Extracellular glucose influences osteoblast differentiation and c-Jun expression

Insulin dependent diabetes mellitus, marked by high blood glucose levels and no insulin secretion, is associated with decreased bone mass and increased fracture rates. Analysis of bone histology suggests that osteoblast phenotype and function are influenced by diabetes. To determine if elevated extracellular glucose levels could directly influence osteoblast phenotype we treated mouse osteoblasts, MC3T3-E1 cells, with 22 mM glucose and analyzed osteoblast gene expression. Collagen I mRNA levels significantly increased while osteocalcin mRNA levels decreased 24 h after the addition of glucose. Expression of other genes, actin, osteopontin, and histone H4, was unaffected. Effects on collagen I expression were seen as early as 1 h after treatment. c-Jun, an AP-1 transcription factor involved in the regulation of osteoblast gene expression and growth, was also modulated by glucose. Specifically, an increase in c-jun expression was found at 1 h and maintained for 24 h following glucose treatment. Treatment of osteoblasts with an equal concentration of mannitol completely mimicked glucose treatment effects on collagen I and c-jun expression, demonstrating that osmotic stress rather than glucose metabolism is responsible for the effects on osteoblast gene expression and phenotype. Additional studies using staurosporine and Ro-31-8220 demonstrate that protein kinase C is required for the glucose up regulation of collagen I and c-jun. Taken together, our results demonstrate that osteoblasts respond to increasing extracellular glucose concentration through an osmotic response pathway that is dependent upon protein kinase C activity and results in upregulation of c-jun and modulation of collagen I and osteocalcin expression.

Prevention of rhinovirus infection in chimpanzees by soluble intercellular adhesion molecule-1

Intercellular adhesion molecule-1 (ICAM-1) is the cell surface receptor for the major class of human rhinoviruses, and tICAM453, a truncated, soluble form of ICAM-1, has been shown previously to be a potent in vitro inhibitor of rhinovirus. In this report, we have investigated the in vivo efficacy of tICAM453 for the prophylaxis of rhinovirus serotype 16 infection in the chimpanzee. Because chimpanzees do not show clinical symptoms of infection after rhinovirus challenge, infection was followed by measuring antirhinovirus serum antibody responses and detection of virus shedding. By both of these measures, intranasal application of tICAM453 was efficacious in preventing rhinovirus infection in chimpanzees subsequently challenged with infectious doses of virus. These results suggest that the use of soluble rhinovirus receptor to inhibit virus binding to host cells should be feasible in humans.

Hepatocyte growth factor (HGF) adsorption kinetics and enhancement of osteoblast differentiation on hydroxyapatite surfaces

Hepatocyte growth factor (HGF) is a growth factor that promotes angiogenesis (tissue vascularization), cell motility, and cell differentiation, making it a potentially beneficial coating for bone implants. However, very little is known about maximizing HGF attachment to surfaces of tissue-engineered scaffolds. Here, we examine methods and kinetics of HGF adsorption onto a dense hydroxyapatite (HA) surface (used in bone implants) and determine the influence of HGF coating on osteoblast phenotype/differentiation. We demonstrate that incubating HA with HGF in solution (and not allowing the solution to dry) resulted in maximal surface adsorption that was not enhanced by extending incubation time beyond 2 days. Daily shaking of the coated HA surface did not remove adsorbed HGF. To further examine the effect of HA on osteoblast phenotype, MC3T3-E1 preosteoblasts were seeded onto HA or HGF-HA surfaces. Gene expression analyses indicate that HGF coating enhanced osteoblast differentiation as demonstrated by increased runx2 (a transcription factor important for osteoblast lineage and differentiation), alkaline phosphatase (marker of mid stage differentiation) and osteocalcin (marker of late stage differentiation) mRNA levels. Taken together, our results demonstrate that HGF can serve as an excellent bone implant coating based on its ability to readily adsorb to HA surfaces, maintain integrity over time, and enhance osteoblast differentiation.

