Reduced alcohol preference and intake after fecal transplant in patients with alcohol use disorder is transmissible to germ-free mice

Alcohol use disorder is a major cause of morbidity, which requires newer treatment approaches. We previously showed in a randomized clinical trial that alcohol craving and consumption reduces after fecal transplantation. Here, to determine if this could be transmitted through microbial transfer, germ-free male C57BL/6 mice received stool or sterile supernatants collected from the trial participants pre-/post-fecal transplant. We found that mice colonized with post-fecal transplant stool but not supernatants reduced ethanol acceptance, intake and preference versus pre-fecal transplant colonized mice. Microbial taxa that were higher in post-fecal transplant humans were also associated with lower murine alcohol intake and preference. A majority of the differentially expressed genes (immune response, inflammation, oxidative stress response, and epithelial cell proliferation) occurred in the intestine rather than the liver and prefrontal cortex. These findings suggest a potential for therapeutically targeting gut microbiota and the microbial-intestinal interface to alter gut-liver-brain axis and reduce alcohol consumption in humans.

Prevalence and genotype of Giardia duodenalis from faecal samples of stray dogs in Hualien city of eastern Taiwan

Giardia duodenalis is a zoonotic protozoan parasite that causes diarrhea through waterborne transmission or fecal-oral infection. The cysts are chlorine-resistant and, therefore, can pollute drinking water and induce a pandemic disease. In this study, we aimed to detect G. duodenalis infection in stray dogs in Hualien, Taiwan. We collected faecal samples from 118 dogs and amplified DNA sequences of the β-giardin gene by nested polymerase chain reactions (nested PCR). Eleven of the 118 faecal samples tested positive for the parasite. The genotype analysis of the 11 samples indicated that 7 samples belonged to assemblage C and four samples belonged to assemblage D. Our study provided a better understanding of the infection rate and genotypes of G. duodenalis in dogs from Hualien City, and human infection could not be induced by this zoonotic infection pathway in Hualien City.

Quasiparticle dynamics and phonon softening in FeSe superconductors

Quasiparticle dynamics of FeSe single crystals revealed by dual-color transient reflectivity measurements (ΔR/R) provides unprecedented information on Fe-based superconductors. The amplitude of the fast component in ΔR/R clearly gives a competing scenario between spin fluctuations and superconductivity. Together with the transport measurements, the relaxation time analysis further exhibits anomalous changes at 90 and 230 K. The former manifests a structure phase transition as well as the associated phonon softening. The latter suggests a previously overlooked phase transition or crossover in FeSe. The electron-phonon coupling constant λ is found to be 0.16, identical to the value of theoretical calculations. Such a small λ demonstrates an unconventional origin of superconductivity in FeSe.

Tirapazamine plus cisplatin in advanced or recurrent carcinoma of the uterine cervix: a Southwest Oncology Group study

The objective of this study was to determine objective response and overall survival (OS) and progression-free survival (PFS) following cisplatin plus tirapazamine treatment in eligible consenting patients with metastatic or recurrent squamous or adenosquamous carcinoma of the cervix. Treatment consisted of intravenous tirapazamine, 260 mg/m(2), followed by cisplatin, 75 mg/m(2), every 21 days for six cycles. Of 56 registered cases, 52 were evaluable for toxicity. There were six grade 4 toxicities (anemia [three], dyspnea [one], neutropenia/granulocytopenia [one], and dehydration [one]). Fifty-three patients were evaluable for response, OS, and PFS. The 6-month OS rate was 56.6% (95% CI 43.3-69.9%). The objective response rate was 32.1% (4 complete [2 confirmed and 2 unconfirmed] and 13 partial [8 confirmed and 5 unconfirmed]). Higher response rates (16/34 [47.1%] vs 1/19 [5.3%], P= 0.0018) were observed in patients who had not previously received radiation-sensitizing chemotherapy, as were OS and PFS (13.9 vs 4.0 months, P < 0.0001; 5.3 vs 1.8 months, P= 0.01). The OS was considered too low to warrant further testing in this disease setting. Despite this, tirapazamine plus cisplatin was active in patients who had not received cisplatin previously. Prior use of radiosensitizing chemotherapy impacted response and survival significantly and should be considered in future clinical trials.

