Tn6198, a novel transposon containing the trimethoprim resistance gene dfrG embedded into a Tn916 element in Listeria monocytogenes

OBJECTIVES: To characterize Tn6198, a novel conjugative transposon from the clinical Listeria monocytogenes strain TTH-2007, which contains the tetracycline and trimethoprim resistance genes tet(M) and dfrG, respectively, and to assess its transferability in vitro and in situ. METHODS: The complete sequence of Tn6198 was determined using a primer walking strategy. Horizontal gene transfer studies were performed by filter matings, as well as on the surface of smear-ripened cheese and smoked salmon. The presence of Tn916-like circular intermediates was determined by PCR. Antibiotic resistance was determined by the broth microdilution method and microarray hybridization. RESULTS: Sequencing of Tn6198 revealed that a 3.3 kb fragment containing dfrG was integrated between open reading frames 23 and 24 of Tn916. Furthermore, an additional copy of Tn916 was present in L. monocytogenes TTH-2007. Both elements were transferred simultaneously and separately in vitro to recipients L. monocytogenes 10403S and Enterococcus faecalis JH2-2 by conjugation, resulting in either tetracycline- and trimethoprim-resistant or solely tetracycline-resistant transconjugants. On the surface of cheese and salmon, only L. monocytogenes 10403S transconjugants were detected. CONCLUSIONS: This study reports the first Tn916-like element associated with a trimethoprim resistance gene, as well as the first fully characterized transposon conferring multidrug resistance in L. monocytogenes. This is of concern, as trimethoprim is administered to listeriosis patients with β-lactam allergy and as Tn6198 has a large potential for dissemination, indicated by both intra-species and inter-genus transfer.

Rapid temperature-dependent wound closure following adipose fin clipping of Atlantic salmon Salmo salar L.

Three groups of Atlantic salmon were kept at a constant temperature of 4, 10 and 14 °C. The adipose fins were removed; six fish/group were sampled at 11 subsequent time points post-clipping. Samples were prepared for histopathological examination to study the course of re-epithelization. A score sheet was developed to assess the regeneration of epidermal and dermal cell types. Wounds were covered by a thin epidermal layer between 4 and 6 h post-clipping at 10 and 14 °C. In contrast, wound closure was completed between 6 and 12 h in fish held at a constant temperature of 4 °C. By 18 h post-clipping, superficial cells, cuboidal cells, prismatic basal cells and mucous cells were discernible in all temperature groups, rapidly progressing towards normal epidermal structure and thickness. Within the observation period, only minor regeneration was found in the dermal layers. A positive correlation between water temperature and healing rates was established for the epidermis. The rapid wound closure rate, epidermal normalization and the absence of inflammatory reaction signs suggest that adipose fin clipping under anaesthesia constitutes a minimally invasive method that may be used to mark large numbers of salmon presmolts without compromising fish welfare.

Effect of temperature and diet on wound healing in Atlantic salmon (Salmo salar L.).

Compromised skin integrity of farmed Atlantic salmon, commonly occurring under low temperature and stressful conditions, has major impacts on animal welfare and economic productivity. Even fish with minimal scale loss and minor wounds can suffer from secondary infections, causing downgrading and mortalities. Wound healing is a complex process, where water temperature and nutrition play key roles. In this study, Atlantic salmon (260 g) were held at different water temperatures (4 or 12 °C) and fed three different diets for 10 weeks, before artificial wounds were inflicted and the wound healing process monitored for 2 weeks. The fish were fed either a control diet, a diet supplemented with zinc (Zn) or a diet containing a combination of functional ingredients in addition to Zn. The effect of diet was assessed through subjective and quantitative skin histology and the transcription of skin-associated chemokines. Histology confirmed that wound healing was faster at 12 °C. The epidermis was more organised, and image analyses of digitised skin slides showed that fish fed diets with added Zn had a significantly larger area of the epidermis covered by mucous cells in the deeper layers after 2 weeks, representing more advanced healing progression. Constitutive levels of the newly described chemokines, herein named CK 11A, B and C, confirmed their preferential expression in skin compared to other tissues. Contrasting modulation profiles at 4 and 12 °C were seen for all three chemokines during the wound healing time course, while the Zn-supplemented diets significantly increased the expression of CK 11A and B during the first 24 h of the healing phase.