Prolyl-hydroxylase inhibition and HIF activation in osteoblasts promotes an adipocytic phenotype

Bone is a dynamic environment where cells sense and adapt to changes in nutrient and oxygen availability. Conditions associated with hypoxia in bone are also associated with bone loss. In vitro hypoxia (2% oxygen) alters gene expression in osteoblasts and osteocytes and induces cellular changes including the upregulation of hypoxia inducible factor (HIF) levels. Our studies show that osteoblasts respond to hypoxia (2% oxygen) by enhancing expression of genes associated with adipocyte/lipogenesis phenotype (C/EBPbeta, PPARgamma2, and aP2) and by suppressing expression of genes associated with osteoblast differentiation (alkaline phosphatase, AP). Hypoxia increased HIF protein levels, hypoxic response element (HRE) binding, and HRE-reporter activity. We also demonstrate that prolyl-hydroxylases 2 and 3 (PHD2, PHD3), one of the major factors coordinating HIF degradation under normoxic but not hypoxic conditions, are induced in osteoblasts under hypoxic conditions. To further determine the contribution of PHDs and upregulated HIF activity in modulating osteoblast phenotype, we treated osteoblasts with a PHD inhibitor, dimethyloxaloylglycine (DMOG), and maintained cells under normoxic conditions. Similar to hypoxic conditions, HRE reporter activity was increased and adipogenic gene expression was increased while osteoblastic genes were suppressed. Taken together, our findings indicate a role for PHDs and HIFs in the regulation of osteoblast phenotype.

Comparative chronic toxicities and carcinogenic potentials of 2-ethylhexyl-containing compounds in rats and mice

Four compounds containing a 2-ethylhexyl moiety [di(2-ethylhexyl)phthalate (DEHP), di(2-ethylhexyl)adipate (DEHA), tris(2-ethylhexyl)phosphate (TEHP), and 2-ethylhexyl sulfate (EHS)] were tested for carcinogenic and other chronic and subchronic toxic effects in 90-day and 2-year studies in male and female Fischer 344 rats and B6C3F1 mice. The low generalized toxic potencies of the test chemicals allowed relatively high doses of all of these compounds to be administered. Despite differences in chemical structure, all four chemicals were related to increased occurrences of hepatocellular neoplasms, principally carcinomas, in female mice. DEHA and DEHP also induced hepatocellular neoplasms in male mice, while DEHP caused hepatocellular neoplasms in both male and female rats. No other neoplasms were considered to be unequivocally related to compound administration in these studies. There was a positive correlation between the magnitude of the hepatocarcinogenic response in female mice and the probability of a hepatocarcinogenic response in male mice and in male and female rats, suggesting quantitative differences in the carcinogenic potentials of these agents. These results suggest that compounds containing a 2-ethylhexyl moiety (and 2-ethylhexanol, by implication) may possess some carcinogenic potential, especially for the rodent liver. No other organ-specific toxic effects common to two or more test chemicals were observed in these studies.

Parathyroid hormone stimulates fra-2 expression in osteoblastic cells in vitro and in vivo

PTH and PTH-related protein (PTHrP) are key mediators of skeletal development and homeostasis through their activation of the PTH-1 receptor. Previous studies have found that several AP-1 family members are regulated by PTH, such as c-fos, fra-1, and c-jun. There are numerous genes in the bone microenvironment that contain AP-1 sites, and different Fos family members are reported to have opposing transcriptional activities at AP-1 sites. The purpose of this study was to identify the effects of PTH on expression of the AP-1 protein complex member, fra-2, to extend our understanding of transcriptional regulators of PTH action. PTH induction of fra-2 messenger RNA (mRNA) levels in MC3T3-E1 preosteoblastic cells was maximal with 0.1 microM PTH (1-34). The expression in vitro was greatest 1 h after treatment and was present with N-terminal PTH but not PTH (7-34) or (53-84). Cycloheximide treatment induced fra-2 expression, and actinomycin D inhibited basal and PTHrP-induced expression. AP-1 protein in nuclear extracts of MC3T3-E1 cells was increased with PTH treatment at 3 h and consisted of high levels of Fra-2 protein, as evidenced by a supershift in an electrophoretic mobility shift assay and Western blot analysis. Up-regulation of steady-state fra-2 mRNA was also noted in vivo, where injection of PTH (1-34) (20 microgram) resulted in a more-than-7-fold maximal increase in fra-2 mRNA expression in the calvaria of mice, after 1 h of treatment. These data add to the transcriptional mediators induced by PTH and suggest that the interplay of AP-1 family members will provide insight into regulatory pathways of PTH and PTHrP for their anabolic and catabolic actions in bone.

