The P4-ATPase Drs2 interacts with and stabilizes the multisubunit tethering complex TRAPPIII in yeast

Multisubunit Tethering Complexes (MTCs) are a set of conserved protein complexes that tether vesicles at the acceptor membrane. Interactions with other components of the trafficking machinery regulate MTCs through mechanisms that are partially understood. Here, we systematically investigate the interactome that regulates MTCs. We report that P4-ATPases, a family of lipid flippases, interact with MTCs that participate in the anterograde and retrograde transport at the Golgi, such as TRAPPIII. We use the P4-ATPase Drs2 as a paradigm to investigate the mechanism and biological relevance of this interplay during transport of Atg9 vesicles. Binding of Trs85, the sole-specific subunit of TRAPPIII, to the N-terminal tail of Drs2 stabilizes TRAPPIII on membranes loaded with Atg9 and is required for Atg9 delivery during selective autophagy, a role that is independent of P4-ATPase canonical functions. This mechanism requires a conserved I(S/R)TTK motif that also mediates the interaction of the P4-ATPases Dnf1 and Dnf2 with MTCs, suggesting a broader role of P4-ATPases in MTC regulation.

Protocooperative Effect of Sphaerodes mycoparasitica Biocontrol and Crop Genotypes on FHB Mycotoxin Reduction in Bread and Durum Wheat Grains Intended for Human and Animal Consumption

The occurrence of Fusarium Head Blight (FHB) mycotoxins in wheat grains is a major threat to global food safety and security. Humans and animals are continuously being exposed to Fusarium mycotoxins such as deoxynivalenol (DON) and its acetylated derivatives 3ADON and 15ADON through the ingestion of contaminated food or grain-based diet. In this study, a host-specific mycoparasite biocontrol agent (BCA), Sphaerodes mycoparasitica, significantly reduced FHB mycotoxin occurrence in harvested wheat grains from Fusarium graminearum 3ADON chemotype infected plants in greenhouse. Four genotypes of wheat, two common wheat and two durum wheat cultivars with varying FHB resistance levels were used in this study. Principal Coordinate Analysis (PCoA) using Illumina ITS sequences depicted beta diversity changes in Fusarium species indicating that both plant cultivar and BCA treatments influenced the Fusarium species structure and mycotoxin occurrence in grains. Fusarium graminearum complex (cluster A), F. avenaceum and F. acuminatum (cluster B), and F. proliferatum (cluster C) variants were associated with different FHB mycotoxins based on LC-MS/MS analyses. The predominant FHB mycotoxins measured were DON and its acetylated derivatives 3ADON and 15ADON. The BCA reduced the occurrence of DON in grains of all four cultivars (common wheat: 1000-30,000 µg·kg^-1.; durum wheat: 600-1000 µg·kg^-1) to levels below the Limit of Quantification (LOQ) of 16 µg·kg^-1. A relatively higher concentration of DON was detected in the two common wheat genotypes when compared to the durum wheat genotype; however, the percentage reduction in the wheat genotypes was greater, reaching up to 99% with some S. mycoparasitica treatments. Similarly, a higher reduction in DON was measured in susceptible genotypes than in resistant genotypes. This study's findings underscore the potential of a Fusarium-specific S. mycoparasitica BCA as a safe and promising alternative that can be used in conjunction with other management practices to minimize FHB mycotoxins in cereal grain, food and feed intended for human and animal consumption.

Use of chatbots for customer service in MSMEs

Purpose

This research work aims to arise from developing new communication channels for customer service in micro, small and medium enterprises (MSMEs), such as chatbots. In particular, the results of the usability testing of three chatbots implemented in MSMEs are presented.

Design/methodology/approach

The methodology employed includes participants, chatbot development platform, research methodology, software development methodology and usability test to contextualize the study's results.

Findings

Based on the results obtained from the System Usability Scale (SUS) and considering the accuracy of the chatbot's responses, it is concluded that the level of satisfaction in using chatbots is high; therefore, if the chatbot is well integrated with the communication systems/channels of the MSMEs, the client receives an excellent, fast and efficient service.

Originality/value

The paper analyzes chatbots for customer service and presents the usability testing results of three chatbots implemented in MSMEs.

Potential use of ivermectin for the treatment and prophylaxis of SARS-CoV-2 infection

PURPOSE OF THE STUDY

Currently no treatment has been proven to be efficacious for patients with early symptoms of COVID-19. Although most patients present mild or moderate symptoms, up to 5-10% may have a poor disease progression, so there is an urgent need for effective drugs, which can be administered even before the onset of severe symptoms, i.e. when the course of the disease is modifiable. Recently, promising results of several studies on oral ivermectin have been published, which has prompted us to conduct the present review of the scientific literature.

METHODS

A narrative review has been carried out, focusing on the following four main topics: a) short-term efficacy in the treatment of the disease, b) long-term efficacy in the treatment of patients with post-acute symptoms of COVID-19, c) efficacy in the prophylaxis of the disease, and c) safety of ivermectin.

RESULTS

The reviewed literature suggests that there seems to be sufficient evidence about the safety of oral ivermectin, as well as the efficacy of the drug in the early-treatment and the prophylaxis of COVID-19.

CONCLUSIONS

In the view of the available evidence, the Frontline COVID-19 Critical Care Alliance (FLCCC) recommends the use of oral ivermectin for both prophylaxis and early-treatment of COVID-19. Further well-designed studies should be conducted in order to explore the efficacy and safety of invermectin at low and high doses, following different dosing schedules, in both, the short and long-term treatment.

