Utilisation of Deep Learning-Enabled Image Analysis for Detection and Enumeration of Plasmodial Forms in Red Cells

Introduction/Objective

Objective: This work investigates utilisation of deep learning enabled peripheral blood smear image analysis for automated detection and enumeration of red cell parasites.

Methods/Case Report

Methods: Peripheral blood smear red cell images from 30 individuals identified as positive and/or negative for plasmodilum falciparum forms were used. Blood submitted to hematology laboratory for complete blood count was evaluated on Sysmex XN 3100 analyzer with routine peripheral blood slides performed on instrument associated SP50 stainer. Images of red cells obtained with Xfinity DX40 microscope mounted camera were subjected to classification using deep learning software (Cognex, ViDi Suite 4.1). The training of the classification tool was performed on 200 peripheral blood smear images divided in two dataset classes: normal/negative and abnormal/positive for plasmodia, 50% of training images represented positive data set. Performance of the developed model was tested on 300 images including 66% positive for plasmodia obtained from 20 patients. Enumeration of parasitic forms was performed for each case. Model performance was compared to expert hematopathology reviewer which was used as gold standard.

Results (if a Case Study enter NA)

Results: Overall, Cognex ViDi Suite 4.1 demonstrates the effectiveness in discriminating between images positive and negative for red cell plasmodial forms as well as enables parasite quantification. Following performance specifications were determined for parasite detection: sensitivity (0.969230769), specificity (0.99383217). High correlation coefficients (0.9961) between automatically detected parasites and ground truth, on both image level and patient level, demonstrate the practicality of our method.

Conclusion

Deep learning enabled image analysis of peripheral blood smears is a promising alternative to manual identification and enumeration of red cell plasmodial forms with performance comparable to expert hematopathology reviewer.

Fatal PML associated with efalizumab therapy: insights into integrin αLβ2 in JC virus control

OBJECTIVES

Progressive multifocal leukoencephalopathy (PML) has become much more common with monoclonal antibody treatment for multiple sclerosis and other immune-mediated disorders.

METHODS

We report 2 patients with severe psoriasis and fatal PML treated for ≥3 years with efalizumab, a neutralizing antibody to αLβ2-leukointegrin (LFA-1). In one patient, we conducted serial studies of peripheral blood and CSF including analyses of leukocyte phenotypes, migration ex vivo, and CDR3 spectratypes with controls coming from HIV-infected patients with PML. Extensive pathologic and histologic analysis was done on autopsy CNS tissue of both patients.

RESULTS

Both patients developed progressive cognitive and motor deficits, and JC virus was identified in CSF. Despite treatment including plasma exchange (PE) and signs of immune reconstitution, both died of PML 2 and 6 months after disease onset. Neuropathologic examination confirmed PML. Efalizumab treatment was associated with reduced transendothelial migration by peripheral T cells in vitro. As expression levels of LFA-1 on peripheral T cells gradually rose after PE, in vitro migration increased. Peripheral and CSF T-cell spectratyping showed CD8+ T-cell clonal expansion but blunted activation, which was restored after PE.

CONCLUSIONS

From these data we propose that inhibition of peripheral and intrathecal T-cell activation and suppression of CNS effector-phase migration both characterize efalizumab-associated PML. LFA-1 may be a crucial factor in homeostatic JC virus control.

Audit of sudden deaths in the accident and emergency department of a tertiary hospital in Trinidad and Tobago

OBJECTIVE

To determine the proportion of deaths due to confirmed myocardial infarction (CMI) and the aetiology of sudden death at the Port-of-Spain General Hospital (A&E) department for January to June 2008.

METHODS

This retrospective study utilized the death register to determine the number of A&E deaths for the study period. Patients dying from MI were investigated using records to obtain ECG and postmortem reports.

RESULTS

During the study period, 150 patients were certified dead in the A&E department. Cardiovascular causes accounted for 42.7% (n = 64) of deaths. Confirmed MI accounted for 27.3% (n = 41) of deaths and 3.3% (n = 5) were certified by a private practitioner without post-mortem examination and were classed as unconfirmed MI. Trauma related deaths followed with 27.3% (n = 41). Deaths from firearm injury were the next most common, 19.3% (n = 29). The mean age of patients dying from CMI was 64.1 years with a male to female ratio of 2:1. Males died from CMI on average 6.3 years before females. Mortality peaked for females in the 80 - 89-year age group while for males it was the 60- 69-year age group. Afro-Trinidadians accounted for 58.5% (n = 24) deaths due to CMI. More CMI patients had combined DM and HTN 36.6% (n = 15) than either condition alone. Afro-Trinidadians were more likely to be hypertensive and Indo-Trinidadians, diabetic. Death on arrival was the most common presentation for MI patients, 65.9% (n = 27).

CONCLUSIONS

This study shows that the main cause of death in the A&E Department at the Port-of-Spain General Hospital was MI. Trauma related deaths followed. Men died from MI at an earlier age than women. Most MI patients were dead on arrival.

The Role of Endoscopic Assisted Microneurosurgery (Image Fusion Technology) in the Performance of Neurosurgical Procedures

The use of endoscopic techniques has gained significant popularity over the past decade. The potential advantages of angled lenses to visualize around tight corridors without retracting have proven to be an attractive feature. The limitation of endoscopy has been the inability to obtain a true three-dimensional perspective for which microscopy is ideal. Therefore we postulated that for complex intradural lesions the merger of the two technologies would prove to be ideal. In this paper we report our experience with simultaneous microscopy and endoscopy, using picture-in-picture technology, for intracranial vascular and oncological surgery. We have found it useful to offer enough visualization to allow for performing surgery and not just for inspection.