Progression of coronary artery disease during long-term follow-up of the Swiss Interventional Study on Silent Ischemia Type II (SWISSI II)

Background: This study evaluates cardiovascular risk factors associated with progression of coronary artery disease (CAD) in patientswith silent ischemia followingmyocardial infarction. Hypothesis: Coronary artery disease only progresses slowly with comprehensive risk factor intervention. Methods: A total of 104 of 201 patients (51.7%) of the Swiss Interventional Study on Silent Ischemia Type II (SWISSI II) with baseline and follow-up coronary angiography were included. All patients received comprehensive cardiovascular risk factor intervention according to study protocol. Logistic regression was used to evaluate associationsbetween baseline cardiovascular risk factors and CAD progression. Results: The mean duration of follow-upwas 10.3 ± 2.4 years. At baseline, 77.9% of patients were smokers, 45.2% had hypertension, 73.1% had dyslipidemia, 7.7% had diabetes, and 48.1% had a family history of CAD. At last follow-up, only 27 patients of the initial 81 smokers still smoked, only 2.1% of the patients had uncontrolled hypertension, 10.6%of the patientshad uncontrolled dyslipidemia, and 2.1%of the patientshad uncontrolled diabetes. Coronary artery disease progression was found in up to 81 (77.9%) patients. Baseline diabetes and younger age were associatedwith increased odds of CAD progression.The time intervalbetween baseline and follow-up angiography was also associatedwith CAD progression. Conclusion: Coronary artery disease progressionwas highly prevalent in these patients despite comprehensive risk factor intervention. Further research is needed to optimize treatment of known risk factors and to identify other unknown and potentiallymodifiable risk factors.

Hair analysis for Delta9-tetrahydrocannabinolic acid A--new insights into the mechanism of drug incorporation of cannabinoids into hair

Differentiation between external contamination and incorporation of drugs or their metabolites from inside the body via blood, sweat or sebum is a general issue in hair analysis and of high concern when interpreting analytical results. In hair analysis for cannabinoids the most common target is Delta9-tetrahydrocannabinol (THC), sometimes cannabidiol (CBD) and cannabinol (CBN) are determined additionally. After repeated external contamination by cannabis smoke these analytes are known to be found in hair even after performing multiple washing steps. A widely accepted strategy to unequivocally prove active cannabis consumption is the analysis of hair extracts for the oxidative metabolite 11-nor-9-carboxy-THC (THC-COOH). Although the acidic nature of this metabolite suggests a lower rate of incorporation into the hair matrix compared to THC, it is not fully understood up to now why hair concentrations of THC-COOH are generally found to be much lower (mostly <10 pg/mg) than the corresponding THC concentrations. Delta9-Tetrahydrocannabinolic acid A (THCA A) is the preliminary end product of the THC biosynthesis in the cannabis plant. Unlike THC it is non-psychoactive and can be regarded as a 'precursor' of THC being largely decarboxylated when heated or smoked. The presented work shows for the first time that THCA A is not only detectable in blood and urine of cannabis consumers but also in THC positive hair samples. A pilot experiment performed within this study showed that after oral intake of THCA A on a regular basis no relevant incorporation into hair occurred. It can be concluded that THCA A in hair almost exclusively derives from external contamination e.g. by side stream smoke. Elevated temperatures during the analytical procedure, particularly under alkaline conditions, can lead to decarboxylation of THCA A and accordingly increase THC concentrations in hair. Additionally, it has to be kept in mind that in hair samples tested positive for THCA A at least a part of the 'non-artefact' THC probably derives from external contamination as well, because in condensate of cannabis smoke both THC and THCA A are present in relevant amounts. External contamination by side stream smoke could therefore explain the great differences in THC and THC-COOH hair concentrations commonly found in cannabis users.

