Repeated large-scale retreat and advance of Totten Glacier indicated by inland bed erosion.

Climate variations cause ice sheets to retreat and advance, raising or lowering sea level by metres to decametres. The basic relationship is unambiguous, but the timing, magnitude and sources of sea-level change remain unclear; in particular, the contribution of the East Antarctic Ice Sheet (EAIS) is ill defined, restricting our appreciation of potential future change. Several lines of evidence suggest possible collapse of the Totten Glacier into interior basins during past warm periods, most notably the Pliocene epoch, causing several metres of sea-level rise. However, the structure and long-term evolution of the ice sheet in this region have been understood insufficiently to constrain past ice-sheet extents. Here we show that deep ice-sheet erosion-enough to expose basement rocks-has occurred in two regions: the head of the Totten Glacier, within 150 kilometres of today's grounding line; and deep within the Sabrina Subglacial Basin, 350-550 kilometres from this grounding line. Our results, based on ICECAP aerogeophysical data, demarcate the marginal zones of two distinct quasi-stable EAIS configurations, corresponding to the 'modern-scale' ice sheet (with a marginal zone near the present ice-sheet margin) and the retreated ice sheet (with the marginal zone located far inland). The transitional region of 200-250 kilometres in width is less eroded, suggesting shorter-lived exposure to eroding conditions during repeated retreat-advance events, which are probably driven by ocean-forced instabilities. Representative ice-sheet models indicate that the global sea-level increase resulting from retreat in this sector can be up to 0.9 metres in the modern-scale configuration, and exceeds 2 metres in the retreated configuration.

Detecting causal relationship between metabolic traits and osteoporosis using multivariable Mendelian randomization.

By adopting the extension approaches of Mendelian randomization, we successfully detected and prioritized the potential causal risk factors for BMD traits, which might provide us novel insights for treatment and intervention into bone-related complex traits and diseases. INTRODUCTION: Osteoporosis (OP) is a common metabolic skeletal disease characterized by reduced bone mineral density (BMD). The identified SNPs for BMD can only explain approximately 10% of the variability, and very few causal factors have been identified so far. METHODS: The Mendelian randomization (MR) approach enables us to assess the potential causal effect of a risk factor on the outcome by using genetic IVs. By using extension methods of MR-multivariable MR (mvMR) and MR based on Bayesian model averaging (MR-BMA)-we intend to estimate the causal relationship between fifteen metabolic risk factors for BMD and try to prioritize the most potential causal risk factors for BMD. RESULTS: Our analysis identified three risk factors T2D, FG, and HCadjBMI for FN BMD; four risk factors FI, T2D, HCadjBMI, and WCadjBMI for FA BMD; and three risk factors FI, T2D, and HDL cholesterol for LS BMD, and all risk factors were causally associated with heel BMD except for triglycerides and WCadjBMI. Consistent with the mvMR results, MR-BMA confirmed those risk factors as top risk factors for each BMD trait individually. CONCLUSIONS: By combining MR approaches, we identified the potential causal risk factors for FN, FA, LS, and heel BMD individually and we also prioritized and ranked the potential causal risk factors for BMD, which might provide us novel insights for treatment and intervention into bone-related complex traits and diseases.

Sequence conservation predicts T cell reactivity against ragweed allergens.

BACKGROUND: Ragweed is a major cause of seasonal allergy, affecting millions of people worldwide. Several allergens have been defined based on IgE reactivity, but their relative immunogenicity in terms of T cell responses has not been studied. OBJECTIVE: We comprehensively characterized T cell responses from atopic, ragweed-allergic subjects to Amb a 1, Amb a 3, Amb a 4, Amb a 5, Amb a 6, Amb a 8, Amb a 9, Amb a 10, Amb a 11, and Amb p 5 and examined their correlation with serological reactivity and sequence conservation in other allergens. METHODS: Peripheral blood mononuclear cells (PBMCs) from donors positive for IgE towards ragweed extracts after in vitro expansion for secretion of IL-5 (a representative Th2 cytokine) and IFN-γ (Th1) in response to a panel of overlapping peptides spanning the above-listed allergens were assessed. RESULTS: Three previously identified dominant T cell epitopes (Amb a 1 176-191, 200-215, and 344-359) were confirmed, and three novel dominant epitopes (Amb a 1 280-295, 304-319, and 320-335) were identified. Amb a 1, the dominant IgE allergen, was also the dominant T cell allergen, but dominance patterns for T cell and IgE responses for the other ragweed allergens did not correlate. Dominance for T cell responses correlated with conservation of ragweed epitopes with sequences of other well-known allergens. CONCLUSIONS AND CLINICAL RELEVANCE: These results provide the first assessment of the hierarchy of T cell reactivity in ragweed allergens, which is distinct from that observed for IgE reactivity and influenced by T cell epitope sequence conservation. The results suggest that ragweed allergens associated with lesser IgE reactivity and significant T cell reactivity may be targeted for T cell immunotherapy, and further support the development of immunotherapies against epitopes conserved across species to generate broad reactivity against many common allergens.