Multiphoton confocal microscopy using a femtosecond Cr:forsterite laser

With its output wavelength covering the infrared penetrating window of most biological tissues at 1,200-1,250 nm, the femtosecond Cr:forsterite laser shows high potential to serve as an excellent excitation source for the multiphoton fluorescence microscope. Its high output power, short optical pulse width, high stability, and low dispersion in fibers make it a perfect replacement for the currently widely used Ti:sapphire laser. In this paper, we study the capability of using a femtosecond Cr:forsterite laser in multiphoton scanning microscopy. We have performed the multiphoton excited photoluminescence spectrum measurement on several commonly used bioprobes using the 1,230 nm femtosecond pulses from a Cr:forsterite laser. Efficient fluorescence can be easily observed in these bioprobes through two-photon or three-photon excitation processes. These results will assist in the selection of dichroic beam splitter and band pass filters in a multiphoton microscopic system. We have also performed the autofluorescence spectrum measurement from chlorophylls in live leaves of the plant Arabidopsis thaliana excited by 1,230 nm femtosecond pulses from the Cr:forsterite laser. Bright luminescence from chlorophyll, centered at 673 and 728 nm, respectively, can be easily observed. Taking advantage of the bright two-photon photoluminescence from chlorophyll, we demonstrated the two-photon scanning paradermal and cross-sectional images of palisade mesophyll cells in live leaves of Arabidopsis thaliana.

The role of the CD19/CD21 complex in B cell processing and presentation of complement-tagged antigens

The CD19/CD21 complex is an essential B cell coreceptor that functions synergistically to enhance signaling through the B cell Ag receptor in response to T cell-dependent, complement-tagged Ags. In this study, we use a recombinant protein containing three tandemly arranged copies of C3d and the Ag hen egg lysozyme, shown to be a highly effective immunogen in vivo, to evaluate the role of the CD19/CD21 complex in Ag processing in B cells. Evidence is provided that coengagement of the CD19/CD21 complex results in more rapid and efficient production of antigenic peptide/class II complexes as compared with B cell Ag receptor-mediated processing alone. The CD19/CD21 complex does not itself target complement-tagged Ags for processing, but rather appears to influence B cell Ag processing through its signaling function. The ability of the CD19/CD21 complex to augment processing may be an important element of the mechanism by which the CD19/CD21 complex functions to promote B cell responses to T cell-dependent complement-tagged Ags in vivo.

Floating the raft hypothesis: the roles of lipid rafts in B cell antigen receptor function

The initiation of antibody responses to foreign antigens requires that B cells receive and integrate a variety of signals through an array of cell surface receptors including the B cell antigen receptor (BCR) as well as a number of essential coreceptors. Recent evidence indicates that cholesterol-rich plasma membrane microdomains, referred to here as lipid rafts, serve as platforms for BCR signaling and trafficking in B cells. The existence of rafts suggests a previously unappreciated level of organization at the B cell surface that may explain, at least in part, how BCR signaling is coordinated. Here the current evidence that lipid rafts play a key role in B cell responses is reviewed.

Translocation of the B cell antigen receptor into lipid rafts reveals a novel step in signaling

The cross-linking of the B cell Ag receptor (BCR) leads to the initiation of a signal transduction cascade in which the earliest events involve the phosphorylation of the immunoreceptor tyrosine-based activation motifs of Ig alpha and Ig beta by the Src family kinase Lyn and association of the BCR with the actin cytoskeleton. However, the mechanism by which BCR cross-linking initiates the cascade remains obscure. In this study, using various A20-transfected cell lines, biochemical and genetic evidence is provided that BCR cross-linking leads to the translocation of the BCR into cholesterol- and sphingolipid-rich lipid rafts in a process that is independent of the initiation of BCR signaling and does not require the actin cytoskeleton. Translocation of the BCR into lipid rafts did not require the Ig alpha/Ig beta signaling complex, was not dependent on engagement of the FcR, and was not blocked by the Src family kinase inhibitor PP2 or the actin-depolymerizing agents cytochalasin D or latrunculin. Thus, cross-linking or oligomerization of the BCR induces the BCR translocation into lipid rafts, defining an event in B cell activation that precedes receptor phosphorylation and association with the actin cytoskeleton.

The CD19/CD21 complex functions to prolong B cell antigen receptor signaling from lipid rafts

The CD19/CD21 complex functions to significantly enhance B cell antigen receptor (BCR) signaling in response to complement-tagged antigens. Recent studies showed that following antigen binding the BCR translocates into plasma membrane lipid rafts that serve as platforms for BCR signaling. Here, we show that the binding of complement-tagged antigens stimulates the translocation of both the BCR and the CD19/CD21 complex into lipid rafts, resulting in prolonged residency in and signaling from the rafts, as compared to BCR cross-linking alone. When coligated to the BCR, the CD19/CD21 complex retards the internalization and degradation of the BCR. The colocalization and stabilization of the BCR and the CD19/CD21 complex in plasma membrane lipid rafts represents a novel mechanism by which a coreceptor enhances BCR signaling.

