Successful thrombolysis of a stroke with a pulmonary embolism in a young woman

BACKGROUND

Paradoxical embolism is a rare event, accounting for < 2% of all arterial emboli. The diagnosis is often difficult, and consequences for the patient can be severe.

CASE REPORT

We describe the case of a 35-year-old female physician who presented to our Emergency Department (ED) in severe hemodynamic compromise, with an altered level of consciousness and major expressive aphasia 1 day after undergoing a leg varicosal stripping procedure under regional anesthesia. She was successfully thrombolyzed with 0.9 mg/kg of Recombinant Tissue Plasminogen Activator (rtPA, Alteplase) and had a full recovery.

CONCLUSION

To our knowledge, this is the first description of a case of massive pulmonary embolism associated with a paradoxical stroke related to patent foramen ovale that was thrombolyzed for both conditions with a "neurological dose" of rtPA. Although thrombolysis was completely successful in this case, indications and contraindications should be thoroughly respected. A more conservative approach with anticoagulation, or a more aggressive approach with surgical thrombectomy, can each potentially have a place in particular cases. Intra-arterial catheter-directed thrombolysis and percutaneous embolectomy are additional options to be considered when available, especially if there are contraindications for systemic thrombolysis.

The responsiveness of three-dimensional knee accelerations used as an estimation of knee instability and loading transmission during gait in osteoarthritis patient's follow-up

OBJECTIVE

Knee instability and joint loading transmission are two important biomechanical factors in subjects with knee osteoarthritis (OA). However, the relationship between these factors in a rehabilitation treatment remains unclear. The purpose of this study is to determine the responsiveness of a new three-dimensional (3D) acceleration method used as an estimation of knee instability and joint loading transmission during gait in OA subjects after a rehabilitation treatment.

METHOD

Twenty-four subjects with medial knee OA were included in this study. They had clinical and gait evaluations before and after 12 weeks of treatment. 3D linear knee accelerations, quadriceps and hamstring isometric strength and Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) pain were quantified, and compared between both evaluations. Nine asymptomatic subjects participated in this study for gait comparison.

RESULTS

A significant reduction of the anterior posterior (AP) knee acceleration peak (P=0.02) had been detected after the treatment. No difference for both distal and lateral knee accelerations peak was found. A significant increase in quadriceps (P<0.001) and hamstring (P=0.006) strength was seen after treatment. The WOMAC of pain had shown significant reduction after the treatment (P<0.001).

CONCLUSION

The present study demonstrates that the estimation of knee acceleration parameters is sensitive to changes in knee OA gait after a rehabilitation treatment. This study also indicates that a treatment of 3 months which combines therapeutic and exercises program could have benefits on knee OA by increasing AP knee stability and stabilize joint loading transmission during gait.

Comparison of respiratory rate estimation based on tracheal sounds versus a capnograph

The objective was to compare the accuracy of estimations of respiratory rate (RR), based on tracheal sounds, with simultaneous estimations from a capnograph, using as a common reference a pneumotachometer. Five subjects without pulmonary diseases were enrolled. Tracheal sounds were acquired using a contact piezoelectric sensor placed on the subject's throat and analyzed using a combined investigation of the sound envelope and frequency content. The capnograph and pneumotachometer were coupled to a face mask worn by the subjects. There was a strong linear correlation (r2= 0.98) between the acoustic method and the pneumotachometer and also between the capnograph and the pneumotachometer (r2 = 0.98). The SEE obtained by the acoustic method was 1.11 and the SEE obtained by the capnograph was 1.23. As a conclusion, the accuracy of the respiratory rate estimated from tracheal sounds on adult subjects was comparable to the accuracy of a commercial capnograph, using as a common reference a pneumotachometer.

Seeing is remembering: do deficits in closure affect visual memory recognition in schizophrenia?

INTRODUCTION

Episodic memory is significantly impaired in people with schizophrenia. The precise cause of this impairment has yet to be determined, as the formation of episodic memories is dependent on other processes, some of which also show impairment in schizophrenia. One such process is closure, that is, the filling-in of missing information. Failure to close adequately incomplete stimuli may cause people with schizophrenia to store inadequate or piecemeal representations in memory.

METHODS

Forty people with schizophrenia and 21 healthy comparison subjects participated in the study. The experiment was divided into six blocks, each of which involved both an encoding and a recognition phase. During the encoding phase, 20 figures were presented sequentially and participants had to determine whether each was symmetric or asymmetric. These figures were either complete or fragmented at three different levels. In subsequent recognition phase, 40 abstract figures (20 new and 20 old) were presented. All figures were complete in this phase.

RESULTS

Memory performance of both groups was affected similarly by fragmentation, with an additional increase in performance afforded by a slight fragmentation for participants with schizophrenia.

CONCLUSION

Slight fragmentation may have induced a perceptual difficulty that was mild enough to increase visual processing without compromising it. Closure was thus not involved in the episodic memory deficit of people with schizophrenia.

[Prefrontal dysfunction in schizophrenia: implication is associative recognition]

OBJECTIVE

We used an event related functional magnetic resonance imaging (fMRI) method to examine the neural basis of associative recognition memory deficit in schizophrenia.

METHODS

Fifteen people with schizophrenia and 18 healthy control subjects were scanned with fMRI while performing a memory task (coding and recognition) of visual objects. During coding, the subjects studied items and pairs of items. During recovery, the subjects had to recognize items (old/new decisions) and recognize associations (intact/rearranged decisions). The study design was based on a random effect model and the fMRI analysis was restricted to correct items only.