A randomized controlled trial of filgrastim for the treatment of hospitalized patients with multilobar pneumonia

This study assessed the safety and efficacy of filgrastim (r-metHuG-CSF [recombinant human methionine granulocyte colony-stimulating factor]), when combined with intravenous (IV) antibiotics, in the treatment of hospitalized adult patients with multilobar community-acquired pneumonia (CAP). Four hundred eighty patients were randomized to receive placebo (n=243) or filgrastim 300 microg/day (n=237), in addition to standard therapy. Treatment with study drug was continued for 10 days, until the peak white blood cell (WBC) count reached 75x109/L, until discharge from the hospital, until death, or until IV antibiotics were discontinued. Study-related observations continued through day 29. Filgrastim increased WBC counts (baseline median, 13.3x109/L; median peak, 43. 8x109/L). The 2 treatment groups were not statistically different with respect to the study end points; however, there was a trend toward reduction of mortality in patients with pneumococcal bacteremia. Although further studies will be required to validate this observation, filgrastim was safe and well tolerated when administered to patients with multilobar CAP.

Concentrations of caffeine greater than 20 mM increase the indo-1 fluorescence ratio in a Ca(2+)-independent manner

The methylxanthine, caffeine, quenches the fluorescence of the ratiometric Ca2+ indicator indo-1, but does not affect the ratio (R) of indo-1 fluorescence at 400 and 500 nm in the presence of caffeine concentrations up to 10 mM [1]. We have found that when caffeine is at concentrations of 20 mM or greater in vitro, or in saponinpermeabilized skeletal muscle fibers, a Ca(2+)-independent increase in R occurs, which leads to an overestimation of the free Ca2+ concentration. Depending on experimental conditions, two factors contribute to the alteration in R in vitro. First, when indo-1 fluorescence is low, fluorescence by caffeine, at 400 nm, can be significant. A second, and more dramatic effect, is that quenching of indo-1 fluorescence by 20-50 mM caffeine is dissimilar at 400 and 500 nm. Quenching at 500 nm is not linear, with respect to the concentration of caffeine, and causes a Ca(2+)-independent increase in R, that occurs even when the fluorescence of caffeine is a small portion of total fluorescence. However, unlike R, the Ca2+ calibration constant of indo-1, KD beta, is unchanged in 50 mM caffeine. Therefore, an accurate quantitation of Ca2+ in the presence of even high concentrations of caffeine can be made in vitro by determining the Ca2+ calibration factors of indo-1 (RMIN and RMAX) for each caffeine concentration. These effects of concentrations of caffeine greater than 20 mM are not observed in intact cells loaded with the cell permeant form of indo-1 when caffeine is applied extracellularly. This suggests either that the concentration of caffeine within the cell does not reach that necessary to produce the effect, or that the effects of caffeine on the dye are modified by the environment within the cell.

Biopharmaceutical drug development: Filgrastim (r-metHuG-CSF) use in patients with HIV infection

Hematopoietic growth factors are well known to increase neutrophil counts and support the administration of myelotoxic and myelosuppressive therapies, especially chemotherapies. Filgrastim (r-metHuG-CSF) has been used in the setting of HIV disease to treat neutropenia and HIV-associated neutrophil defects. This article reviews the biology, product characteristics, and preclinical and clinical development of Filgrastim. Emphasis is given on the use of Filgrastim in the setting of HIV infection and AIDS.

The use of Filgrastim in AIDS-related neutropenia

Neutropenic individuals are at high risk for bacterial and fungal infections. Filgrastim (r-metHuG-CSF, NEUPOGEN) has been shown to improve chemotherapy-induced neutropenia significantly. Because a high incidence of HIV-infected patients have neutropenia, often associated with myelosuppressive antiretroviral medication, Filgrastim is frequently used as a treatment strategy for this HIV-associated neutropenia. This review summarizes published work related to the use of Filgrastim in HIV-infected patients. Literature bases (EMBASE, MEDLINE, Int. Pharm. Abs., SciSearch, and Aidsline) from 1970 to 1998 were searched for articles describing the relationship of Filgrastim and ANC to bacterial infection rates, bacterial infection outcome, and overall survival. Thirty-five related articles were identified during this search. Filgrastim appears to have a significant role in increasing peripheral ANC and enhancing neutrophil function in patients with HIV infection and AIDS. This may translate into a clinical benefit of delivery of full-dose myelosuppressive antiretroviral therapy and decreased susceptibility to infections and increased survival in this patient population.

Fungal spinal osteomyelitis in the immunocompromised patient: MR findings in three cases

The MR imaging findings of fungal spinal osteomyelitis in three recipients of organ transplants showed hypointensity of the vertebral bodies on T1-weighted sequences in all cases. Signal changes and enhancement extended into the posterior elements in two cases. Multiple-level disease was present in two cases (with a total of five intervertebral disks involved in three cases). All cases lacked hyperintensity within the disks on T2-weighted images. In addition, the intranuclear cleft was preserved in four of five affected disks at initial MR imaging. MR features in Candida and Aspergillus spondylitis that are distinct from pyogenic osteomyelitis include absence of disk hyperintensity and preservation of the intranuclear cleft on T2-weighted images. Prompt recognition of these findings may avoid delay in establishing a diagnosis and instituting treatment of opportunistic osteomyelitis in the immunocompromised patient.