Confocal and multi-photon microscopy of dental hard tissues and biomaterials

Confocal microscopy is a technique that can be used both in the clinic and the high-resolution microscopy suite. This form of optical microscopy enables high-resolution images to be made of samples with minimum requirements for specimen preparation. Images may be made of either reflections from the sample surface or, if an immersion medium is used to optically couple the objective lens, then sub-surface images can be produced of reflective or fluorescent structures within semi transparent materials such as cells and dental hard tissues. These images are like optical sections, giving thin (> 0.35 microm) slices up to 200 microm below the surface of a mineralized tissue. The technique generates significant improvements in resolution, lying somewhere between that of conventional light microscopy and TEM/SEM. Instruments that work at video-rate allow high-speed events to be examined, such as in vivo clinical studies, cutting of dental tissues and fracture of adhesive interfaces. New dyes offer many exciting prospects for labeling changes in chemical composition in materials or biological tissues, while new imaging techniques such as multi-photon laser excitation of dyes give the potential of greater depth penetration and improved resolution. As with all new techniques the inexperienced should be aware of some of the artifacts inherent to the system. However, the widespread availability of conventional confocal microscopes should give ample opportunity for dental researchers to capitalize on this new technology.

A role for MHC class II antigen processing in B cell development

For mature B cells, the encounter with foreign antigen results in the selective expansion of the cells and their differentiation into antibody secreting cells or memory B cells. The response of mature B cells to antigen requires not only antigen binding to and signaling through the B cell antigen receptor (BCR) but also the processing and presentation of the BCR bound antigen to helper T cells. Thus, in mature B cells, the ability to process and present antigen to helper T cells plays a critical role in determining the outcome of antigen encounter. In immature B cells, the binding of antigen results in negative selection of the B cell, inducing apoptosis, anergy or receptor editing. Negative selection of immature B cells requires antigen induced signaling through the BCR, analogous to the signaling function of the BCR in mature B cells. However, the role of class II antigen processing and presentation in immature B cells is less well understood. Current evidence indicates that the ability to process and present antigen bound to the BCR is a late acquisition of developing B cells, suggesting that during negative selection B cells may not present BCR bound antigen and interact with helper T cells. However, the expression of class II molecules is an early acquisition of B cells and recent evidence indicates that the expression of class II molecules early in development is required for the generation of long lived mature B cells. Here we review our current understanding of the processing and presentation of antigen by mature B cells and the role for antigen processing and class II expression during B cell development.

Allelic loss and microsatellite alterations of chromosome 3p14.2 are more frequent in recurrent cervical dysplasias

Epidemiological studies have documented the unpredictable clinical progression or recurrence of cervical dysplasia. Recent studies have shown several molecular changes in cervical cancers and their associated dysplasia. We conducted molecular analyses on a retrospectively ascertained cohort of recurrent and nonrecurrent cervical dysplasia cases in an attempt to define molecular biomarkers to predict progressive or recurrent disease. Cases were chosen if long-term follow-up (3-5 years after conization) and biopsy confirmation were available. Paraffin-embedded, postconization cervical tissues from 19 recurrent and 18 nonrecurrent dysplasias were analyzed. Human papillomavirus (HPV) was identified by PCR for general and type-specific (HPV-16 and HPV-18) primers. Allelotyping analysis was performed by multiplex PCR using a panel of 16 microsatellite markers targeting putative tumor suppressor gene regions on chromosomes 3p, 5p, 6p, 9p, 11q, and 17p. The overall rate of HPV infection was similar in both groups. In the allelotyping analysis, loss of heterozygosity at the fragile histidine triad region in 3p14.2 was significantly higher in the recurrent group than in the nonrecurrent group (P = 0.005). Furthermore, microsatellite alterations (MAs) were more frequent in the recurrent group (mean MA index, 0.254) as compared with the nonrecurrent group (mean MA index, 0.085; P = 0.0025). These findings suggest that HPV status alone does not predict recurrence and that loss of heterozygos. ity at the fragile histidine triad region may represent a potential biomarker in predicting recurrence. Frequent MAs in the recurrent group may represent an underlying genomic instability that creates susceptibility for allelic loss, thus increasing the risk for recurrence or progression.

