Hemoglobin quantification in red blood cells via dry mass mapping based on UV absorption

SIGNIFICANCE

The morphological properties and hemoglobin (Hb) content of red blood cells (RBCs) are essential biomarkers to diagnose or monitor various types of hematological disorders. Label-free mass mapping approaches enable accurate Hb quantification from individual cells, serving as promising alternatives to conventional hematology analyzers. Deep ultraviolet (UV) microscopy is one such technique that allows high-resolution, molecular imaging, and absorption-based mass mapping.

AIM

To compare UV absorption-based mass mapping at four UV wavelengths and understand variations across wavelengths and any assumptions necessary for accurate Hb quantification.

APPROACH

Whole blood smears are imaged with a multispectral UV microscopy system, and the RBCs' dry masses are computed. This approach is compared to quantitative phase imaging-based mass mapping using data from an interferometric UV imaging system.

RESULTS

Consistent Hb mass and mean corpuscular Hb values are obtained at all wavelengths, with the precision of the single-cell mass measurements being nearly identical at 220, 260, and 280 nm but slightly lower at 300 nm.

CONCLUSIONS

A full hematological analysis (including white blood cell identification and characterization, and Hb quantification) may be achieved using a single UV illumination wavelength, thereby improving the speed and cost-effectiveness.

TADs and Their Borders: Free Movement or Building a Wall?

The tridimensional (3D) organization of mammalian genomes combines structures from different length scales. Within this organization, Topologically Associating Domains (TADs) are visible in Hi-C heat maps at the sub-megabase scale. The integrity of TADs is important for correct gene expression, but in a context-dependent and variable manner. The correct structure and function of TADs require the binding of the CTCF protein at both borders, which appears to block an active and dynamic mechanism of "Cohesin-mediated loop extrusion." As a result, mammalian TADs appear as so-called "loop domains" in Hi-C data, which are the focus of this review. Here, we present a reanalysis of TADs from three "golden-standard" mammalian Hi-C data sets. Despite the prominent presence of TADs in Hi-C heat maps from all studies, we find consistently that regions within these domains are only moderately insulated from their surroundings. Moreover, single-cell Hi-C and superresolution microscopy have revealed that the structure of TADs and the position of their borders can vary from cell to cell. The function of TADs as units of gene regulation may thus require additional aspects, potentially incorporating the mechanism of loop extrusion as well. Recent developments in single-cell and multi-contact genomics and superresolution microscopy assays will be instrumental to link TAD formation and structure to their function in transcriptional regulation.

Ex Vivo Microscopy: A Promising Next-Generation Digital Microscopy Tool for Surgical Pathology Practice

CONTEXT.—

The rapid evolution of optical imaging modalities in recent years has opened the opportunity for ex vivo tissue imaging, which has significant implications for surgical pathology practice. These modalities have promising potential to be used as next-generation digital microscopy tools for examination of fresh tissue, with or without labeling with contrast agents.

OBJECTIVE.—

To review the literature regarding various types of ex vivo optical imaging platforms that can generate digital images for tissue recognition with potential for utilization in anatomic pathology clinical practices.

DATA SOURCES.—

Literature relevant to ex vivo tissue imaging obtained from the PubMed database.

CONCLUSIONS.—

Ex vivo imaging of tissues can be performed by using various types of optical imaging techniques. These next-generation digital microscopy tools have a promising potential for utilization in surgical pathology practice.

Adaptation of microscopy with ultraviolet surface excitation for enhancing STEM and undergraduate education

Microscopy with ultraviolet surface excitation (MUSE) is investigated as a means to enhance curricula and education in the life sciences based on simplicity of use, the incorporation of inexpensive hardware, and the simplest methods of tissue preparation. Ultraviolet excitation in effect replaces tissue sectioning because it penetrates only a few micrometers below the tissue surface at the single cell level, preventing the generation of out-of-focus light. Although tissue autofluorescence may be used, image quality and content can be enhanced by a brief immersion in a solution of nontoxic fluorescent dyes that selectively highlight different cellular compartments. Safe mixed-dye powder combinations have been developed to provide students who have minimal lab proficiencies with a one-step tissue staining process for rapid tissue preparation.

Evidence of the late lignification of the G-layer in Simarouba tension wood, to assist understanding how non-G-layer species produce tensile stress

To recover verticality after disturbance, angiosperm trees produce 'tension wood' allowing them to bend actively. The driving force of the tension has been shown to take place in the G-layer, a specific unlignified layer of the cell wall observed in most temperate species. However, in tropical rain forests, the G-layer is often absent and the mechanism generating the forces to reorient trees remains unclear. A study was carried out on tilted seedlings, saplings and adult Simarouba amara Aubl. trees-a species known to not produce a G-layer. Microscopic observations were done on sections of normal and tension wood after staining or observed under UV light to assess the presence/absence of lignin. We showed that S. amara produces a cell-wall layer with all of the characteristics typical of G-layers, but that this G-layer can be observed only as a temporary stage of the cell-wall development because it is masked by a late lignification. Being thin and lignified, tension wood fibres cannot be distinguished from normal wood fibres in the mature wood of adult trees. These observations indicate that the mechanism generating the high tensile stress in tension wood is likely to be the same as that in species with a typical G-layer and also in species where the G-layer cannot be observed in mature cells.

Xylan deposition and lignification in the multi-layered cell walls of phloem fibres in Mallotus japonicus (Euphorbiaceae)

Phloem fibres in Mallotus japonicus Müll. Arg. were found to have a multi-layered structure that is S1 + S2 + n(G + L), where a non-lignified gelatinous layer (G) and a lignified layer (L) are formed alternately and n indicates the number of repetitions of these two layers. The aim of this study was to determine the process of xylan deposition and lignification in the multi-layered cell walls of phloem fibres. The formation process of the multi-layered structure of secondary phloem fibres was examined by light microscopy, ultraviolet microscopy and transmission electron microscopy. The distribution of glucuronoxylan was examined by immunoelectron microscopy. The activity of peroxidase was also determined using metal-enhanced diaminobenzidine substrates. Immunolabelling of glucuronoxylan occurred in lignified cell wall layers, except in the compound middle lamella (CML), i.e., the S1, S2 and L layers but not the G layers. Change in immunolabelling density suggests that xylan deposition in these lignified layers occurs appositionally, i.e., xylan is deposited into the lignified layers directly and not by a penetrative mechanism, and deposition does not occur after the layers are fully deposited. Peroxidase activity was found in CML including cell corners during S2 layer formation, then in developing G layers during G layer formation. Peroxidase activity was also found in the thin L layers that formed recently and was not found in the L layers already present. Xylan labelling was not found in the thin L layers that formed recently but did occur in L layers that developed earlier. Lignification of the S1 and S2 layers continued during the formation of the G layers, whereas in the L layers it finished just after deposition of the L layer.

