Subsegmental pulmonary embolism: yet another case for being a medical conservative

Background

The advent of multi-detector computed tomographic pulmonary angiography has allowed better assessment of the peripheral pulmonary arteries, thereby increasing the incidence of pulmonary embolism (PE). Even though most patients with PE are treated with anticoagulation, its value in the subsegmental setting (SSPE) has not yet been confirmed.

Purpose

To perform a meta-analysis aimed at ascertaining the extent to which anticoagulation results in a net positive effect in patients with SSPE.

Methods

We systematically searched MEDLINE, Embase, Web of Science, Cochrane Library and Google Scholar, from inception to March 2021, for controlled studies addressing the effect of anticoagulation on SSPE patients. Specifically, venous thromboembolism (VTE) recurrence served as the primary efficacy endpoint, whereas clinically significant bleeding represented the primary safety outcome. Furthermore, major bleeding, PE-related and all-cause mortality were also studied, as secondary endpoints. All anticoagulation strategies, namely oral or parenteral, met inclusion criteria. Study-specific odds ratios (ORs) were pooled, under a random-effects model.

Results

1 cross-sectional, 8 retrospective and 4 prospective non-randomized studies, encompassing 82, 641 and 157 patients, respectively, were regarded as eligible for quantitative evaluation. 667 patients (75.8%) were allocated to the anticoagulation arm. The absolute number of events for each outcome may be reported as follows: primary efficacy endpoint, 5; primary safety endpoint, 60; major bleeding, 38; PE-related mortality, 0; all-cause mortality, 25. 7 studies reported their respective outcomes under a prespecified 3-month follow-up period, while only 1 featured cancer patients as its entire sample. As for the primary efficacy endpoint, and despite the surprising adjudication of all its 5 events to the anticoagulated patients, their relative overrepresentation (371 vs. 143 patients) stemmed a non-significant tendency towards a decrease in VTE recurrence in this arm (OR 0.59, 95% CI 0.09–3.81, P 0.58, i2 0%). On the other hand, anticoagulation was associated with a significant increase in clinically significant hemorrhages (OR 2.89, 95% CI 1.07–7.80, P 0.04, i2 0%) and a non-significant propensity towards an increment in major bleeding (OR 2.44, 95% CI 0.79–7.59, P 0.12, i2 0%). Lastly, and even though no events of PE-related mortality were reported, anticoagulation was linked with a meaningful reduction in all-cause mortality (OR 0.31, 95% CI 0.11–0.82, P 0.02, i2 0%).

Conclusion

Currently available evidence underpins marginal efficacy and safety concerns regarding the use of anticoagulation in SSPE patients, who are expected to experience very low to none PE-related mortality. The association of anticoagulation with lower all-cause death may be attributable to selection bias. Randomized controlled trials are, however, still needed to fully validate this hypothesis.

Funding Acknowledgement

Type of funding sources: None.

Anticancer efficacy of 6-thioguanine loaded chitosan nanoparticles with or without curcumin

6-Thioguanine encapsulated chitosan nanoparticles (6-TG-CNPs) has formulated by the ionic-gelation method. Morphologically, the 6-TG-CNPs were spherical and showed mean size, PDI, zeta potential, and entrapment efficiency of 261.63 ± 6.01 nm, 0.34 ± 0.10, +15.97 ± 0.46 mV and 44.27%, respectively. The IR spectra confirmed the 6-TG complex with chitosan. The in vitro drug release profile of 6-TG-CNPs revealed an increase in sustained-release (91.40 ± 1.08% at 48 h) at pH 4.8 compared to less sustained-release (73.96 ± 1.12% at 48 h) at pH 7.4. The MTT assay was conducted on MCF-7 and PA-1 cell lines at 48 h incubation to determine % cell viability. The IC₅₀ values of 6-TG, 6-TG-CNPs, and curcumin for MCF-7 were 23.09, 17.82, and 15.73 μM, respectively. Likewise, IC₅₀ values of 6-TG, 6-TG-CNPs, and curcumin for PA-1 were 5.81, 3.92, and 12.89 μM, respectively. A combination of 6-TG-CNPs (IC₂₅) with curcumin (IC₂₅) on PA-1 and MCF-7 showed % cell viability of 43.67 ± 0.02 and 49.77 ± 0.05, respectively. The in vitro cytotoxicity potential in terms of % cell viability, early apoptosis, G2/M phase arrest, and DNA demethylating activity of 6-TG-CNPs alone and combination with curcumin proved to be more effective than that of 6-TG on PA-1 cells.