Appendicitis risk prediction models in children presenting with right iliac fossa pain (RIFT study): a prospective, multicentre validation study

BACKGROUND

Acute appendicitis is the most common surgical emergency in children. Differentiation of acute appendicitis from conditions that do not require operative management can be challenging in children. This study aimed to identify the optimum risk prediction model to stratify acute appendicitis risk in children.

METHODS

We did a rapid review to identify acute appendicitis risk prediction models. A prospective, multicentre cohort study was then done to evaluate performance of these models. Children (aged 5-15 years) presenting with acute right iliac fossa pain in the UK and Ireland were included. For each model, score cutoff thresholds were systematically varied to identify the best achievable specificity while maintaining a failure rate (ie, proportion of patients identified as low risk who had acute appendicitis) less than 5%. The normal appendicectomy rate was the proportion of resected appendixes found to be normal on histopathological examination.

FINDINGS

15 risk prediction models were identified that could be assessed. The cohort study enrolled 1827 children from 139 centres, of whom 630 (34·5%) underwent appendicectomy. The normal appendicectomy rate was 15·9% (100 of 630 patients). The Shera score was the best performing model, with an area under the curve of 0·84 (95% CI 0·82-0·86). Applying score cutoffs of 3 points or lower for children aged 5-10 years and girls aged 11-15 years, and 2 points or lower for boys aged 11-15 years, the failure rate was 3·3% (95% CI 2·0-5·2; 18 of 539 patients), specificity was 44·3% (95% CI 41·4-47·2; 521 of 1176), and positive predictive value was 41·4% (38·5-44·4; 463 of 1118). Positive predictive value for the Shera score with a cutoff of 6 points or lower (72·6%, 67·4-77·4) was similar to that of ultrasound scan (75·0%, 65·3-83·1).

INTERPRETATION

The Shera score has the potential to identify a large group of children at low risk of acute appendicitis who could be considered for early discharge. Risk scoring does not identify children who should proceed directly to surgery. Medium-risk and high-risk children should undergo routine preoperative ultrasound imaging by operators trained to assess for acute appendicitis, and MRI or low-dose CT if uncertainty remains.

FUNDING

None.

Self-monitored smoking motives

The motives for smoking in 73 low, medium, and high rate smokers were surveyed and were evaluated the validity of the Reasons for Smoking scale (RFS) by correlating RFS scores with self-monitored reasons for smoking. Combined sample correlations were significant for 5 of the 6 RFS reasons. However, all correlations were modest, the number of correlations varied with smoking rate, and the RFS was not a valid measure of pleasurable relaxation, the reason most frequently reported during self-monitoring. The unexpected finding that pleasurable relaxation, not reduction of negative affect, was the most frequently endorsed reason conflicts with previous surveys, almost all of which sampled older smokers. Smoking behavior of younger smokers may differ from older smokers in ways important to the study of smoking motivation. These differences may explain why experimental studies with undergraduates generally find no relationship between smoking and negative affect while studies with older subjects do.

Psychosis following acute alteration of thyroid status

OBJECTIVE

Mania with psychotic features presenting following abrupt normalisation of thyroid function from severe Graves's disease is reported.

CLINICAL PICTURE

A 33-year-old man with severe, untreated Graves's disease was treated aggressively, with rapid restoration of normal serum thyroid hormone levels. Symptoms of mania and psychosis then developed.

TREATMENT

Time limited antipsychotic medication and continuing medical treatment.

OUTCOME

There was resolution of psychiatric symptoms.