Correlation between joint effusion and clinical symptoms, magnetic resonance imaging and arthroscopic findings in patients with temporomandibular joint disease

OBJECTIVES

The aim of this study was to evaluate the relationship between temporomandibular joint (TMJ) effusions and clinical, magnetic resonance imaging and arthroscopic variables.

METHODS

We designed a retrospective cohort study of patients attending our Department who presented temporomandibular joint disease according to the Research Diagnostic Criteria for Temporomandibular Disorders. According to the presence of effusion in magnetic resonance imaging, the sample was divided into 2 groups: patients with or without joint effusion.

RESULTS

A total of 203 patients fulfilled the inclusion criteria, of which 99 (48.8%) showed no joint effusion and 104 (51.2%) presented effusion. We found no significant differences between clinical variables and joint effusion. However, patients without effusion showed significantly longer duration of symptoms that patients with effusion (mean = 34.8 months, standard deviation = 43.41 vs 20.25, 23.76; p = 0.005). We found no significant differences in magnetic resonance imaging and arthroscopic variables associated with the presence of effusions. For both groups, there were statistically significant differences in values of mean pain scores and mean maximum interincisal distance between the different times of examination (before surgery and 3, 6 and 12 months after surgery).

CONCLUSION

Joint effusion is not associated with clinical, imaging or arthroscopic variables, but may be a clinical characteristic of early stages of temporomandibular joint disease.

Comparing complications of small-bore chest tubes to large-bore chest tubes in the setting of delayed hemothorax: a retrospective multicenter cohort study

Background

Previous studies have provided initial data suggesting that small-bore (SB, ≤ 14Fr) chest tubes have the same efficacy as large-bore (LB, > 14 Fr) chest tubes for acute hemothorax (HTX), but data continue to be lacking in the setting of delayed HTX. This study compared complications of SB chest tubes to LB tubes in patients with delayed HTX.

Methods

This was a retrospective observational study across 7.5 yrs. at 6 Level 1 trauma centers. Patients were included if 1) diagnosed with a HTX or > 1 rib fracture with bloody effusion from chest tube; 2) initial chest tube placed ≥36 h of hospital admission. Patients were excluded for hemopneumothoraces. The primary endpoint was having at least one of the following chest tube complications: tube replacement, VATS, tube falling out, tube clogging, pneumonia, retained HTX, pleural empyema. Secondary outcomes included chest tube output volume and drainage rate. Dependent/independent and parametric/non-parametric analyses were used to assess primary and secondary outcomes.

Results

There were 160 SB patients (191 tubes) and 60 LB patients (72 tubes). Both comparison groups were similar in multiple demographic, injury, clinical features. The median (IQR) tube size for each group was as follows: SB [12 Fr (12–14)] and LB [32 Fr (28–32)]. The risk of having at least one chest tube complication was similar for LB and SB chest tubes (14% vs. 18%, p = 0.42). LB tubes had significantly larger risk of VATS, while SB tubes had significantly higher risk of pneumonia. SB tubes had significantly slower least squares (LS) mean initial output drainage rate compared to LB tubes (52.2 vs. 213.4 mL/hour, p < 0.001), but a non-parametric analysis suggested no significant difference in median drainage rates between groups 39.7 [23.5–242.0] mL/hr. vs. 38.6 [27.5–53.8], p = 0.81. LB and SB groups had similar initial output volume (738.0 mL vs. 810.9, p = 0.59).

Conclusions

There was no clearly superior chest tube diameter size; both chest tube sizes demonstrated risks and benefits. Clinicians must be aware of these potential tradeoffs when deciding on the diameter of chest tube for the treatment of delayed HTXs.

Impact of telemedicine on assisted reproduction treatment in the public health system

AIM

Telemedicine has helped to make health care more efficient. However, to date no studies have measured its impact on infertility and fertility healthcare. We assessed the potential care benefits and clinical advantages of an initiative implementing electronic patient portal (EPP) for patients scheduled to undergo assisted reproduction treatment, to reduce waiting times for medical consultation and treatment.

METHODS

This was designed as a retrospective cohort study. The experimental group comprised 1972 referral requests received by the assisted reproduction unit of our institution between 2015 and 2016, which were included in the group receiving telemedicine, while the control group was defined by 283 requests received in 2013, all of which were assigned face-to-face care.

RESULTS

We found a statistically significant reduction in the experimental group in terms of the days elapsed between the receipt of the assessment request and the first outpatient visit (68 days vs. 180 days, p<.001). Time to initiation of treatment was also significantly lower in this group (169 days vs. 229 days; p<.001). The experimental group contained around 7 times as many patients receiving treatment as the control group. No differences were observed in the pregnancy rate (29.9% vs. 31.1%; p=.77) or in the complication rate (3.2% vs. 0%; p=.16).

CONCLUSIONS

Use of telemedicine in electronic portal patient form reduces the total waiting time involved in patient requests for infertility treatment and indirectly increases the number of patients treated, causing no negative impact on treatment outcome.

Venetoclax, bendamustine, and rituximab in patients with relapsed or refractory NHL: a phase Ib dose-finding study

Background

Venetoclax is a selective, potent inhibitor of the anti-apoptotic B-cell leukemia/lymphoma-2 protein approved for treatment of chronic lymphocytic leukemia. We conducted a dose-finding study of venetoclax in combination with bendamustine-rituximab (BR) in patients with relapsed/refractory non-Hodgkin's lymphoma (NHL).

Patients and methods

BR was given for six cycles at standard doses. Intermittent and continuous oral venetoclax administration was explored at 50-1200 mg daily doses. Co-primary objectives included safety, pharmacokinetics (PKs), maximum-tolerated dose (MTD), and recommended phase II dose (RP2D); secondary objective was preliminary efficacy.