A role for lipid rafts in B cell antigen receptor signaling and antigen targeting

The B cell antigen receptor (BCR) serves both to initiate signal transduction cascades and to target antigen for processing and presentation by MHC class II molecules. How these two BCR functions are coordinated is not known. Recently, sphingolipid- and cholesterol-rich plasma membrane lipid microdomains, termed lipid rafts, have been identified and proposed to function as platforms for both receptor signaling and membrane trafficking. Here we show that upon cross-linking, the BCR rapidly translocates into ganglioside G(M1)-enriched lipid rafts that contain the Src family kinase Lyn and exclude the phosphatase CD45R. Both Igalpha and Lyn in the lipid rafts become phosphorylated, and subsequently the BCR and a portion of G(M1) are targeted to the class II peptide loading compartment. Entry into lipid rafts, however, is not sufficient for targeting to the antigen processing compartments, as a mutant surface Ig containing a deletion of the cytoplasmic domain is constitutively present in rafts but when cross-linked does not internalize to the antigen processing compartment. Taken together, these results provide evidence for a role for lipid rafts in the initial steps of BCR signaling and antigen targeting.

MHC class II antigen processing in B cells: accelerated intracellular targeting of antigens

Processing and presentation by Ag-specific B cells is initiated by Ag binding to the B cell Ag receptor (BCR). Cross-linking of the BCR by Ag results in a rapid targeting of the BCR and bound Ag to the MHC class II peptide loading compartment (IIPLC). This accelerated delivery of Ag may be essential in vivo during periods of rapid Ag-driven B cell expansion and T cell-dependent selection. Here, we use both immunoelectron microscopy and a nondisruptive protein chemical polymerization method to define the intracellular pathway of the targeting of Ags by the BCR. We show that following cross-linking, the BCR is rapidly transported through transferrin receptor-containing early endosomes to a LAMP-1+, beta-hexosaminadase+, multivesicular compartment that is an active site of peptide-class II complex assembly, containing both class II-invariant chain complexes in the process of invariant chain proteolytic removal as well as mature peptide-class II complexes. The BCR enters the class II-containing compartment as an intact mIg/Igalpha/Igbeta complex bound to Ag. The pathway by which the BCR targets Ag to the IIPLC appears not to be identical to that by which Ags taken up by fluid phase pinocytosis traffick, suggesting that the accelerated BCR pathway may be specialized and potentially independently regulated.

Trafficking of the Igalpha/Igbeta heterodimer with membrane Ig and bound antigen to the major histocompatibility complex class II peptide-loading compartment

The binding of antigen to the B cell antigen receptor (BCR) initiates two major cellular events. First, upon cross-linking by antigen, the BCR induces signal transduction cascades leading to the transcription of a number of genes associated with B cell activation. Second, the BCR internalizes and delivers antigens to processing compartments, where processed antigenic peptides are loaded onto major histocompatibility complex (MHC) class II molecules for presentation to T helper cells. The BCR consists of membrane Ig (mIg) and Igalpha/Igbeta heterodimer (Igalpha/Igbeta). The Igalpha/Igbeta, the signal transducing component of the BCR, has been indicated to play a role in antigen processing. In order to understand the function of the Igalpha/Igbeta in antigen transport, we studied the intracellular trafficking pathway of the Igalpha/Igbeta. We show that in the absence of antigen binding, the Igalpha/Igbeta constitutively traffics with mIg from the plasma membrane, through the early endosomes, to the MHC class II peptide-loading compartment. Cross-linking the BCR does not alter the trafficking pathway; however, it accelerates the transport of the Igalpha/Igbeta to the MHC class II peptide-loading compartment. This suggests that the Igalpha/Igbeta heterodimer is involved in BCR-mediated antigen transport through the entire antigen transport pathway.

Iterative X-ray Cone-Beam Tomography for Metal Artifact Reduction and Local Region Reconstruction

: X-ray cone-beam reconstruction from incomplete projection data has important practical applications, especially in microtomography. We developed expectation maximization (EM)-type and algebraic reconstruction technique (ART)-type iterative cone-beam reconstruction algorithms for metal artifact reduction and local reconstruction from truncated data. These iterative algorithms are adapted from the emission computerized tomography (CT) EM formula and the ART. A key step in our iterative algorithms is introduction of a projection mask and computation of a 3-D spatially varying relaxation factor that allows compensation for beam divergence and data incompleteness. The algorithms are simulated with projection data synthesized from mathematical phantoms. In simulation, the EM-type and ART-type iterative algorithms are demonstrated to be effective for metal artifact reduction and local region reconstruction. They perform similarly in terms of visual quality, image noise, and discrepancy between measured and reprojected data. The EM-type and ART-type iterative cone-beam reconstruction algorithms have potential for metal artifact reduction and local region reconstruction in X-ray CT.