Astrogliosis and HSP 70 activation in neonate rats' brain exposed to sodium metavanadate through lactation

The effect of sodium metavanadate (NaVO3) exposure on lipid oxidative damage in the CNS of suckling rats was studied. Using histological markers of cellular injury, we also studied the morphological alterations of neurons and astroglial cells in different regions of neonate rats CNS after NaVO3 exposure. Dams of treated litters were intraperitoneally injected with 3mgNaVO3/kgbody weight/day during 12days starting on post-natal day (PND) 10. On the 21st PND, four pups of each litter were sacrificed by decapitation and six brain areas were removed for lipid peroxidation assay by the thiobarbituric acid (TBA) reaction, the other four were transcardially perfused-fixed and their brains were removed and cut with a cryostat. Brain sections were processed for: NADPHd histochemistry and anti-HSP70, anti-GFAP and anti-S100 immunohistochemistry. The relative optical density of the NADPHd stained layers and of S100 (+) astrocytes and the GFAP (+) astrocyte surface area in Cer and Hc were measured. Although MDA levels, S100 immunostaining and NADPHd activity didn't show differences between experimental and control groups, both astrogliosis and HSP70 activation were detected in Cer, while only the former was detected in Hc of V-exposed pups.

Lignification in poplar tension wood lignified cell wall layers

The lignification process in poplar tension wood lignified cell wall layers, specifically the S(1) and S(2) layers and the compound middle lamella (CML), was analysed using ultraviolet (UV) and transmission electron microscopy (TEM). Variations in the thickness of the gelatinous layer (G-layer) were also measured to clarify whether the lignified cell wall layers had completed their lignification before the deposition of G-layers, or, on the contrary, if lignification of these layers was still active during G-layer formation. Observations using UV microscopy and TEM indicated that both UV absorbance and the degree of potassium permanganate staining increased in the CML and S(1) and S(2) layers during G-layer formation, suggesting that the lignification of these lignified layers is still in progress during G-layer formation. In the context of the cell-autonomous monolignol synthesis hypothesis, our observations suggest that monolignols must go through the developing G-layer during the lignification of CML and the S(1) and S(2) layers. The alternative hypothesis of external synthesis (in the rays) does not require that monolignols go through the G-layer before being deposited in the CML, or the S(1) and S(2) layers. Interestingly, the previous observation of lignin in the poplar G-layer was not confirmed with the microscopy techniques used in the present study.

[Distribution of lignin in Chinese fir branches determined by ultraviolet microspectrometer]

Distribution of lignin in the cell walls of Chinese fir branches emerged in the spring season were first studied by using ultraviolet microscope based on their cell microstructure observation and lignin qualitative measurement by the lightmicroscope and confocal laser scanning microscope. The results showed that the contents of lignin are inhomogeneously distributed in different micro-areas of the cell walls. The order of lignin concentrations is the cell corner>the middle lamellar>the secondary with the absorbance values of ultraviolet wave of 0.489, 0.307 and 0.278, respectively. The result of quantitative analysis consists with that of qualitative analysis. A new measurement method was proposed to study the distribution of lignin content in wood cell walls in CFhina.

[Paravasal connective tissue of the in-wall blood vessels of the heart during aging]

The structural organization of the paravasal connective tissue of the in-wall myocardial blood vessels in the stages of postnatal ontogenesis was studied. The study was carried out on preparations of the heart 80 corpses of men in three age groups (the first period of adulthood (n = 20) and elderly (n = 30) and old (n = 30) ages.) The peculiarities of the structure as well as qualitative and quantitative transformation of fibrous component of the paravasal connective tissue in each age period were revealed.

An accessible micro-capillary electrophoresis device using surface-tension-driven flow

We present a rapidly fabricated micro-capillary electrophoresis chip that utilizes surface-tension-driven flow for sample injection and extraction of DNA. Surface-tension-driven flow (i.e. passive pumping) [G. M. Walker et al., Lab. Chip. 2002, 2, 131-134] injects a fixed volume of sample that can be predicted mathematically. Passive pumping eliminates the need for tubing, valves, syringe pumps, and other equipment typically needed for interfacing with microelectrophoresis chips. This method requires a standard micropipette to load samples before separation, and remove the resulting bands after analysis. The device was made using liquid phase photopolymerization to rapidly fabricate the chip without the need of special equipment typically associated with the construction of microelectrophoresis chips (e.g. cleanroom) [A. K. Agarwal et al., J. Micromech. Microeng. 2006, 16, 332-340; S. K. Mohanty et al., Electrophoresis 2006, 27, 3772-3778]. Batch fabrication time for the device presented here was 1.5 h including channel coating time to suppress electroosmotic flow. Devices were constructed out of poly-isobornyl acrylate and glass. A standard microscope with a UV source was used for sample detection. Separations were demonstrated using Promega BenchTop 100 bp ladder in hydroxyl ethyl cellulose (HEC) and oligonucleotides of 91 and 118 bp were used to characterize sample injection and extraction of DNA bands. The end result was an inexpensive micro-capillary electrophoresis device that uses tools (e.g. micropipette, electrophoretic power supplies, and microscopes) already present in most labs for sample manipulation and detection, making it more accessible for potential end users.

"Hairy blobs:" microbial suspects preserved in modern and ancient extremely acid lake evaporites

"Hairy blobs" are unusual clumps of organic bodies and sulfate crystals that have been found in evaporite minerals grown in acid saline lakes. Here, we document modern hairy blobs in halite and gypsum from 5 modern acid saline lakes in southern Western Australia, and Permian hairy blobs trapped in halite from the mid-Permian Opeche Shale in the subsurface of North Dakota. These are among the first microbial remains described from acid saline lake environments. They give clues about the role of microorganisms in the acidity, geochemistry, and mineralogy of these extreme environments. This study also may add to the inventory of life in extreme environments and help predict possible martian life-forms and the method of preservation.

Determination of polymethoxylated flavones in peels of selected Jamaican and Mexican citrus (Citrus spp.) cultivars by high-performance liquid chromatography

The concentrations of the polymethoxylated flavones (PMFs) in peels of selected citrus cultivars grown in Jamaica and Mexico were determined. The PMFs were extracted from sun-dried citrus peels with reagent-grade methanol. Analyses were carried out by reverse-phase HPLC and UV detection. The column used was a C(18) 5 microm (150 x 4.6 mm) Discovery column. Elution was in the gradient mode, using a ternary mobile phase. The results showed that all the citrus cultivars used contained at least three of the six major PMFs quantified. Ortanique peel contained the highest quantity of PMFs (34,393 +/- 272 ppm), followed by tangerine (28,389 +/- 343 ppm) and Mexican sweet orange (sample 1; 21,627 +/- 494 ppm). The major PMFs, i.e. sinensetin, nobiletin, tangeretin, heptamethoxyflavone, tetramethylscutellarein and hexamethyl-o-quercetagetin, present in the peels of 20 citrus cultivars, was quantified. The results were compared with those of Florida citrus peels. A large amount of citrus peels and byproducts are produced in the Caribbean which could provide a cheap and convenient source of PMFs.

Green bone

OBJECTIVE

To describe the unusual finding of yellow-green-colored bone during routine orbital surgery, to detail its investigation, and to demonstrate its benign nature.

METHODS

When green bone was found, specimens were sent for light and fluorescent microscopy, ultraviolet photography, and spectrophotometry.

RESULTS

Yellow-green bone was encountered in 3 patients during orbital tumor excision or orbital fracture repair procedures. The only common cause was prior use of tetracycline during adolescence. All patients had healthy white dentition. In all cases, absence of neoplasia was demonstrated histologically. The bone fluoresced with a bright yellow-green color when exposed to 365-nm ultraviolet light. Histologic analysis demonstrated fluorescence located near the haversian canals. Spectrophotometry revealed absorption at 4 wavelengths specific to tetracycline: 230, 275, 380, and 440 nm.