Results

Sixty patients were enrolled: 32 with follicular lymphoma, 22 with diffuse large B-cell lymphoma, and 6 with marginal zone lymphoma. Nausea (70%), neutropenia (68%), diarrhea (55%), and thrombocytopenia (52%) were the most frequent adverse events (AEs). Most common grade 3/4 AEs were neutropenia (60%) and lymphopenia (38%). Serious AEs were reported in 24 patients; the most frequent were febrile neutropenia and disease progression (8% each). Five patients died from either disease progression (n = 4) or respiratory failure (n = 1). MTD was not reached; RP2D for venetoclax-BR combination was established as 800 mg daily continuously. Venetoclax PK exposure with and without BR was comparable. For all patients, overall response rate was 65%. Median duration of overall response, overall survival, and progression-free survival was 38.3 months [95% confidence interval (CI) 10.4-NR], not yet reached, and 10.7 months (95% CI 4.3-21.0), respectively.

Conclusions

This study established the safety profile of venetoclax in combination with BR, and results demonstrated tolerability and preliminary efficacy of the combination. Additional follow-up is needed to better determine the future role of BR plus venetoclax in the treatment of relapsed/refractory B-cell NHL.

Trial registered

Clinicaltrials.gov, NCT01594229.

Phylogenetic Diversity, Antimicrobial Susceptibility and Virulence Characteristics of Escherichia coli Isolates from Pigeon Meat

Monitoring resistance to antibiotics in wild animals may assist in evaluating tendencies in the evolution of this major public health problem. The aims of this research work were to determine the patterns of antibiotic resistance in Escherichia coli isolates from the meat of wild or domestically reared pigeons from Spain, to detect the presence of virulence and antibiotic resistance genes, and to carry out a phylogenetic classification of the isolates. Of the 37 E. coli strains tested, 32.43% of them belonged to the B2 phylogenetic group, which is often implicated in extra-intestinal infections. None of the strains showed extended-spectrum beta-lactamase activity. All the isolates presented resistance or reduced susceptibility to two or more antibiotics, with high levels of resistance to β-lactams, aminoglycosides and tetracycline. Ten resistance genes were detected, the most frequent of which were ampC, conferring resistance to ampicillin and aadA, conferring resistance to streptomycin. In total, 97.30% of the strains carried virulence factors (between one and five). The strains from pigeons reared in captivity harboured higher average numbers of resistance and virulence genes than isolates from wild pigeons. Pigeon meat is an important reservoir of E. coli with genes for antibiotic resistance and virulence having the potential to cause disease in humans.

Microbial Load and Antibiotic Resistance Patterns of Escherichia coli and Enterococcus faecalis Isolates from the Meat of Wild and Domestic Pigeons

An expansion in the consumption of pigeon meat has occurred in recent years. However, little is known about microbial load and antibiotic resistance of this foodstuff. The hygiene status and the antibiotic resistance patterns (disc diffusion; Clinical and Laboratory Standards Institute, CLSI) of Escherichia coli and Enterococcus faecalis isolates from wild and domestic pigeon carcasses were investigated. Average microbial loads (log10 cfu/cm2) ranged from 1.40 ± 1.17 (fecal coliforms) to 3.68 ± 1.40 (psychrotrophs). The highest (p < 0.05) microbial loads were observed in domestic pigeons. No substantial differences were found between isolates from domestic and wild pigeons with regard to the prevalence of antibiotic resistance. Of the E. coli strains, 20.00% were susceptible, 25.00% showed resistance or reduced susceptibility to one antimicrobial and 55.00% were multi-resistant. Among the E. faecalis isolates, 2.22% were susceptible and 97.78% were multi-resistant. The greatest prevalence of resistance or reduced susceptibility among E. coli was observed for amoxicillin-clavulanic acid (20.00% strains), ampicillin (26.67%), streptomycin (55.00%) and tobramycin (20.00%). The prevalence of resistance or reduced susceptibility among E. faecalis ranged from 31.11% (trimethoprim/sulfamethoxazole) to 97.78% (erythromycin). Meat from pigeons is a major reservoir of antibiotic-resistant bacteria. The need for the correct handling of this foodstuff in order to reduce risks to consumers is underlined.

Bacterial microbiome associated with the rhizosphere and root interior of crops in Saskatchewan, Canada

Rhizosphere and root associated bacteria are key components of plant microbiomes and influence crop production. In sustainable agriculture, it is important to investigate bacteria diversity in various plant species and how edaphic factors influence the bacterial microbiome. In this study, we used high-throughput sequencing to assess bacterial communities associated with the rhizosphere and root interior of canola, wheat, field pea, and lentil grown at four locations in Saskatchewan, Canada. Rhizosphere bacteria communities exhibited distinct profiles among crops and sampling locations. However, each crop was associated with distinct root endophytic bacterial communities, suggesting that crop species may influence the selection of root bacterial microbiome. Proteobacteria, Actinobacteria, and Bacteroidetes were the dominant phyla in the root interior, whereas Gemmatimonadetes, Firmicutes, and Acidobacteria were prevalent in the rhizosphere soil. Pseudomonas and Stenotrophomonas were predominant in the rhizosphere and root interior, whereas Acinetobacter, Arthrobacter, Rhizobium, Streptomyces, Variovorax, and Xanthomonas were dominant in the root interior of all crops. The relative abundance of specific bacterial groups in the rhizosphere correlated with soil pH and silt and organic matter contents; however, there was no correlation between root endophytes and analyzed soil properties. These results suggest that the root microbiome may be modulated by plant factors rather than soil characteristics.