Spatial and temporal dynamics of DNA replication sites in mammalian cells

Fluorescence microscopic analysis of newly replicated DNA has revealed discrete granular sites of replication (RS). The average size and number of replication sites from early to mid S-phase suggest that each RS contains numerous replicons clustered together. We are using fluorescence laser scanning confocal microscopy in conjunction with multidimensional image analysis to gain more precise information about RS and their spatial-temporal dynamics. Using a newly improved imaging segmentation program, we report an average of approximately 1,100 RS after a 5-min pulse labeling of 3T3 mouse fibroblast cells in early S-phase. Pulse-chase-pulse double labeling experiments reveal that RS take approximately 45 min to complete replication. Appropriate calculations suggest that each RS contains an average of 1 mbp of DNA or approximately 6 average-sized replicons. Double pulse-double chase experiments demonstrate that the DNA sequences replicated at individual RS are precisely maintained temporally and spatially as the cell progresses through the cell cycle and into subsequent generations. By labeling replicated DNA at the G1/S borders for two consecutive cell generations, we show that the DNA synthesized at early S-phase is replicated at the same time and sites in the next round of replication.

Experimental System for X-ray Cone-Beam Microtomography

: A laboratory test of X-ray tomography employing a diverging beam of X-rays rather than the usual parallel X-ray beam is described. We chose to test and demonstrate the advantages of divergent beam tomography by imaging an extracted juvenile human premolar using an ordinary dental X-ray source and a cooled CCD camera. Experiments with a three-piece cover-glass sample and with the human tooth demonstrated that three-dimensional reconstruction can be achieved at 34 µm per pixel resolution employing an X-ray tube spot 800 µm in its smallest direction without requiring close contact with the fluorescent screen. Reconstruction of a 256 x 256 pixel single-plane image from 100 projection images took only 45 sec on a personal computer with a Pentium 166 MHz processor. We have also demonstrated a volume reconstruction of 256 x 256 x 256 voxels from the data. Successful extension of this work to submicrometer projection X-ray microscopy is predicted. Improved resolution of medical tomography is another possible application.

Three-dimensional laser scanning two-photon fluorescence confocal microscopy of polymer materials using a new, efficient upconverting fluorophore

Three-dimensional confocal imaging of polymer samples was achieved by the use of two-photon excited fluorescence in both positive and negative contrast modes. The fluorophore was a new and highly efficient two-photon induced upconverter, resulting in improved signal strength at low pumping power. Because of the relatively long wavelength of the excitation source (798 nm from a mode-locked Ti:Sapphire laser), this technique shows a larger penetration depth into the samples than provided by conventional single-photon fluorescence confocal microscopy. Single-photon and two-photon images of the same area of each sample show significant differences. The results suggest the possibility of using two-photon confocal microscopy, in conjunction with highly efficient fluorophores, as a tool to study the surface, interface, and fracture in material science applications.

Potential role of the inactivated X chromosome in ovarian epithelial tumor development

BACKGROUND

Ovarian epithelial tumors can be divided into subcategories often regarded as different stages of neoplastic transformation. Cystadenomas belong to the least aggressive subgroup and are noninvasive and nonmetastatic. Ovarian tumors of low malignant potential (LMP) are intermediate between cystadenomas and carcinomas and show markedly reduced invasive and metastatic abilities. Invasion and metastasis are the hallmarks of carcinomas, which constitute the most aggressive subgroup and can be further subdivided into different grades.

PURPOSE

We performed comparative allelotype analyses of ovarian cystadenomas, LMP tumors, and carcinomas, reasoning that such analyses could provide clues about the molecular determinants of their phenotypic differences. Because we realized that allelic losses involving the X chromosome might be associated with LMP tumor development, we determined whether such losses were interstitial and whether they involved the active or the inactive X chromosome.

METHODS

Frequencies of loss of heterozygosity (LOH) at specific loci in every chromosomal arm were determined in 16 ovarian cystadenomas, 23 ovarian LMP tumors, 15 low-grade ovarian carcinomas, and 35 high-grade ovarian carcinomas by use of either the polymerase chain reaction (PCR) or Southern blot analyses. We took advantage of the fact that DNA methylation is an important mechanism of X-chromosome inactivation to determine whether losses involving the X chromosome were in the active or the inactive copy. We analyzed the methylation status of retained alleles on the X chromosome by determining whether they could be amplified by PCR after digestion with the methylation-sensitive restriction endonuclease Hpa II.

RESULTS

High-grade carcinomas contained frequent(>50%) LOH in four autosomal chromosome arms, i.e., 6q, 13q, 17p, and 17q. Except for 13q, these same chromosomal arms showed frequent LOH in low-grade carcinomas. LOH in autosomal chromosomes was comparatively rare in LMP tumors and was absent in cystadenomas. In contrast, half (eight of 16) of LMP tumors informative for a locus in the proximal portion of chromosome Xq showed LOH at that locus. These losses were the result of interstitial deletions in six of the eight cases and involved the inactive copy of the X chromosome exclusively. Similar losses in the X chromosome were not seen in either cystadenomas or low-grade carcinomas.