Lack of allergy to timothy grass pollen is not a passive phenomenon but associated with the allergen-specific modulation of immune reactivity.

BACKGROUND: Timothy grass (TG) pollen is a common seasonal airborne allergen associated with symptoms ranging from mild rhinitis to severe asthma. OBJECTIVE: The aim of this study was to characterize changes in TG-specific T cell responses as a function of seasonality. METHODS: Peripheral blood mononuclear cells (PBMCs) obtained from allergic individuals and non-allergic controls, either during the pollen season or out of season, were stimulated with either TG extract or a pool of previously identified immunodominant antigenic regions. RESULTS: PBMCs from allergic subjects exhibit higher IL-5 and IL-10 responses in season than when collected out of season. In the case of non-allergic subjects, as expected we observed lower IL-5 responses and robust production of IFN-γ compared to allergic individuals. Strikingly, non-allergic donors exhibited an opposing pattern, with decreased immune reactivity in season. The broad down-regulation in non-allergic donors indicates that healthy individuals are not oblivious to allergen exposure, but rather react with an active modulation of responses following the antigenic stimulus provided during the pollen season. Transcriptomic analysis of allergen-specific T cells defined genes modulated in concomitance with the allergen exposure and inhibition of responses in non-allergic donors. CONCLUSION AND CLINICAL RELEVANCE: Magnitude and functionality of T helper cell responses differ substantially in season vs. out of season in allergic and non-allergic subjects. The results indicate the specific and opposing modulation of immune responses following the antigenic stimulation during the pollen season. This seasonal modulation reflects the enactment of specific molecular programmes associated with health and allergic disease.

Meta-analysis of immune epitope data for all Plasmodia: overview and applications for malarial immunobiology and vaccine-related issues.

We present a comprehensive meta-analysis of more than 500 references, describing nearly 5000 unique B cell and T cell epitopes derived from the Plasmodium genus, and detailing thousands of immunological assays. This is the first inventory of epitope data related to malaria-specific immunology, plasmodial pathogenesis, and vaccine performance. The survey included host and pathogen species distribution of epitopes, the number of antibody vs. CD4(+) and CD8(+) T cell epitopes, the genomic distribution of recognized epitopes, variance among epitopes from different parasite strains, and the characterization of protective epitopes and of epitopes associated with parasite evasion of the host immune response. The results identify knowledge gaps and areas for further investigation. This information has relevance to issues, such as the identification of epitopes and antigens associated with protective immunity, the design and development of candidate malaria vaccines, and characterization of immune response to strain polymorphisms.

N6(Methylnitroso)adenosine: a carcinogenic nitrosamine derived from a naturally-occurring nucleoside.

N6(Methylnitroso) adenosine (M6(NO)Ado) is found readily under acidic conditions by the interaction of nitrite with 6-methyladenosine, a naturally-occurring nucleoside. Swiss mice were treated with M6(NO)Ado by injection (40 mg/kg each treatment) transplacentally and then as newborns and young adults. The incidences of lymphomas, primary lung tumors, and hepatic neoplasms were significantly greater in these treated animals than in controls. These results demonstrate the tumorigenicity of M6(NO)Ado.

Draft Genome Sequence of a Single Cell of SAR86 Clade Subgroup IIIa.

SAR86 denotes a 16S clade of gammaproteobacteria that are ubiquitous in ocean surface waters. So far, SAR86 is resistant to cultivation; thus, little is known about the genome contents or physiology of this clade. Recently, four partial genome sequences for SAR86 subclades I and II were published. Here, we present the draft genome sequence of a single cell from SAR86 subgroup IIIa isolated from coastal waters in San Diego, CA.

Fractures of the odontoid in children with an open basilar synchondrosis.

Fractures of the odontoid in children with an open basilar synchondrosis differ from those which occur in older children and adults. We have reviewed the morphology of these fractures and present a classification system for them. There were four distinct patterns of fracture (types IA to IC and type II) which were distinguished by the site of the fracture, the degree of displacement and the presence or absence of atlantoaxial dislocation. Children with a closed synchondrosis were classified using the system devised by Anderson and D'Alonzo. Those with an open synchondrosis had a comparatively lower incidence of traumatic brain injury, a higher rate of missed diagnosis and a shorter mean stay in hospital. Certain subtypes (type IA and type II) are likely to be missed on plain radiographs and therefore more advanced imaging is recommended. We suggest staged treatment with initial stabilisation in a Halo body jacket and early fusion for those with unstable injuries, severe displacement or neurological involvement.

Allergic rash: does it exist?