Effects of a short workplace exercise program on body composition in women: A randomized controlled trial

Physical inactivity and poor diet cause alterations in body composition, which in turn increases risk factors for cardiovascular and metabolic diseases. Sixty-three women from different work environments were randomly assigned to an intervention (n = 34) or control (n = 29) group. The intervention was a short-term aerobic exercise program (12 weeks) at their workplace. Participants assigned to the control group did not perform any form of physical exercise. Body composition was measured by dual-energy X-ray absorptiometry (DXA). Diet was assessed using the Mediterranean Diet Quality Questionnaire (KIDMED) and nutrient balance by the Food Frequency Questionnaire. Researchers suggest that a short-term aerobic exercise program produces beneficial effects on body composition.

Low birth weight and PM2.5 in Puerto Rico

BACKGROUND

Low birth weight (LBW) has been associated with adverse health outcomes across the lifespan. Among ethnic/racial minority populations, few studies have examined the association between LBW (<2,500 or ≥2,500 g) and prenatal exposure to air pollution, a key modifiable environmental risk factor.

METHODS

We examined the association between LBW and prenatal exposure to PM2.5 in a Hispanic and black population in Puerto Rico between 1999 and 2013, adjusting for individual and municipality-level confounders. We used modified Poisson regression to estimate the association and performed sensitivity analyses treating birth weight as continuous or polychotomous. In secondary analyses, we applied a 2-stage mixed effects model suitable for longitudinally measured exposures and binary outcomes.

RESULTS

Among 332,129 total and 275,814 term births, 12.2% and 6.3% of infants had LBW, respectively. Eighty-eight percent of mothers were Hispanic. Mean (SD) PM2.5 concentrations declined from 9.9 (1.7) μg/m3 in 1999 to 6.1 (1.1) μg/m3 in 2013. Mean birth weights dropped to 3,044 g in 2010 and rose steadily afterward. Among term births, a SD increase in PM2.5 was associated with a 3.2% (95% CI = -1.0%, 6.3%) higher risk of LBW. First (risk ratio, 1.02; 95% CI = 1.00, 1.04) and second (1.02; 95% CI = 1.01, 1.05) trimester exposures were associated with increased LBW risk. In a 2-stage approach that longitudinally modeled monthly prenatal exposure levels, a standard deviation increase in average PM2.5 was associated with higher risk of LBW (odds ratio, 1.04; 95% CI = 1.01, 1.08).

CONCLUSIONS

In Puerto Rico, LBW is associated with prenatal PM2.5 exposure.

TGIF1 homeodomain interacts with Smad MH1 domain and represses TGF-β signaling

TGIF1 is a multifunctional protein that represses TGF-β-activated transcription by interacting with Smad2-Smad4 complexes. We found that the complex structure of TGIF1-HD bound to the TGACA motif revealed a combined binding mode that involves the HD core and the major groove, on the one hand, and the amino-terminal (N-term) arm and the minor groove of the DNA, on the other. We also show that TGIF1-HD interacts with the MH1 domain of Smad proteins, thereby indicating that TGIF1-HD is also a protein-binding domain. Moreover, the formation of the HD-MH1 complex partially hinders the DNA-binding site of the complex, preventing the efficient interaction of TGIF1-HD with DNA. We propose that the binding of the TGIF1 C-term to the Smad2-MH2 domain brings both the HD and MH1 domain into close proximity. This local proximity facilitates the interaction of these DNA-binding domains, thus strengthening the formation of the protein complex versus DNA binding. Once the protein complex has been formed, the TGIF1-Smad system would be released from promoters/enhancers, thereby illustrating one of the mechanisms used by TGIF1 to exert its function as an active repressor of Smad-induced TGF-β signaling.

[Benign focal liver lesions detected by computed tomography: Review of 1,184 examinations]

BACKGROUND

Multidetector computed tomography (MDCT) of the abdomen, with use of contrast medium, is able to detect and differentiate most focal liver lesions.

AIM

To determine the prevalence and features of benign focal liver lesions (BFLL) detected by abdominal MDCT.

PATIENTS AND METHODS

We reviewed the reports of contrast abdominal MDCT performed to outpatients between August 2011 and July 2012. Clinical data of examined patients and imaging findings in terms of description of the hepatic parenchyma and the presence of BFLL, were recorded.

RESULTS

Data from 1,184 studies were analyzed. Of these, 461 studies (38.4%) reported BFLL. The most prevalent lesions were simple cysts in 290 studies (24%) and hemangiomas in 61 studies (5.1%), granuloma-calcification in 39 (3.2%), focal nodular hyperplasia in 19 (1.6%) and one adenoma. If patients with known causes of liver disease were excluded, the prevalence of BFLL did not change substantially (lesions were found in 396 (37.5%) patients). Compared with livers with signs of damage, normal livers had more cystic lesions (27 and 16.2% respectively, p = 0.014) and hemangiomas (5.3 and 1.1% respectively, p = 0.043).

CONCLUSIONS

BFLL are very common findings in MDCT studies. Most of these lesions are simple cysts and hemangiomas.