RESULTS

At the behavioral level, both groups performed equally well on item recognition, whereas people with schizophrenia demonstrated poorer performance on associative recognition. At the brain level, comparison between associative and item recognition tasks revealed greater left dorsolateral prefrontal and right inferior prefrontal activations in the control group relative to the schizophrenia group.

CONCLUSIONS

The findings of this fMRI study suggest the prefrontal cortex as the basis for the selective memory deficit for associative recognition observed in schizophrenia.

Estimation of tibial and femoral 3D linear accelerations during gait

Shock wave traveling through the skeletal are more and more considered in the development of articular disorders. A method to quantify those skeletal transients is to estimate body segment linear accelerations. However, linear accelerations magnitude is influenced by many factors such as location and fixation of sensors, walking velocity, walking level and also by wearing conditions. Hence, experimental results in literature can't be easily compared and normative data haven't been established yet. The present paper proposes a method to estimate three-dimensional (3D) tibial and femoral linear accelerations during treadmill walking. 15 able-bodied subjects were evaluated. 3D kinematics data recorded from an optoelectronic system (Optotrak 3010, Northern Digital, Canada) at knee joint level were derived to estimated 3D linear accelerations of the tibia and the femur at their respective coordinate system origins.

Analyse spatiale des conflits urbains

Cette étude exploratoire des conflits urbains de la région de Québec entre 1990 et 2000 montre que la fréquence des conflits est plus élevée dans les secteurs où, d’une part, la densité de commerces de quartier est la plus forte et le tissu urbain plus ancien et, d’autre part, où la population est la plus scolarisée et dispose d’un horaire de travail flexible. Cette étude confirme ainsi que certains cadres urbains sont plus susceptibles que d’autres de générer des conflits et que certains groupes sont plus disposés à s’y engager. Elle montre aussi que ces relations sont sensiblement les mêmes, quel que soit le type d’enjeux défendus par les protagonistes de ces conflits. Deux exceptions sont toutefois à relever. Tout d’abord, les conflits liés à des enjeux environnementaux montrent parfois des relations différentes avec les variables caractérisant les lieux de conflits (indépendamment du niveau d’éducation et le type de profession). Ensuite, alors que la densité de population n’a dans l’ensemble pas d’influence sur l’émergence des conflits, on observe tout de même que dans les secteurs où la population est la plus dense, les conflits liés à des enjeux de transports ou des enjeux sociaux sont plus nombreux

Interleukin-15 increases neutrophil adhesion onto human respiratory epithelial A549 cells and attracts neutrophils in vivo

Interleukin-15 (IL-15) is a neutrophil agonist that plays a role in inflammatory disorders, including a variety of pulmonary diseases. Adhesion of neutrophils onto pulmonary cells is a major event leading to development of inflammation. Recently, elevated levels of IL-15 have been associated with different pulmonary diseases. There is no clear evidence that IL-15 modulates cell surface expression of adhesion molecules in neutrophils, or that IL-15 is involved in neutrophil adhesion onto pulmonary cells. Also, it is not clear if IL-15 induces a neutrophilic inflammation in vivo. This study was aimed at elucidation of these issues. Neutrophils were treated with IL-15 and cell surface expression of CD11a, CD11b, CD11c and CD18 was monitored by flow cytometry. The human respiratory epithelial A549 cell line was used as a substrate for the neutrophil adhesion assay and cell surface expression of CD50, CD54 and CD106 was monitored in IL-15-induced A549 cells. The murine air pouch model was used for investigating potential neutrophilic inflammation induced by IL-15 in vivo. IL-15 significantly increased neutrophil cell surface expression of CD11b and CD18 and up-regulated A549 cell surface expression of CD54. Moreover, A549 cells were found to express IL-15R components and adhesion of neutrophils onto A549 cells was increased when neutrophils or A549 cells were treated with IL-15. Finally, IL-15 induced neutrophilic inflammation in vivo and concentrations of IL-6 and CXCL2/MIP-2 were increased in IL-15-induced pouches. IL-15 might participate in inflammatory pulmonary diseases by attracting neutrophils, modulating cell surface expression molecules and increasing neutrophil adhesion onto pulmonary cells.

Dieldrin induces human neutrophil superoxide production via protein kinases C and tyrosine kinases

We have recently found that dieldrin is a potent human neutrophil agonist in vitro and induces neutrophilic inflammation in vivo. Among the responses observed in vitro, dieldrin was found to induce superoxide (O2-) production by a yet unknown mechanism. In the present study, dieldrin- and phorbol 12-myristate 13-acetate (PMA)-induced O2- responses were compared. For this purpose, cells were preincubated with a panel of signal transduction inhibitors including genistein, H-7, HA-1077, pertussis toxin, staurosporine, calphostin C, SB203580, PD098059, and wortmannin. Dieldrin-induced O2- response was significantly reduced with treatment with genistein, H-7, HA-1077, staurosporine, and calphostin C, whereas PMA-induced response was significantly reduced by treatment with H-7, HA-1077, and staurosporine. This indicates that dieldrin mediates its effect via protein kinases C (PKCs) and tyrosine kinases. Involvement of tyrosine kinases in dieldrin-induced human neutrophils was further demonstrated by an increase in tyrosine phosphorylated protein level expression. Finally, we found that treatment with the mitochondrial stabilizer bongkrekic acid and with the inhibitor of vesicular transport brefeldin A did not reverse dieldrin-induced O2- response.