CONCLUSIONS

The association of mania and psychosis with thyroid disease is rare, but aggressive medical treatment and rapid restoration of normal serum thyroid levels may increase the risk of the emergence of such symptoms.

Isolation of a single polypeptide leucyl-tRNA synthetase from bakers' yeast

A single polypeptide of leucyl-tRNA synthetase (LRS) has been purified from budding bakers' yeast by a modification of the procedure published earlier. On denaturing polyacrylamide gel electrophoresis LRS was one band corresponding to molecular weight of 120,000 +/- 5,000 daltons. Variable amounts of LRS with a similar molecular weight but which dissociated into equal subunits of 58,000 were also isolated. The affinities (KM) for substrates for this form of the enzyme were similar to those previously reported for the dimeric form of the enzyme.

Sexual health promotion and nursing

The HIV epidemic provides continued impetus for effective sexual health promotion. Sexual health promotion in nursing practice has traditionally been equated to prevention at primary, secondary and tertiary levels. Increasing demands on practitioners to address the psycho-social aspects of sexual health, together with a greater emphasis on primary prevention, is leading to the adoption of theoretical paradigms from the behavioural sciences and the increasing use of counselling skills. The limitations of individualist interventions for primary prevention are explored, and the assumption that health care professionals are effective promoters of sexual health is questioned. The importance of placing sexual health and nursing practice within a wider social, political and cultural context is emphasized.

Lecture 5: erectile dysfunction in the HIV-positive male: a review of medical, legal and ethical considerations in the age of oral pharmacotherapy

Urologists and health care professionals treating erectile dysfunction face a significant challenge in caring for the HIV-positive patient who seeks restoration of normal sexual function. The encounter between the health care provider and the patient in this setting requires knowledge of HIV disease and potential drug interactions specific to this population, as well as thorough counseling on strategies aimed at reducing the infectiousness of HIV-1. The interaction extends beyond the immediate boundaries of the doctor-patient relationship and their respective rights, to include careful consideration of the rights of the partner/s and the society as a whole. This paper is a summary and analysis of presentations and discussions by medical, legal, nursing and bioethics specialists in an interactive seminar on this topic.

Epithelioid hemangioendothelioma mimicking a nerve sheath tumor clinically and on MR imaging

Epithelioid hemangioendothelioma is a tumor of the soft tissues arising from the vascular endothelium. It is considered an intermediate grade malignancy. A 42-year-old female patient presented with pain and tingling down her right arm and a mass at the right medial upper extremity. MRI revealed an oblong mass along the course of the neurovascular bundle. Given the clinical and MR findings, a nerve sheath tumor was suspected. At surgery, the mass was adherent to both the brachial artery medially and the median nerve posteriorly. Pathology revealed epithelioid hemangioendothelioma. The imaging characteristics of epithelioid hemangioendothelioma on ultrasound, CT, and MRI are reviewed. Epithelioid hemangioendothelioma can mimic a nerve sheath tumor clinically and radiologically and should be considered in the differential diagnosis of tumors involving or adjacent to a neurovascular bundle.

Evaluation of associations between feed withdrawal and other management factors with Salmonella contamination of broiler chickens at slaughter in Alberta

Salmonellosis is one of the most common bacterial foodborne diseases of public health concern in industrialized countries. Poultry products are considered an important source of Salmonella-related foodborne disease in humans. This study was undertaken to evaluate the relationship between various management factors including feed withdrawal and transportation time with Salmonella contamination in crops, ceca, and carcasses of broiler chickens at slaughter in Alberta. Using a two-stage sampling procedure, 30 matched crop and cecal samples before evisceration and an additional 30 neck skin samples after final wash of broiler chickens were collected at slaughter. A questionnaire was administered at the time of sampling to collect information on flock management risk factors. Cecal contents were individually screened with Salmonella-specific real-time PCR to detect positive flocks, and all cecal, crop, and neck skin samples from positive flocks were processed further for Salmonella isolation and characterization. The flock prevalence of Salmonella was 57.1% and within-flock prevalence of Salmonella for positive flocks was 17.2, 8.1, and 53.9% for ceca, crops, and neck skins, respectively. Salmonella Hadar was the most common serovar identified from crops, ceca, and neck skins of broiler chickens tested. Longer transport (P = 0.04 for neck skins) and waiting time in-plant (P = 0.04 for crops, P = 0.03 for ceca) were identified as important risk factors for Salmonella contamination of broiler chickens at slaughter. Salmonella contamination of broiler chickens could potentially be minimized by reducing waiting time in-plant for flocks with longer transport time.