Acute WNT signalling activation perturbs differentiation within the adult stomach and rapidly leads to tumour formation

A role for WNT signalling in gastric carcinogenesis has been suggested due to two major observations. First, patients with germline mutations in adenomatous polyposis coli (APC) are susceptible to stomach polyps and second, in gastric cancer, WNT activation confers a poor prognosis. However, the functional significance of deregulated WNT signalling in gastric homoeostasis and cancer is still unclear. In this study we have addressed this by investigating the immediate effects of WNT signalling activation within the stomach epithelium. We have specifically activated the WNT signalling pathway within the mouse adult gastric epithelium via deletion of either glycogen synthase kinase 3 (GSK3) or APC or via expression of a constitutively active β-catenin protein. WNT pathway deregulation dramatically affects stomach homoeostasis at very short latencies. In the corpus, there is rapid loss of parietal cells with fundic gland polyp (FGP) formation and adenomatous change, which are similar to those observed in familial adenomatous polyposis. In the antrum, adenomas occur from 4 days post-WNT activation. Taken together, these data show a pivotal role for WNT signalling in gastric homoeostasis, FGP formation and adenomagenesis. Loss of the parietal cell population and corresponding FGP formation, an early event in gastric carcinogenesis, as well as antral adenoma formation are immediate effects of nuclear β-catenin translocation and WNT target gene expression. Furthermore, our inducible murine model will permit a better understanding of the molecular changes required to drive tumourigenesis in the stomach.

Chondroitin sulphate-mediated fusion of brain neural folds in rat embryos

Previous studies have demonstrated that during neural fold fusion in different species, an apical extracellular material rich in glycoconjugates is involved. However, the composition and the biological role of this material remain undetermined. In this paper, we show that this extracellular matrix in rat increases notably prior to contact between the neural folds, suggesting the dynamic behaviour of the secretory process. Immunostaining has allowed us to demonstrate that this extracellular matrix contains chondroitin sulphate proteoglycan (CSPG), with a spatio-temporal distribution pattern, suggesting a direct relationship with the process of adhesion. The degree of CSPG involvement in cephalic neural fold fusion in rat embryos was determined by treatment with specific glycosidases.In vitro rat embryo culture and microinjection techniques were employed to carry out selective digestion, with chondroitinase AC, of the CSPG on the apical surface of the neural folds; this was done immediately prior to the bonding of the cephalic neural folds. In all the treated embryos, cephalic defects of neural fold fusion could be detected. These results show that CSPG plays an important role in the fusion of the cephalic neural folds in rat embryos, which implies that this proteoglycan could be involved in cellular recognition and adhesion.

[Smoking habits among sixth-year medical students in Spain]

OBJECTIVE

To describe and analyze the smoking habits of sixth-year Spanish medical students.

MATERIAL AND METHODS

The target population of this descriptive cross-sectional study was students completing their sixth year in Spanish medical schools. An anonymous, self-administered questionnaire was sent to the students' homes by ordinary mail. The relationships between the variables were analyzed using contingency tables, the chi2 test, the Student t test, and analysis of variance with a significance level of P< .05. The software package was SPSS.

RESULTS

A total of 3840 questionnaires were distributed to students, and 1340 were returned completed (34.9%). Of the respondents, 27% were smokers (8.7% smoked only on weekends, and 18.3% were daily smokers). The mean (SD) number of cigarettes smoked per day was 10.54 (7.89). Consumption was significantly higher among men than among women. The mean age of initiation was 17.20 years. Of the students who were smokers, 32.54% stated that they had started smoking during their medical studies. The percentage of smokers who stated that they wanted to quit was 76.3%, and 56.6% said that they had already made at least one quit attempt.

CONCLUSIONS

It is cause for concern that a large number of students start smoking after they enter medical school. One of the reasons for this is the lack of concern about smoking as a health problem within medical schools. The smoking habits of medical students are affected by the same phenomena that affect those of the general public, such as the increase in the number of women smokers, the influence of sociocultural factors, and the increasingly broader age range of initiation. The lower prevalence of smoking among medical students with respect to other populations is probably due to the fact that, in general, these students have better health habits than the general public, and/or the reasons that led them to study medicine also make them disinclined to smoke.

The intramedullary elongation nail for femoral lengthening

We have analysedin the results of 24 femoral lengthenings in 23 patients operated on between 1993 and 2000, using a gradual elongation intramedullary nail (Albizzia). Of the 23 patients, 22 had femoral deficiency and one was of short stature. Their mean age was 16.9 years. Technical difficulties encountered during the procedure were mild or moderate in 18 femora and severe in six femora. Distraction was obtained by 15 ratchetings per day (1 mm/day).

There were 18 excellent results although in two patients this was achieved after the development of a pseudarthrosis which required further surgery. There were four good and two fair results in which the lengthening obtained was at least 3 cm less than had been projected. The consolidation index was 35.2 days/cm. No patient had associated long-term stiffness of the knee.

Femoral lengthening using an elongation nail gives good results and is a comfortable procedure.

The intramedullary elongation nail for femoral lengthening

We have analysed the results of 24 femoral lengthenings in 23 patients operated on between 1993 and 2000, using a gradual elongation intramedullary nail (Albizzia). Of the 23 patients, 22 had femoral deficiency and one was of short stature. Their mean age was 16.9 years. Technical difficulties encountered during the procedure were mild or moderate in 18 femora and severe in six femora. Distraction was obtained by 15 ratchetings per day (1 mm/day). There were 18 excellent results although in two patients this was achieved after the development of a pseudarthrosis which required further surgery. There were four good and two fair results in which the lengthening obtained was at least 3 cm less than had been projected. The consolidation index was 35.2 days/cm. No patient had associated long-term stiffness of the knee. Femoral lengthening using an elongation nail gives good results and is a comfortable procedure.

Impacted morsellised allograft and cemented cup in acetabular revision surgery. A five to nine year follow-up study

Seventy cemented cups associated with impacted morsellised allograft in revision surgery in hips with an acetabular bone defect greater than 30% (Paprosky Grades 3A and 3B) were analyzed. The mean follow-up was 6.8 years. One hip showed cup migration and was re-revised; this represents a total cumulative probability of re-revision of the cup of 1.4 2.8%. Radiolucent lines were uncommon: six cups showed radiolucent lines in DeLee and Charnley zone 1, five in zones 1 and 2, one in all three zones, while one hip showed migration.Although the frequent use of a metallic mesh makes graft remodeling difficult to evaluate, six hips showed minor and one major bone resorption. The mid-term results with impacted allograft and cemented all-polyethylene cups are favourable in acetabular revision surgery. (Hip International 2002; 12: 281-8).