IgE-mediated urticaria and angioedema, serum sickness and idiosyncratic mechanisms all cause rashes. However, only mechanisms involving IgE should be labelled allergic, and they are the only ones with potentially fatal results. The most common type of rash seen by an allergy specialist is urticaria, acute and chronic. Acute urticaria lasts less than six to eight weeks and is most often caused by infection, medication and some foods. Chronic urticaria is caused by animal dander, ASA, certain food additives and some systemic diseases. Treatment is removal of the allergen, plus H1 and H2 antagonists and beta agonists. Both forms of urticaria eventually resolve spontaneously.

Topical treatment of allergic rhinitis.

Topical medications have dramatically changed the treatment of rhinitis. While systemic treatment is often more potent, topical treatment has fewer side effects. However, topical preparations also have side effects which should be considered when treating rhinitis. Topical steroids are potent anti-inflammatories but may cause nasal bleeding; sodium cromoglycate improves allergic and general inflammation but is less potent than steroids. Topical decongestants are beneficial for short-term use when there is nasal obstruction or copious discharge, but can cause damage to nasal epithelium or atrophy and dryness of the nasal mucous membrane after years of use. Anticholinergic spray is effective when watery discharge predominates, and saline is helpful when there is nasal dryness. Treatment of associated conjunctivitis is also discussed.

Software quality assurance and system safety.

The medical field is faced with the increasing sophistication of software-controlled medical equipment. Clinical engineers must understand and become familiar with these sophisticated software-driven medical devices and stand-alone medical software programs in order to evaluate their suitability for the desired purpose. They must be able to assess the nature of the software, its potential and its risks. Numerous aspects of software development and safety must be considered when developing and/or evaluating such software devices and programs.

The interaction of Escherichia coli replication factor Y with complementary strand origins of DNA replication. Contact points revealed by DNase footprinting and protection from methylation.

A defined region of the viral (+) strand of phi X174 and of each strand of pBR322 DNA serves as an effector for the ATPase activity of replication factor Y from Escherichia coli. These loci can also function as complementary strand origins of DNA replication in a single-stranded circular leads to replicative form pathway whose protein requirements are characteristic of phi X174 DNA. Despite this functional similarity, these three sites possess no extensive sequence homology. To uncover a possible common structural determinant, factor Y recognition sequences were treated with pancreatic DNase or dimethyl sulfate in the presence and absence of this replication protein. When factor Y was present, the action of the nuclease was altered in a similar manner on each of the three templates, indicating that factor Y was bound to the entire length of its effector site. Factor Y-mediated modification of the dimethyl sulfate methylation patterns gave evidence of specific, tight protein-DNA contacts. Protection maps, devised by plotting the results of the methylation and footprinting experiments on duplex structures, suggest that tertiary interactions are either involved in the formation of a factor Y effector site or are induced by the binding of the protein.

Mutational analysis of primosome assembly sites. Evidence for alternative DNA structures.

Primosome assembly sites are complex DNA structures that share common functions (they elicit the DNA-dependent ATPase of replication factor Y from Escherichia coli and serve as origins of complementary strand DNA synthesis), but display little sequence homology. In order to ascertain a common basis for factor Y-DNA recognition, a primosome assembly site and its mutated derivatives have been functionally and structurally analyzed. Under conditions in which they lose the capacity to function as ATPase effectors these DNA templates have been (i) assayed for their ability to bind factor Y, and (ii) probed, with pancreatic DNase, for structural alterations. In this ATPase-inactivating environment (suboptimal concentrations of MgCl2 and NaCl, and high levels of the E. coli single-stranded DNA binding protein), factor Y does not bind to its cognate DNA and the DNase cleavage pattern characteristic of this site is perceptibly changed: compared to the DNase digest obtained under activating conditions, cleavage is notably decreased in the 5' half of the site and enhanced at the 3' end. The results of this study strongly indicate that the structure of the primosome assembly site under analysis consists of two hairpins which interact with each other. When the sites of pancreatic DNase attack are plotted on the proposed double hairpin structure, the 5' cleavage sites all map to one duplex while the 3' sites map to the other. The observation that, under factor Y ATPase-activating conditions, the 3' hairpin is largely refractory to the action of pancreatic DNase indicates that tertiary interactions between the two duplexes render a portion of the DNA structure inaccessible to the nuclease.

Investigation and management of rhinitis.

The family physician is ideally situated to deal with most chronic-recurrent nasal problems. The physician is alerted to the real problem by the recognition that terms such as 'sinus' and 'colds' often camouflage the problem of chronic rhinitis and chronic nasal obstruction. Avoidance of offending substances, the use of medications, the occasional judicious use of allergen injection treatment and sometimes surgical intervention for nasal polyps provide different modalities of treatment which can have a major beneficial effect upon symptoms. Improved results are often achieved with a more analytic approach to the use of antihistimine and the availability of topical steroids and topical cromoglycate. The treatment method described embodies a systematic approach involving the sequential addition of modalities until specified objectives are achieved.

