Impact of nursing home residence on hospital epidemiology of meticillin-resistant Staphylococcus aureus: a perspective from Asia

In a Singapore hospital practising meticillin-resistant Staphylococcus aureus (MRSA) admission screening, the relative risk for MRSA colonization for those admitted from nursing homes was 6.89 (95% confidence interval: 5.74-8.26; 41% of 190 vs 6.0% of 14,849). However, the MRSA burden on admission attributable to nursing home residence was low (6.9%). Risk factors independently associated with MRSA colonization in patients admitted from nursing homes were previous hospital admissions, broken skin, prior use of antibiotics and Chinese ethnicity. Low rates of nursing home use means that the overall impact of nursing home residence on MRSA in our hospital is low.

An ongoing large outbreak of measles in Merseyside, England, January to June 2012

From 1 January to 30 June 2012, 359 confirmed and 157 probable cases of measles were reported in Merseyside, England. The most affected age groups were children under five years and young adults from 15 years of age. Most cases have been sporadic. There have been few outbreaks in nurseries; however, no outbreaks have been reported in schools. Of the cases eligible for vaccination, only 3% of the confirmed cases were fully immunised.

An ongoing large outbreak of measles in Merseyside, England, January to June 2012

From 1 January to 30 June 2012, 359 confirmed and 157 probable cases of measles were reported in Merseyside, England. The most affected age groups were children under five years and young adults from 15 years of age. Most cases have been sporadic. There have been few outbreaks in nurseries; however, no outbreaks have been reported in schools. Of the cases eligible for vaccination, only 3% of the confirmed cases were fully immunised.

Compositional studies of human RPE lipofuscin: mechanisms of molecular modifications

The accumulation of lipofuscin has previously been implicated in several retinal diseases including Best's macular dystrophy, Stargardt's disease and age-related macular degeneration (AMD). Previously one of the major fluorophores of lipofuscin was identified as a bis-retinoid pyridinium salt called A2E, which is known to photochemically cause damage. In addition to A2E, there are numerous components in RPE lipofuscin that are unidentified. These compounds were determined to be structurally related to A2E by their fragmentation pattern with losses of 106, 190, 174 and/or 150 amu from the parent ion and the formation of fragments of ca 592 amu. The vast majority consists of relatively hydrophobic components corresponding to derivatized A2E with molecular weights in discrete groups of 800-900, 970-1080 and > 1200 m/z regions. In order to determine the mechanism of these modifications, A2E was chemically modified by; (1) the formation of specific esters, (2) reaction with specific aldehydes and (3) spontaneous auto-oxidation. The contribution of ester formation to the naturally occurring components of lipofuscin was discounted since their fragmentation patterns were different to those found in vivo. Alternatively, reactions with specific aldehydes result in nearly identical products as those found in vivo. Artificial aging of RPE lipofuscin gives a complex mixture of structurally related components. This results from the auto- and/or photooxidation of A2E to form aldehydes, which then back react with A2E giving a series of higher molecular weight products. The majority of these modifications result in compounds that are much more hydrophobic than A2E. These higher molecular weight materials have increased values of log P compared to A2E. This increase in hydrophobicity most likely aids in the sequestering of A2E into granules with the concomitant diminution of its reactivity. Therefore, these processes may serve as protective mechanisms for the RPE.

Compositional studies of human RPE lipofuscin

Age-related macular degeneration (AMD) is an ocular disease that causes visual loss and legal blindness in the elderly population. The etiology of AMD is complex and may include genetic predispositions, accumulation of lipofuscin and drusen, local inflammation and neovascularization. The accumulation of lipofuscin has been shown to precede the death of photoreceptor cells and the deterioration of the RPE. As a result, the determination of the photosensitive components of lipofuscin has been of major interest. One of these components, previously identified as a bis-retinoid pyridinium compound, is referred to as A2E. A2E has been characterized by mass spectrometry and is known to have a mass of 592 Da. Most remaining chromophores in RPE lipofuscin are structurally related to A2E as determined by their fragmentation pattern with losses of M ± 190, 174 and/or 150 Da. Analysis of lipofuscin from various donors indicated that the extracts consist of as many as 15 of these hydrophobic components, which are also observed to form spontaneously in vitro over extended periods of time. These consist of ca 90% of the A2E-like components in RPE lipofuscin and correspond to derivatized A2E with discrete molecular weights of 800-900 m/z, 970-1080 m/z and above 1200 m/z regions. It was determined that these species are formed from self-reaction of A2E oxidation products or their reaction with A2E itself to form higher molecular weight products. The majority of modifications are much more hydrophobic than A2E and exhibit increasingly higher values of log P. This acts as a driving force for the sequestering of A2E into granules resulting in a concomitant diminution of its reactivity in vivo.