Effects of polyethylene and alpha-alumina particles on IL-6 expression and secretion in primary cultures of human osteoblastic cells

The effect of two biomaterials, polyethylene and alpha-alumina, on interleukin-6 (IL-6) secretion and expression has been studied in human osteoblasts in primary culture. Human osteoblastic cells were derived from fresh trabecular bone explants removed during total knee arthroplasty. On reaching confluence, cells were subcultured in 6 well plates; the resulting subcultures were incubated until confluence and polyethylene or alpha-alumina particles were added to some while the rest were left as controls. The IL-6 mRNA levels were assessed by reverse transcription (RT) followed by polymerase chain reaction (PCR). IL-6 secretion was measured in the conditioned medium. The IL-6 expression was higher in the presence of both biomaterials. Maximum expression occurred in response to a dose of 50 mg particles well with both biomaterials and was greater after polyethylene particle addition than after alpha-alumina particle addition at this dose. The maximum IL-6 secretion elicited by alpha-alumina was produced at 10 mg particles well while maximum response with polyethylene required 50 mg well. At a dose of 10 mg/well, alpha-alumina particles induced more secretion than 10 mg of polyethylene particles. Nevertheless, at a dose of 50 mg/well maximum secretion was produced with polyethylene particles. In conclusion and in our experimental conditions, polyethylene as well as alpha-alumina increased both the expression and the secretion of IL-6 in human osteoblastic cells in primary culture and stimulation from polyethylene appears stronger than that from alpha-alumina at the same dose.

Urinary infection after orthopedic procedures

We have investigated prospectively the incidence of urinary tract infection (UTI) in 5320 orthopaedic patients. There were 74 UTIs (1.39%). Enterobacteriaceae was the most frequent etiological agent. Each infection increased the length of stay in hospital by more than 8 days. Statistically independent risk factors for the development of urinary infection were a preoperative stay of more than 4 days, inadequate preoperative preventive measures, central venous catheterization and urinary catheterization. Sex, age, or type of surgery had no statistical influence on the development of infection.

Influence of particle size in the effect of polyethylene on human osteoblastic cells

The influence of two different sizes of polyethylene particles (< 30 and 20-200 microm) on osteoblastic function has been studied in primary human bone cell cultures. Cells were obtained from trabecular bone fragments of patients undergoing knee reconstructive surgery. On reaching confluency, cells were subcultured in three flasks: < 30 microm polyethylene particles were added to the first flask, 20-200 microm particles to the second flask and none to the third flask, which was the control. The resulting subcultures were incubated until confluence. Osteoblastic function was evaluated by assaying the secretion of osteocalcin, alkaline phosphatase, and C-terminal type I procollagen (PICP), with or without 1.25(OH)2D3 stimulation in the cell-conditioned medium. Adding < 30 microm polyethylene particles to these osteoblastic cell cultures increased the levels of osteocalcin secreted after 1,25(OH)2D3 stimulation. Treating stimulated or basal osteoblastic cultures with either polyethylene particle size did not affect alkaline phosphatase secretion. However, the addition of <30 microm polyethylene particles decreased PICP levels in the basal and stimulated cultures. A parallel series of osteoblastic cultures was treated with < 30 microm polyethylene particles and stimulated or not with 1,25(OH)2D3 to determine the effect on osteocalcin mRNA expression using RT-PCR amplification. Polyethylene particle-treated cultures had higher osteocalcin mRNA expression regardless of whether they had been stimulated with 1,25(OH)2D3 or not. We conclude that particle size affects the influence of polyethylene on osteoblastic function markers. Particles with a diameter of less than 30 microm increase osteocalcin expression and secretion.

Plasma beta-endorphin levels in obese and non-obese patients with polycystic ovary disease

The aim of this study was to determine the influence of body weight on circulating plasma levels of beta-endorphin and insulin in women with polycystic ovary disease (PCOD), as well as the correlation between the plasma levels of beta-endorphin and insulin. One-hundred and sixty-seven consecutive subjects with PCOD were recruited, 117 of whom had normal weight (body mass index (BMI) < 25) while 50 were obese (BMI > 25). A venous blood sample was taken and plasma concentrations of beta-endorphin, insulin, gonadotropins, prolactin, progesterone, 17 beta-estradiol, estrone, androgens, dehydroepiandrosterone sulfate and sex hormone-binding globulin (SHBG) were measured. Mean beta-endorphin and insulin plasma levels were significantly higher (p < 0.05) in obese PCOD women than in non-obese ones. Correlation analysis showed a positive association between insulin and beta-endorphin, beta-endorphin and BMI (and weight), insulin and BMI (and weight), and a negative correlation was found between insulin and SHBG. A weak association was found between beta-endorphin and luteinizing hormone (LH) in peripheral plasma. Stratified and linear regression analysis showed that plasma beta-endorphin concentrations correlate more with BMI than with insulinemia.

