Hydroxyproline ingestion and urinary oxalate and glycolate excretion

Endogenous synthesis of oxalate is an important contributor to calcium oxalate stone formation and renal impairment associated with primary hyperoxaluria. Although the principal precursor of oxalate is believed to be glyoxylate, pathways in humans resulting in glyoxylate synthesis are not well defined. Hydroxyproline, a component amino acid of collagen, is a potential glyoxylate precursor. We have investigated the contribution of dietary hydroxyproline derived from gelatin to urinary oxalate and glycolate excretion. Responses to the ingestion of 30 g of gelatin or whey protein were compared on controlled oxalate diets. The time course of metabolism of a 10 g gelatin load was determined as well as the response to varying gelatin loads. Urinary glycolate excretion was 5.3-fold higher on the gelatin diet compared to the whey diet and urinary oxalate excretion was 43% higher. Significant changes in plasma hydroxyproline and urinary oxalate and glycolate were observed with 5 and 10 g gelatin loads, but not 1 and 2 g loads. Extrapolation of these results to daily anticipated collagen turnover and hydroxyproline intake suggests that hydroxyproline metabolism contributes 20-50% of glycolate excreted in urine and 5-20% of urinary oxalate derived from endogenous synthesis. Our results also revealed that the kidney absorbs significant quantities of hydroxyproline and glycolate, and their metabolism to oxalate in this tissue warrants further consideration.

The analysis of 51 genes in DSM-IV combined type attention deficit hyperactivity disorder: association signals in DRD4, DAT1 and 16 other genes

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder, starting in early childhood and persisting into adulthood in the majority of cases. Family and twin studies have demonstrated the importance of genetic factors and candidate gene association studies have identified several loci that exert small but significant effects on ADHD. To provide further clarification of reported associations and identify novel associated genes, we examined 1,038 single-nucleotide polymorphisms (SNPs) spanning 51 candidate genes involved in the regulation of neurotransmitter pathways, particularly dopamine, norepinephrine and serotonin pathways, in addition to circadian rhythm genes. Analysis used within family tests of association in a sample of 776 DSM-IV ADHD combined type cases ascertained for the International Multi-centre ADHD Gene project. We found nominal significance with one or more SNPs in 18 genes, including the two most replicated findings in the literature: DRD4 and DAT1. Gene-wide tests, adjusted for the number of SNPs analysed in each gene, identified associations with TPH2, ARRB2, SYP, DAT1, ADRB2, HES1, MAOA and PNMT. Further studies will be needed to confirm or refute the observed associations and their generalisability to other samples.

Rituximab resistance and its association with changes in the internal domain of CD20 antigen and down-regulation of pro-apoptotic protein Bax and Bak in both rituximab-resistant cell lines (RRCL) and diffuse large B-cell lymphoma (DLBCL) patient (pt) samples

17509

Background: Resistance to rituximab (R) has been observed in lymphoma pts. To define the molecular basis for rituximab resistance we developed various RRCL and previously demonstrated changes in CD20 structure, membrane reorganization following rituximab exposure and deregulation of pro-apoptotic proteins Bax/Bak leading to rituximab/chemotherapy resistance. In our current work we evaluated changes in the structure/expression of CD20 and/or pro-apoptotic proteins in primary tumor specimens from DLBCL pts treated with rituximab in combination with CHOP (R-CHOP). Methods: We obtained frozen lymphoid material from patients with DLBCL who achieved a remission (sensitive lymphoma) or failed (resistant lymphoma) R-CHOP therapy. Protein lysates were obtained from each sample. Structural changes in CD20 were determined by Western blotting using various antibodies recognizing epitopes located in the internal (GST77 and 1439) and external domain (rituximab) of CD20. In addition, we studied the expression of Bax and Bak. Results: Variability in the expression and structure of CD20 was found in the pt samples. Rituximab binding to its surface CD20 antigen was preserved in all patients. However, differences in C- and N-terminal expression were found across DLBCL specimens. In addition, down-regulation of Bax/Bak was observed in some pts with resistant lymphomas. Patients who responded to R-CHOP were noted to either have an intact CD20 and/or express Bax/Bak. On the other hand, resistant lymphomas had altered CD20 isoforms and a downregulation of Bax/Bak. Conclusions: Our current preliminary data suggests a positive correlation to our pre-clinical data generated from B-cell NHL cell-lines and will be evaluated in a larger number of primary NHL tumor specimens.

No significant financial relationships to disclose.