Compositional studies of human RPE lipofuscin

Age-related macular degeneration (AMD) is an ocular disease that causes visual loss and legal blindness in the elderly population. The etiology of AMD is complex and may include genetic predispositions, accumulation of lipofuscin and drusen, local inflammation and neovascularization. The accumulation of lipofuscin has been shown to precede the death of photoreceptor cells and the deterioration of the RPE. As a result, the determination of the photosensitive components of lipofuscin has been of major interest. One of these components, previously identified as a bis-retinoid pyridinium compound, is referred to as A2E. A2E has been characterized by mass spectrometry and is known to have a mass of 592 Da. Most remaining chromophores in RPE lipofuscin are structurally related to A2E as determined by their fragmentation pattern with losses of M ± 190, 174 and/or 150 Da. Analysis of lipofuscin from various donors indicated that the extracts consist of as many as 15 of these hydrophobic components, which are also observed to form spontaneously in vitro over extended periods of time. These consist of ca 90% of the A2E-like components in RPE lipofuscin and correspond to derivatized A2E with discrete molecular weights of 800-900 m/z, 970-1080 m/z and above 1200 m/z regions. It was determined that these species are formed from self-reaction of A2E oxidation products or their reaction with A2E itself to form higher molecular weight products. The majority of modifications are much more hydrophobic than A2E and exhibit increasingly higher values of log P. This acts as a driving force for the sequestering of A2E into granules resulting in a concomitant diminution of its reactivity in vivo.

Age-related accumulation of 3-nitrotyrosine and nitro-A2E in human Bruch's membrane

Age-related macular degeneration (AMD) is a disease leading to severe visual loss and legal blindness in the elderly population. The pathophysiology of AMD is complex and may include genetic predispositions, accumulation of lipofuscin and drusen, local inflammation and neovascularization. Recently four independent research groups have identified a commonly inherited variant (Y402H) of the complement factor H gene in the genome from different groups of AMD patients. The Y402H variant of CFH significantly increases the risk of AMD and links the genetics of the disease with inflammation. During inflammation there is activation of inducible nitric oxide synthase and release of nitric oxide, which in principal could lead to non-enzymatic nitration within extracellular deposits and/or intrinsic extracellular matrix protein components of human Bruch's membrane. We have identified two biomarkers for non-enzymatic nitration in aged human Bruch's membrane, indicative of inflammation, that include 3-nitrotyrosine identified in Bruch's membrane preparations and nitrated A2E from the lipid soluble extract of the Bruch's membrane preparation. Approximately 30-40 times more A2E is observed in samples of the organic soluble extract of lipofuscin compared to the extract of Bruch's membrane. It is of interest to note that although A2E is a major constituent of RPE lipofuscin, nitrated A2E could not be detected in RPE extracts. We show here that nitro-A2E is a specific biomarker of nitrosative stress in Bruch's membrane and its concentration correlates directly with tissue age.

Whipple's procedure for an oligometastasis to the pancreas from a leiomyosarcoma of the thigh

BACKGROUND

Pancreatic tumours are most frequently primary, with lesions secondary to metastasis uncommon.

METHODS

This report describes the case of a 61-year-old man who underwent resection of a right thigh leiomyosarcoma 2 years prior to presentation with obstructive jaundice. Subsequent CT and endoscopic ultrasound (EUS) diagnosed metastatic leiomyosarcoma to the pancreatic head for which he underwent a Whipple's pancreaticoduodenectomy.

CONCLUSION

Metastasis from an extremity leiomyosarcoma to the pancreas is an extremely rare entity, which can be diagnosed by EUS and treated successfully by pancreaticoduodenectomy.

A study of the safety of current gastrointestinal endoscopy (EGD)

BACKGROUND AND STUDY AIMS

Previous attempts at assessing the safety of upper gastrointestinal endoscopy have been hampered by incomplete data collection. We aimed to assess the 30-day mortality associated with esophagogastroduodenoscopy (EGD) and assess the important risk factors.