Modulation of interleukin-15-induced human neutrophil responses by the plant lectin Viscum album agglutinin-I

The plant lectin Viscum album agglutinin-I (VAA-I) and the interleukin-15 (IL-15) cytokine are two molecules with potential therapeutic properties known to modulate neutrophil functions when used separately. This study was conducted in order to better understand the mode of action of VAA-I and to elucidate how VAA-I could modulate IL-15-induced neutrophil responses. We found that VAA-I cannot induce phosphorylation events in human neutrophils. However, it enhances phagocytosis by itself without altering IL-15-induced phagocytosis. VAA-I was found to reverse the ability of IL-15 to delay neutrophil apoptosis and this was correlated with an inhibition of IL-15-induced de novo protein synthesis. In addition, we also found that IL-15 cannot reverse or attenuate the caspase-induced gelsolin fragmentation observed during apoptosis as assessed by immunoblotting. We conclude that VAA-I can be used to modulate some, but not all, IL-15-induced neutrophil responses and that it acts independent of phosphorylation events.

Arginine methylation of a mitochondrial guide RNA binding protein from Trypanosoma brucei

RBP16 is a mitochondrial Y-box protein from the parasitic protozoan Trypanosoma brucei that binds guide RNAs and ribosomal RNAs. It is comprised of an N-terminal cold-shock domain and a C-terminal domain rich in glycine and arginine residues, resembling the RGG RNA-binding motif. Arginine residues found within RGG domains are frequently asymmetrically dimethylated by a class of enzymes termed protein arginine methyltransferases (PRMTs). As Arg-93 of RBP16 exists in the context of a preferred sequence for asymmetric arginine dimethylation (G/FGGRGGG/F), we investigated whether modified arginines are present in native RBP16 by MALDI-TOF and post-source decay analyses. These analyses confirmed that Arg-93 is dimethylated. In addition, Arg-78 exists as an unmodified or as a monomethylated derivative, and Arg-85 is present in forms corresponding to the unmodified, di-, and tri-methylated state. While Arg-93 is apparently constitutively dimethylated, the methylation of Arg-78 and Arg-85 is mutually exclusive. Furthermore, whole cell extracts from procyclic form T. brucei are able to methylate bacterially expressed RBP16 (rRBP16), as well as endogenous proteins, in the presence of S-adenosyl-L-[methyl-3H]methionine. While assays of mitochondrial extracts suggest a small amount of PRMT may also be present in this subcellular compartment, the majority of trypanosome PRMT activity is extramitochondrial. We show that rRBP16 is methylated in trypanosome extracts through the action of a type I methyltransferase as well as serving as a substrate for heterologous mammalian type I PRMTs. In addition, we demonstrate the presence of type II PRMT activity in trypanosome cell extracts. These results suggest that protein arginine methylation is a common posttranslational modification in trypanosomes, and that it may regulate the function of RBP16.

Activation of human neutrophils in vitro and dieldrin-induced neutrophilic inflammation in vivo

Many chemicals of environmental concern are known to alter the immune system and are considered toxic molecules because they affect immune cell functions. Inflammation related to environmental chemical exposure, however, is poorly documented, except that from air pollutants. In this study, we found that the organochlorine insecticide dieldrin could not alter the ability of human neutrophils to phagocytose opsonized sheep red blood cells at nonnecrotic concentrations (0.1, 1, 10, and 50 microM). However, dieldrin was found to increase human neutrophil superoxide production, RNA synthesis, and proinflammatory cytokine interleukin-8 production. The normal apoptotic rate of neutrophils evaluated by both cytology and flow cytometry (CD-16 staining) was not altered by dieldrin treatments, and this was correlated with its inability to inhibit spreading of neutrophils onto glass. Using the murine air pouch model, we found that dieldrin induces a neutrophilic inflammation. Taken together, these results demonstrated that dieldrin is a proinflammatory contaminant. To our knowledge, this is the first report establishing that dieldrin is a contaminant exhibiting proinflammatory properties. In addition, it is the first time that the murine air pouch model has been successfully used to confirm that a chemical of environmental concern can induce an inflammatory response in vivo.

A new syndrome with craniofacial and skeletal dysmorphisms and developmental delay

We report a 16-year-old boy with multiple craniofacial and skeletal dysmorphic features including brachycephaly, acrocephaly, hypertelorism, wide palpebral fissures, broad nose, anteverted nares, broad columella, long and smooth philtrum, thin upper lip, macrostomia, carp-like mouth, micrognathia, low-set and posteriorly angulated ears with small and abnormal pinnae, a low posterior hairline, a short neck, hypoplastic and widely-spaced nipples, multiple severe pterygia, an umbilical hernia, metatarsus varus, low implantation of the halluces, and delayed motor and language development. An MRI of the head showed bilateral frontal pachygyria but no sign of heterotopia. The unique features of our patient suggest that he represents a new syndrome.