Impaired Ca++ mobilization in rituximab-resistant cells (RRCL) is associated with changes in the structure of CD20 antigen, down-regulation of Bax/Bak pro-apoptotic proteins and up-regulation of the endoplasmic reticulum (ER) Ca++ pump protein SERCA-3

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Ca++ mobilization leading to apoptosis has been observed following rituximab biding to CD20 in lymphoma cells. Extending rituximab (R) exposure (e.g. as via R maintenance regimens) could potentially accelerate the emergence of resistance to rituximab. To define the molecular basis for rituximab resistance we developed several RRCL and demonstrated changes in CD20 expression/structure and membrane reorganization following rituximab therapy. Specifically, changes in the N-terminal and the C-terminal region of the internal domain of CD20 were observed in RRCL as determined by Western blotting using various antibodies recognizing epitopes located in the internal (GST77 and 1439) and external domain (B1) of CD20. In our current work we evaluated the effects that CD20 structure/expression changes have upon Ca++ mobilization. Extracellular and intracellular Ca++ mobilization was measured by flow cytometric analysis using FLUO-3 AM (acetoxymethyl ester). Optimization of the Ca++ indicator and calibration curves were performed for each cell line. Raji and RRCL were labeled under optimal conditions with FLUO-3 AM/Pluronic Acid F-127. Subsequently, cells were then re-suspended in HANKS media with or without Ca++ and exposed to rituximab or isotype (10μg/ml) ± human serum (25%). Surface CD20 expression was similar between Raji cells and RRCL. Expression of pro- or anti-apoptotic proteins and Ca++ regulatory proteins SERCA3, SERCA2 and Calreticulin was also determined by western blotting. In vitro exposure of Raji cells to rituximab + HS resulted in Ca++ mobilization even in Ca++ depleted media. Notably, Ca++ mobilization was impaired in RRCL when compared to Raji parental cells. In addition, down-regulation of Bax/Bak and up-regulation of SERCA3 was demonstrated in RRCL. Our data suggest that the acquirement of rituximab resistance is associated with changes in the intracellular domain of CD20 and in Ca++ regulator/pro-apoptotic proteins (SERCA3 and Bax/Bak) resulting in a decrease in the intracellular mobilization of Ca++.

No significant financial relationships to disclose.

Program report: GENECOUNTING support programs

We describe a suite of programs which enhance the usability of GENECOUNTING, a program for estimating haplotype frequencies in unrelated subjects. The programs, called RUNGC, SCANASSOC, COMPGR, SCANGROUP and LDPAIRS, carry out likelihood ratio tests and permutation tests to detect differences in haplotype frequencies between cases and controls,or between predefined groups, and output likely haplotype assignments and tables of linkage disequilibrium statistics between all pairs of markers in a dataset.

Prevalence of back and neck pain amongst ENT consultants: national survey

Back and neck pain is an established occupational disease for many professions. No previous studies have shown the association of back and neck pain with ENT surgery. Our objective was to determine the prevalence of neck and back pain in ENT consultants in the United Kingdom and which sub-specialities were most at risk. A national survey from 325 ENT consultants in the UK revealed that 72 per cent had either back pain or neck pain or even both. Of those with pain 53 per cent attributed their symptoms directly to ENT surgery. Highest figures were received from otologists, related to microscope work and prolonged sitting. The importance of these findings has demonstrated the lack of awareness and adequate training to prevent long-term disability in ENT surgeons.

Supercontinuum generation system for optical coherence tomography based on tapered photonic crystal fibre

We report smooth and broad continuum generation using a compact femtosecond Ti:Sapphire laser as a pump source and a tapered photonic crystal fibre as a nonlinear element. Spectral output is optimized for use in optical coherence tomography, providing a maximum longitudinal resolution of 1.5 microm in free space at 809 nm centre wavelength without use of additional spectral filtering.

Ruptured splenic artery aneurysm in pregnancy presenting in a manner similar to pulmonary embolus

We report a patient, 33 weeks pregnant with twins, who sustained a ruptured splenic artery aneurysm. This presented with left sided chest pain, breathlessness, low oxygen saturations and electrocardiogram (ECG) changes supportive of a diagnosis of massive pulmonary embolus. The diagnosis of splenic artery rupture was made at emergency Caesarean section performed for fetal distress.

DNA pooling analysis of ADHD and genes regulating vesicle release of neurotransmitters

ADHD is one of the most prevalent, and heritable behavioural disorders in childhood. Genetic associations have been reported with polymorphic variants within or near to dopamine pathway genes. Recently snap-25 has also shown association with ADHD in several datasets. We therefore investigated other genes that produce proteins that interact with SNAP-25 in the mechanism of vesicular release of neurotransmitters at the synapse. A total of 106 SNPs were screened for minor allele frequency greater than 5% and 61 SNPs selected for analysis in DNA pools made up from an ADHD clinical sample of DSM-IV combined type probands (n = 180) and a control sample of 90 males and 90 females. Initial screening identified several SNPs that showed allele frequency differences of 5% or more. One SNP in the synaptophysin gene showed suggestive evidence of association following case-control and TDT analysis and warrants further investigation.