CONCLUSIONS AND IMPLICATIONS

LOH at multiple loci is associated with the development of ovarian carcinomas but not with the development of cystadenomas and LMP tumors. However, the integrity of a locus in chromosome Xq that possibly escapes X-chromosome inactivation is important for the control of LMP tumor development. The fact that this locus does not appear to be involved in the genesis of low-grade carcinomas suggests that LMP tumors are not precursors of such carcinomas.

Stable High-Order Molecular Sandwiches: Hydrocarbon Polyanion Pairs with Multiple Lithium Ions Inside and Out

Stable ten-component sandwich compounds have been characterized in which four lithium ions reside between two tetraanions derived from corannulene or its alkyl-substituted derivatives and four additional lithium ions decorate the exterior. In tetrahydrofuran solution, the four lithium ions inside the sandwich can exchange environments with the four external lithium atoms, but the two tetraanion decks of the sandwich never separate from one another on the time scale of nuclear magnetic resonance. Theoretical calculations point to a "stacked bowl" conformation and a low energy barrier for synchronous double inversion of the tetraanion bowls in the solvated sandwich compounds.

Half-scan cone-beam x-ray microtomography formula

An x-ray shadow projection microtomographic system using a scannable point source is under development at AMIL-ARTS, SUNY at Buffalo. To overcome the limitations of the commonly used Feldkamp's cone-beam reconstruction formula, we have developed a generalized Feldkamp-type cone-beam reconstruction formula. In the generalized Feldkamp-type cone-beam reconstruction, a scanning locus can be either planar or helix-like, and a transaxial slice is reconstructed using projection data collected from a 360 degrees angular range (full scan). In this paper, the full-scan cone-beam formula is modified to require only projection data of approximate 180 degrees plus two fan-angles (half scan). First, a half-scan derivative-free noncircular fan-beam reconstruction formula is formulated. Then, a half-scan cone-beam reconstruction formula is derived as an extension of the half-scan fan-beam reconstruction formula using Feldkamp's procedure. Typical numerical simulation results are given for both half-scan formulae. Compared with the full-scan cone-beam formula, the half-scan cone-beam formula reduces the involved angular range of projection data and allows better longitudinal/temporal resolution.

Visualization and interactive exploration of multidimensional confocal images

A confocal image analysis system is developed for automatic extraction of surface representation of biological structures. A visualization system is also developed to manipulate these surface representations and to obtain morphometrical parameters and provides a powerful tool for biomedical research such as microstructural characterization, morphogenesis, cell differentiation, tissue organization, and embryo development.

A derivative-free noncircular fan-beam reconstruction formula

In order to perform fan-beam reconstruction using projection data collected from a noncircular scanning locus, existing noncircular fan-beam formulas require a derivative of the scanning locus with respect to the rotation angle. A derivative-free noncircular fan-beam reconstruction formula that is based on a geometrical explanation of the circular equispatial fan-beam reconstruction formula is obtained here. A mathematical proof is then provided under the conditions that the source-to-origin distance is symmetric with respect to the origin of the reconstruction coordinate system, is differentiable almost everywhere, and does not change too fast with respect to the rotation angle. The derivative-free noncircular fan-beam reconstruction formula is the same as the circular one, except that the source-to-origin distance is a function of the rotation angle. A typical simulation result for the noncircular fan-beam formula is given.

The comparative efficacy of cilofungin, fluconazole and amphotericin B in disseminated Candida tropicalis infection in neutropenic mice

There is insufficient in vivo data on the efficacy of new antifungal agents against invasive Candida tropicalis infection. Disseminated infection with Candida tropicalis in neutropenic mice was treated with cilofungin, fluconazole, or amphotericin B intraperitoneally, and compared to untreated controls. Early survival rates at the end of treatment (day 10) were similar for amphotericin B (97.5%) and fluconazole (100%), and superior to cilofungin (62.6%) which was better than no treatment (0%). Late survival rates (day 31) were highest for amphotericin B (95%), and significantly lower for cilofungin (48.7%) and fluconazole (43.9%), p = 0.0001. Rates of sterilization of the lung, liver, and spleen were high in survivors for all regimens (85.1-100%) but lower for the kidneys: fluconazole, 21.3%; amphotericin B, 39.3%; and cilofungin, 65.5%. Amphotericin B was the most effective agent in this study of disseminated Candida tropicalis (C. tropicalis) infection.