107 Low-flow low-gradient aortic stenosis: aortic valve area estimated by continuity equation versus simplified method of projected aortic valve area

Introduction

The evaluation of real severity of "low-flow low-gradient" aortic stenosis (LFLG AS) is particularly challenging. TOPAS study demonstrated that projected aortic valve area at a normal transvalvular flow rate (AVAproj) derived from dobutamine stress echocardiography (DSE) is superior to the traditional Doppler indices to discriminate true severe-AS and pseudosevere-AS.

Purpose

To compare two echocardiographic methods to estimate severity of LFLG AS with DSE (aortic valve area (AVA) estimated by continuity equation (AVA-CE) and simplified method of AVAproj) in patients (pts) with low transvalvular flow rate (<250mL/seg).

Methods

Unicentric, retrospective study, that included pts with LFLG AS undergoing DSE with low dose dobutamine protocol, during Nov 2013-Dec 2018 period. Evaluation at rest and peak DSE of vital signs, mean transaortic gradient, aortic VTI, LVOT VTI and VTI ratio, valvulo-arterial impedance (ZVA), AVA-CE, simplified method of AVAproj and global longitudinal strain (GLS).

Results

A total of 27 DSE were performed in 23 different pts, mean age of 76 ± 8 years, 82% male. At rest 55% in sinus rhythm, mean heart rate (HR) was 76 ± 12 bpm, mean systolic arterial pressure (SAP) was 122 ± 22 mmHg, mean ZVA 4.3 ± 2 mmHg/ml/m2; mean diameter of LVOT was 21,7 ± 2,6cm, mean of mean aortic gradients 21 ± 7 mmHg, 67% of pts had a VTI ratio at rest compatible with severe AS and remaining compatible with moderate AS. Estimated mean AVA-CE was 0.86 ± 0.29 cm2 with 67% of pts classified as severe AS. Mean left ventricular ejection fraction at rest was 31 ± 9%, systolic volume index 28,7 ± 8 mL/m2 and GLS -5,9%.

During low dose perfusion protocol of dobutamine

100% patients remained asymptomatic, mean HR was 110 ± 25 bpm, mean SAP was 123 ± 26 mmHg, mean ZVA 3.6 ± 1.7 mmHg/mL/m2, mean of mean aortic gradients 28 ± 9mmHg, 37% of pts presented VTI ratio compatible with severe AS and remaining compatible with moderate AS. Mean flow reserve was 16 ± 16% and mean GLS-7.2%. AVA-CE was 1,06 ± 0,35 cm2 with 56% of pts classified as severe AS and mean projected AVA was 1.01 ± 0.22cm2, without significant difference in AVA estimated by the two methods (p = 0.344). Projected AVA allowed re-classification of AS in 22% of pts (5 patients), with 31% of severe AS reclassified as moderate AS while AVA-CE allowed re-classification in 13% (3 patients), with 19% of severe AS reclassified as moderate AS.

Considering medium follow up of 24 months, 6 patients were submitted aortic valve replacement surgery and another 6 patients to transcatheter aortic valve replacement. The simplified projected valve area calculation show no significant therapeutic impact in the selection of this patients.