IcePick: a flexible surface-based system for molecular diversity

IcePick is a system for computationally selecting diverse sets of molecules. It computes the dissimilarity of the surface-accessible features of two molecules, taking into account conformational flexibility. Then, the intrinsic diversity of an entire set of molecules is calculated from a spanning tree over the pairwise dissimilarities. IcePick's dissimilarity measure is compared against traditional 2D topological approaches, and the spanning tree diversity measure is compared against commonly used variance techniques. The method has proven easy to implement and is fast enough to be used in selection of reactants for numerous production-sized combinatorial libraries.

Interactions of a reversible ryanoid (21-amino-9alpha-hydroxy-ryanodine) with single sheep cardiac ryanodine receptor channels

The binding of ryanodine to a high affinity site on the sarcoplasmic reticulum Ca2+-release channel results in a dramatic alteration in both gating and ion handling; the channel enters a high open probability, reduced-conductance state. Once bound, ryanodine does not dissociate from its site within the time frame of a single channel experiment. In this report, we describe the interactions of a synthetic ryanoid, 21-amino-9alpha-hydroxy-ryanodine, with the high affinity ryanodine binding site on the sheep cardiac sarcoplasmic reticulum Ca2+-release channel. The interaction of 21-amino-9alpha-hydroxy-ryanodine with the channel induces the occurrence of a characteristic high open probability, reduced-conductance state; however, in contrast to ryanodine, the interaction of this ryanoid with the channel is reversible under steady state conditions, with dwell times in the modified state lasting seconds. By monitoring the reversible interaction of this ryanoid with single channels under voltage clamp conditions, we have established a number of novel features of the ryanoid binding reaction. (a) Modification of channel function occurs when a single molecule of ryanoid binds to the channel protein. (b) The ryanoid has access to its binding site only from the cytosolic side of the channel and the site is available only when the channel is open. (c) The interaction of 21-amino-9alpha-hydroxy-ryanodine with its binding site is influenced strongly by transmembrane voltage. We suggest that this voltage dependence is derived from a voltage-driven conformational alteration of the channel protein that changes the affinity of the binding site, rather than the translocation of the ryanoid into the voltage drop across the channel.

Structural components of ryanodine responsible for modulation of sarcoplasmic reticulum calcium channel function

Comparative molecular field analysis (CoMFA) was used to analyze the relationship between the structure of a group of ryanoids and the modulation of the calcium channel function of the ryanodine receptor. The conductance properties of ryanodine receptors purified from sheep heart were measured using the planar, lipid bilayer technique. The magnitude of the ryanoid-induced fractional conductance was strongly correlated to specific structural loci on the ligand. Briefly, electrostatic effects were more prominent than steric effects. The 10-position of the ryanoid had the greatest influence on fractional conductance. Different regions of the ligand have opposing effects on fractional conductance. For example, steric bulk at the 10-position is correlated with decreased fractional conductance, whereas steric bulk at the 2-position (isopropyl position) is correlated with increased fractional conductance. In contrast to fractional conductance, the 3-position (the pyrrole locus) had the greatest influence on ligand binding, whereas the 10-position had comparatively little influence on binding. Two possible models of ryanodine action, a direct (or channel plug) mechanism and an allosteric mechanism, were examined in light of the CoMFA. Taken together, the data do not appear to be consistent with direct interaction between ryanodine and the translocating ion. The data appear to be more consistent with an allosteric mechanism. It is suggested the ryanoids act by inducing or stabilizing a conformational change in the ryanodine receptor that results in the observed alterations in cation conductance.

The pharmacology of ryanodine and related compounds

The goal of this review has been to describe the current state of the pharmacology of ryanodine and related compounds relative to the vertebrate RyRs. Resolution of questions concerning the molecular properties of RyR channel function and the contributions made by the RyR isoforms to cellular signaling in a variety of tissues will require the production of new pharmacological agents directed against these proteins. Novel naturally occurring ryanodine congeners have been identified, and significant advances have been made in developing chemical approaches that permit the structure of ryanodine to be derivatized in selective ways. Moreover, several of these changes have yielded compounds that differ in their binding affinities and in their abilities to modify the properties of the RyR channels. These advances give substance to the possibility of designing the required pharmacological agents based on rational design changes of the structure ryanodine.

Automatic identification and representation of protein binding sites for molecular docking

Molecular docking is a popular way to screen for novel drug compounds. The method involves aligning small molecules to a protein structure and estimating their binding affinity. To do this rapidly for tens of thousands of molecules requires an effective representation of the binding region of the target protein. This paper presents an algorithm for representing a protein's binding site in a way that is specifically suited to molecular docking applications. Initially the protein's surface is coated with a collection of molecular fragments that could potentially interact with the protein. Each fragment, or probe, serves as a potential alignment point for atoms in a ligand, and is scored to represent that probe's affinity for the protein. Probes are then clustered by accumulating their affinities, where high affinity clusters are identified as being the "stickiest" portions of the protein surface. The stickiest cluster is used as a computational binding "pocket" for docking. This method of site identification was tested on a number of ligand-protein complexes; in each case the pocket constructed by the algorithm coincided with the known ligand binding site. Successful docking experiments demonstrated the effectiveness of the probe representation.