CONCLUSIONS

Fixation of tetracycline and ensuing fluorescence occurs mostly in areas of new bone growth and mineralization. This happens during childhood but also with bone remodeling associated with tumors or fractures. Once mineralized, teeth should therefore not be affected if tetracycline exposure occurs after ages 8 to 10 years. This paucity of external clues can lead to the surprising but innocuous surgical finding of green bone. Careful history and proper investigation can confirm its origin.

Synthesis of Zn(II)-cloxacillin sodium complex and study of its interaction with calf thymus DNA

In this paper, a solid complex of cloxacillin sodium (CS) with Zn(II) was prepared by coprecipitation and characterized by UV, fluorescence, IR, and thermal spectra. Furthermore, the nature of the complex has been studied by 1H-NMR and 13C-NMR spectroscopy. The influence of Zn(II) on the combination of CS and calf thymus DNA (CT DNA) was studied using fluorescence spectrophotometry, and the formation of binary CS-Zn(II) and CS-CT DNA complexes and ternary CS-Zn(II)-CT DNA complex was studied. The results show that the fluorescence intensity of CS can be quenched in the presence of Zn(II) or DNA. In the presence of Zn(II), the fluorescence quenching action of DNA on CS was strongly enhanced. Based on the fluorescence intensity, the formation constants of CS-Zn(II) and CS-CT DNA complexes were calculated, and the mechanism of interaction between CS, Zn(II), and DNA is discussed.

Diffuse interstellar bands: a comprehensive laboratory study

As a result of the search for the identity of the chromophores responsible for producing the diffuse interstellar bands, a comprehensive exposition of experimental data is presented, which implicates the following molecules: (1) The extremely stable organic molecules, magnesium tetrabenzoporphyrin (MgTBP) and H(2)TBP. (2) A paraffin matrix (referred to as "grains") containing TBPs. (3) A low concentration of pyridine (also within the grains), whose transmission window at 2175 A, accounts for the ubiquitous UV bump. The blue emission spectra associated with the central star, HD44179, of the Red Rectangle displays the fluorescence excitation spectra of bare MgTBP. This unique spectrum matches the low temperature lab data of MgTBP in the vapor phase. An effective grain temperature of 2.728 K (+/-0.008) was deduced, based on MgTBP's lowest measured vibrational state of 341 GHz.

Multiple glycerol shocks increase the calcium phosphate transfection of non-synchronized CHO cells

The exposure of CHO DG44 cells to an osmotic shock, after DNA uptake, results in a cellular volume decrease of approx. 55%. Repetitive osmotic shocks targeted different sub-populations of cells as was demonstrated using two different fluorescent reporter genes. Also the exposure of a calcium phosphate-DNA coprecipitate to high osmolarity in vitro caused the release of the DNA from the precipitate. The results demonstrate the importance of the osmotic shock on the efficient delivery of plasmid DNA to the nucleus of CHO cells following calcium phosphate-mediated transfection.

Noninvasive techniques for the evaluation of skin color

Visual assessment remains one of the "gold standard" methods of assessing skin color and a number of tools are currently available to reduce the interobserver variability. Ultraviolet light examination remains a mainstay of the assessment of pigmentary disorders, while polarized light photography is useful for the appraisal of dermal changes, in particular those related to vascularity. With the introduction of modern instruments, reflectance spectroscopy using tristimulus colorimeters or narrowband spectrophotometers provides a convenient, objective, and reproducible methodology for the evaluation of pigmentation and skin color. In vivo confocal scanning laser microscopy is a powerful technique for the examination of pigmented lesions, which shows promise in the detection and diagnosis of early melanoma. Dermoscopy is also useful for the differential diagnosis of benign melanocytic lesions and melanoma, and its use has been shown to significantly improve diagnostic accuracy.

Lignification in cell cultures of Pinus radiata: activities of enzymes and lignin topochemistry

Enzymatic and topochemical aspects of lignification were studied in a Pinus radiata D. Don cell culture system that was induced to differentiate tracheary elements and sclereids with lignified secondary cell walls. The activities of the lignin-related enzymes phenylalanine ammonia lyase (PAL; EC 4.3.1.5) and cinnamyl alcohol dehydrogenase (CAD; EC 1.1.1.195) increased concomitantly with cell differentiation, indicating that the increase in enzyme activity was related to lignification of the cell walls and was not induced by stress. This result also indicates that PAL and CAD are suitable markers for tracheary element differentiation in coniferous gymnosperms. To further characterize lignification in this cell culture system, cellular UV-microspectrophotometry and thioacidolysis were employed. Typical UV-absorption spectra of lignin were obtained from the secondary cell walls of the tracheary elements and sclereids and from the compound middle lamella connecting differentiated cells, and the presence of lignin was confirmed by thioacidolysis. Certain aspects of lignin topochemistry in the cell walls of the tracheary elements were similar to cell walls of P. radiata wood, such as the high lignin concentration in the compound middle lamella connecting adjacent cells and the lower lignin concentration in the secondary cell walls. Therefore, the P. radiata cell culture system appears to be well suited to study the formation of lignified secondary cell walls in coniferous gymnosperms.

UV Protection in the Photosymbiotic Ascidian Didemnum molle Inhabiting Different Depths

Didemnum molle is a colonial ascidian that harbors the prokaryotic photosymbiont Prochloron in its cloacal cavity. Colonies occur over a relatively wide bathymetric range (approximately 0-30 m), and colony color is widely variable, partly depending on depth. Colonies in shallow sites are bright white, with densely distributed spicules, and often with brown or dark gray pigmentation, while colonies in deeper sites are less pigmented, with sparsely distributed spicules. Didemnum molle colonies contain mycosporine-like amino acids (MAAs) as UV-absorbing substances. These include mycosporine-glycine, shinorine, and porphyra-334. Among colonies from 5-, 10-, 15-, and 20-m depths, the concentration of total MAAs was significantly high at 10 m and low at 20 m. Colonies at 10 m need to maintain low spicule densities to have enough photosynthetically active radiation (PAR) to maintain the photosymbionts, and they probably concentrate MAAs to block UV radiation without attenuating PAR. Because high levels of PAR cause photoinhibition of photosynthesis, spicules and pigment cells would be more effective for photoprotection in shallow water. Colonies of D. molle may adjust the light conditions for photosymbionts by combining MAAs, spicules, and pigment cells in varying amounts.

Evaluation of rat and rabbit sera lipoproteins in experimentally induced hyperlipidemia by analytical ultracentrifugation

Animals of various species are widely used as models with which to study atherosclerosis and the lipoprotein metabolism. The objective of this study was to investigate the lipoprotein profiles in Wistar rats and New Zealand white rabbits with experimentally induced hyperlipidemia by means of ultracentrifugation. The Schlieren curves were utilized to compare suckling and adult rat sera to determine whether aging causes alterations in lipoprotein profiles. A striking feature of the data is the high concentration of low-density lipoproteins (LDL), (>5.2 mmol/l cholesterol) in the 2-week old rat serum pool which was greatly decreased in the 3-weeks rat serum pool (<1.3 mmol/l cholesterol). Additional experiments were performed to permit a direct comparison of the amounts of lipoprotein present in rat sera in experimental hyperlipidemia post-Triton WR 1339 administration. Rapid changes in concentrations in very low-density lipoproteins (VLDL), LDL and high-density lipoproteins (HDL) were observed after Triton injection. The administration of Triton WR 1339 to fasted rats resulted in an elevation of serum cholesterol levels. Triton physically alters VLDL, rendering them refractive to the action of lipolytic enzymes in the blood and tissues, preventing or delaying their removal from the blood. Whereas the VLDL concentration was increased markedly, those of LDL and HDL were decreased at 20 h after Triton treatment. Rabbits were fed a diet containing 2% cholesterol for 60 days to develop hyperlipidemia and atheromatous aortic plaques. A combination of preparative and analytical ultracentrifugation was used to investigate of LDL aliquots, to prepare radioactive-labeled lipoproteins and to study induced hyperlipidemia in rabbits. Analytical ultracentrifugation was applied to investigate the LDL flotation peaks before and after cholesterol feeding of rabbits. Modified forms of LDL were detected in the plasma of rabbits with experimentally induced atherosclerosis. ApoB-containing particles, migrating as LDL, intermediate density lipoproteins and VLDL were the most abundant lipoproteins. Gamma camera in vivo scintigraphy on rabbits with radiolabeled lipoproteins revealed visible signals corresponding to atherosclerotic plaques of the aorta and carotid arteries.