Conclusion

The simplified projected valve area calculation is technically feasible and accessible. This study shows a good correlation in pts with low cardiac flow. If AVAproj method had been used 2 extra patients would have been reclassified during DSE.

Correction: FOXO3a represses VEGF expression through FOXM1-dependent and -independent mechanisms in breast cancer

In the published version of this article, the images for cytoplasmic and nuclear FGF7 in MDA-MB-231 cells were duplicated and mistaken for total FGF7 in SKBR-3 and MDA-MB-231 cells.

Physical exercise, pain and musculoskeletal function in patients with haemophilia: a systematic review

INTRODUCTION

Exercise can provide numerous benefits to haemophilia patients, including bleeding reduction in muscles and joints.

AIM

This systematic review (SR) aims to evaluate the effects of physical exercise on pain and the musculoskeletal function of patients with hemophilia.

METHODS

Literature searches of Pubmed, Web of Science, PEDro, Cochrane, Clinical Trials SciELO and Lilacs were performed. The risks of bias were measured using the JADAD scale.

RESULTS

Nine controlled clinical trials were included in the SR.

CONCLUSION

Physical exercise can promote a reduction in the perception of pain and can increase ROM and muscle strength in haemophilia patients. Future RCTs with greater methodological rigor that focus on the parameters used to prescribe exercises are necessary.

Paclitaxel targets FOXM1 to regulate KIF20A in mitotic catastrophe and breast cancer paclitaxel resistance

FOXM1 has been implicated in taxane resistance, but the molecular mechanism involved remains elusive. In here, we show that FOXM1 depletion can sensitize breast cancer cells and mouse embryonic fibroblasts into entering paclitaxel-induced senescence, with the loss of clonogenic ability, and the induction of senescence-associated β-galactosidase activity and flat cell morphology. We also demonstrate that FOXM1 regulates the expression of the microtubulin-associated kinesin KIF20A at the transcriptional level directly through a Forkhead response element (FHRE) in its promoter. Similar to FOXM1, KIF20A expression is downregulated by paclitaxel in the sensitive MCF-7 breast cancer cells and deregulated in the paclitaxel-resistant MCF-7Tax(R) cells. KIF20A depletion also renders MCF-7 and MCF-7Tax(R) cells more sensitive to paclitaxel-induced cellular senescence. Crucially, resembling paclitaxel treatment, silencing of FOXM1 and KIF20A similarly promotes abnormal mitotic spindle morphology and chromosome alignment, which have been shown to induce mitotic catastrophe-dependent senescence. The physiological relevance of the regulation of KIF20A by FOXM1 is further highlighted by the strong and significant correlations between FOXM1 and KIF20A expression in breast cancer patient samples. Statistical analysis reveals that both FOXM1 and KIF20A protein and mRNA expression significantly associates with poor survival, consistent with a role of FOXM1 and KIF20A in paclitaxel action and resistance. Collectively, our findings suggest that paclitaxel targets the FOXM1-KIF20A axis to drive abnormal mitotic spindle formation and mitotic catastrophe and that deregulated FOXM1 and KIF20A expression may confer paclitaxel resistance. These findings provide insights into the underlying mechanisms of paclitaxel resistance and have implications for the development of predictive biomarkers and novel chemotherapeutic strategies for paclitaxel resistance.

FOXA1 repression is associated with loss of BRCA1 and increased promoter methylation and chromatin silencing in breast cancer

