acetoxy-11beta,12-epoxy-7,17-sacculatadien-11alpha-ol and 1beta,15xi-diacetoxy-11,12-epoxy-8(12),9(11),17-sacculatatriene along with sacculatal and sacculatanolide have been isolated from axenic cultures of the liverwort Fossombronia wondraczekii and their structures assigned on the basis of their spectroscopical properties.     

Comparison of techniques for the measurement of skin temperature during exercise in a hot,humid environment

Exercising or working in a hot, humid environment can results in the onset of heat-related illness when an individual''s temperature is not carefully monitored. The purpose of the present study was to compare three techniques (data loggers, thermal imaging, and wired electrodes) for the measurement of peripheral (bicep) and central (abdominal) skin temperature. Young men and women (N = 30) were recruited to complete the present study. The three skin temperature measurements were made at 0 and every 10-min during 40-min (60% VO₂max) of cycling in a hot (39±2°C), humid (45±5% RH) environment. Data was statistically analyzed using the Bland-Altman method and correlation analysis. For abdominal skin temperature, the Bland-Altman limits of agreement indicated that data loggers (1.5) were a better index of wired than was thermal imaging (3.5), For the bicep skin temperature the limits of agreement was similar between data loggers (1.9) and thermal (1.9), suggesting the both were suitable measurements. We also found that when skin temperature exceeded 35°C, we observed progressively better prediction between data loggers, thermal imaging, and wired skin sensors. This report describes the potential for the use of data loggers and thermal imaging to be used as alternative measures of skin temperature in exercising, human subjects.     

Antiangiogenic properties of Koetjapic acid, a natural triterpene isolated from Sandoricum koetjaoe Merr

Background

Angiogenesis, the formation of new blood vessels, has become an important target in cancer therapy. Angiogenesis plays an important role in tumor growth and metastasis. Koetjapic acid (KA) is a seco-A-ring oleanene triterpene isolated from S. koetjape. The solvent extract of this plant species was shown previously to have strong antiangiogenic activity; however the active ingredient(s) that conferred the biological activity and the mode of action was not established. Given the high concentration of KA in S. koetjape, an attempt has been made in this study to investigate the antiangiogenic properties of KA.

Results

Treatment with 10-50 μg/ml KA resulted in dose dependent inhibition of new blood vessels growth in ex vivo rat aortic ring assay. KA was found to be non-cytotoxic against HUVECs with IC₅₀ 40.97 ± 0.37 μg/ml. KA inhibited major angiogenesis process steps, endothelial cell migration and differentiation as well as VEGF expression.

Conclusions

The non-cytotoxic compound, KA, may be a potent antiangiogenic agent; its activity may be attributed to inhibition of endothelial cells migration and differentiation as well VEGF suppression.     

A high-throughput assay for the adenylation reaction of bacterial DNA ligase

DNA ligase catalyzes the closure of single-strand nicks in double-stranded DNA that arise during replication and recombination. Inhibition of bacterial ligase is expected to cause chromosome degradation and cell death, making it an attractive target for new antibacterials. The prototypical bacterial ligase couples the hydrolysis of NAD(+) to phosphodiester bond formation between an adjacent 3'OH and 5'-terminal phosphate of nicked duplex DNA. The first step is the reversible formation of a ligase-adenylate from the reaction between apoenzyme and NAD(+). Inhibitors that compete with NAD(+) are expected to be bacterial specific because eukaryotic DNA ligases use ATP and differ in the sequence composition of their adenylation domain. We report here a high-throughput assay that measures the adenylation reaction specifically by monitoring ligase-AMP formation via scintillation proximity technologies. Escherichia coli DNA ligase was biotinylated in vivo; after reaction with radiolabeled NAD(+), ligase-[(3)H]AMP could be captured onto the streptavidin-coated surface of the solid scintillant. The method was ideal for high-throughput screening because it required minimal manipulations and generated a robust signal with minimal scatter. Certain adenosine analogs were found to inhibit the adenylation assay and had similar potency of inhibition in a DNA ligation assay.     

Portable optical fiber probe-based spectroscopic scanner for rapid cancer diagnosis: a new tool for intraoperative margin assessment

There continues to be a significant clinical need for rapid and reliable intraoperative margin assessment during cancer surgery. Here we describe a portable, quantitative, optical fiber probe-based, spectroscopic tissue scanner designed for intraoperative diagnostic imaging of surgical margins, which we tested in a proof of concept study in human tissue for breast cancer diagnosis. The tissue scanner combines both diffuse reflectance spectroscopy (DRS) and intrinsic fluorescence spectroscopy (IFS), and has hyperspectral imaging capability, acquiring full DRS and IFS spectra for each scanned image pixel. Modeling of the DRS and IFS spectra yields quantitative parameters that reflect the metabolic, biochemical and morphological state of tissue, which are translated into disease diagnosis. The tissue scanner has high spatial resolution (0.25 mm) over a wide field of view (10 cm × 10 cm), and both high spectral resolution (2 nm) and high spectral contrast, readily distinguishing tissues with widely varying optical properties (bone, skeletal muscle, fat and connective tissue). Tissue-simulating phantom experiments confirm that the tissue scanner can quantitatively measure spectral parameters, such as hemoglobin concentration, in a physiologically relevant range with a high degree of accuracy (<5% error). Finally, studies using human breast tissues showed that the tissue scanner can detect small foci of breast cancer in a background of normal breast tissue. This tissue scanner is simpler in design, images a larger field of view at higher resolution and provides a more physically meaningful tissue diagnosis than other spectroscopic imaging systems currently reported in literatures. We believe this spectroscopic tissue scanner can provide real-time, comprehensive diagnostic imaging of surgical margins in excised tissues, overcoming the sampling limitation in current histopathology margin assessment. As such it is a significant step in the development of a platform technology for intraoperative management of cancer, a clinical problem that has been inadequately addressed to date.