Low-friction arthroplasty in patients younger than 40 years old: 20- to 25-year results

A total of 67 low-friction arthroplasties were performed from 1971 through 1978 in patients <40 years old and followed an average of 21.7 years. There have been 33 cup loosenings and 17 stem loosenings. The average rate of wear of the cup was 0.12 mm/y for the entire series and 0.16 mm/y for the revised cups. Although the preoperative diagnosis leading to low-friction arthroplasty commonly reflected some deficiency in bone structure, particularly in the acetabulum, there were no primary osteoarthrosis cases. The femoral stem proved to be durable, but acetabular cups gave poorer results in younger patients than in older patients. The 2 major factors limiting the longevity of the cemented cup were acetabular bone quality and wear.

Transforming growth factor beta receptors in verrucous and squamous cell carcinoma

OBJECTIVES

To study the intracellular location of transforming growth factor beta type II receptors (TbetaR-II) in verrucous carcinoma (VC) and squamous cell carcinoma (SqCC), and to evaluate their role in the biological behavior of both neoplasias.

DESIGN

Ten VC and 10 well-differentiated SqCC specimens were analyzed by immunohistochemistry and in situ hybridization for the expression and intracellular location of TbetaR-II. Receptor expression was evaluated in areas of invasion and in areas of transformation of VC into SqCC. TbetaR-II expression was compared with expression of the type I receptor (TbetaR-I).

SUBJECTS

Formalin-fixed, paraffin-embedded tissue sections from VCs and well-differentiated SqCCs, operated on at the H. L. Moffitt Cancer Center and Research Institute from May 1987 to January 1998, were selected for the study.

INTERVENTIONS

None.

RESULTS

While in all VCs TbetaR-II was found to be located along the membrane of the neoplastic keratinocytes, TbetaR-II expression in SqCC was observed predominantly in a cytoplasmic location. This cytoplasmic location of TbetaR-II was also seen in areas of transition from VC to SqCC. Expression of TbetaR-I was found in a cytoplasmic location in both tumor types.

CONCLUSIONS

The membranous location of TbetaR-II in VC exposes the receptor to the growth inhibitory control of TGF-beta and may explain why VC tumors are less aggressive clinically. The marked reduction of membranous TbetaR-II and their predominant cytoplasmic location diminishes TGF-beta growth inhibition and may contribute to the transformation of VC into the more aggressive SqCC.

Expression of transforming growth factor beta type II receptors in head and neck squamous cell carcinoma

Transforming growth factor (TGF)-beta is a potent regulator of growth and differentiation in normal squamous epithelium. TGF-beta exerts its antiproliferative effect via the TGF-beta type II receptor (TbetaR-II). A decrease in TbetaR-II expression is believed to be responsible, in part, for the resistance of squamous cell carcinoma (SqCC) to the anti-proliferative effects of TGF-beta. In the present study, we used immunohistochemistry and in situ hybridization to analyze the expression of TbetaR-II along the successive oncogenic stages of head and neck squamous neoplasia, from normal epithelium to dysplasia to carcinoma. Quantitation of TbetaR-II expression in 38 SqCCs was assessed on a visual scale ranging from negative (absence of staining) to 3+ (strong staining). Normal squamous epithelium and squamous epithelium in the vicinity of the tumors showed homogenous receptor expression with moderate intensity. Dysplastic epithelium and carcinoma in situ showed a mild decrease in receptor expression intensity. Well-differentiated to moderately differentiated carcinomas showed heterogeneous expression of variable intensity, and poorly differentiated carcinomas were completely devoid of TbetaR-II. In every tumor, the superficial component showed more intense receptor expression than the invasive component. These results indicate that TbetaR-II expression inversely correlates with disease aggressiveness and suggest that aberrant TbetaR-II expression is a contributing factor to the pathogenesis of SqCC.

[Congenital cyanotic heart disease and peripheral neurogenic tumor]

The association between neuroblastic tumours and congenital heart disease is widely confirmed in the literature references. The authors describe a case of a patient with congenital heart disease, high blood pressure, renal artery stenosis and high levels in 24 hours urine metanephrines. A MIBG-I-123 scintigraphy was essential for the diagnosis of neuroblastic tumour.

Circulating levels of immunoreactive beta-endorphin in polycystic ovary syndrome

The plasma levels of beta-endorphin were studied in 64 women with polycystic ovarian disease (PCOD), from whom was selected a group of 23 women with normal weight and amenorrhea of < 36 days. On day 21, beta-endorphin levels were: mean 64.92 pg/ml; SD 37.32 pg/ml; 95% CI 48.38-81.47 pg/ml. It was also observed that their levels of opioid peptide were reduced, compared with women who had normal ovulatory cycles, both in the follicular phase (mean 70.93 pg/ml; SD 24.59 pg/ml; 95% CI 76.84-99.77 pg/ml) and luteal phase (mean 88.30 pg/ml; SD 31.80 pg/ml; 95% CI 76.84-99.77 pg/ml). The results were statistically significant (p < 0.05) for levels in PCOD patients compared with those of the luteal phase in women with normal ovulatory cycles. The decreased levels of beta-endorphin were negatively related to luteinizing hormone (LH) levels, which might explain the rise of LH levels in women with PCOD who control their weight and at the time of amenorrhea, although it is not clear if central opioid activity is reflected in the peripheral blood.

Antimicrobial properties of Honduran medicinal plants

Ninety-two plants used in the traditional pharmacopoeia of the Pech and neighboring Mestizo peoples of central Honduras are reported. The results of in vitro antimicrobial screens showed that 19 of the extracts from medicinal plants revealed signs of antifungal activity while 22 demonstrated a measurable inhibitory effect on one or more bacterial cultures. Bioassay-guided fractionation of extracts from Mikania micrantha, Neurolaena lobata and Piper aduncum produced weak to moderately active isolates. The broad spectrum of activity of the extracts helps to explain the widespread use of these plants for wound healing and other applications.