FOXA1 expression correlates with the breast cancer luminal subtype and patient survival. RNA and protein analysis of a panel of breast cancer cell lines revealed that BRCA1 deficiency is associated with the downregulation of FOXA1 expression. Knockdown of BRCA1 resulted in the downregulation of FOXA1 expression and enhancement of FOXA1 promoter methylation in MCF-7 breast cancer cells, whereas the reconstitution of BRCA1 in Brca1-deficent mouse mammary epithelial cells (MMECs) promoted Foxa1 expression and methylation. These data suggest that BRCA1 suppresses FOXA1 hypermethylation and silencing. Consistently, the treatment of MMECs with the DNA methylation inhibitor 5-aza-2'-deoxycitydine induced Foxa1 mRNA expression. Furthermore, treatment with GSK126, an inhibitor of EZH2 methyltransferase activity, induced FOXA1 expression in BRCA1-deficient but not in BRCA1-reconstituted MMECs. Likewise, the depletion of EZH2 by small interfering RNA enhanced FOXA1 mRNA expression. Chromatin immunoprecipitation (ChIP) analysis demonstrated that BRCA1, EZH2, DNA methyltransferases (DNMT)1/3a/3b and H3K27me3 are recruited to the endogenous FOXA1 promoter, further supporting the hypothesis that these proteins interact to modulate FOXA1 methylation and repression. Further co-immunoprecipitation and ChIP analysis showed that both BRCA1 and DNMT3b form complexes with EZH2 but not with each other, consistent with the notion that BRCA1 binds to EZH2 and negatively regulates its methyltransferase activity. We also found that EZH2 promotes and BRCA1 impairs the deposit of the gene silencing histone mark H3K27me3 on the FOXA1 promoter. These associations were validated in a familial breast cancer patient cohort. Integrated analysis of the global gene methylation and expression profiles of a set of 33 familial breast tumours revealed that FOXA1 promoter methylation is inversely correlated with the transcriptional expression of FOXA1 and that BRCA1 mutation breast cancer is significantly associated with FOXA1 methylation and downregulation of FOXA1 expression, providing physiological evidence to our findings that FOXA1 expression is regulated by methylation and chromatin silencing and that BRCA1 maintains FOXA1 expression through suppressing FOXA1 gene methylation in breast cancer.

Forkhead box K2 modulates epirubicin and paclitaxel sensitivity through FOXO3a in breast cancer

The forkhead transcription factor FOXK2 has recently been implicated in cancer cell proliferation and survival, but a role in cancer chemotherapeutic drug resistance has hitherto not been explored. Here we demonstrate that FOXK2 has a central role in mediating the cytotoxic drug response in breast cancer. Clonogenic and cell viability assays showed that enhanced FOXK2 expression sensitizes MCF-7 breast cancer cells to paclitaxel or epirubicin treatment, whereas FOXK2 depletion by small interfering RNAs (siRNAs) confers drug resistance. Our data also showed that the activation of the tumour suppressor FOXO3a by paclitaxel and epirubicin is mediated through the induction of FOXK2, as depletion of FOXK2 by siRNA limits the induction of FOXO3a by these drugs in MCF-7 cells. Chromatin immunoprecipitation (ChIP) analysis showed that in response to drug treatment, FOXK2 accumulates and binds to the proximal FOXO3a promoter region in MCF-7 cells. Furthermore, we also uncovered that FOXK2 is deregulated and, therefore, can express at high levels in the nucleus of both the paclitaxel and epirubicin drug-resistant MCF-7 cells. Our results showed that ectopically overexpressed FOXK2 accumulates in the nuclei of drug-resistant MCF-7 cells but failed to be recruited to target genes, including FOXO3a. Crucially, we found that FOXO3a is required for the anti-proliferative and epirubicin-induced cytotoxic function of FOXK2 in MCF-7 cells by sulphorhodamine and clonogenic assays. The physiological importance of the regulation of FOXO3a by FOXK2 is further confirmed by the significant correlations between FOXO3a and FOXK2 expression in breast carcinoma patient samples. Further survival analysis also reveals that high nuclear FOXK2 expression significantly associates with poorer clinical outcome, particularly in patients who have received conventional chemotherapy, consistent with our finding that FOXK2 is deregulated in drug-resistant cells. In summary, our results suggest that paclitaxel and epirubicin target the FOXK2 to modulate their cytotoxicity and deregulated FOXK2 confers drug resistance.