Alcohol, young people and the media: a study of radio output in six radio stations in England

BACKGROUND

This research investigated the representation of alcohol in radio output. The study was prompted by concerns that media output might be part of a developing culture of excessive drinking among young people.

METHODS

Alcohol comments were examined across six radio stations in England. 1200 h of weekend output was screened and the sampling frame included periods when references to alcohol would be expected, such as the Christmas period. Statistical analysis identified the volume and proportion of comments, whereas qualitative analysis explored these in more depth, focusing on the themes and discourses surrounding alcohol talk.

RESULTS

Of 703 alcohol comments identified, 244 involved presenters. The volume of comments about alcohol varied between stations, being lower on BBC than on commercial stations and being influenced by music genre. Seventy-three percent of comments initiated by presenters, compared with 45% of comments from all sources, encouraged drinking. The majority of comments by presenters support drinking in relation to partying and socializing. Alcohol comments seem to create identity for programmes and forge connections between presenters and audiences, although some presenters achieve this without mentioning drinking. The assumption that alcohol is necessary to have a good time is seldom directly challenged.

CONCLUSIONS

While it may be unsurprising that much of this content reflected themes of weekend drinking and partying, the study suggests that alcohol comments play a particular role in marketing and branding of radio output. Comments about alcohol are shaped by broadcasting conventions that make it difficult to challenge discourses surrounding excessive drinking. Further research is needed on the influence that radio output may have on drinking behaviour among young people.

Efficacy of amoxycillin/clavulanic acid in experimental Staphylococcus aureus endocarditis in the rat

The efficacy of amoxycillin/clavulanic acid was compared with that of flucloxacillin, vancomycin and amoxycillin in an experimental model of Staphylococcus aureus endocarditis. Doses of the antibiotics were selected to produce peak concentrations in rat serum similar to those achievable in man after administration of parenteral therapeutic doses. Amoxycillin clavulanic acid was more effective than amoxycillin alone against endocarditis caused by beta-lactamase producing strains of Staph. aureus, illustrating the beta-lactamase inhibitory activity of clavulanic acid in vivo. Amoxycillin/clavulanic acid was as effective as flucloxacillin in these infections whereas vancomycin was generally less active. These results illustrate the clinical potential of amoxycillin/clavulanic acid in the prophylaxis, or in the therapy of severe staphylococcal infections.

Efficacy of ticarcillin-clavulanic acid for treatment of experimental Staphylococcus aureus endocarditis in rats

The efficacy of ticarcillin-clavulanic acid was compared with the efficacies of standard antistaphylococcal agents (flucloxacillin, oxacillin, nafcillin, and vancomycin) and ticarcillin in an experimental model of Staphylococcus aureus endocarditis. Therapy was either initiated soon (8 h) after infection, when numbers of bacteria in aortic valve vegetations were relatively low (approximately 6 to 8 log10 CFU/g), or delayed until 24 h after infection, when the vegetations usually contained greater than 9 log10 CFU/g. Doses of the antibiotic were selected to produce peak concentrations in rat serum similar to those achievable in humans after administration of parenteral therapeutic doses. Ticarcillin-clavulanic acid was more effective overall than ticarcillin alone against endocarditis caused by beta-lactamase-producing strains of S. aureus, illustrating the beta-lactamase-inhibitory activity of clavulanic acid in vivo. Ticarcillin-clavulanic acid was as effective as the standard antistaphylococcal beta-lactam agents flucloxacillin, oxacillin, and nafcillin in these infections, whereas vancomycin was generally less active. These results illustrate the clinical potential of ticarcillin-clavulanic acid in the prophylaxis or therapy of severe staphylococcal infections.