Conformational changes in single-strand DNA as a function of temperature by SANS

Small-angle neutron scattering (SANS) measurements were performed on a solution of single-strand DNA, 5'-ATGCTGATGC-3', in sodium phosphate buffer solution at 10 degrees C temperature increments from 25 degrees C to 80 degrees C. Cylindrical, helical, and random coil shape models were fitted to the SANS measurements at each temperature. All the shapes exhibited an expansion in the diameter direction causing a slightly shortened pitch from 25 degrees C to 43 degrees C, an expansion in the pitch direction with a slight decrease in the diameter from 43 degrees C to 53 degrees C, and finally a dramatic increase in the pitch and diameter from 53 degrees C to 80 degrees C. Differential scanning calorimeter scans of the sequence in solution exhibited a reversible two-state transition profile with a transition temperature of 47.5 +/- 0.5 degrees C, the midpoint of the conformational changes observed in the SANS measurements, and a calorimetric transition enthalpy of 60 +/- 3 kJ mol(-1) that indicates a broad transition as is observed in the SANS measurements. A transition temperature of 47 +/- 1 degrees C was also obtained from ultraviolet optical density measurements of strand melting scans of the single-strand DNA. This transition corresponds to unstacking of the bases of the sequence and is responsible for the thermodynamic discrepancy between its binding stability to its complementary sequence determined directly at ambient temperatures and determined from extrapolated values of the melting of the duplex at high temperature.

Methyl-β-Cyclodextrin Treatment and Filipin Staining Reveal the Role of Cholesterol in Surface Membrane Antigen Sequestration of Schistosoma mansoni and S. haematobium Lung-Stage Larvae

Ex vivo lung-stage larvae of Schistosoma mansoni and S. haematobium do not bind specific antibodies in the indirect membrane immunofluorescence test (IF), probably as a result of confinement of the surface membrane antigens in immobile, lipid-rich sites. Treatment with the membrane-impermeable, cholesterol-extracting drug methyl-beta-cyclodextrin (MBCD) and staining with filipin III (filipin), a fluorescent polyene antibiotic widely used for the detection and quantitation of cholesterol in biomembranes, allowed us to examine the role of cholesterol in surface membrane antigen sequestration of S. mansoni and S. haematobium ex vivo lung-stage larvae. Treatment of S. mansoni larvae with MBCD elicited appreciable cholesterol depletion as judged by filipin-cholesterol fluorescence diminution, which was accompanied by a considerable increase in specific antibody binding in IF, thus suggesting that cholesterol plays a predominant role in sequestration of the surface membrane antigens of S. mansoni lung-stage schistosomula. Despite that, MBCD induced an almost complete depletion of cholesterol from the outer membrane of S. haematobium larvae; no increase in specific antibody binding in IF was evident, implying that cholesterol is not responsible for masking surface membrane antigens of S. haematobium lung-stage larvae.

Xanthones from a microfungus of the genus Xylaria

Chemical investigations of a microfungus Xylaria sp. isolated from the Australian rainforest tree Glochidion ferdinandi have afforded two new natural products, 2-hydroxy-6-methyl-8-methoxy-9-oxo-9H-xanthene-1-carboxylic acid (1) and 2-hydroxy-6-hydroxymethyl-8-methoxy-9-oxo-9H-xanthene-1-carboxylic acid (2). Compound 1 has previously been synthesised but only partially characterised. Methylation of 1 using diazomethane afforded the crystalline compound 2,8-dimethoxy-6-methyl-9-oxo-9H-xanthene-1-carboxylic acid methyl ester (3), whose structure was determined by single crystal X-ray analysis. This paper reports the full spectroscopic characterisation of compounds 1-3 by NMR, UV, IR and MS data. All compounds were inactive in a brine shrimp lethality assay and several antimicrobial screens.

Acylated flavonoids and phenol glycosides from Veronica thymoides subsp. pseudocinerea

A new acylated flavone glucoside, 3'-hydroxyscutellarein 7-O-(6''-O-protocatechuoyl)-beta-glucopyranoside (1), and a new phenol glucoside, 3,5-dihydroxyphenethyl alcohol 3-O-beta-glucopyranoside (6) were isolated from Veronica thymoides subsp. pseudocinerea together with seven known flavone, phenol and lignan glycosides; 3'-hydroxyscutellarein 7-O-(6''-O-trans-feruloyl)-beta-glucopyranoside (2), 3'-hydroxy, 6-O-methylscutellarein 7-O-beta-glucopyranoside (3), luteolin 7-O-beta-glucopyranoside (4), isoscutellarein 7-O-(6'''-O-acetyl)-beta-allopyranosyl (1''' --> 2'')-beta-glucopyranoside (5), 3,4-dihydroxyphenethyl alcohol 8-O-beta-glucopyranoside (7), benzyl alcohol 7-O-beta-xylopyranosyl (1" --> 2')-beta-glucopyranoside (8), and (+)-syringaresinol 4'-O-beta-glucopyranoside (9). Compounds 2, 3 and 7-9 were reported for the first time in the genus Veronica. The structures of the isolates were determined by means of spectroscopic (UV, IR, 1D and 2D NMR, HR ESI-MS) methods. Isolated compounds (1-7) exhibited potent radical scavenging activity against the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical.

Antimitotic activity of glaupalol-related coumarins from Glaucidium palmatum

Two new coumarins, glaumacidines A (1) and B (2), and the related coumarins (3-7) have been isolated from the rhizomes of Glaucidium palmatum (Glaucidiaceae). The absolute configurations of 1 and 2 and trans- and cis-glaupadiols (3 and 4, respectively) were elucidated by spectroscopic data, chemical derivatization, and exciton chirality method. Glaupalol (5) enhanced the polymerization of tubulin and affected synergistically with paclitaxel on inhibition of KB cell proliferation.

Study of the Incidence and Nature of "Very Subtle Epidermal Melasma" in Relation to Intense Pulsed Light Treatment

BACKGROUND

Skin rejuvenation with intense pulsed light (IPL) is effective for clearing epidermal pigment disorders. Complications are mild and limited to epidermal burns caused by excessive settings. Some patients, however, experience IPL-induced melasma-like hyperpigmentation despite the appearance of normal skin. These patients seem to have very subtle epidermal melasma not visible to the naked eye. Ultraviolet photography has been useful in identifying these patients and preventing complications.

OBJECTIVE

The study investigated the incidence of very subtle melasma in patients using UV photography, and assessed this tool in identifying high-risk patients.