Sodium cromoglycate in ragweed-allergic conjunctivitis.

Sodium cromoglycate (SCG), in a 4% solution instilled into each eye 4 times daily, was compared with placebo in a double-blind, noncrossover trial in 30 matched patients with troublesome ragweed pollen-induced conjunctivitis. In the SCG group, eye symptom scores were significantly less (p = 0.05), and all patients judged that their symptoms were improved over the previous year (p less than 0.05). Less antihistamine was used by the SCG group but the difference was not significant. It was concluded that SCG was effective in the treatment of ragweed-induced seasonal allergic conjunctivitis.

Comparative tolerability of two formulations of Rhinalar (flunisolide) nasal spray in patients with seasonal allergic rhinitis.

This double-blind, randomized, crossover study compared the incidence of nasal burning and stinging, as well as overall tolerability of the currently marketed formulation of Rhinalar (original formulation) to a new formulation of Rhinalar containing less propylene glycol. In addition, patient and investigator subjective evaluations were used to compare the effectiveness of the test medications in controlling the nasal symptoms of seasonal allergic rhinitis. A total of 122 patients were enrolled in this 4-week trial. Each patient received one formulation of Rhinalar for 2 weeks and then crossed over to receive the alternate formulation for an additional 2 weeks. Eighteen patients withdrew from the trial prematurely. Ten patients were lost to follow-up and eight withdrew due to side effects and/or inadequate therapeutic response. Statistical comparisons of patient evaluations of nasal burning and stinging with the two formulations of Rhinalar showed a very significant difference in terms of severity (P less than .001), duration (P less than .001), and tolerability (P = .006) in favour of the new formulation. A reduction in severity of throat irritation with the new formulation was also shown to be statistically significant (P = .006). Nausea, headache, and other side effects including watery eyes, taste perversion, and runny nose were seldom reported with either test medication. Both formulations were shown to be equally effective in relieving the nasal symptoms of seasonal allergic rhinitis. The considerable reduction in nasal burning and stinging and throat irritation with the new formulation of Rhinalar was shown to enhance patient acceptability and may lead to better compliance.

Urticaria from allergy to a purified human anti-Rh antibody preparation.

This case presentation describes a young woman who developed generalized urticaria after receiving the human anti-RhD(D) preparation, WinRho, intravenously. Allergy skin tests and the radioallergosorbent test (RAST) for IgE antibodies to the human anti-D immunoglobulin preparation were positive. Further studies using high-pressure liquid chromatography and protein A column chromatography implicated a nonimmunoglobulin low-molecular-weight contaminant. This case report illustrates an allergic reaction to a highly purified human immunoglobulin preparation, and demonstrates approaches to assessment of such a reaction.

N6-(Methylnitroso)adenosine: a carcinogen from a nucleic acid component.

Substituted aminopurines in nucleic acids may be nitrosated to yield carcinogenic nitrosaminopurines. To investigate this possibility, we studied the nitrosation of N6-methyladenosine under conditions simulating the gastric environment. We administered the product of this reaction, N6-(methylnitroso)adenosine (m6(NO)Ado), parenterally and orally to mice. A high incidence of thymic lymphomas, lung adenomas and some liver tumours were found in mice given m6(NO)Ado i.p. during early life. Oral administration of m6(NO)Ado to adult mice resulted in the formation of reproductive system tumours in 80% of the exposed female mice, as well as lung tumours in both sexes. The precursors of m6(NO)Ado (m6Ado and nitrite) did not elevate tumour incidence when given separately, but resulted in a significant increase in numbers of lung tumours in males when administered together. The nitrosamine base, N6-(methylnitroso)-adenine, was found to be a less potent carcinogen than m6(NO)Ado, causing lung tumours only in males and possibly a few mammary tumours in females. These results indicate the in vivo formation of a carcinogen from the precursors, N6-methyladenosine and nitrite, and show that m6(NO)Ado induces neoplasms in the reproductive system of mice, an unusual target for an N-nitroso carcinogen. Complete inhibition of nitrosaminopurine formation in vitro was obtained with ascorbic acid.

Synovial chondromatosis affecting the temporomandibular joint. Case report and literature review.

A case of synovial chondromatosis affecting the temporomandibular joint is reported and the literature is reviewed. Chondromatosis occurs most frequently in this joint in middle-aged women, and it presents with pain and tenderness over the joint. Radiologically, the condition is detected by widening of the joint space with variable presence of radiodense loose bodies. Pathologically, the loose bodies in the case presented were demonstrated arise from cartilaginous metaplasia of the synovial lining. The stimulus for synovial chondrometaplasia at this site is unknown.