The calcium-sensing receptor in bone metabolism: from bench to bedside and back

The calcium-sensing receptor (CaSR), a key player in the maintenance of calcium homeostasis, can influence bone modeling and remodeling by directly acting on bone cells, as demonstrated by in vivo and in vitro evidence. The modulation of CaSR signaling can play a role in bone anabolism.

INTRODUCTION

The calcium-sensing receptor (CaSR) is a key player in the maintenance of calcium homeostasis through the regulation of PTH secretion and calcium homeostasis, thus indirectly influencing bone metabolism. In addition to this role, in vitro and in vivo evidence points to direct effects of CaSR in bone modeling and remodeling. In addition, the activation of the CaSR is one of the anabolic mechanisms implicated in the action of strontium ranelate, to reduce fracture risk.

METHODS

This review is based upon the acquisition of data from a PubMed enquiry using the terms "calcium sensing receptor," "CaSR" AND "bone remodeling," "bone modeling," "bone turnover," "osteoblast," "osteoclast," "osteocyte," "chondrocyte," "bone marrow," "calcilytics," "calcimimetics," "strontium," "osteoporosis," "skeletal homeostasis," and "bone metabolism."

RESULTS

A fully functional CaSR is expressed in osteoblasts and osteoclasts, so that these cells are able to sense changes in the extracellular calcium and as a result modulate their behavior. CaSR agonists (calcimimetics) or antagonists (calcilytics) have the potential to indirectly influence skeletal homeostasis through the modulation of PTH secretion by the parathyroid glands. The bone anabolic effect of strontium ranelate, a divalent cation used as a treatment for postmenopausal and male osteoporosis, might be explained, at least in part, by the activation of CaSR in bone cells.

CONCLUSIONS

Calcium released in the bone microenvironment during remodeling is a major factor in regulating bone cells. Osteoblast and osteoclast proliferation, differentiation, and apoptosis are influenced by local extracellular calcium concentration. Thus, the calcium-sensing properties of skeletal cells can be exploited in order to modulate bone turnover and can explain the bone anabolic effects of agents developed and employed to revert osteoporosis.

The influence of particle size on radionuclide activity concentrations in Tejo River sediments

Sediment samples from Tejo River were analyzed for (228)Ra, (226)Ra, (137)Cs and (40)K by HPGe gamma spectrometry. The activity concentration data were statistically analyzed. The activity concentrations values were in the range of about two orders of magnitude for each radionuclide. The influence of the particle size on the radionuclide concentrations was observed. The different environmental origins of the radionuclides (228)Ra, (226)Ra, (137)Cs and (40)K, in the sediments were demonstrated through correlation analysis. Cluster analysis showed a close relationship between (228)Ra and (226)Ra and a different behavior for (40)K. The data obtained in this study provides useful information on the background radioactivity of the studied area and can be further used for radiological mapping of the Tejo River.

SUMOylation inhibits FOXM1 activity and delays mitotic transition

The forkhead box transcription factor FOXM1 is an essential effector of G2/M-phase transition, mitosis and the DNA damage response. As such, it is frequently deregulated during tumorigenesis. Here we report that FOXM1 is dynamically modified by SUMO1 but not by SUMO2/3 at multiple sites. We show that FOXM1 SUMOylation is enhanced in MCF-7 breast cancer cells in response to treatment with epirubicin and mitotic inhibitors. Mutation of five consensus conjugation motifs yielded a SUMOylation-deficient mutant FOXM1. Conversely, fusion of the E2 ligase Ubc9 to FOXM1 generated an auto-SUMOylating mutant (FOXM1-Ubc9). Analysis of wild-type FOXM1 and mutants revealed that SUMOylation inhibits FOXM1 activity, promotes translocation to the cytoplasm and enhances APC/Cdh1-mediated ubiquitination and degradation. Further, expression of the SUMOylation-deficient mutant enhanced cell proliferation compared with wild-type FOXM1, whereas the FOXM1-Ubc9 fusion protein resulted in persistent cyclin B1 expression and slowed the time from mitotic entry to exit. In summary, our findings suggest that SUMOylation attenuates FOXM1 activity and causes mitotic delay in cytotoxic drug response.