SUBJECTS AND METHODS

223 Japanese women, 30-69 years old, participated in the study. Very subtle melasma invisible to the naked eye under normal light was diagnosed by UV photography by two physicians, and any relationship among the disease incidence, age, and regular sunscreen use was examined.

RESULTS

Sixty-three cases of very subtle melasma (28.3%) were identified among the 223 subjects, with a significantly lower incidence in sunscreen users.

CONCLUSIONS

Patients diagnosed with subtle epidermal melasma and treated with mild IPL parameters did not suffer induced secondary hyperpigmentaion. To help avoid complications after treatment, IPL users should be aware of the age and sunscreen-related incidence of this phenomenon in Asian patients.

An in vitro study of the susceptibility of mobile and cystic forms of Borrelia burgdorferi to tinidazole

The susceptibility of mobile and cystic forms of Borrelia burgdorferi to tinidazole (TZ) was examined. The minimal bactericidal concentration (MBC) of TZ against the mobile spirochetes was >128 microg/ml at 37 degrees C in micro-oxic atmosphere when incubated for 14 days. TZ significantly reduced the conversion of mobile spirochetes to cystic forms during incubation. The MBC for older (10-months-old) cysts at 37 degrees C in a micro-oxic atmosphere was >0.5 microg/ml, but >0.125 microg/ml for young (1-day-old) cysts. Acridine orange staining, dark-field microscopy and transmission electron microscopy revealed that, when the concentration of TZ was > or = MBC, the contents of the cysts were partly degraded, core structures did not develop inside the young cysts, and the amount of RNA in these cysts decreased significantly. When cysts were exposed to TZ, both the spirochetal structures and core structures inside the cysts dissolved, and the production of blebs was significantly reduced. These observations may be valuable in the treatment of resistant infections caused by B. burgdorferi, and suggest that a combination of TZ and a macrolide antibiotic could eradicate both cystic and mobile forms of B. burgdorferi.

Bayesian framework for the evaluation of fiber evidence in a double murder—a case report

Fiber evidence found on a suspect vehicle was the only useful trace to reconstruct the dynamics of the transportation of two corpses. Optical microscopy, UV-Vis microspectrophotometry and infrared analysis were employed to compare fibers recovered in the trunk of a car to those of the blankets composing the wrapping in which the victims had been hidden. A "pseudo-1:1" taping permitted to reconstruct the spatial distribution of the traces and to further strengthen the support to one of the hypotheses. The Likelihood Ratio (LR) was calculated, in order to quantify the support given by forensic evidence to the explanations proposed. A generalization of the Likelihood Ratio equation to cases analogous to this has been derived. Fibers were the only traces that helped in the corroboration of the crime scenario, being absent any DNA, fingerprints and ballistic evidence.

Preliminary characterization of a light-rare-earth-element-binding peptide of a natural perennial fern Dicranopteris dichotoma

A light-rare-earth-element (LREE)-binding peptide was isolated from LREE hyperaccumulator Dicranopteris dichotomaleaves and characterized in terms of molecular weight and ultraviolet absorption spectrum. The molecular weight of the LREE-binding peptide was determined to be 2208 Da by matrix-assisted laser-desorption ionization-time of flight mass spectrometry (MALDI-TOFMS). The characteristic ultraviolet absorption spectrum of the peptide was observed at 220-300 nm, suggesting that the peptide chain contained aromatic amino acids. Compared to the unique features of the phytochelatins with a low absorption at 280 nm, the LREE-binding peptide is unlikely to be a typical phytochelatin. The present study suggests that the LREE-binding peptide is probably a natural peptide in D. dichotoma, and it may play an important role in hyperaccumulation of LREEs.

Acrylamide axonopathy revisited

Distal swelling and eventual degeneration of axons in the CNS and PNS have been considered to be the characteristic neuropathological features of acrylamide (ACR) neuropathy. These axonopathic changes have been the basis for classifying ACR neuropathy as a central-peripheral distal axonopathy and, accordingly, research over the past 30 years has focused on the primacy of axon damage and on deciphering underlying mechanisms. However, based on accumulating evidence, we have hypothesized that nerve terminals, and not axons, are the primary site of ACR action and that compromise of corresponding function is responsible for the autonomic, sensory, and motor defects that accompany ACR intoxication (NeuroToxicology 23 (2002) 43). In this paper, we provide a review of data from a recently completed comprehensive, longitudinal silver stain study of brain and spinal cord from rats intoxicated with ACR at two different daily dosing rates, i.e., 50 mg/kg/day, ip or 21 mg/kg/day, po. Results show that, regardless of dose-rate, ACR intoxication was associated with early, progressive nerve terminal degeneration in all CNS regions and with Purkinje cell injury in cerebellum. At the lower dose-rate, initial nerve terminal argyrophilia was followed by abundant retrograde axon degeneration in white matter tracts of spinal cord, brain stem, and cerebellum. The results support and extend our nerve terminal hypothesis and suggest that Purkinje cell damage also plays a role in ACR neurotoxicity. Substantial evidence now indicates that axon degeneration is a secondary effect and is, therefore, not pathophysiologically significant. These findings have important implications for future mechanistic research, classification schemes, and assessment of neurotoxicity risk.

Ultraviolet-light-absorbing tunic cells in didemnid ascidians hosting a symbiotic photo-oxygenic prokaryote, Prochloron

Coral reef invertebrates that host phototrophic symbionts are thought to protect themselves and their symbionts with mycosporine-like amino acids (MAAs)-UV-absorbing substances that act as sunscreens (Dunlap, W. C., and J. M. Shick, 1998. J. Phycol. 34: 418-430). However, the histological distribution of MAAs in the host tissues has not yet been visualized. We have localized the UV-absorbing substances in the tissues of two colonial didemnid ascidians-Lissoclinum patella and Diplosoma sp.-that contain the symbiotic photo-oxygenic prokaryote Prochloron sp. Cross-sections of unfixed tissue from these ascidians were examined by UV-light microscopy at 320 or 330 nm, wavelengths at which UV light is absorbed by MAAs. Within the tunic, the gelatinous integument of the colony, UV light was exclusively absorbed by a particular type of cell, the tunic bladder cell. Tunic bladder cells with strong UV absorption were denser in the upper tunic, which lies over a colony's zooids, than in the basal tunic underlying the zooid. In the upper tunic, those cells with strong UV absorption were most dense near the surface. The tunic bladder cell is highly vacuolated, and the vacuole contains strong acid, which destabilizes MAAs. Furthermore, the UV-absorbing portion of tunic bladder cells seemed to be cup-shaped, indicating that the MAAs are not localized in the vacuole, but in the cytoplasm. These results strongly suggest that didemnid ascidians accumulate MAAs in tunic bladder cells as a protection against UV radiation.

Efficiency of lipofection of adherent cells is limited by apoptosis

Stability of gene expression and transfection efficiency plays the main role in the application of gene transfer method. In somatic cell gene delivery, expression of the gene product is limited by the function of the cell to which it is delivered. In the present study analyzing the lipofected adherent cells, we have shown that lower level of transgene: beta-galactosidase activity at later time period correlated with decrease in cell viability, which was shown to be due to apoptosis. Apoptosis following DNA uptake occurred only when DNA was present during lipofection.