The pyrrole locus is the major orienting factor in ryanodine binding

Ryanodine, a natural product, is a complex modulator of a class of intracellular Ca2+ release channels commonly called the ryanodine receptors. Ryanodine analogs can cause the channel to persist in long-lived, subconductance states or, at high ligand concentrations, in closed, nonconducting states. In this paper, we further explore the relationship between structure and ryanodine binding to striated muscle. Ryanodine, 3-epiryanodine, and 10-ryanodine are three structural isomers of ryanodine. The dissociation constants of these compounds were measured using rabbit skeletal muscle ryanodine receptors. Placing the pyrrole carbonyl group at the 3-epi- and 10-positions of ryanodol largely restores the large loss of binding energy observed when ryanodine is hydrolyzed to ryanodol. Comparative molecular field analysis successfully predicts the enhanced binding and indicates that the pyrrole group controls the orientation of ligand binding. We propose that the ryanoids are reorientated in the binding site of the ryanodine receptors such that the pyrrole always occupies the same subsite. By applying this model, the binding constants of other ryanoids are predicted.

Hammerhead: fast, fully automated docking of flexible ligands to protein binding sites

BACKGROUND

Molecular docking seeks to predict the geometry and affinity of the binding of a small molecule to a given protein of known structure. Rigid docking has long been used to screen databases of small molecules, because docking techniques that account for ligand flexibility have either been too slow or have required significant human intervention. Here we describe a docking algorithm, Hammerhead, which is a fast, automated tool to screen for the binding of flexible molecules to protein binding sites.

RESULTS

We used Hammerhead to successfully dock a variety of positive control ligands into their cognate proteins. The empirically tuned scoring function of the algorithm predicted binding affinities within 1.3 log units of the known affinities for these ligands. Conformations and alignments close to those determined crystallographically received the highest scores. We screened 80 000 compounds for binding to streptavidin, and biotin was predicted as the top-scoring ligand, with other known ligands included among the highest-scoring dockings. The screen ran in a few days on commonly available hardware.

CONCLUSIONS

Hammerhead is suitable for screening large databases of flexible molecules for binding to a protein of known structure. It correctly docks a variety of known flexible ligands, and it spends an average of only a few seconds on each compound during a screen. The approach is completely automated, from the elucidation of protein binding sites, through the docking of molecules, to the final selection of compounds for assay.

Electrophysiological effects of ryanodine derivatives on the sheep cardiac sarcoplasmic reticulum calcium-release channel

We have examined the effects of a number of derivatives of ryanodine on K+ conduction in the Ca2+ release channel purified from sheep cardiac sarcoplasmic reticulum (SR). In a fashion comparable to that of ryanodine, the addition of nanomolar to micromolar quantities to the cytoplasmic face (the exact amount depending on the derivative) causes the channel to enter a state of reduced conductance that has a high open probability. However, the amplitude of that reduced conductance state varies between the different derivatives. In symmetrical 210 mM K+, ryanodine leads to a conductance state with an amplitude of 56.8 +/- 0.5% of control, ryanodol leads to a level of 69.4 +/- 0.6%, ester A ryanodine modifies to one of 61.5 +/- 1.4%, 9,21-dehydroryanodine to one of 58.3 +/- 0.3%, 9 beta,21beta-epoxyryanodine to one of 56.8 +/- 0.8%, 9-hydroxy-21-azidoryanodine to one of 56.3 +/- 0.4%, 10-pyrroleryanodol to one of 52.2 +/- 1.0%, 3-epiryanodine to one of 42.9 +/- 0.7%, CBZ glycyl ryanodine to one of 29.4 +/- 1.0%, 21-p-nitrobenzoyl-amino-9-hydroxyryanodine to one of 26.1 +/- 0.5%, beta-alanyl ryanodine to one of 14.3 +/- 0.5%, and guanidino-propionyl ryanodine to one of 5.8 +/- 0.1% (chord conductance at +60 mV, +/- SEM). For the majority of the derivatives the effect is irreversible within the lifetime of a single-channel experiment (up to 1 h). However, for four of the derivatives, typified by ryanodol, the effect is reversible, with dwell times in the substate lasting tens of seconds to minutes. The effect caused by ryanodol is dependent on transmembrane voltage, with modification more likely to occur and lasting longer at +60 than at -60 mV holding potential. The addition of concentrations of ryanodol insufficient to cause modification does not lead to an increase in single-channel open probability, such as has been reported for ryanodine. At concentrations of > or = 500 mu M, ryanodine after initial rapid modification of the channel leads to irreversible closure, generally within a minute. In contrast, comparable concentrations of beta-alanyl ryanodine do not cause such a phenomenon after modification, even after prolonged periods of recording (>5 min). The implications of these results for the site(s) of interaction with the channel protein and mechanism of the action of ryanodine are discussed. Changes in the structure of ryanodine can lead to specific changes in the electrophysiological consequences of the interaction of the alkaloid with the sheep cardiac SR Ca2+ release channel.

Variation in the expression and/or phosphorylation of the human low molecular weight stress protein during in vitro cell differentiation

Members of the low molecular weight heat shock protein (hsp) family show regulated expression in both Drosophila and mice during development and differentiation. Here we have examined whether similar regulation of the single low molecular weight hsp (hsp 28) of humans exhibits differences in either its expression and/or phosphorylation during the course of in vitro differentiation of hematopoietic cells. In the promyelocytic leukemic cell line, HL-60, we show that early after commitment of the cells to a macrophage-like phenotype (via exposure to phorbol ester myristate, PMA) there occurs an accompanying increased phosphorylation of hsp 28. Over time and as the cells become terminally differentiated the levels of hsp 28 increase significantly. In contrast, cells stimulated to adopt a granulocyte-like phenotype (e.g. exposed to either dimethyl sulfoxide or retinoic acid) show no changes in either the phosphorylation or expression of hsp 28. Moreover, once differentiated the granulocyte-like cells no longer appear capable of phosphorylating hsp 28. Human K562 cells, in response to hemin, rapidly increase their expression and phosphorylation of hsp 28 during the course of their differentiation into erythroid-like cells. Addition of PMA to the K562 cells induces differentiation into a megakaryocyte-like phenotype but is not accompanied by changes in hsp 28 phosphorylation/expression. In the case of the HL-60 cells, differentiation toward the macrophage like lineage is accompanied by an increased adherence of the cells to their substratum and an apparent association of hsp 28 with the actin cytoskeleton.