Eating behaviours in youths: A comparison between female and male athletes and non-athletes

This study compared the different factors associated with eating behaviors among young female and male athletes and non-athletes. A total of 580 female and male athletes and 362 female and male non-athletes between 10 and 19 years old participated. We used the subscales of the Eating Attitudes Test (EAT-26) to evaluate the factors associated with unhealthy eating behaviors. We found higher scores for females on the diet subscale compared with males, regardless of athletic group (P < 0.05). Non-athlete youths scored higher on this subscale compared with male athletes (P < 0.05). Our findings indicate higher scores for female athletes with regard to the bulimia and preoccupation with food subscale compared with other the groups (P < 0.05). Moreover, we observed that non-athlete males were more likely to engage in binge eating compared with athletes of the same sex (P < 0.05). Finally, females had higher scores on the oral self subscale than males, regardless of athletic group (P < 0.05). We concluded that the factors associated with eating behaviors differ with regard to sex and group.

Hepatocellular carcinoma and chemotherapy: the role of p53

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common primary neoplasm of the liver. A major proportion of HCCs also present mutation of the gene that encodes p53, which confers chemoresistance. The main goal of this work is to investigate the effect of cisplatin, doxorubicin and 5-fluoruracil (5-FU) in three human HCC cell lines which differ in p53 expression.

METHODS

HepG2 (expressing normal p53), HuH7 (expressing mutated p53) and Hep3B2.1-7 (not expressing p53) cell lines were cultivated in the presence of cisplatin, doxorubicin and 5-FU. Cell proliferation was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (MTT assay). The type of cell death and Bax and Bcl2 activation were assessed by flow cytometry.

RESULTS

It was found that for all of the cell lines studied, the agent that gave the most satisfactory results was doxorubicin. 5-FU demonstrated no activity in these cell lines.

CONCLUSIONS

For all the cell lines studied, doxorubicin was the most satisfactory agent. In HepG2 and HuH7 cell lines, it can activate Bax with statistical significance.

Incidence of subclinical mastitis and prevalence of major mastitis pathogens in organized farms and unorganized sectors

Subclinical mastitis (SCM) represents a major proportion of the burden of mastitis. Determining somatic cell count (SCC) and electrical conductivity (EC) of milk are useful approaches to detect SCM. In order to correlate grades of SCM with the load of five major mastitis pathogens, 246 milk samples from a handful of organized and unorganized sectors were screened. SCC (>5 × 10(5)/mL) and EC (>6.5 mS/cm) identified 110 (45 %) and 153 (62 %) samples, respectively, to be from SCM cases. Randomly selected SCM-negative samples as well as 186 samples positive by either SCC or EC were then evaluated for isolation of five major mastitis-associated bacteria. Of the 323 isolates obtained, 95 each were S. aureus and coagulase-negative staphylococci (CoNS), 48 were E. coli and 85 were streptococci. There was no association between the distribution of organisms and (a) the different groups of SCC, or (b) organised farms and unorganised sectors. By contrast, there was a significant difference in the distribution of CoNS, and not other species, between organized farms and unorganized sectors. In summary, bacteria were isolated irrespective of the density of somatic cells or the type of farm setting, and the frequency of isolation of CoNS was higher with organized farms. These results suggest the requirement for fine tuning SCC and EC limits and the higher probability for CoNS to be associated with SCM in organized diary sectors, and have implications for the identification, management and control of mastitis in India.