PATIENTS AND METHODS

A retrospective cohort study was conducted of patients who underwent endoscopy at Ninewells Hospital in Dundee between 1 June 2000 and 31 May 2003. A total of 11 501 EGDs were performed in 8926 patients. These patients were record-linked to the death registry and the database of hospital admissions in order to calculate the all-cause 30-day mortality. An expert panel judged whether EGD had caused or contributed to the deaths. Logistic regression analysis was performed on outcomes of all-cause and EGD-contributed mortality.

RESULTS

The median age of the patients was 62 years (interquartile range 48 - 74 years), 54 % were women, and 94 % of procedures were diagnostic. A total of 395 patients died within 30 days (all-cause 30-day mortality rate 4.4 %). One patient death was caused directly by the EGD (procedure-caused mortality rate 1 in 9000). EGD was judged to have contributed to patient deaths at a rate of 1 in 182, based on majority agreement of experts: some factors associated with these deaths were percutaneous endoscopic gastrostomy insertion (odds ratio [OR] 18.39, 95 % confidence interval [CI] 5.71 - 59.22), melena or hematemesis indications (OR 9.01, 95 % CI 3.53 - 22.99), and esophageal varices (OR 6.28, 95 % CI 1.54 - 25.60).

CONCLUSIONS

A causal death rate of 1 in 9000 suggests that EGD is very safe. However, certain patient groups have an increased mortality, and the risks and benefits of EGD should be carefully evaluated in each patient.

Molecular characterization of the metabotropic glutamate receptor family in Caenorhabditis elegans

mGluRs (metabotropic glutamate receptors) are G-protein-coupled receptors that play an important neuromodulatory role in the brain. Glutamatergic transmission itself plays a fundamental role in the simple nervous system of the model organism Caenorhabditis elegans, but little is known about the contribution made by mGluR signalling. The sequenced genome of C. elegans predicts three distinct genes, mgl-1, mgl-2 and mgl-3 (designated Y4C6A.2). We have used in silico and cDNA analyses to investigate the genes encoding mgls. Our results indicate that mgl genes constitute a gene family made up of three distinct subclasses of receptor. Our transcript analysis highlights potential for complex gene regulation with respect to both expression and splicing. Further, we identify that the predicted proteins encoded by mgls harbour structural motifs that are likely to regulate function. Taken together, this molecular characterization provides a platform to further investigate mGluR function in the model organism C. elegans.

Antioxidant Properties of Melanin in Retinal Pigment Epithelial Cells

The retinal pigment epithelium (RPE) is a monolayer of highly pigmented cells lining the inner aspect of Bruch's membrane. This pigmentation is due to eumelanin and a possible antioxidant role of melanin is reported here. The photo-oxidation of A2E, a constituent of RPE lipofuscin, leads to the sequential addition of up to nine oxygen atoms and/or the addition or loss of two hydrogen atoms. These photo-oxidations were investigated in the presence and absence of either calf or human RPE melanin in A2E-laden RPE cells. It was found that calf melanin was protective against the photo-oxidation of A2E, with an inhibition of oxidation of up to 50% in the case of the addition of two oxygen atoms. Calf melanin was also protective against blue light-induced damage to RPE cells. In addition this ability appears to decrease in humans as they grow older. With aging, a melanin-lipofuscin complex called melanolipofuscin forms. It is suggested that the oxidation or photo-oxidation of A2E in vivo may contribute to the age-related deterioration of the anti-oxidant role of RPE melanin and lead to various retinal disorders, such as age-related macular degeneration.

Determining calmodulin binding to metabotropic glutamate receptors with distinct protein-interaction methods

mGluRs (metabotropic glutamate receptors) are G-protein-coupled receptors that modulate synaptic transmission. The eight mammalian mGluRs form three groups based on sequence and functional similarities: group I (1 and 5), group II (2 and 3) and group III (4, 6-8) mGluRs. In the present study, we used a Y2H (yeast two hybrid) screen to identify proteins that interact with the C-terminal intracellular tail of mGluR3. Prominent among the candidate receptor interacting proteins was calmodulin, a Ca(2+) sensor known to bind identifiable sequences in group I and III mGluRs. The Y2H method was used to investigate calmodulin binding to mGluRs but failed to confirm the documented interaction with group III mGluRs. Furthermore, subsequent biochemical analysis showed that calmodulin does not interact with group II mGluRs. This illustrates that certain Ca(2+)-dependent interactions are not recapitulated in yeast. Moreover, it highlights the necessity for supporting biochemical data to substantiate interactions identified with Y2H methods.