Plasma glutathione concentrations in children infected with human immunodeficiency virus

BACKGROUND

Glutathione (GSH) is the principal intracellular defense against oxidants, and HIV-infected individuals tend to have subnormal concentrations in plasma. This GSH deficiency may contribute to the pathogenesis of disease progression. In the pediatric population correlations between GSH concentrations with clinical, immunologic and virologic disease profiles are scarce.

OBJECTIVES

The main objectives of this study were (1) to compare plasma GSH concentrations of HIV-infected children and healthy controls and (2) to correlate GSH values with clinical, immunologic and virologic disease indices.

METHODS

Twenty-four HIV-infected and 24 healthy control children entered the study. Plasma concentrations of total glutathione and related thiols were determined.

RESULTS

The difference in mean plasma GSH concentrations between HIV-infected (2.96 +/- 0.31 microM) and control (6.62 +/- 0.58 microM) groups was highly significant (P < 0.0001). Linear regression analyses in HIV-infected patients revealed significant correlations between GSH and both absolute CD4+ cell counts (r = 0.56, P = 0.004) and viral load measured as log HIV-RNA PCR (r = -0.49, P = 0.018). GSH concentrations did not significantly correlate with CDC clinical stage but were lower in HIV-infected patients with growth failure (1.60 +/- 0.54 microM) vs. non-growth failure (3.23 +/- 0.33 microM); P = 0.05.

CONCLUSIONS

This study confirmed that HIV-infected children are deficient in plasma GSH concentrations compared with healthy controls. We documented that low GSH concentrations in HIV-infected children are directly correlated with CD4+ cell counts and inversely correlated with viral loads. These findings support a possible role of GSH in the pathogenesis of HIV disease progression.

Practical guidelines for developing a hospital-based wound and ostomy clinic

Multidisciplinary teams save time and money while improving quality of patient care. Hospital-based wound/ostomy clinics provide patients with holistic, one-stop, expert care with access to a variety of diagnostic and treatment modalities. The authors discuss how to assemble all the ingredients for a successful multidisciplinary hospital-based clinic, how to make it work, and how to measure its cost-effectiveness for patient, hospital, community and nation. The original model clinic established in Costa Rica using these methods was so successful at providing efficient, high quality, cost-effective care that it has been adopted in 17 different locations there, and similar clinics are being developed in other countries. This model is applicable to industrialized and developing countries. By focusing hospital resources on evidence-based wound/ostomy care, it has the potential to revolutionize wound and ostomy care around the world.

Influence of bacterial strains on bone infection

Experiments were performed on 120 rabbits to compare the probability of infection after bone surgery without an implant, with polymethylmethacrylate, and with autografts. Staphylococcus aureus phage type 94/96, isolated from a human osteomyelitis, was instilled into the intramedullar cavity after reaming of the femoral canal and before insertion of the implant. The different 50% infective doses were determined for each of the groups for comparative purposes. The bacterial concentrations required to produce infection in femora without an implant were two times less than those necessary in femora implanted with polymethylmethacrylate. The bone graft required bacterial concentrations nine times less than those necessary to infect femora containing polymethylmethacrylate and four times less than those required to infect femora without an implant. The results presented here confirm that the susceptibility to infection in orthopaedic surgery is not only material dependent but also bacteria dependent.

The influence of the chemical composition and surface of the implant on infection

The influence of the localization and size of orthopaedic implants on infection has been analyzed extensively, but the influence of implant shape and chemical composition has rarely been studied, and the influence of the surface has only been described in one single report. Several experimental studies have tried to compare the incidence of infection for different materials. PMMA usually appears as the implant material most prone to causing infection, while titanium (Ti) and cobalt-chromium (CoCr) are the materials most resistant to infection. On the polished surface of cylinders implanted in rabbit femora, it took 40 times more inoculum to produce a clinical infection than it took for porous CoCr implants. The polished surface implants required 2.5 times more inoculum than porous Ti to produce infection.

[Experience of a single center in liver transplantation in adults and children]

Orthotopic liver transplantation (THO) is the treatment of choice for a variety of liver diseases. The national experience before 1993 has been scarce. In November 1993 we started our experience in THO at Clínica Las Condes, as part of a multiorgan transplant program (liver, kidney, pancreas). Until January 1995 we have performed 14 THO in 13 recipients (one retransplantation), of which 5 were in pediatric cases. The recipients range of age fluctuated between 1 and 61 years. In two pediatric cases a liver allograft reduction was performed. Six recipients (46%) required treatment for acute cellular rejection. One recipient had an hepatic artery thrombosis and had to be retransplanted. There was no operative mortality up to 30 days in cases of primary liver transplants. The retransplanted adult recipient, and another pediatric recipient that died from a late recurrence of a hepatoblastoma, accounted for the mortality of this experience. After an average follow up of 10 months, the actual patient survival in 85%. Of the 11 surviving recipients, 9 are in excellent conditions with a very good quality of life. This experience shows that an active liver transplant program in our country can be successful in obtaining results comparable to those published by very experienced foreign transplant centers.

The fixation of porous-coated femoral stems. A radiographic study of 113 cases with a 4 to 8 year follow up

Changes occurring in the fixation of 113 porous-coated PCA uncemented femoral stems were studied in 90 patients who were operated on between 1984 and 1988. The average follow up was 5 years. Fixation was classified in radiographs as osteointegration, stable fibrous fixation or unstable. Four femoral components were revised. Metaphyseal osteoporosis was associated with those with a stem diameter greater than 13 mm. After 2 years, osteointegration was present in 73% and instability in 24% which was not related to the position of the stem. At the end of the follow up period, 20% of the stems showing osteointegration had changed and become unstable.