Frameless stereotactic guidance. An intraoperative adjunct in the transoral approach for ventral cervicomedullary junction decompression

METHODS

The application of a video-interactive frameless stereotactic guidance system for the treatment of ventral cervicomedullary junction compression is described in a patient with basilar invagination, odontoid dysgenesis, and a Chiari malformation who had irreducible impingement on the ventral brainstem by a partially fused mass of bone made up of the malformed odontoid peg, the inferior clivus, and dorsally protruding osteophytes at the odontoid-clival junction.

RESULTS

This technology permitted instantaneous feedback of the surgeon's orientation in all planes, facilitating extensive removal of the dens and clival tip to achieve adequate ventral brainstem decompression. In view of the distortion of the craniovertebral anatomy produced by the patient's anomalies, the ability to visualize three dimensionally the location of the vertebral arteries also added an element of safety to the lateral bone removal. Similarly, the ability to localize the rostral limit of the clivus that needed to be resected and the caudal extent of C2 that needed to be removed to achieve an adequate decompression helped ensure that the extent of bone removal was appropriately tailored to the patient's anatomy.

CONCLUSION

The authors believe this technique represents a significant advance over standard radiographic intraoperative localization techniques during transoral approaches to the ventral cervicomedullary junction for patients in whom the odontoid is fixed in position in relation to the clivus. This is based on the speed with which localization can be obtained, the accuracy of the information provided, the ability to obtain localization in multiple planes simultaneously, and the lack of radiation exposure during the procedure.

Structural determinants of high-affinity binding of ryanoids to the vertebrate skeletal muscle ryanodine receptor: a comparative molecular field analysis

Ryanodine binds to specific membrane proteins, altering the calcium permeability of intracellular membranes. In this study 19 ryanoids were isolated or synthesized and the structures correlated to the strength of binding to vertebrate skeletal muscle ryanodine receptors. Global minima were determined by employment of molecular mechanics and dynamics augmented by systematic searching of conformational space. Overall, steric and electrostatic factors contribute about equally to the differences in the experimentally determined dissociation constants. The dominant electrostatic interaction is localized to a hydroxyl group in an apolar region of the molecule. The pyrrole and isopropyl groups located together at one pole of the molecule have the greatest effect on steric interactions between ligand and receptor. We suggest ryanodine binds to the receptor with the pyrrole and isopropyl groups buried deep inside a cleft in the protein. This arrangement places special importance on the conformation of the pyrrole and isopropyl groups. In contrast, the opposite pole appears to be positioned at the entrance of the binding pocket because bulky adducts placed in the 9 position of ryanodine alter binding minimally. For example, a fluorescent ryanodine adduct was synthesized which has a dissociation constant close to that of ryanodine. Detailed examination reveals subtle interactions between ryanoid and receptor. In many cases, the major factors altering the strength of binding were found to be conformational alterations in the molecule remote from the site of covalent modification.

The concentrations of collagen-associated amino acids are higher in GnRH agonist-treated uterine myomas

OBJECTIVE

To test the hypothesis that the effects of estrogen reduction on uterine leiomyoma regression are mediated through changes in cell density or the extracellular matrix.

METHODS

Uterine myomas were obtained from 20 women who had received randomly either the GnRH agonist leuprolide acetate depot for 3 months or placebo. The biochemical and morphologic characteristics studied included: total protein, DNA, and amino acid concentrations; histologic appearance; collagen content; and nuclear density.

RESULTS

The absolute and relative concentrations of hydroxylysine, hydroxyproline, glycine, and proline were significantly greater (P < .05) in uterine myomas from patients pretreated with a GnRH agonist compared with placebo-treated controls. The GnRH agonist was also associated with trends toward increased mean total protein, DNA, and nuclear density, but the differences did not reach statistical significance.

CONCLUSIONS

The concentrations of the amino acids contained in collagen were significantly greater in uterine myomas from patients treated with the GnRH agonist compared to myomas from placebo-treated controls. In addition, our observations suggest that the reduction in uterine myoma volume associated with GnRH agonist therapy is associated with alterations in the extracellular matrix.

High throughput DNA sequencing using an automated electrophoresis analysis system and a novel sequence assembly program

The combination of high-resolution scanning, image-databasing technology and sequence assembly software makes it possible to assemble contiguous overlapping sequences of DNA in a fraction of the time required by manual methods. This paper describes and evaluates an assembly program that rapidly generates contigs from scanned images and provides a unique ability to verify disagreements between overlapping strands or fragments of complementary DNA sequences on-screen, further increasing sequencing throughput.

A cluster of coagulase-negative staphylococcal bacteremias associated with peripheral vascular catheter colonization in a neonatal intensive care unit

BACKGROUND

A cluster of six neonatal cases of coagulase-negative staphylococcal bacteremias occurred in a Los Angeles County neonatal intensive care unit in March 1989.