Activation of human neutrophils by technical toxaphene

Toxaphene is a persistent organic pollutant (POP) known to be composed of numerous congeners. Toxaphene technical mixture applied as a pesticide consists of over 800 congeners. Among these, T(2) and T(12) are the two environmentally prevalent forms found in humans. Although toxaphene is known to exert some toxic effects, including potential proinflammatory properties, little is known concerning its action on cells of the human immune system, especially neutrophils. In the present study, we found that toxaphene was not necrotic for human neutrophils incubated for up to 24 h with concentrations ranging from 0.1 to 50 microg/ml. Toxaphene was found to induce neutrophil superoxide production (O(-)(2)) in a concentration-dependent manner. The potency and the kinetics of toxaphene-induced O(-)(2) by neutrophils were found to be similar to that of the classical neutrophil agonists phorbol 12-myristate 13-acetate (PMA). Furthermore, the use of various transduction signal inhibitors (genistein, pertussis toxin, staurosporine, H-7, and HA-1077), suggests that, as for PMA, toxaphene mediates its effect primarily via PKCs and, to a lesser extend, via tyrosine kinases. In this respect, staurosporine, H-7, and genistein were found to inhibit toxaphene- and PMA-induced O(-)(2) production by 52, 72, and 31% and by 63, 62, and 23%, respectively. Toxaphene was also found to significantly enhance neutrophil phagocytosis of opsonized sheep red blood cells and to induce neutrophil apoptosis. The induction of neutrophil apoptosis was paralleled with a decrease in CD16 expression. T(2) and T(12), the two prevalent congeners found in humans, were also found to significantly increase the O(-)(2) production in neutrophils at a concentration of 5 microg/ml. We conclude that neutrophils are important targets for toxaphene, as this POP can activate O(-)(2) production by a PKC- and tyrosine kinase-dependent mechanism, induce phagocytosis, and accelerate the apoptotic rate. This is the first study that focuses on toxaphene/human neutrophil interactions.

Activation of human neutrophils by the plant lectin Viscum album agglutinin-I: modulation of de novo protein synthesis and evidence that caspases are involved in induction of apoptosis

The plant lectin Viscum album agglutinin-I (VAA-I) was recently found to modulate protein synthesis and to induce apoptosis in various cells of immune origin. We found that VAA-I induces de novo protein synthesis of metabolically 35S-labeled human neutrophils when used at low concentrations (< 100 ng/mL) but acts as an inhibitor at higher concentrations. Using both flow cytometry (FITC-Annexin-V/PI labeling) and cytology (Diff-Quick staining) approaches, we found that VAA-I could not modulate neutrophil apoptosis at low concentrations but could induce it in >98% of cells at 500 and 1000 ng/mL. VAA-I was also found to reverse the delaying effect of GM-CSF on neutrophil apoptosis and to inhibit GM-CSF-induced de novo protein synthesis. In contrast to GM-CSF, VAA-I does not induce tyrosine phosphorylation by itself and does not alter the GM-CSF-induced response. Among the inhibitors used, genistein, pertussis toxin, staurosporine, H7, Calphostin C, manoalide, BpB, quinacrine HA-1077, and z-VAD-FMK, only the latter (inhibitor of caspases-1, -3, -4, and -7) was found to inhibit VAA-I-induced neutrophil apoptosis as the percentage of apoptotic cells decrease from 98 +/- 1.3 to 54 +/- 3.2% (n=4). Furthermore, we confirm that caspases are involved in VAA-I-induced neutrophil apoptosis as we have observed the fragmentation of the cytoskeletal gelsolin protein that is known to be caspase-3-dependent. Such degradation was reversed by the z-VAD-FMK inhibitor. We conclude that induction of neutrophil apoptosis by VAA-I is a caspase-dependent mechanism that does not involve tyrosine phosphorylation events, G-proteins, PKCs, and PLA2. In addition, we conclude that at least caspase-3 is involved. Correlation between VAA-I-induced neutrophil apoptosis and VAA-I-induced inhibition of de novo protein synthesis is discussed.

Sediment toxicity assessment: comparison of standard and new testing designs

Standard methods of sediment toxicity testing are fairly well accepted; however, as with all else, evolution of these methods is inevitable. We compared a standard ASTM 10-day amphipod toxicity testing method with smaller, 48- and 96-h test methods using very toxic and reference sediments. In addition we compared parallel exposures of single species, either the amphipod Ampelisca abdita or the mysid Americamysis bahia, to multiple species, mysid, and amphipod, cohabiting the same types of chambers. These comparisons were performed for both water-only and sediment-water tests. Results of the comparison of the standard ASTM 10-day amphipod test with the smaller, 48- and 96-h test chambers indicate that survival was high in both test designs using the reference sediment. With toxic sediments, complete mortality occurred in less than 48 h using the smaller experimental chambers and only after 96 h in the larger experimental chambers. We concluded that although time to death is shorter in the smaller, shorter exposure chambers, there was no overall change in mortality for the organisms, and that the smaller chambers were predictive of the results obtained with larger chambers and longer exposures. For multiple species testing in whole sediment exposures there was no change in toxicity to either the amphipod or the mysid when they cohabited the same chamber. In contrast, for water-only exposures, A. bahia demonstrated less sensitivity when cohabiting the same chamber as A. abdita. Therefore, during whole sediment testing we can add A. bahia and A. abdita to the same test chamber without changing the toxicity to either species; however, in our 10-ml water-only exposures, the species should be tested separately.