The effects of water-soluble cyclodextrins on the histological integrity of the rat nasal mucosa

The aim of this study was to investigate the effect of highly water-soluble cyclodextrins (CDs) on the histological integrity of the nasal mucosa. In order to evaluate their effects, the in vivo single and repeated nasal exposure studies were performed using male Wistar rats. The rat nasal cavity was excised after an application of various CD solutions at different times. The morphological appearances of the rat nasal mucosae were analyzed with the light microscopic and the scanning electron microscopic studies. By utilizing 5-min exposure of each CD solution to the nasal mucosa, no tissue damage was visible for 1.5% w/v beta-CD and 5 and 20% w/v hydroxypropyl beta-CD (HP beta-CD), and the effects were quite similar to controls. However, using 20% w/v randomly methylated beta-CD (RM beta-CD) showed severe damage on the integrity of nasal mucosa. The severity was similar to 1% w/v polyoxyethylene-9-lauryl ether or l% w/v sodium deoxycholate. Meanwhile, 30 or 60 min exposure to 10% w/v HP beta-CD or RM beta-CD resulted in no obvious mucosal damage. In addition, in vivo repeated dosing of RM beta-CD did not show any toxicity up to 20% w/v. These results suggest that at least, less than 10% w/v CD solutions do not induce gross tissue damage and can keep the histological integrity of the nasal mucosa.

The ratio of polymorphonuclear leucocytes (PMN) to non-PMN cells--a novel method of assessing acute lung inflammation

Polymorphonuclear leucocyte (PMN) numbers are an indicator of the degree of acute lung inflammation. However, there is no standardized system for accurately quantifying their numbers in tissue sections. Also, the effect of lung inflation on the quantification of PMN's is usually overlooked. Lung specimens obtained from clinical biopsies are usually deflated, while inflated lung tissue is commonly used in experimental studies. We report a method, which is independent of the degree of inflation, for measuring the degree of PMN infiltration in the both inflated and non-inflated lungs. Using light microscopy, we counted the numbers of PMN and non-PMN cells in 240 fields from each of five inflated and five non-inflated lung sections and calculated a ratio of PMN: non-PMN cells (the PMN ratio). The effect on accuracy and precision of number of fields counted was investigated by randomly selecting 200, 160, 80 or 40 readings from the original 240 fields. The mean PMN ratio, its 95% confidence interval (CI) and the coefficient of variation (CV) were calculated for each of the four levels of sampling. Both CI and CV increased as the number of readings decreased. Inflated lung tissue had consistently higher values for CV compared to non-inflated lung. In practice, we recommend that for both inflated and non-inflated lungs, 80-160 fields (approximate 0.23-0.45 mm2 of absolute area evaluated) need to be counted to yield a PMN ratio with acceptable accuracy and precision. The PMN ratio provides a simple and objective way of quantifying the degree of acute inflammation in clinical histopathology and experimental toxicology studies involving lungs. It is suitable for use in research of lung inflammation, and as an accessory diagnostic tool and an objective descriptor for clinical histopathology.

Ultrastructural examination of rabbit aortic wall following high-fat diet feeding and selenium supplementation: a transmission electron microscopy study

Experiments were carried out to examine the changes occurring in the wall of rabbit aortae following high-fat diet (HFD) feeding as well as HFD + selenium supplementation. Male New Zealand White rabbits were divided into three groups-control, HFD-fed and HFD + Se supplementation-and were treated for three months. The study depicted that levels of serum total cholesterol and triglycerides were markedly increased in the HFD-fed group as compared with control animals. However, in the HFD + Se-fed group, these levels were markedly suppressed vis-à-vis animals fed on HFD only. Development of atherogenic and atheromatic plaques has been shown at the light microscopy level in HFD-fed rabbits, whereas these developments were not visible in the HFD + Se-fed rabbits. Transmission electron microscopy findings indicated altered ultrastructure in the endothelial cells of the intimal layer as well as smooth-muscle cells of the medial layer in HFD-fed animals. However, these findings indicated normal ultrastructure in most of the cells, with little ultrastructural alterations from animals supplemented with Se along with HFD feeding. The study on the whole depicted the ability of Se to inhibit the onset of progression of aortic disease and hence has relevance to its therapeutic potential.

Metabolic pathways of carcinogenic chromium

The products of hexavalent chromium [Cr(VI)] reduction by glutathione (GSH) alone or in the presence of equimolar quantities of aspartate (Asp) and/or glutamate (Glu) and a chromium-containing material extracted from bovine liver were studied by ultraviolet-visible spectrum (UV-vis) studies, electrospray mass spectrometry (ES-MS), electron paramagnetic resonance (EPR), and nuclear magnetic resonance (NMR). Reduction of chromate by GSH was followed by UV-vis and NMR, revealing the formation of a paramagnetic complex in which GSH acts as a ligand. ES-MS and EPR measurements provided unequivocal evidence of a dimeric Cr(V)(2)GSH(2) species in which the two metal ions are bridged by the Gamma-Glu carboxylate. The analysis of the (1)H and (13)C shifts experienced by GSH protons and the values of paramagnetic contributions to proton spin-lattice relaxation rates provided a set of constraints for structural determination. The same experiments were repeated in the presence of an equimolar concentration of Asp, revealing the formation of a dimeric Cr(V) paramagnetic complex in which the two metals are now bridged by Asp. Nuclear magnetic resonance dispersion profiles show that water is not displaced by Asp and that the correlation time of this complex is slowed by the increased complexity. When Glu is also included in the solution in equimolar concentration to GSH and Asp, data are consistent with the formation of many mono- and dinuclear species, with the three ligands competing with each other. Finally, the spectroscopic investigation of the chromium-containing material extracted from bovine liver revealed the presence of a complicate mixture of Cr(IV) or Cr(V) complexes, among which some Cr(V)-GSH species are present alone or with other ligands in the metal coordination sphere.

Cell-specific expression of homospermidine synthase, the entry enzyme of the pyrrolizidine alkaloid pathway in Senecio vernalis, in comparison with its ancestor, deoxyhypusine synthase

Pyrrolizidine alkaloids (PAs) are constitutive plant defense compounds with a sporadic taxonomic occurrence. The first committed step in PA biosynthesis is catalyzed by homospermidine synthase (HSS). Recent evidence confirmed that HSS evolved by gene duplication from deoxyhypusine synthase (DHS), an enzyme involved in the posttranslational activation of the eukaryotic translation initiation factor 5A. To better understand the evolutionary relationship between these two enzymes, which are involved in completely different biological processes, we studied their tissue-specific expression. RNA-blot analysis, reverse transcriptase-PCR, and immunolocalization techniques demonstrated that DHS is constitutively expressed in shoots and roots of Senecio vernalis (Asteraceae), whereas HSS expression is root specific and restricted to distinct groups of endodermis and neighboring cortex cells located opposite to the phloem. All efforts to detect DHS by immunolocalization failed, but studies with promoter-beta-glucuronidase fusions confirmed a general expression pattern, at least in young seedlings of tobacco (Nicotiana tabacum). The expression pattern for HSS differs completely from its ancestor DHS due to the adaptation of HSS to the specific requirements of PA biosynthesis.

Acute bacterial endocarditis secondary to transrectal ultrasound-guided prostatic biopsy

We report the first case of a patient with no history of diabetes or cardiac problems who developed an endocarditis secondary to a transrectal prostatic biopsy. Urinalysis prior to the biopsy was normal and the patient had a course of ciprofloxacin 2 hours preoperatively.