Evaluation of antimicrobial resistance profiles of Salmonella isolates from broiler chickens at slaughter in Alberta, Canada

Antimicrobial-resistant Salmonella species are threatening to become a serious public health problem. Therefore, surveillance and prudent use of antimicrobials is needed in both the agricultural and human health sectors. The aim of this study was to describe the antimicrobial susceptibility profiles of Salmonella isolates recovered from healthy broiler chickens at slaughter from November 2004 to April 2005. Salmonella isolates recovered from 36 broiler flocks in Alberta, Canada, were serotyped and tested for antimicrobial susceptibility against 15 antimicrobials. Of 272 Salmonella isolates tested, 64.0% were resistant to one or more antimicrobials, 10.0% were resistant to three or more antimicrobials, and 1.8% were resistant to five antimicrobials. All isolates were susceptible to amikacin, amoxicillin-clavulanic acid, ceftiofur, cefoxitin, ceftriaxone, ciprofloxacin, and nalidixic acid. The highest prevalence of resistance was to tetracycline (54.8%), followed by streptomycin (24.2%) and sulfisoxazole (8.4%). The most common multiantimicrobial resistance patterns were to streptomycin-tetracycline (24.3%), streptomycin-sulfisoxazole-tetracycline (6.6%), and ampicillin-streptomycin-sulfisoxazole-tetracycline (3.7%). The strongest associations were observed between resistance to kanamycin and tetracycline (odds ratio = 65.7, P = 0.001) and to ampicillin and sulfisoxazole (odds ratio = 62.9, P = 0.001). Salmonella Hadar and Salmonella Heidelberg were the two most common serovars accounting for 40.4 and 13.6% of the total isolates, respectively. Eighty-one percent and 12.7% of Salmonella Hadar isolates and 62.0 and 8.1% of Salmonella Heidelberg isolates were resistant to 1 or more and three or more antimicrobials, respectively. The flock level prevalence of resistance ranged from 5.6% for trimethoprim-sulfamethoxazole to 83.3% for tetracycline. This study provides baseline information on antimicrobial susceptibility of Salmonella isolates of broiler chickens at slaughter in Alberta that can serve as a benchmark for future research.

Subcutaneous emphysema of the neck and colonic perforation

Subcutaneous emphysema may result from pathological changes in the thorax or lung, as a result of localised infection with gas producing organisms, after abdominal procedures, or herald an intestinal perforation. The location and spread of extraperitoneal gas is determined by the anatomical barriers and fixed fascial layers surrounding the region of pathological change. The case highlights the extent of extraperitoneal gas after colonic perforation despite minimal clinical features and the importance of intra-abdominal causes of cervical subcutaneous emphysema.

Verification of an alternative sludge treatment process for pathogen reduction at two wastewater treatment plants in Victoria, Australia

At South East Water wastewater treatment plants (WwTPs) in Victoria, Australia, biosolids are stockpiled for three years in compliance with the State guidelines to achieve the highest pathogen reduction grade (T1), suitable for unrestricted use in agriculture and landscaping. However, extended stockpiling is costly, may increase odour nuisance and greenhouse gas emissions, and reduces the fertiliser value of the biosolids. A verification programme of sampling and analysis for enteric pathogens was conducted at two WwTPs where sludge is treated by aerobic and anaerobic digestion, air drying (in drying pans or solar drying sheds) and stockpiling, to enumerate and, if present, monitor the decay of a range of enteric pathogens and parasites. The sludge treatment processes at both WwTPs achieved T1 grade biosolids with respect to prescribed pathogenic bacterial numbers (<1 Salmonella spp. 50 g^-1 dry solids (DS) and <100 Escherichia coli g^-1 DS) and >3 log₁₀ enteric virus reduction after a storage period of one year. No Ascaris eggs were detected in the influent to the WwTPs, confirming previous studies that the presence of helminth infections in Victoria is extremely low and that Ascaris is not applicable as a control criterion for the microbiological quality of biosolids in the region.