METHODS

A retrospective cohort study assessed the impact of host-and delivery-related variables, length of hospitalization, duration of antibiotic treatment, performance or duration of invasive procedures, and staffing variables on risk of coagulase-negative staphylococcal bacteremia.

RESULTS

Unstratified analyses yielded eight risk factors with risk ratios greater than 2. After stratification by gestational age (less than 29 weeks) and low birth weight (less than 1500 gm), frequency of blood transfusions, duration of respiratory therapy, heparin lock and central vascular line placement, and hyperalimentation remained associated with elevated risk. Two species were identified, arguing against a common source of infection. Of four cohort months with more than 15 very low birth weight infants in the neonatal intensive care unit, an elevation of coagulase-negative staphylococcus-positive blood cultures and diagnosed bacteremias occurred in only two.

CONCLUSIONS

This cluster of coagulase-negative staphylococcal bacteremia was probably caused by frequent manipulation of catheters in neonates who were at heightened risk because of low birth weight and prematurity.

Diagnostic and therapeutic value of thoracotomy in advanced pulmonary neoplasms

This study analyses retrospectively 100 consecutive thoracotomies performed for lung cancer before end 1986. Chest CT scan assessed mediastinal lymph node disease, chest wall invasion and mediastinal invasion, with an overall accuracy of 75, 93 and 91 per cent respectively; mediastinal lymph node disease was significantly more underestimated in the stage III group. Characteristics, type of surgical and adjuvant therapy and follow-up were analysed in the T3 (16 patients) and the N2 (18 patients) group. Complete resection was possible in only a minority of the cases: 3 in the T3 group and one in the N2 group. Of the T3 group, 3 patients have survived more than 3 years and 3 are actually still alive. Of the N2 group, only 2 patients are still alive. Most deaths were due to generalization of the disease.

Binding of captan to DNA polymerase I from Escherichia coli and the concomitant effect on 5'----3' exonuclease activity

Captan (N-[(trichloromethyl)thio]-4-cyclohexene-1,2-dicarboximide) was shown to bind to DNA polymerase I from Escherichia coli. The ratio of [14C] captan bound to DNA pol I was 1:1 as measured by filter binding studies and sucrose gradient analysis. Preincubation of enzyme with polynucleotide prevented the binding of captan, but preincubation of enzyme with dGTP did not. Conversely, when the enzyme was preincubated with captan, neither polynucleotide nor dGTP binding was blocked. The modification of the enzyme by captan was described by an irreversible second-order rate process with a rate of 68 +/- 0.7 M-1 s-1. The interaction of captan with DNA pol I altered each of the three catalytic functions. The 3'----5' exonuclease and polymerase activities were inhibited, and the 5'----3' exonuclease activity was enhanced. In order to study the 5'----3' exonuclease activity more closely, [3H]hpBR322 (DNA-[3H]RNA hybrid) was prepared from pBR322 plasmid DNA and used as a specific substrate for 5'----3' exonuclease activity. When either DNA pol I or polynucleotide was preincubated with 100 microM captan, 5'----3' exonuclease activity exhibited a doubling of reaction rate as compared to the untreated sample. When 100 microM captan was added to the reaction in progress, 5'----3' exonuclease activity was enhanced to 150% of the control value. Collectively, these data support the hypothesis that captan acts on DNA pol I by irreversibly binding in the template-primer binding site associated with polymerase and 3'----5' exonuclease activities. It is also shown that the chemical reaction between DNA pol I and a single captan molecule proceeds through a Michaelis complex.(ABSTRACT TRUNCATED AT 250 WORDS)

A patient with two chronic posttraumatic aneurysms of the thoracic aorta

A case of successful replacement of two coexistent chronic post-traumatic aneurysms of the thoracic aorta is presented. Presumably, these aneurysms at the aortic isthmus and the descending thoracic aorta resulted from two different deceleration traumas.

Similarity of an estrogen-induced protein and a luteinizing hormone releasing hormone-induced protein

Estradiol induces a 70 kDa protein ('EI70') which is synthesized in vivo in the female rat ventromedial hypothalamus (VMH) and transported to the midbrain central gray, suggesting a role for EI70 in the female mating behavior, lordosis. Luteinizing hormone releasing hormone (LHRH), in addition to stimulating gonadotropin release, potentiates pituitary responsiveness to subsequent exposure to LHRH (the 'priming' effect), facilitates lordosis and induces the synthesis of a 70 kDa protein ('LHRH70') in pituitary in vitro. We now report that EI70 precisely co-migrates on two-dimensional (2-D) gels with the pituitary protein induced by LHRH both in vitro and in vivo. Furthermore, both proteins migrate on 2-D gels in the vicinity of a protein recognized after immunoblotting by antibodies to the heat-shock-70 kDa protein family. The induction of a common protein by estrogen or LHRH could represent a common mechanism by which these hormones facilitate secretion, and by which these hormones interact.

Diagnosis of arterial occlusive disease of the lower extremities by laser Doppler flowmetry

Laser Doppler Flowmetry offers the possibility of non-invasive and continuous recording of tissue blood flow. Skin blood flux in resting state and during postocclusive reactive hyperemia was measured at the pulpa of the toe in 21 normal lower limbs and in 58 limbs with arterial occlusive disease. Proper assessment of postischemic flux- and time- parameters (beginning of reactive hyperemia, peak flux, time of peak flux and duration of hyperemic flux) permits accurate separation of healthy and diseased limbs.