A natural freshwater origin for two chlamydial species, Candidatus Piscichlamydia salmonis and Candidatus Clavochlamydia salmonicola, causing mixed infections in wild brown trout (Salmo trutta)

Gill disease in salmonids is characterized by a multifactorial aetiology. Epitheliocystis of the gill lamellae caused by obligate intracellular bacteria of the order Chlamydiales is one known factor; however, their diversity has greatly complicated analyses to establish a causal relationship. In addition, tracing infections to a potential environmental source is currently impossible. In this study, we address these questions by investigating a wild brown trout (Salmo trutta) population from seven different sites within a Swiss river system. One age class of fish was followed over 18 months. Epitheliocystis occurred in a site-specific pattern, associated with peak water temperatures during summer months. No evidence of a persistent infection was found within the brown trout population, implying an as yet unknown environmental source. For the first time, we detected 'Candidatus Piscichlamydia salmonis' and 'Candidatus Clavochlamydia salmonicola' infections in the same salmonid population, including dual infections within the same fish. These organisms are strongly implicated in gill disease of caged Atlantic salmon in Norway and Ireland. The absence of aquaculture production within this river system and the distance from the sea, suggests a freshwater origin for both these bacteria and offers new possibilities to explore their ecology free from aquaculture influences.

Pulmonary hypertension in high-altitude dwellers: novel mechanisms, unsuspected predisposing factors

Studies of high-altitude populations, and in particular of maladapted subgroups, may provide important insight into underlying mechanisms involved in the pathogenesis of hypoxemia-related disease states in general. Over the past decade, studies involving short-term hypoxic exposure have greatly advanced our knowledge regarding underlying mechanisms and predisposing events of hypoxic pulmonary hypertension. Studies in high altitude pulmonary edema (HAPE)-prone subjects, a condition characterized by exaggerated hypoxic pulmonary hypertension, have provided evidence for the central role of pulmonary vascular endothelial and respiratory epithelial nitric oxide (NO) for pulmonary artery pressure homeostasis. More recently, it has been shown that pathological events during the perinatal period (possibly by impairing pulmonary NO synthesis), predispose to exaggerated hypoxic pulmonary hypertension later in life. In an attempt to translate some of this new knowledge to the understanding of underlying mechanisms and predisposing events of chronic hypoxic pulmonary hypertension, we have recently initiated a series of studies among high-risk subpopulations (experiments of nature) of high-altitude dwellers. These studies have allowed to identify novel risk factors and underlying mechanisms that may predispose to sustained hypoxic pulmonary hypertension. The aim of this article is to briefly review this new data, and demonstrate that insufficient NO synthesis/bioavailability, possibly related in part to augmented oxidative stress, may represent an important underlying mechanism predisposing to pulmonary hypertension in high-altitude dwellers.

[Impact of tobacco use on the periodontium--an update (I)--Part 1: Epidemiologic und pathogenetic aspects of tobacco-related periodontal diseases]

This literature review represents the second in a series of articles from the Swiss task force "Smoking--Intervention in the private dental office" on the topic "tobacco use and dental medicine". In this article, the epidemiological background as well as some pathogenetic processes are described and discussed critically for tobacco-related periodontal diseases. Earlier publications confirmed tobacco consumption as a risk factor for periodontal diseases. Over the last few years, oral health research has significantly contributed to the understanding of the mechanisms leading to the deterioration of the hard and soft tissues supporting the teeth. With the recording of the number of cigarettes smoked per day and the amount of years tobacco was used, a dose response relationship was established. Various, potentially significant pathogenic effects of tobacco-related substances may exist on the periodontal tissues, the immune response system or the composition of the oral flora. Moreover, there is reference that tobacco consumption may change the genetically determined susceptibility for periodontal diseases.

Whole-body MRI of multiple myeloma: comparison of different MRI sequences in assessment of different growth patterns