Fas and Fas ligand immunolocalization in pancreatic islets of NOD mice during spontaneous and cyclophosphamide-accelerated diabetes

During insulin-dependent diabetes mellitus, immune cells which infiltrate pancreatic islets mediate beta cell destruction over a prolonged asymptomatic prediabetic period. The molecular mechanisms of beta cell death in vivo remain unresolved. At least two major molecular processes of destruction have been proposed. One involves the Fas-FasL (Fas-Fas ligand) system and the other, the perforin pathway. Here, dual-label immunohistochemistry was employed to examine the intra-islet expression, distribution and cellular sources of Fas and FasL in the NOD mouse, during spontaneous diabetes (days 21, 40 and 90) and following acceleration of diabetes with cyclophosphamide (days 0, 4, 7, 11 and 14 after cyclophosphamide administration). The expression of the proteins was correlated with advancing disease. FasL was expressed constitutively in most beta cells but not in glucagon or somatostatin cells or islet inflammatory cells and paralleled the loss of insulin immunolabelling with advancing disease. It was also expressed in beta cells of non-diabetes prone CD-1 and C57BL/6 mice from a young age (day 21). Strong immunolabelling for Fas was first observed in extra-islet macrophages and those close to the islet in NOD and non-diabetes-prone mice. During spontaneous and cyclophosphamide diabetes, it was observed in a higher proportion of islet infiltrating macrophages than CD4 and CD8 T cells, concomitant with advancing insulitis. In cyclophosphamide-treated mice, the proportion of Fas-positive intra-islet CD4 and CD8 T cells at day 14 (with and without diabetes) was considerably higher than at days 0, 4, 7 and 11. At days 11 and 14, a proportion of Fas-positive intra-islet macrophages co-expressed interleukin-1beta and inducible nitric oxide synthase. Fas was not detectable in beta cells and other islet endocrine cells during spontaneous and cyclophosphamide induced diabetes. Our results show constitutive expression of FasL in beta cells in the NOD mouse and predominant expression of Fas in intra-islet macrophages and to a lesser extent in T cells prior to diabetes onset. Interleukin-1beta in intra-islet macrophages may induce Fas and inducible nitric oxide synthase expression in an autocrine and paracrine manner and mediate beta cell destruction or even death of some macrophages and T cells. However, other mechanisms of beta cell destruction during spontaneous and cyclophosphamide-accelerated diabetes and independent of Fas-FasL, require examination.

(F(8)TPP)Fe(II)/O(2) reactivity studies [F(8)TPP = tetrakis(2,6-difluorophenyl)porphyrinate(2-)]: spectroscopic (UV-Visible and NMR) and kinetic study of solvent-dependent (Fe/O(2) = 1:1 or 2:1) reversible O(2)-reduction and ferryl formation

In this report, we describe in detail the O(2)-binding chemistry of the metalloporphyrin (F(8)TPP)Fe(II) (1). This complex was synthesized from aqueous dithionite reduction of (F(8)TPP)Fe(III)-Cl (X-ray structure reported: C(55)H(36)ClF(8)FeN(4)O; a = 13.6517(2) A, b = 13.6475(2) A, c = 26.3896(4), alpha = 90 degrees, beta = 89.9776(4) degrees, gamma = 90 degrees; monoclinic, P2(1)/c, Z = 4). Complex 1 crystallizes from toluene/heptane solvent system as a bis(toluene) solvate, (F(8)TPP)Fe(II).(C(7)H(8))(2), with ferrous ion in the porphyrin plane (C(58)H(36)F(8)FeN(4); a = 20.9177(2) A, b = 11.7738(2) A, c = 19.3875(2), alpha = 90 degrees, beta = 108.6999(6) degrees, gamma = 90 degrees; monoclinic, C2/c, Z = 4; Fe-N(4)(av) = 2.002 A; N-Fe-N (all) = 90.0 degrees ). Close metal-arene contacts are also observed at 3.11-3.15 A. Upon oxygenation of 1 at 193 K in coordinating solvents, UV-visible and (2)H and (19)F NMR spectroscopies revealed the presence of a reversibly formed dioxygen adduct, formulated as the heme-superoxo complex (S)(F(8)TPP)Fe(III)-(O(2)(-)) (2) (S = solvent) [(i) tetrahydrofuran (THF) solvent: UV-visible, 416 (Soret), 536 nm; (2)H NMR: delta(pyrrole) 8.9 ppm; (ii) EtCN solvent: UV-visible, 414 (Soret), 536 nm; (iii) acetone solvent: UV-visible, 416 (Soret), 537 nm; (2)H NMR: delta(pyrrole) 8.9 ppm]. Dioxygen-uptake manometry (THF, 193 K) revealed an O(2):1 oxygenation stoichiometry of 1.02:1, consistent with the heme-superoxo formulation of 2. Stopped-flow UV-visible spectrophotometry studies of the (F(8)TPP)Fe(II) (1)/O(2) reaction in EtCN and THF solvents were able to provide kinetic and thermodynamic insight into the reversible formation of 2 [(i) EtCN: Delta H degrees = -40 +/- 5 kJ/mol; Delta S degrees = -105 +/- 23 J/(K mol); k(1) = (5.57 +/- 0.04) x 10(3) M(-)(1) s(-)(1) (183 K); Delta H(++) = 38.6 +/- 0.2 kJ/mol; Delta S(++) = 42 +/- 1 J/(K mol); (ii) THF: Delta H* = -37.5 +/- 0.4 kJ/mol; Delta S* = -109 +/- 2 J/(K mol)]. The (F(8)TPP)Fe(II) (1)/O(2) reaction was also examined at reduced temperatures in noncoordinating solvents (toluene, CH(2)Cl(2)), where UV-visible and (2)H and (19)F NMR spectroscopies also revealed the presence of a reversibly formed adduct, formulated as the peroxo-bridged dinuclear complex [(F(8)TPP)Fe(III)](2)-(O(2)(2)(-)) (3) [CH(2)Cl(2): UV-visible, 414 (Soret), 535 nm; (2)H NMR, delta(pyrrole) 17.5 ppm]. Dioxygen-uptake spectrophotometric titrations revealed a stoichiometry of 2 (F(8)TPP)Fe(II) (1) per O(2) upon full formation of 3. Addition of a nitrogenous base, 4-(dimethylamino)pyridine, to a cold solution of 3 in dichloromethane gave rapid formation of the iron(IV)-oxo ferryl species (DMAP)(F(8)TPP)Fe(IV)==O (4), based upon UV-visible [417 (Soret), 541 nm] and (2)H NMR (delta(pyrrole) = 3.5 ppm) spectroscopic characterization. These detailed investigations into the O(2)-adducts and "ferryl" species formed from (F(8)TPP)Fe(II) (1) may be potentially important for a full understanding of our ongoing heme-copper oxidase model studies, which employ 1 or similar "tethered" (i.e., covalently attached Cu-chelate) porphyrin analogues in heme/Cu heterobinuclear systems.

Orthodontic tooth movement enhances bone healing of surgical bony defects in rats

BACKGROUND

The question of whether the repair of an alveolar bony defect can be enhanced by orthodontic tooth movement was addressed.

METHODS

Alveolar bone defects were created in 52 Wistar male rats anterior to both maxillary first molars. After 1 week of healing, orthodontic protraction was applied for 2 weeks on the right side, resulting in mesial tipping and displacement movement. Subsequently, a retention appliance was inserted for 1 week. The left side served as the untreated (control) group. Vital bone staining (procion brilliant red H-8) was administered before and after orthodontic traction. Histomorphometric analysis was performed on 62 hemimaxillae using UV confocal microscopy and an imaging program. The total area of the bony defect was divided into 4 equal quadrants, and the area of bony apposition in each quadrant was measured.