The induction of the major heat-stress protein in purified rat glial cells

Cultured purified oligodendroglia and astroglia exposed to heat stress (45 degrees C, 10 or 20 min) synthesized a 68-kDa heat-stress protein, which migrates on two-dimensional gel electrophoresis and reacts with a specific monoclonal antibody suggesting it is similar to a major 72-kDa heat-shock protein previously reported in other cell types. This protein was not detected in control glial cultures. Actinomycin D prevented synthesis of this protein demonstrating an absolute requirement for newly synthesized mRNA. The response was prolonged by increasing the period of heat stress from 10 to 20 min. In addition to the 68-kDa HSP protein, the incorporation of radioactivity into 70-, 89-, and 97-kDa proteins was also increased after heating, but in contrast to the 68 kDa protein these proteins appeared to be made in control glial cultures.

Aortocolic fistula caused by an ingested chicken bone

Primary aortocolic fistulas are a rare but lethal complication of aortic or iliac aneurysms. A case of fistula between a nonaneurysmal aortic bifurcation and sigmoid colon caused by an ingested chicken bone is presented. This cause of rectal bleeding, which has never been described, might have been suspected after careful examination of abdominal x-ray films. Surgical management included removal of the foreign body and primary repair of the colonic and aortic rent and appeared to be adequate.

Posttraumatic rupture of the thoracic aorta

Ten patients with traumatic lesions of the thoracic aorta were seen in a hospital. Most were victims of traffic accidents and presented severe associated lesions along with their vascular trauma. We found that the vascular injuries were clinically manifest in only a minority of patients. The remaining ruptures were discovered through CT-scanning of the mediastinum or angiography. We believe that in every major trauma victim aortic lesions should be actively sought for by complimentary examinations to guarantee maximum survival of the patients.

Comparison of auscultation, continuous wave Doppler imaging, intravenous digital subtraction angiography and conventional angiography in diagnosis of carotid artery disease

The reliability of auscultation, continuous wave (CW) Doppler imaging, and intravenous digital subtraction angiography (IV DSA) in the assessment of carotid artery disease has been evaluated in comparison with conventional angiography in 30 patients. With auscultation, specificity and sensitivity for internal carotid artery (ICA) stenosis of 50% or more were 81% and 67% respectively. CW Doppler imaging detected ICA stenosis of 50% or more with a sensitivity of 83% and a specificity of 92% and ICA occlusion with a sensitivity of 60%. The specificity of IV DSA was 95% and the sensitivity for ICA stenosis of 50% or more and ICA occlusion were 75% and 100% respectively. Combining CW Doppler and IV DSA findings raised sensitivity for ICA stenosis of 50% or more and ICA occlusion to 89% and 100% respectively and specificity to 95%. The combination of CW Doppler and IV DSA is a safe and accurate test battery in the detection and categorization of carotid disease.

Transaxillary thoracotomy for treatment of spontaneous pneumothorax

This study reports the retrospective analysis of operative treatment of 20 cases of spontaneous pneumothorax during the last 4 years. Surgical indications included recurrence, recollapse of the lung on clamping the chest tube, nonexpansion of the lung despite adequate drainage or persistent air leak, and giant bulla. A transaxillary thoracotomy was used in all cases to treat sites of air leak and subpleural blebs by resection (14 cases) or oversutering (4 cases) combined with pleural abrasion (19 cases) or apical pleurectomy (1 case). This approach has met with excellent results without major morbidity or mortality.

Repair of pericardial rupture by abdominal transphrenic approach solely

The abdominal transphrenic approach enabled us to repair a left lateral pericardial rupture on a polytrauma patient who also had a rupture of the spleen and a retroperitoneal hemorrhage. A pericardial exploration was necessary because of a sudden upper venous congestion syndrome during operation, suggestive of a cardiac tamponade.

Posterior mediastinal sarcoidosis

We report two cases of enlargement of the posterior mediastinal lymph nodes due to sarcoidosis. Bilateral hilar enlargement, pulmonary parenchymal involvement, or extrathoracic manifestations of sarcoidosis were absent. A diagnostic thoracotomy had to be performed in both instances.

Femorofemoral bypass grafting in high-risk patients

A total of 37 extra-anatomic femorofemoral bypasses were inserted for severe unilateral iliac artery stenosis or a thrombosed graft limb of an aorto-bifemoral bifurcation graft. All patients were severely debilitated and at high risk for direct aorto-iliac reconstruction. 30% suffered severe claudication; 70% had ischemic restpain or trophic lesions. 43% died during a mean follow-up period of 17 months. This study demonstrates that the extra-anatomic femoro-femoral bypass procedure is an effective alternative therapeutic modality for high-risk patients with an acceptable operative mortality (5.4%) and morbidity to improve the quality of life.

Fibromuscular dysplasia of the internal carotid artery

An observation on symptomatic fibromuscular dysplasia of the internal carotid artery, surgically treated by graduated internal dilatation is presented. Fibromuscular dysplasia is a segmental, nonatheromatous disease of small to medium-sized arteries, affecting mainly renal arteries. Involvement of the internal carotid artery is often an incidental angiographic finding in asymptomatic patients, but can be associated with specific neurologic symptoms requiring surgical treatment. The histopathologic character, the pathogenesis, the clinical manifestation, the diagnosis and the therapeutic possibilities of this affection are discussed.