Origins and evolution of methicillin-resistant Staphylococcus aureus clonal lineages

Most methicillin-resistant Staphylococcus aureus (MRSA) isolates identified among blood isolates collected in Denmark between 1957 and 1970 belonged to either phage group III or the closely related 83A complex and had a PSTM antibiotype (resistance to penicillin [P], streptomycin [S], tetracycline [T], and methicillin [M]). Recently, some of these isolates were shown to have the same genetic backgrounds as contemporary epidemic MRSA isolates, and Danish methicillin-susceptible S. aureus (MSSA) isolates from the 1960s with a PST antibiotype were proposed to have been the recipients of the mecA gene in those lineages. In this study, we investigated the genetic backgrounds of isolates from the 83A complex that were fully susceptible or resistant to penicillin only in order to try to trace the evolutionary trajectory of contemporary MRSA lineages. We also studied MSSA and MRSA isolates from other phage groups in order to investigate if they had the potential to develop into contemporary MRSA clones. Most susceptible or penicillin-resistant isolates from phage group III or the 83A complex belonged to sequence type 8 (ST8) or ST5, while four isolates were ST254. STs 30, 45 and 25 were represented by MSSA isolates from other phage groups, which also included several singletons. Representatives of most of the current major epidemic MRSA lineages were identified among fully susceptible isolates collected in the 1960s, suggesting that these were MSSA lineages which carried genetic traits important for superior epidemicity before the acquisition of methicillin resistance.

Analysis of the genetic variability of virulence-related loci in epidemic clones of methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) isolates have previously been classified into major epidemic clonal types by pulsed-field gel electrophoresis in combination with multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec typing. We aimed to investigate whether genetic variability in potentially polymorphic domains of virulence-related factors could provide another level of differentiation in a diverse collection of epidemic MRSA clones. The target regions of strains representative of epidemic clones and genetically related methicillin-susceptible S. aureus isolates from the 1960s that were sequenced included the R domains of clfA and clfB; the D, W, and M regions of fnbA and fnbB; and three regions in the agr operon. Sequence variation ranged from very conserved regions, such as those for RNAIII and the agr interpromoter region, to the highly polymorphic R regions of the clf genes. The sequences of the clf R domains could be grouped into six major sequence types on the basis of the sequences in their 3' regions. Six sequence types were also observed for the fnb sequences at the amino acid level. From an evolutionary point of view, it was interesting that a small DNA stretch at the 3' clf R-domain sequence and the fnb sequences agreed with the results of MLST for this set of strains. In particular, clfB R-domain sequences, which had a high discriminatory capacity and with which the types distinguished were congruent with those obtained by other molecular typing methods, have potential for use for the typing of S. aureus. Clone- and strain-specific sequence motifs in the clf and fnb genes may represent useful additions to a typing methodology with a DNA array.

High-performance liquid chromatographic separation and determination of the process related impurities of mebendazole, fenbendazole and albendazole in bulk drugs

Simple, specific and rapid reversed-phase high-performance liquid chromatographic methods to separate and determine potential impurities of anthelmintic drugs viz., mebendazole, fenbendazole and albendazole are reported. These methods afforded efficient separation, good resolution and identification of all the impurities examined. The methods were successfully applied not only for quality assurance, but also process development of the select anthelmintic drugs.

Molecular epidemiology of methicillin-resistant Staphylococcus aureus in Colombian hospitals: dominance of a single unique multidrug-resistant clone

The first study on the molecular characterization of methicillin-resistant Staphylococcus aureus (MRSA) isolates from Colombia was performed as part of a global surveillance established by the CEM/NET Initiative, under Project RESIST. Seventy-six MRSA isolates recovered from five hospitals during 1996-1998 were analyzed by the hybridization of ClaI restriction digests with mecA- and Tn554-specific probes, and by pulsed-field gel electrophoresis (PFGE) of chromosomal SmaI digests. All MRSA isolates, with one exception, belonged to a single clonal type II::NH::D. This clone, which was previously described among MRSA isolates recovered in the early 1990s in European and New York and South American hospitals, showed resistance to beta-lactam antibiotics only and appeared to be associated almost exclusively with pediatric infections ("Pediatric clone" of MRSA). While sharing identical molecular typing properties with the Pediatric clone, the Colombian isolates differed by extensive multidrug resistance and were recovered from patients of all ages. It is also noteworthy that the Brazilian clone of MRSA (XI::B::B), another multidrug-resistant international clone currently widely spread in Brazil, Argentina, Uruguay, Chile, and also in several European countries, was completely absent from this set of isolates from Colombia.