Activation of human neutrophils by the air pollutant sodium sulfite (Na(2)SO(3)): comparison with immature promyelocytic HL-60 and DMSO-differentiated HL-60 cells reveals that Na(2)SO(3) is a neutrophil but not a HL-60 cell agonist

Sulfite exposure can induce inflammatory responses characterized by an influx of neutrophils into the airways leading to lung malfunctions. Studies focusing on sodium sulfite (Na(2)SO(3))/neutrophil interactions have shown that this chemical possesses proinflammatory properties based on its ability to induce a respiratory burst. Information regarding how this chemical could alter other neutrophil responses/functions as well as its role on immature promyelocytic cells is currently lacking in the literature. In this study, we report that Na(2)SO(3) can induce tyrosine phosphorylation events in human neutrophils but not in both HL-60 and HL-60 + DMSO. As a positive control, GM-CSF was found to induce tyrosine phosphorylation of a particular protein of 120-130 kDa in both HL-60 and HL-60 + DMSO cells testifying that these cells were responsive. In addition, we report that Na(2)SO(3) does not alter neutrophil phagocytosis and that this chemical increases the release of the proinflammatory cytokine IL-8 but not TNF-alpha. Paradoxically, we found that Na(2)SO(3) acts as a potent inhibitor of de novo neutrophil protein synthesis in a concentration-dependent fashion (0.1, 1, or 10 mM) as assessed by SDS-PAGE from metabolically [(35)S]-labeled cells. In contrast to mature neutrophils, we found that Na(2)SO(3) does not modulate de novo protein synthesis in HL-60 cells treated with low concentrations (0. 1 or 1 mM) and that this pollutant was toxic at 10 mM as judged by a drastic decrease of total protein content stained with Coomassie blue. We conclude that Na(2)SO(3) can activate human neutrophils and that its proinflammatory potential is further supported by its ability to increase IL-8 production. In addition, our results clearly indicate that HL-60 and HL-60 + DMSO respond differently than mature human neutrophils to the inflammatory pollutant Na(2)SO(3). Extrapolation of data obtained with HL-60 (and/or HL-60 + DMSO) to neutrophils should be taken with caution. Our data obtained with Na(2)SO(3) are an example.

SCF(beta-TRCP) and phosphorylation dependent ubiquitinationof I kappa B alpha catalyzed by Ubc3 and Ubc4

NF kappa B is an important transcriptional regulator of multiple pro-inflammatory genes. In non-stimulated cells NF kappa B is anchored in the cytoplasm via the inhibitory protein I kappa B alpha. Following exposure to diverse pro-inflammatory signals (e.g. TNF alpha, IL1, LPS) various signal transduction cascades are initiated converging on the I kappa B kinase (IKK). IKK phosphorylates I kappa B alpha on serines 32 and 36 signaling the inhibitory protein for ubiquitin-mediated degradation. The SCF beta-TRCP complex is the ubiquitin ligase responsible for mediating phosphorylation dependent ubiquitination of I kappa B alpha. Here we reconstitute phosphorylation dependent ubiquitination of I kappa B alpha using recombinant components. Our results suggest that the cullin specificity of the SCF complex may reflect its ability to associate with Rbx1. We demonstrate specific ubiquitination of I kappa B alpha by Ubc3 and Ubc4 in a phosphorylation and SCF beta-TRCP dependent manner and that both are capable of associating with the SCF beta-TRCP complex isolated from human cells. Finally, we show that Ubc4 is in excess to Ubc3 in THP.1 cells and 19 times more efficient in catalyzing the reaction, suggesting that Ubc4 is the preferentially used Ubc in this reaction in vivo. Our results also suggest that ubiquitin is transferred directly from the Ubc to phospho-I kappa B alpha in a SCF beta-TRCP dependent reaction. Oncogene (2000) 19, 3529 - 3536

Double blind randomized clinical trial examining the efficacy of bupivacaine suprascapular nerve blocks in frozen shoulder

OBJECTIVE

To determine whether the pain, contracture, and disability associated with idiopathic frozen shoulder are diminished by a series of 3 indirect bupivacaine suprascapular nerve blocks delivered in an ambulatory care clinic.

METHODS

A double blind randomized controlled trial of patients referred by primary care and specialty clinics in Montreal to an ambulatory tertiary care academic facility. Patients and controls underwent a series of 3 indirect suprascapular nerve blocks at 7 day intervals using either 10 c.c. bupivacaine 0.5 (Marcaine) in the treatment group or 10 c.c. of physiological saline in controls. Subjects in both groups were taught a program of shoulder range of motion exercises to be done at home. The primary outcome measure was the McGill-Melzack Pain Questionnaire (MPQ) short form at 1 month post-randomization (2 weeks after last injection). The secondary outcome measures were disability measured by the simple shoulder test and glenohumeral joint contracture measured by shoulder range of motion measurements.

RESULTS

Thirty-four subjects were randomized from 58 screened. Average age of subjects was 52 years. Mean duration of pain prior to randomization was one year. Dropout rate was 11% in the treatment group, 30% in the placebo group. A 64% reduction in pain in the treatment group versus 13% in the placebo group was observed at one month as measured by the MPQ multidimensional pain descriptors score (p = 0.03). A nonsignificant 15.8% improvement in shoulder function in the treatment group versus 4% in the placebo group (p = 0.24) was also noted. No improvement in shoulder range of movement was noted. No side effects other than transient vagal symptoms and local tenderness at the injection site were reported.

CONCLUSION

The use of bupivacaine suprascapular nerve blocks was effective in reducing the pain of frozen shoulder at one month. Clinical studies with a larger number of subjects and a longer study period will help determine the duration and nature of the effect of bupivacaine suprascapular nerve blocks in treating the pain, disability, and glenohumeral joint contracture of frozen shoulder.