RESULTS

The total area of bony apposition was 6.5-fold larger in the treated (26.41 x 10(4) +/- 28.92 x 10(4) microm2) than in the control group (4.07 x 10(4) +/- 2.82 x 10(4) microm2), approaching statistical significance (P = 0.065). The treated occlusal quadrants demonstrated highly significant (P= 0.010), greater bone apposition compared to the control group (13.8-fold) and to the treated apical quadrants (P= 0.04, 5-fold).

CONCLUSIONS

This study confirms that orthodontic tooth movement is a stimulating factor of bone apposition. A conversion in the repair pattern of the bony defect from apicoocclusal in the control group (no tooth movement) to occlusoapical in the treated group (with tooth movement) further supports the linkage between tooth movement and enhanced bone deposition. Clinical implication suggests incorporation of orthodontic tooth movement in regenerative therapy.

New applications for an old lignified element staining reagent

The use is reported of Mirande's reagent in epifluorescence microscopy which permits a clear distinction between cellulosic and lignified tissues. Homogeneous Prespermatophytae and gymnosperm xylem appeared entirely green with Mirande's reagent under ultraviolet excitation, whereas heteroxyled angiosperm wood showed a mixed pink and blue-green colour. This coloration was due to the fluorescence of cellulose, since certain elements in dicotyledonous wood (parenchyma, fibres, xylem rays) are not entirely lignified. Monocotyledonous (Poaceae) lignin showed an intense blue fluorescence due to hydroxycinnamic acids bound to the cell wall. The method showed that lignification occurs first in the middle lamella, and later in the secondary wall of xylem cells. In addition, this staining technique proved useful in the study of lignin and suberin deposition in response to various stress factors.

SIN-1-induced DNA damage in isolated human peripheral blood lymphocytes as assessed by single cell gel electrophoresis (comet assay)

Human lymphocytes were exposed to increasing concentrations of SIN-1, which generates superoxide and nitric oxide, and the formation of single-strand breaks (SSB) in individual cells was determined by the single-cell gel electrophoresis assay (comet assay). A dose- and time-dependent increase in SSB formation was observed rapidly after the addition of SIN-1 (0.1-15 mM). Exposure of the cells to SIN-1 (5 mM) in the presence of excess of superoxide dismutase (0.375 mM) increased the formation of SSB significantly, whereas 1000 U/ml catalase significantly decreased the quantity of SSB. The simultaneous presence of both superoxide dismutase and catalase before the addition of SIN-1 brought the level of SSB to that of the untreated cells. Moreover, pretreatment of the cells with the intracellular Ca(2+)-chelator BAPTA/AM inhibited SIN-1-induced DNA damage, indicating the involvement of intracellular Ca(2+) changes in this process. On the other hand, pretreatment of the same cells with ascorbate or dehydroascorbate did not offer any significant protection in this system. The data suggest that H2O2-induced changes in Ca(2+) homeostasis are the predominant pathway for the induction of SSB in human lymphocytes exposed to oxidants.

The microaerophilic flagellate Giardia intestinalis: Allium sativum (garlic) is an effective antigiardial

Whole garlic (Allium sativum L.) extract and some of its components were assayed for antigiardial activity. Whole garlic extract gave an IC(50) at 24 h of 0.3 mg ml(-1). Most of the components assayed were inhibitory to the organism, especially allyl alcohol and allyl mercaptan, with IC(50) values of 7 microg ml(-1) and 37 microg ml(-1) respectively. Studies with calcofluor white indicated that whole garlic and allyl alcohol collapse the transmembrane electrochemical membrane potential (Deltapsi) of the organism, as indicated by uptake of the fluorochrome. Electron microscopy allowed the morphological changes that occur with garlic inhibition to be recorded. Both the surface topography and internal architecture of the organism changed during incubation with the biocides. Both whole garlic and allyl alcohol resulted in fragmentation of the disc and an overexpression of disc microribbons, internalization of flagella, vacuole formation and an increase in distended vesicles. Allyl mercaptan, however, only gave an increase in distended vesicles, suggesting that this biocide has a different mode of action.

The behaviour of the plasma membrane during plasmolysis: a study by UV microscopy

A high resolution ultraviolet (UV) bright-field microscope was used to analyse the formation of Hechtian strands and the Hechtian reticulation that remain attached to the cell wall after plasmolysis and deplasmolysis of onion inner epidermal cells. In real time video images, UV microscopy allowed a detailed investigation of the dynamic behaviour of the plasma membrane during the processes of osmotic water loss and uptake. Furthermore, the role of cytoskeletal elements as possible linkers of the plasma membrane to the cell wall was probed by application of cytoskeletal drugs during plasmolysis. Microtubules were depolymerized in oryzalin, and latrunculin B was used to destabilize actin microfilaments. The results showed no visible changes in the formation of the Hechtian reticulation or strands. Plasmolysis forms appeared to be normal, indicating stong membrane-to-wall attachments independent of cytoskeletal elements. During re-expansion of the protoplast in deplasmolysis, the plasma membrane incorporated Hechtian strands and subprotoplasts, fused with the Hechtian reticulation and finally realigned at the cell wall.

In vivo diffuse damage in human vertebral trabecular bone

Accumulation of microdamage in vivo may lead to loss of bone quality. Until recently, linear microcracks were the only known form of in vivo microdamage, but through the use of confocal microscopy an additional level of damage (diffuse damage) has been identified. In this study, in vivo diffuse damage was characterized and quantified in human vertebral trabecular bone as a function of tissue morphology, age, race, gender, and previously quantified in vivo linear microcracks. Presence of diffuse damage in human vertebral tissue was confirmed and validated by simultaneous use of polarized, ultraviolet, and laser confocal microscopy. Diffuse damage was found to occur preferentially within trabecular packets rather than in interstitial bone (p < 0.05). It was consistently higher in men compared with women (p < 0.05), but was not different by race or age group. Diffuse damage did not correlate with linear microcracks, but both exhibited the same probability distribution in which the percentage of individuals having a particular amount of damage decreased exponentially as damage content increased. These findings suggest that diffuse damage accumulation and repair are governed by the same biological phenomena as microcracks, but diffuse damage contributes independently to the microdamage content of bone.

Ultraviolet microscopy of purine compounds in the yeast vacuole

Svihla, G. (Argonne National Laboratory, Argonne, Ill.), J. L. Dainko, and F. Schlenk. Ultraviolet microscopy of purine compounds in the yeast vacuole. J. Bacteriol. 85:399-409. 1962.-Yeast cells (Candida utilis and Saccharomyces cerevisiae) suspended in nitrogen-free medium were exposed to various ultraviolet-absorbing biological compounds, particularly nucleic acid constituents. Ultraviolet photomicrography was used to locate these substances in the cells. Purines were taken up readily and concentrated in the vacuoles of C. utilis but not of S. cerevisiae. Crystallization occurred, as observed earlier by other techniques. Neither organism assimilated pyrimidine bases, or purine or pyrimidine nucleosides, at a detectable rate. From the selective uptake and release of some purine derivatives, it can be concluded that the properties of the vacuolar membrane and the cytoplasmic membrane differ in several respects.