Comparison of the efficacy of cilofungin, fluconazole and amphotericin B in the treatment of systemic Candida albicans infection in the neutropenic mouse

The relative efficacies of cilofungin, amphotericin B and fluconazole were compared in the treatment of systemic Candida albicans infection in neutropenic mice. Thirty-one day survival rates were lowest for cilofungin (14.6%), intermediate for amphotericin B (37.6%) and highest for fluconazole (50.5%). Residual tissue infection in surviving animals was observed with all agents, but was heaviest with fluconazole, especially in the kidneys.

Initial results of laser angioplasty under angioscopic guidance for salvage of an ischemic lower limb: preliminary report

From March to July 1989, nine patients at risk for peripheral artery disease underwent intraoperative Nd:YAG laser angioplasty using angioscopy at the Veterans General Hospital (Taipei, Taiwan, Republic of China). Following the laser angioplasty, balloon dilatation was performed in all cases. Eight men and one woman at an average age of 68 were included in the study (range: 58 to 78 years old). Ischemic symptoms included five patients with disabling claudication, four with pain at rest and one with gangrene on the toes. Eight of the nine patients had complete occlusions ranging from 2 to 19 cm in length. Two patients had high degree multiple segmental stenosis of the superficial femoral artery from 1 to 2 cm in length. Initial clinical success (indicated by relief of symptoms and increase in Doppler ankle pressure and index) and improvement in the angiographic luminal diameter was noted in 9 of 10 occluded vessels (90%) that underwent Nd:YAG laser treatment which was delivered at 10 to 12 watts through laser probes. Prelaser intraluminal diameter increased from 0.05 +/- 0.07 to 0.53 +/- 0.07 mm, Doppler ankle pressure index rose from 0.51 +/- 0.12 to 0.81 +/- 0.12, Doppler ankle pressure increased from 62.44 +/- 16.10 to 104 +/- 21.21 mmHg and the amplitude of pulse volume recorder at ankle level rose from 5.77 +/- 2.80 to 12.11 +/- 2.77 mm as compared with prelaser therapy (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Fungicidal effect of amphotericin B in urine: in vitro study to assess feasibility of bladder washout for localization of site of candiduria

An in vitro study was performed to determine the optimum amphotericin B concentration and exposure time required to kill various strains of Candida albicans in urine. This is a preliminary study to assess the feasibility of using amphotericin B bladder washout for localization of the site of candiduria. In broth kinetic killing studies, amphotericin B at a concentration of greater than 100 micrograms/ml produced almost complete killing of 5 x 10(5) CFU of C. albicans per ml within 1.5 to 2 h. In urine studies (with various pH values, osmolalities, and electrolyte concentrations), amphotericin B at a concentration of 200 micrograms/ml with a 2-h exposure time decreased fungal counts of 21 strains of C. albicans from 5 x 10(6) to less than 200 CFU/ml. Bladder washout with greater than or equal to 200 micrograms of amphotericin B per ml and a dwell time of 2 h can therefore sufficiently sterilize the bladder of yeasts and may be a useful localization test.

The use of confocal microscopy and STERECON reconstructions in the analysis of sea urchin embryonic cell division

A laser scanning confocal microscope has been used to investigate the development of the sea urchin embryo. The samples were fixed in Carnoy's solution at various developmental stages, stained for DNA with the Feulgen reaction, and optically sectioned with a BioRad MRC-500 confocal microscope. Computer-generated stereographic projection images and a three-dimensional contour tracing and reconstruction system were employed to investigate the cleavage pattern during the 6th cleavage division. Cell division is found to be asynchronous during the 6th cleavage, with macromere derivatives completing division first, followed by mesomeres, and finally by the outer quartet of micromeres (which begins division only after macromeres and mesomeres have completed their respective divisions). Sixth cleavage produces an embryo comprising 60 cells. Asynchronous division was also observed within individual tiers of blastomeres. Variations in the orientations of cell division axes within individual tiers of cells were also observed. The utility of computer-graphics reconstruction techniques for both quantitative and qualitative developmental analysis are discussed.