RNA-binding properties of the mitochondrial Y-box protein RBP16

We have previously identified a mitochondrial Y-box protein in Trypanosoma brucei that we designated RBP16. The predicted RBP16 amino acid sequence revealed the presence of a cold-shock domain at its N-terminus and a glycine- and arginine-rich C-terminus reminiscent of an RGG RNA-binding motif. Since RBP16 is capable of interacting with different guide RNAs (gRNAs) in vitro and in vivo primarily via the oligo(U) tail, as well as with ribosomal RNAs, possible functions of RBP16 may be in kinetoplastid RNA editing and/or translation. Herein, we report experiments that further define the RNA-binding properties of RBP16. RBP16 forms a single stable complex with the gRNA gA6[14] at low protein concentration, while at higher protein concentration two stable complexes that possibly represent two different conformations are observed. Both complexes are stable at relatively high salt and moderate heparin concentrations indicating that the binding of RBP16 to gA6[14] does not rely primarily on ionic interactions. Phenylglyoxal treatment of the protein indicates that arginine residues are important in RNA binding. The minimal length of RNA sequence necessary for the binding of RBP16 was assessed by gel retardation and UV cross-linking competition assays using oligo(U) ribonucleotides of varying lengths (4-40 nt). Although RBP16 can bind to oligonucleotides as small as U(4), its affinity increases with the length of the oligo(U) ribonucleotide, with a dramatic increase in binding efficiency observed when the length is increased to 10 nt. Gel retardation assays employing T.brucei mRNAs demonstrated that, although it acts as a major binding determinant, a 3' U tail is not an absolute requirement for efficient RBP16-RNA binding. Experiments with oligonucleotides containing U stretches embedded at different positions in oligo(dC) indicated that high-affinity binding requires both a uridine stretch, as well as 5' and 3' non-specific sequences. These results suggest a model for the molecular interactions involved in RBP16-RNA binding.

Role of surgical residents in undergraduate surgical education

OBJECTIVES

To identify the role and impact of surgical residents on the various activities of a senior (4th year) surgical clerkship, and to explore students' perceptions of differences between the teaching behaviours of attending physicians and residents.

DESIGN

A survey by questionnaire.

SETTING

McGill University, Montreal.

METHOD

A 67-item questionnaire was administered to fourth-year medical students at the end of their 8-week surgical clerkship. Analysis of the data was performed using the Wilcoxon signed-rank test, Dunn's multiple comparison test and mean average.

MAIN OUTCOME MEASURES

Overall satisfaction with the clerkship, teaching behaviours and teaching of clinical skills and basic principles.

RESULTS

Overall satisfaction with the clerkship was 6.31 out of 10. Surgical residents were perceived as being significantly more active than the attending staff in 14 out of 15 teaching behaviours. They were also seen as important in teaching certain clinical skills such as suturing, assisting in the operating room and managing emergency situations. They also contributed significantly to teaching the basic principles of surgery such as infections, surgical bleeding and fluid and electrolytes. On a 10-point scale, students felt that more learning was achieved by independent reading, tutorials and residents' teaching than by other teaching modalities, including attending physicians' and nurses' teaching.

CONCLUSIONS

Medical students perceive surgical residents as being significantly more active in their education process than the attending staff. Residents appear to be responsible for teaching various technical and patient management skills necessary for patient care. Along with independent reading and tutorials, resident teaching contributes a significant portion of the medical student's acquisition of knowledge and appears to contribute to the students' choice of surgery as a career.

The receptor for the orexigenic peptide melanin-concentrating hormone is a G-protein-coupled receptor

Gene-knockout studies of melanin-concentrating hormone (MCH) and its effect on feeding and energy balance have firmly established MCH as an orexigenic (appetite-stimulating) peptide hormone. Here we identify MCH as the ligand for the orphan receptor SLC-1. The rat SLC-1 is activated by nanomolar concentrations of MCH and is coupled to the G protein G alpha i/o. The pattern of SLC-1 messenger RNA expression coincides with the distribution of MCH-containing nerve terminals and is consistent with the known central effects of MCH. Our identification of an MCH receptor could have implications for the development of new anti-obesity therapies.

Virus-inducible expression of a host chemokine gene relies on replication-linked mRNA stabilization

Analysis of the host response to viral infection generally has focused on the capacity of viruses to activate or repress transcription of cellular genes, and this approach is also characteristic of work on RNA viruses such as respiratory syncytial virus (RSV). In the present study, it appeared initially that RSV-driven expression of a critical immune regulator, the beta-chemokine RANTES (regulated upon activation, normal T cell expressed and secreted), in primary-culture airway epithelial cells also depended on inducible gene transcription because expression was accompanied by coordinate increases in transcriptional initiation rate and gene promoter activity. However, RSV-driven increases in RANTES gene transcription and promoter activity were small and transient relative to RANTES expression, and they were no different in size and duration than for inactivated RSV that was incapable of fully inducing RANTES expression. These findings suggested that the increase in RANTES gene transcription was not sufficient for inducible expression and that critical regulatory effects occurred at a posttranscriptional level. This type of mechanism for virus-inducible expression of RANTES was established when we found that replicating (but not inactivated) RSV markedly increased RANTES mRNA half-life (from 0.8 to 6.8 h). In addition, RNase protection assays of heterologous promoter/reporter plasmids indicate that basal instability of RANTES mRNA is mediated at least in part by nucleotides 11-389 of the RANTES gene, and this region is also the target for induction by virus. The distinct pathway for production of RANTES (in combination with cytokine-dependent expression of RANTES and related immune-response genes) may more effectively coordinate immune cell interaction with epithelial barrier cells to mediate host defense.