PURPOSE: To determine sensitivity, specificity and inter-observer variability of different whole-body MRI (WB-MRI) sequences in patients with multiple myeloma (MM). METHODS AND MATERIALS: WB-MRI using a 1.5T MRI scanner was performed in 23 consecutive patients (13 males, 10 females; mean age 63+/-12 years) with histologically proven MM. All patients were clinically classified according to infiltration (low-grade, n=7; intermediate-grade, n=7; high-grade, n=9) and to the staging system of Durie and Salmon PLUS (stage I, n=12; stage II, n=4; stage III, n=7). The control group consisted of 36 individuals without malignancy (25 males, 11 females; mean age 57+/-13 years). Two observers independently evaluated the following WB-MRI sequences: T1w-TSE (T1), T2w-TIRM (T2), and the combination of both sequences, including a contrast-enhanced T1w-TSE with fat-saturation (T1+/-CE/T2). They had to determine growth patterns (focal and/or diffuse) and the MRI sequence that provided the highest confidence level in depicting the MM lesions. Results were calculated on a per-patient basis. RESULTS: Visual detection of MM was as follows: T1, 65% (sensitivity)/85% (specificity); T2, 76%/81%; T1+/-CE/T2, 67%/88%. Inter-observer variability was as follows: T1, 0.3; T2, 0.55; T1+/-CE/T2, 0.55. Sensitivity improved depending on infiltration grade (T1: 1=60%; 2=36%; 3=83%; T2: 1=70%; 2=71%; 3=89%; T1+/-CE/T2: 1=50%; 2=50%; 3=89%) and clinical stage (T1: 1=58%; 2=63%; 3=79%; T2: 1=58%; 2=88%; 3=100%; T1+/-CE/T2: 1=50%; 2=63%; 3=100%). T2w-TIRM sequences achieved the best reliability in depicting the MM lesions (65% in the mean of both readers). CONCLUSIONS: T2w-TIRM sequences achieved the highest level of sensitivity and best reliability, and thus might be valuable for initial assessment of MM. For an exact staging and grading the examination protocol should encompass unenhanced and enhanced T1w-MRI sequences, in addition to T2w-TIRM.

Female patients with atherosclerotic lesions of the lower limbs. Not all are alike

BACKGROUND: Data on female patients with atherosclerotic peripheral arterial disease (PAD) are scarce, and limited primarily to the elderly population with multilevel disease. In this longitudinal observational study we compare female patients below 60 years of age with isolated lesions at the aortic bifurcation or focal superficial femoral artery disease. PATIENTS AND METHODS: Analysis is based on consecutive series of 43 female patients with PAD limited to the aortoiliac bifurcation (n = 28, group I) or an isolated femoral segment at the adductor channel (n = 15, group II) seen in a tertiary referral center between 1998 and 2000. The first assessment provided baseline data, with follow up data obtained at this study. Traditional risk factors, carotid artery disease and clinical outcome (mortality, cardiovascular events, vascular re-intervention rate, PAD progression) were evaluated over an interval of 5 (2 to 8) years. RESULTS: Female patients with aortic disease [group I] were younger (51.8 +/- 7.7 vs. 56.7 +/- 7.6 years in group II; p = 0.048), presented a more masculine phenotype, and smoked significantly more often (82% vs. 40%; p = 0.007). Arterial hypertension and diabetes mellitus were more common in group II, though it missed statistical significance (p = 0.068 and p = 0.085). Cardiovascular and limb outcome were comparable in both groups of female patients, while carotid artery disease was more severe in group I (i.e., carotid plaques in 71 vs. 53%). CONCLUSION: Our data support previous findings that cigarette smoking is a stronger risk factor for aortic disease as compared to femoral disease in younger female patients, with the strongest effect of smoking on a localized region of the aortic bifurcation.

Pain and swelling after periapical surgery related to oral hygiene and smoking

OBJECTIVES: To evaluate pain and swelling during the first week after periapical surgery and its relation to patient age, gender, oral hygiene, and smoking. STUDY DESIGN: One hundred two patients (31 men and 71 women) with a mean age of 40.2 years underwent periapical surgery. Age, gender, and oral hygiene and cigarette smoking before and during the postoperative course were noted. Pain and swelling scores were recorded on a descriptive 4-point scale at 2, 6, and 12 hours after surgery, and each day thereafter for 1 week. The data were statistically evaluated for significant differences. RESULTS: The highest intensity of pain occurred during the first 48 hours, and swelling peaked on the second postoperative day. Patient age and gender had no significant effect on postoperative symptoms (P > .05). Patients with poor oral hygiene before surgery presented greater pain and swelling during the first postsurgical hours, and smokers before surgery also suffered more pain. The number of cigarettes smoked in the postoperative period and oral hygiene after surgery had no effect on pain or inflammation (P > .05). CONCLUSIONS: Periapical surgery caused little pain and moderate swelling during the first 2 days after the intervention; these findings were more distinct in patients with poor oral hygiene before surgery and in smokers.