Recurrent pulmonary embolism: importance, diagnosis, management and prevention

Pulmonary emboli, even small, cause irreparable lung damage. Recurrent pulmonary emboli further increase the amount of non functional lung tissue and may result in incapacitating respiratory disease or death. It is therefore mandatory that the disease be correctly diagnosed and adequately treated. As prevention is better than cure, every patient presenting with clinical signs of deep venous thrombosis (DVT) should be correctly explored. The site and size of thrombosis must be visualized preferably with contrast venography with imaging of the veins of the limbs, iliac veins and vena cava. Risk factors such as obesity, immobilization etc. must be taken into account. Underlying disease such as heart disease and venous insufficiency must be treated. Malignancy must be looked for as in a recent series of patients with primary DVT which were studied, 15% presented with an up till then unknown malignant disease. In patients presenting with recurrent DVT this percentage rose to 20%. When a patient presents with DVT of the femoro-iliac vena cava axis, aggressive treatment must be adopted. Fibrinolysis or if this is contra-indicated, thrombectomy will be used. A vena cava filter may be necessary and longterm anticoagulation is mandatory. The same rationale is applicable in cases of pulmonary embolus whether it is a primary event or a recurrence.

Small artery syndrome in women

During the past four years, 106 women underwent aortography and peripheral runoff studies for peripheral vascular disease. Eleven patients presented with "small vessels" and were selected for this study. They were significantly younger than the rest of the group (a mean age of 52 versus 66 years). A clear history of claudication was elicited in all patients. Rest pain was present in four patients. Most patients were small in stature but not obese. Weak or absent femoral and distal pulses and abdominal or femoral bruits were common. Angiography demonstrated a narrow infrarenal aorta, narrow iliac and common femoral arteries and a straight course of iliac arteries. Atherosclerotic lesions involved mainly the aortoiliac segment, but were confined to the superficial femoral artery in two patients. Reconstruction was achieved by endarterectomy or transluminal angioplasty in segmental aortoiliac disease and aortobifemoral or aortobi-iliac graft in diffuse disease. Femorpopliteal or iliopopliteal graft or lumbar sympathectomy was performed in patients with significant femoral disease. In one patient, an acutely occluded femoral segment was replaced by a venous interposition graft. Two patients were treated conservatively. There were no operative deaths. Nine patients were markedly improved at follow-up examination. Graft thrombosis occurred in one patient with combined aortobi-iliac and iliopopliteal graft. The high incidence of single bifurcating lumbar arteries at the fourth and fifth lumbar vertebrae supports the hypothesis that aortic hypoplasia may result from embryonic overfusion of the dorsal aortas. Lipid abnormalities existed in 54 per cent of the patients. All women were heavy smokers and 73 per cent had a positive family history of cardiovascular disease.

[Systematic research on an etiology in apparently primary deep venous thrombosis. Apropos of 59 cases]

Primary deep vein thrombosis was confirmed by phlebography in 59 cases between Jan. 1981 and Jan. 1984 in the department of Cardiovascular Surgery of the Academic Hospital of the V.U.B. Brussels. Investigations conducted in all patients included blood and urine analyses, chest radiography, electrocardiogram, gynecologic or urologic examinations and abdominal and pelvic ultrasound imaging. Findings demonstrated one or more risk factors in 92% of cases, the principal ones being obesity, a history of thromboemboli and, in women, the use of oral contraceptives. Nine patients had cancer and 4 of these received combined surgery-chemotherapy. All cases of so-called primary deep vein thrombosis should be investigated routinely for risk factors, because of the need and possibilities for treatment in some of them, particularly since procedures are non-invasive, of low cost, and easily performed during initial heparin therapy.

The effect of nordihydroguaiaretic acid and related lignans on formyltetrahydrofolate synthetase and carboxylesterase

The lignans nordihydroguaiaretic acid (NDGA), heminordihydroguaiaretic acid (HNDGA) and norisoguaiacin were found to inhibit formyltetrahydrofolate synthetase (formate:tetrahydrofolate ligase (ADP-forming), EC 6.3.4.3) and carboxylesterase (carboxylic-ester hydrolase, EC 3.1.1.1) activity from a wide variety of sources. In all cases, NDGA was the most effective inhibitor. Synthetase activity was reduced by half at NDGA concentrations between 0.11 and 0.24 mM. Esterase activity consisted of NDGA-sensitive and NDGA-resistant forms. The sensitive class was half-inhibited by 2-4 microM NDGA. Irreversible inhibition of formyltetrahydrofolate synthetase by NDGA was observed both at low protein concentration (less than 0.2 mg/ml) and at high protein concentration where precipitation of protein was observed. Inhibition of formyltetrahydrofolate synthetase by NDGA arises from a decrease in Vmax and increase in Km for all substrates. In contrast, NDGA affects only the Vmax parameter of the esterase activity. It is suggested that the broad range of enzymes inhibited by NDGA may be a consequence of the amphipathic character of the molecule and the flexibility to accommodate to a variety of binding sites. It is also suggested that the previously reported ability of NDGA to inhibit phagocytosis may be due to the compound's ability to inhibit carboxylesterases.

Isolated paratracheal mass of tuberculous origin in an adult patient

A 40-year-old man presented with a solitary mediastinal (right paratracheal) mass which proved to be due to Mycobacterium tuberculosis. While the incidence of tuberculosis has diminished in our countries, such unusual manifestations of tuberculosis as the present case, are still encountered. Tuberculosis, the "perfect imitator", should be included in the differential diagnosis of a mediastinal mass. Excision for therapeutic, as well as histological and bacteriological diagnostic, purposes should be supplemented by appropriate antituberculous chemotherapy.