Cloning and characterization of a cDNA encoding a novel subtype of rat thyrotropin-releasing hormone receptor

A cDNA encoding a thyrotropin-releasing hormone (TRH) receptor expressed in the pituitary was previously cloned (De La Pena, P., Delgado, L. M., Del Camino, D., and Barros, F. (1992) Biochem. J. 284, 891-899; De La Pena, P., Delgado, L. M., Del Camino, D., and Barros, F. (1992) J. Biol. Chem. 267, 25703-25708; Duthie, S. M., Taylor, P. L., Anderson, J., Cook, J., and Eidne, K. A. (1993) Mol. Cell Endocrinol. 95, R11-R15). We now describe the isolation of a rat cDNA encoding a novel subtype of TRH receptor (termed TRHR2) displaying an overall homology of 50% to the pituitary TRH receptor. Introduction of TRHR2 cDNA in HEK-293 cells resulted in expression of high affinity TRH binding with a different pharmacological profile than the pituitary TRH receptor. De novo expressed receptors were functional and resulted in stimulation of calcium transient as assessed by fluorometric imaging plate reader analysis. The message for TRHR2 was exclusive to central nervous system tissues as judged by Northern blot analysis. Studies of the expression of TRHR-2 message by in situ hybridization revealed a pattern of expression remarkably distinct (present in spinothalamic tract, spinal cord dorsal horn) from that of the pituitary TRH receptor (present in hypothalamus, and ventral horn of the spinal cord, anterior pituitary). Therefore, we have identified a novel, pharmacologically distinct receptor for thyrotropin-releasing hormone that appears to be more restricted to the central nervous system particularly to the sensory neurons of spinothalamic tract and spinal cord dorsal horn, which may account for the sensory antinociceptive actions of TRH.

Functional responses of human neutrophils to sodium sulfite (Na2SO3) in vitro

An influx of neutrophils into the airways is a common feature observed during pulmonary inflammation induced by air pollutants, including sulfur dioxide and sulfates. In the present study focusing on the in vitro interactions of sodium sulfite (Na2SO3) with human neutrophils, we confirm results indicating that this sulfite induces superoxide production (O2-) by itself. We demonstrated that this response can occur more rapidly than previously reported (within 5 min), and that Na2SO3 can act as a priming agent, in a concentration-dependent fashion, to the bacterial tripeptide N-formyl-methionine-leucine-phenylalanine (fMLP) by increasing O2-production. In addition, our results show that Na2SO3 induces gene expression in human neutrophils in a concentration-dependent manner as assessed by incorporation of 5-[3H] uridine into total RNA. However, it does not induce cell shape changes. We also demonstrated that Na2SO3 does not modulate neutrophil apoptosis nor reverse the well-known delaying effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) on apoptosis. We conclude that Na2SO3 acts rapidly on neutrophil physiology, within a few minutes with respect to superoxide production, and a few hours (4 h) with respect to gene expression without altering a biological process such as the rate of apoptosis evaluated after a long period of incubation (20 h). We further conclude that Na2SO3-induced production of O2does not drive neutrophils to undergo apoptosis, a mechanism known to occur in other conditions. Therefore, the potential toxicity of Na2SO3 during pulmonary inflammation or lung-associated diseases may be related to its ability to induce superoxide production without altering neutrophil apoptosis rate.

Induction of a caspase-3-like activity by calcium in normal cytosolic extracts triggers nuclear apoptosis in a cell-free system

Calcium is involved in several steps of the apoptotic process. In nuclei, endonucleases are presumed to be the main targets of calcium; however, little is known about its role during the cytosolic phase of apoptosis. We used a cell-free system to address this question. Our results show that CaCl2 triggered nuclear apoptosis (i.e. typical morphological change and DNA fragmentation) at concentrations of 5 mM. This concentration was lowered 10-fold by the co-incubation with cytosolic extracts from nonapoptotic cells. Apoptotic changes induced by the incubation of nuclei with CaCl2 in the presence of these cytosols were strongly reduced in the presence of an inhibitor of caspase-3 and to a lesser extent by an inhibitor of caspase-1. We also show that calcium-induced apoptosis is affected by protease inhibitors such as N-tosyl-L-phenylalanine chloromethyl ketone, but not by calpain or several lysosomal protease inhibitors. The addition of CaCl2 to the cell-free system increased a caspase-3 activity in nonapoptotic cytosols as shown by specific antibodies and an enzymatic assay. No activation of a caspase-3-like activity by the addition of cytochrome c was observed in these extracts under similar conditions. The enhanced caspase-3 activity induced by calcium was inhibited by protease inhibitors affecting morphological nuclear apoptosis except for those responsible for the degradation of lamin A. These results suggest that CaCl2 could trigger, in normal cells, an apoptotic cascade through the activation of cytosolic caspase-3 activity.

The phosphoenolpyruvate:mannose phosphotransferase system of Streptococcus salivarius. Functional and biochemical characterization of IIABL(Man) and IIABH(Man)