[Results of vascular reconstruction in lower limbs ischemia: a six-year clinical experience]

During the period between Dec. 1982 to Nov. 1988, a total of 412 patients with 471 limbs at risk of peripheral arterial occlusive disease underwent vascular surgical treatment at the Veterans General Hospital. There were 382 men and 30 women, who ranged in age from 20 to 84 years (mean 63.17 +/- 11.85 years). 95 cases were isolated aortoiliac occlusive disease, 94 cases were combined aortoiliac and femoropopliteal disease, 169 cases were femoropopliteal occlusive disease and 54 cases were femorotibialperoneal occlusive disease. Various reconstructive procedures were performed in the these patients. The cumulative limb salvage rate (LSR) exceeded cumulative patency rate (CPR) in all categories and the result of LSR and CPR were 97.6% and 91% for aortoiliac reconstructive surgery in six years, 96% and 77% for above-knee femoropopliteal saphenous vein bypass (SVB) in six years, 79% and 74% for below-knee femoropopliteal SBV and 63% and 34% for femoro-distal SVB in five years. 88% and 76% for above-knee femoropopliteal human umbilical vein (HUV) bypass in four years. 67% and 45% for femoro-distal HUV bypass in three years follow-up period individually. The immediate good symptomatic results of the vascular reconstruction was 88% encountered in isolated aortoiliac disease, 63% in combined aortoiliac and femoropopliteal disease, 70.4% in isolated femoropopliteal disease and only 26% in femorotibial-peroneal disease (FTP). No change symptoms was still higher (33%) in FTP than the other vascular reconstruction due to poor distal runoff in this series. The early postoperative mortality rate was 1.6%, the late mortality rate was 2.7%, the incidence of postoperative complication rate was 13.6%. The major lower limb amputation rate was low as 7% in our series.(ABSTRACT TRUNCATED AT 250 WORDS)

[Preliminary report on the clinical application of anti-Jo-1 antibody]

Jo-1 antigen was purified from the rabbit thymus acetone powder. Using it as antigen, we found anti-Jo-1 antibody in 25% of polymyositis, 7.1% in dermatomyositis, none in other connective tissue diseases nor non-connective tissue diseases. Other antinuclear antibodies, eg anti-RNP, anti-SSA were also found in our polymyositis-dermatomyositis patients. Our study suggested, the positivity of anti-Jo 1 antibody not only confirmed the patient's diagnosis of polymyositis but also demonstrated the autoimmune pathogenesis of this disease.

Monitor unit calculations for breast or chest wall treatments

Tangential breast fields always "flash" beyond the surface of the patient. Since the portion of the beam that is in air does not contribute scatter, external beam treatment planning computers that utilize stored beam data can lead to dose errors of up to 10%. These errors can be reduced by using an irregular field calculation program to adjust the monitor units to account for the loss of scatter.

Unexpectedly large dose rate dependent output from a linear accelerator

During our routine calibration of a Varian Clinac-20 linear accelerator, the absorbed dose for a fixed monitor unit (mu) was found to decrease with increasing dose rate. Between dose rates of 100 and 500 mu/min, there was up to 20% difference in absorbed dose for a 20-MeV electron beam. The cause of this problem was a failure in the electronics circuit of an integrating board. This paper presents our analysis of the problem and suggests a possible means of isolating such a failure to warn technologists, physicists, and engineers.

Formation of postsynaptic specializations induced by latex beads in cultured muscle cells

An early event in the formation of neuromuscular junctions is an accumulation of acetylcholine receptors (AChRs) in the postsynaptic membrane. This concentration of receptors is essential for the establishment of the synaptic transmission. Previously, we showed that latex beads coated with positively charged polypeptide molecules can induce the formation of AChR clusters at the bead-muscle contacts (Peng, H. B., P.-C. Cheng, and P. W. Luther (1981) Nature 292: 831-834). In this study, we demonstrate that, in addition to AChR clusters, a set of postsynaptic specializations normally present at the adult neuromuscular junction also develops at the bead-muscle contacts in the absence of nerve. These specializations include the membrane-associated cytoplasmic density and its associated thin (6- to 8-nm) filaments, clusters of intramembranous particles, membrane invaginations, the basal lamina, and 60- to 100-nm coated vesicles. Our results indicate that the mechanism for the formation of the postsynaptic specializations is preprogramed in the muscle and can be triggered by an interaction with polypeptide-coated latex beads. Thus, this bead-muscle system can be used as a simple model for understanding the postsynaptic development during synaptogenesis.

Detection and analysis of paraquat in confiscated marijuana samples

A spectrophotometric method used to test for paraquat in 160 confiscated marijuana samples is described. Twenty of these samples (12.5 per cent) tested positive for paraquat. Nine confiscated hash oil samples tested negative. The identification of paraquat was proven by isolation, chromatography, and spectral methods. The cannabinoids in paraquat positive Cannabis samples were analysed.

Aortocoronary bypass surgery and chronic renal failure: case report

A successful case of aortocoronary bypass operation in a patient with chronic renal failure managed by home haemodialysis and being considered for renal transplantation is described.