[Progressive myositis ossificans. Stone man]

Myositis ossificans progressiva (MOP) is a rare hereditary connective tissue disease, genetically inherited as an autossomal dominant trait with complete penetrance but variable expression. The onset usually takes place during childhood and progressive involvement of the spinal cord and proximal extremities leads to immobilization and articular dysfunction. We present a case of a 29-year-old woman with the typical features of MOP and review the pathogenesis, clinical manifestations and treatment options of this rare disease.

Fibrodysplasia ossificans progressiva: report of two cases

Fibrodysplasia Ossificans Progressiva (FOP) is a rare hereditary connective tissue disease, genetically inherited as an autosomal dominant trait with complete penetrance but variable expressivity. Onset is typically in childhood and progressive involvement of the spine and proximal extremities leads to immobility and articular dysfunction. We present two cases with the typical features of FOP and a review of the pathogenesis, clinical manifestations and treatment options of this rare disease.

Slipped capital femoral epiphysis. A report of 4 cases occurring in one family

We describe slipped capital femoral epiphysis in 4 members of a black, obese family, who were all first-degree relatives. The aetiology of slipped capital femoral epiphysis is unknown, although it is thought to be multifactorial. Genetic predisposition and environmental factors have been associated with the condition. A familial incidence with at least two cases in the same family has been reported. In epidemiological studies, this incidence ranges from 3% to 35%. Our cases were investigated in an attempt to find a possible aetiological genetic factor. A genetic predisposition with an autosomal dominant pattern of transmission is suggested, although environmental variables must be considered as provocative factors.

[The risk of seroconversion in surgeons of the hepatitis B, hepatitis C and human immunodeficiency viruses (in a specific surgical population)]

The prevalence of hepatitis B surface antigen (HBs Ag) and antibody to hepatitis C virus (HCV) and human immunodeficiency virus (HIV) was determined in the serum specimens of 288 patients treated surgically in the orthopaedic department of an urban public teaching hospital. The cumulative risk of HBV, HCV and HIV seroconversion for an orthopaedic surgeon during the surgical career span was calculated. We found that 1.4%, 3.1% and 1.7% of patients were seropositive for HBsAg, HCV antibody and HIV antibody, respectively. Seropositivity was neither associated with age nor with trauma, whereas male patients had a greater likelihood of seropositivity. Risk factor assessment did not prove to be discriminating in identifying which patients may pose a potential exposure risk. This study supports the concept of universal infection control precautions for orthopaedic surgeons regardless of the patients' risk factor or serologic status.

Growth Responses and Adaptations of Fraxinus pennsylvanica Seedlings to Flooding

Flooding induced several physiological and morphological changes in Fraxinus pennsylvanica seedlings, with stomatal closure among the earliest responses. Subsequent changes included: reduction in dry weight increment of roots, stems, and leaves; formation of hypertrophied lenticels and production of adventitious roots on submerged portions of the stem above the soil line; leaf necrosis; and leaf abscission. After 15 days of stomatal closure as a result of flooding, stomata began to reopen progressively until stomatal aperture was similar in flooded and unflooded plants. Adventitious roots began to form at about the time stomatal reopening began. As more adventitious roots formed, elongated, and branched, the stomata opened further. The formation of adventitious roots was an important adaptation for flooding tolerance as shown by the high efficiency of adventitious roots in absorption of water and in high correlation between the production of adventitious roots and stomatal reopening.