Previous studies have suggested that the phosphoenolpyruvate:mannose phosphotransferase system of Streptococcus salivarius consists of a nonphosphorylated enzyme II domain that functions in tandem with a separate enzymatic complex called III(Man). The III(Man) complex is believed to be composed of two protein dimers with molecular masses of approximately 72 kDa. Analysis of these proteins by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate has indicated that one dimer is composed of two 38.9-kDa subunits called IIIH(Man), and the other of two 35.2-kDa subunits called IIIL(Man). This study was undertaken to determine (1) the number and nature of the phosphorylated residue(s) on IIIH(Man) and IIIL(Man) and the phosphorylation sequence allowing the transfer of the phosphoryl group from HPr(His approximately P) to the mannose:PTS substrates; (2) whether IIIH(Man) and IIIL(Man) originate from two different genes or result from a posttranslational modification; and (3) whether these two proteins are involved in the phosphorylation of 2-deoxyglucose, a substrate of the phosphoenolpyruvate:mannose phosphotransferase system. We showed that both IIIH(Man) and IIIL(Man) were phosphorylated on two histidine residues. One phosphate bond was heat-labile (phosphorylation at the N1 position of the imidazole ring), while the second was heat-resistant (phosphorylation at the N3 position of the imidazole ring). The sequence of the first phosphorylation site was deduced by comparing the N-terminal amino acid sequence of both forms of III(Man) with IIA domains of the EII-mannose family. The sequences of both forms were identical over the 15 first amino acids, that is, MIGIIIASHGKFAEG. The sequence of the second phosphorylation site was determined for IIIL(Man) as IHGQVATNxTP. Hence, IIIH(Man) and IIIL(Man) are PTS proteins of the IIAB type and should be renamed IIABH(Man) and IIABL(Man). IIABH(Man) and IIABL(Man) had different peptide profiles after digestion with proteases, indicating that these two proteins are encoded by two different genes. In vitro PEP-dependent phosphorylation assays conducted with a spontaneous mutant devoid of both forms of IIAB(Man) suggested that the phosphoenolpyruvate:mannose phosphotransferase system of S. salivarius is composed of an uncharacterized nonphosphorylated membrane component that works in tandem with IIABL(Man). The physiological functions of IIABH(Man) remain unknown.

Successful treatment of acquired factor VIII inhibitors with cyclosporin

The treatment of Factor VIII inhibitors remains controversial and no standard therapy exists. We describe in this report two consecutive patients with this inhibitor that responded to cyclosporin. Clinical improvement of the bleeding diathesis, a return to normal of the PTT, a decrease in the level of the inhibitor, and a return to normal of the factor VIII level followed use of this drug. We believe that cyclosporin is effective in the treatment of factor VIII inhibitors and deserves further investigation.

The phosphoenolpyruvate:sugar phosphotransferase system of oral streptococci and its role in the control of sugar metabolism

Oral streptococci are sugar-fermentative bacteria comprising at least 19 distinct species and are a significant proportion of the normal microbial population of the mouth and upper respiratory tract of humans. These streptococci transport several sugars by the phosphoenolpyruvate:sugar phosphotransferase system (PTS) which concomitantly catalyzes the phosphorylation and translocation of mono- and disaccharides via a chain of enzymic reactions that transfer a phosphate group from phosphoenolpyruvate to the incoming sugar. A number of PTS components, including HPr, Enzyme I and some Enzymes II, have been studied at the biochemical and/or genetical level in Streptococcus salivarius, Streptococcus mutans and Streptococcus sobrinus. Moreover, compelling evidence indicates that the oral streptococcal PTS is involved in the regulation of sugar metabolism. Results are accumulating suggesting that a protein called IIABMan, as well as the phosphocarrier protein HPr, are key regulatory components that allow these bacteria to select rapidly metabolizable sugars, such as glucose or fructose, over less readily utilizable carbohydrates. Circumstantial evidence suggests that the molecular mechanisms by which oral streptococcal PTS exert their regulatory functions differ from mechanisms in other Gram-negative or Gram-positive bacteria.

Structure of the human retinoic acid receptor beta 1 gene

We report the isolation and characterization of genomic sequences coding for the 5' end of human retinoic acid receptor beta 1, a fetal RAR isoform which is also expressed in small cell lung cancers. Primer extension analysis revealed a principal transcription start site with a secondary site 23 bp further upstream in both SCLC and fetal tissues. The sequences isolated were CpG-rich between -60 and the 3' end of the first exon but there were no features like a TATA-box or an Inr element. In several important aspects, the human RAR beta 1 differs from its mouse counterpart. The 5'-UTR is 823 bp long and is encoded by four exons (vs two in the mouse giving a 477 bp UTR). The 5' end of the mouse cDNA has been mapped to a 67 bp CT repeat which is absent in our sequences. We were also unable to find evidence for a human isoform RAR beta 3 which is widely expressed in mouse tissues.

Plantar fasciitis: sonographic evaluation

PURPOSE

To evaluate the sonographic findings of plantar fasciitis.

MATERIALS AND METHODS

Both feet of 15 patients who had a clinical diagnosis of plantar fasciitis were evaluated with ultrasound (US) by using a 7.0-MHz linear-array transducer. Heel pain was unilateral in 11 patients and bilateral in four. Sagittal sonograms were obtained, and the thickness of the plantar fascia was measured at its proximal end near its insertion into the calcaneus. Other observations included hypoechoic fascia, fiber rupture, perifascial fluid collections, and calcifications. Both feet of 15 healthy volunteers were also evaluated as a control group.

RESULTS

Plantar fascia thickness was significantly increased in the heels in patients with plantar fasciitis (3.2-6.8 mm; mean, 5.2 mm +/- 1.13) compared with their asymptomatic heels (2.0-4.0 mm; mean, 2.9 mm +/- 0.70) (P < .0001) and compared with the heels of the patients in the control group (1.6-3.8 mm; mean, 2.6 mm +/- 0.48) (P < .0001). The proximal plantar fascia of 16 (84%) symptomatic heels were diffusely hypoechoic compared with none of the patients' asymptomatic heels and only one heel of a patient in the volunteer group. No fascia rupture, perifascial fluid collection, or calcifications were identified.

CONCLUSION

Increased thickness of the fascia and hypoechoic fascia are sonographic findings of plantar fasciitis. US may be a valuable noninvasive technique for the diagnosis of plantar fasciitis.