A New Approach to Measuring the Action Spectrum for Singlet Oxygen Production by Human Retinal Lipofuscin

The human retinal pigment epithelial (RPE) layer contains a complex mixture of components called lipofuscin; this mixture forms with age and with various genetic disorders such as Stargardt's disease. Its presence may contribute to retinal deterioration via several mechanisms including photochemical processes. In the lipofuscin mixture, both type I and II mechanisms have been identified, with the latter consisting of the generation of singlet oxygen. Several components of that mixture have been identified, most notably a bis-retinoid pyridinium compound called A2E and its derivatives. Photooxidative studies on the compound A2E have revealed that its dominant photochemical mechanism is via free radical or type I processes. Because singlet oxygen is an important photooxidative intermediate in tissue, its generation in the RPE may contribute to retinal maculopathies. It is therefore necessary to determine which specific component(s) in the lipofuscin mixture produce singlet oxygen upon excitation with light. This was ascertained by evaluating the action spectrum for singlet oxygen production for the whole lipofuscin mixture using time-resolved spectroscopy. Singlet oxygen was generated by excitation of the sample at different wavelengths while maintaining a constant beam energy, and was directly detected by its phosphorescence decay at 1270 nm using a Ge photodiode. The action spectrum for singlet oxygen sensitization by the organic soluble portion of lipofuscin had an absorption maximum at ca 380 nm, which is to the blue of A2E (maximum at 430 nm). Compounds with a similar absorption maximum eluted in the HPLC earlier than A2E and were detected in human lipofuscin. The concentration of this component apparently increased in concentration in human RPE lipofuscin mixture as a function of age up to 90 years old.

The photochemical oxidation of A2E results in the formation of a 5,8,5′,8′-bis-furanoid oxide

With age and certain diseases, the retinal pigment epithelium (RPE) accumulates a complex mixture of fluorophores generally called lipofuscin. This mixture has been implicated in those diseases via several possible mechanisms including photochemically mediated damage and detergent effects. Recently, a component of that mixture has been identified, a bis-retinoid pyridinium compound called A2E. Furthermore, the photolysis of this compound has been shown to lead to a series of photooxidation products each differing by 16 amu; with the addition of up to a total of nine oxygen atoms to A2E. It has been suggested that these products consist of a series of epoxides forming along the acyclic side chains. The present study reinvestigates this hypothesis and demonstrates that the bis-oxygenated product is in fact a relatively stable 5-8 5'-8'-bis-furanoid oxide. This is in agreement with the oxidation products observed for a homologue of A2E, beta-carotene. In addition, it was found that the bis-oxygenated photoproduct of A2E contained a mixture of symmetrical and unsymmetrical oxidized products where the second oxygen was present in the cyclohexenyl ring structure in the unsymmetrical product. Most importantly, both of these oxidation products of A2E were detected in lipofuscin extracts from human RPE cells, suggesting that these processes occur in vivo.

Fluoxetine improves functional work capacity in women with premenstrual dysphoric disorder

Interference with social and occupational functioning is a key criterion for premenstrual dysphoric disorder (PMDD) and distinguishes it from the less severe premenstrual syndrome (PMS). We conducted a post hoc analysis of the results of a previously reported study evaluating the efficacy of fluoxetine in the management of PMDD, to determine the extent to which women with PMDD perceived impairment in their functional work capacity during the luteal phase of their menstrual cycle. The effects of two doses of fluoxetine vs placebo in alleviating PMDD symptoms and restoring normal work capacity during this period were assessed. We measured baseline follicular vs luteal phase presence of 8 patient-rated functional work capacity-related symptoms on the Premenstrual Tension Scale-Self Rated in 320 women who met diagnostic criteria for late luteal phase dysphoric disorder, now known as PMDD. Women were then randomized to double-blind treatment with either fluoxetine 20 mg/d, fluoxetine 60 mg/d, or placebo daily for 6 menstrual cycles. All 8 work capacity-related symptoms were more likely to be present in the baseline luteal phase than in the baseline follicular phase. A statistically significant improvement from baseline to the average treatment score for the work capacity subscale was detected for both fluoxetine groups compared to the placebo group. This beneficial response to fluoxetine was evident by the first cycle of treatment. Our results demonstrate that fluoxetine at a relatively low dose of 20 mg/d quickly reduced symptoms that negatively affect work capacity and was well tolerated.