Emphysema and secondary pneumothorax in young adults smoking cannabis

BACKGROUND: We observed a remarkable increase in the number of young patients who presented with lung emphysema and secondary spontaneous pneumothorax (SSP) at our institution for over a period of 30 months; most of them have a common history of marijuana abuse. STUDY DESIGN: Retrospective case series. METHODS: Seventeen young patients presented with spontaneous pneumothorax with bullous lung emphysema were systematically evaluated over a period of 30 months. All were regular marijuana smokers. Clinical history, chest X-ray, CT-scan, lung function test, and laboratory and histological examinations were assessed. We compared the findings of this group (group I) with the findings of non-marijuana smoking patients (group II) in the same period. The findings of this series were also compared with the findings of 75 patients presented with pneumothorax in a previous period from January 2000 till March 2002 (group III). RESULTS: In group I, there were 17 patients: the median age of the patients was 27 years (range 19-43 years), 16 males and 1 female. All were living in Switzerland. All but one smoked marijuana daily for a mean of 8.8 years and tobacco for 11.8 years. CT-scan showed multiple bullae at the apex or significant bullous emphysema with predominance in the upper lobes only in two patients. Only two patients had reduced forced first second expiratory volume (FEV1) and one reduced vital capacity (VC) below the predicted 50%. This correlated with the subjectively asymptomatic condition of the patients. All but two patients were treated by video-assisted thoracoscopic surgery (VATS) for prevention of relapsing pneumothorax. Histology showed severe lung emphysema, inflammation, and heavily pigmented macrophages. In group II, there were 85 patients: there were 78 males, the median age was 24 years (range 17-40 years), 74 patients smoked tobacco for 13.4 years but no marijuana. CT-scan in 72 patients showed only small bullae at the apex but no significant emphysema; other clinical, laboratory, and histopathological findings showed no significant difference in group I. In group III, there were 75 patients: there were 71 males and 4 females. Mean age was 25 years (range 16-46 years). Six smoked marijuana daily for a mean of 3.2 years, and 62 smoked tobacco for 14 years. CT-scan done in 59 patients showed few small bullae at the apex but no significant lung emphysema. The presence of lung emphysema on CT-scan in group I was significantly different than in groups II and III (p=0.14). No significant difference was found among all groups in the form of clinical, laboratory, and histopathological findings. CONCLUSIONS: In case of emphysema in young individuals, marijuana abuse has to be considered in the differential diagnosis. The period of marijuana smoking seems to play an important role in the development of lung emphysema. This obviously quite frequent condition in young and so far asymptomatic patients will have medical, financial, and ethical impact, as some of these patients may be severely handicapped or even become lung transplant candidates in the future.

Long-term effects of supervised exercise training on walking capacity and quality of life in patients with intermittent claudication

Supervised exercise training has been shown to improve walking capacity in several studies of patients with intermittent claudication. However, data on long-term outcome are quite limited. The aim of this prospective study was to evaluate long-term effects of supervised exercise training on walking capacity and quality of life in patients with intermittent claudication. Patients and methods: Sixty-seven consecutive patients with intermittent claudication who completed a supervised 12-week exercise training program were asked for follow up evaluation 39 +/- 20 months after program completion. Pain-free walking distance (PWD) and maximum walking distances (MWD) were assessed by treadmill test and several questionnaires. Results: Forty (60%) patients agreed to participate, 22 (33%) refused participation, and 5 (7%) died during follow-up. PWD and MWD significantly improved at completion of 12-weeks supervised exercise training as compared to baseline (PWD 114 +/- 100 vs. 235 +/- 248, p = 0.002; MWD 297 +/- 273 vs. 474 +/- 359, p = 0.001). Improvement of PWD and MWD could be maintained at follow up (197 +/- 254, p = 0.014; 390 +/- 324, p = 0.035, respectively) with non-smokers showing significantly better sustained PWD and MWD improvement as compared to baseline. Overall, walking capacity correlated with functional status of quality of life. Conclusions: Major findings of this investigation were that improvement in walking capacity is sustained after completion of supervised exercise training program with best results in patients who quitted or never smoked. Improved walking capacity is associated with increased functional status of quality of life.