Realizing low loss air core photonic crystal fibers by exploiting an antiresonant core surround

The modal properties of an air core photonic crystal fiber which incorporates an anti-resonant feature within the region that marks the transition between the air core and the crystal cladding are numerically calculated. The field intensity at the glass/air interfaces is shown to be reduced by a factor of approximately three compared to a fiber with more conventional core surround geometry. The reduced interface field intensity comes at the expense of an increased number of unwanted core interface modes within the band gap. When the interface field intensity is associated with modal propagation loss, the findings are in accord with recent measurements on fabricated fibers which incorporate a similar antiresonant feature.

Loss in solid-core photonic crystal fibers due to interface roughness scattering

The loss resulting from roughness scattering at hole interfaces within solid core photonic crystal fibers is theoretically analyzed and compared with measurements on fabricated fibers. It is found that a model roughness spectrum corresponding to frozen in capillary waves gives results in reasonably good agreement with experiments on small core fibers. In particular, the roughness scattering loss is shown to be only weakly dependent on wavelength. Agreement at a larger core size requires a long length-scale cut-off to be introduced to the roughness spectrum. Due to the long range nature of the roughness correlations, the scattering is non Rayleigh in character and cannot be interpreted in terms of a local photon density of states.

Hollow-core PCF for guidance in the mid to far infra-red

A major limitation to attaining low-loss single-mode guidance in hollow core photonic crystal fibre (PCF) is surface guided modes that are trapped in the core surround. This is particularly severe when high index (n > 2) glasses are used. By modelling a structure that has the characteristic features of a realistic fibre we show that, by tuning the thickness of the core wall, the influence of these 'surface' modes can be minimised. For a refractive index of 2.4 we predict power-in-air fractions of over 95% over a fractional bandwidth of ~ 5%, peaking at over 98%. The designs are appropriate for mid- to far-IR PCFs for which suitable glasses (e.g., tellurites and chalcogenides) have high refractive indices.

Single-mode mid-IR guidance in a hollow-core photonic crystal fiber

We report, for the first time, bandgap guidance above 3 mum in a silica based air-core photonic crystal fiber. The peak of the bandgap is at 3.14mum with a typical attenuation of ~ 2.6 dB m-1. By further optimization of the structure, modeling suggests that a loss below 1 dB m-1 should be achievable, greatly extending the useful operating range of silica-based single-mode fibers. Such fibers have many potential applications in the mid-IR, offering an alternative to fluoride, tellurite or chalcogenide glass based optical fibers for chemical and biological sensing applications.

Highly birefringent lamellar core fiber

We report a polarization-maintaining fiber in which the birefringence is due to artificially introduced anisotropy in the core material. The beat length was measured by direct observation at three different wavelengths, giving a shortest result of 85 microm at a wavelength of 543 nm. The measured phase-index birefringence is about one third of that expected, which is explained by diffusion between the core layers, which are each less than 200 nm thick. By taking account of this diffusion, we can accurately model the experimental beat length and differential group delay over a wide wavelength range.

Intermediate asymptotic evolution and photonic bandgap fiber compression of optical similaritons around 1550 nm

We report the complete characterization of the self-similar scaling of parabolic pulse similaritons in an optical fiber amplifier. High dynamic range frequency resolved optical gating allows the direct observation of the evolution of a hyperbolic secant-like input pulse to an asymptotic amplifier similariton, and reveals the presence of intermediate asymptotic wings about the parabolic pulse core. These results are used to optimize additional self-similar propagation in highly-nonlinear fiber and subsequent compression in hollow-core photonic bandgap fiber.

CHHIPS (Controlling Hypertension and Hypotension Immediately Post-Stroke) Pilot Trial: rationale and design

RATIONALE

High and low blood pressure (BP) levels are common following acute stroke, with up to 60% of patients being hypertensive (SBP > 160 mmHg) and nearly 20% having relative hypotension (SBP < or = 140 mmHg), within the first few hours of ictus, both conditions being associated with an adverse prognosis. At present, the optimum management of blood pressure in the immediate post-stroke period is unclear.

OBJECTIVE

The primary aim of the Controlling Hypertension and Hypotension Immediately Post-Stroke (CHHIPS) Pilot Trial is to assess whether hypertension and relative hypotension, manipulated therapeutically in the first 24 h following acute stroke, affects short-term outcome measures.

DESIGN

The CHHIPS Pilot Trial is a UK based multi-centre, randomized, double-blind, placebo-controlled, titrated dose trial.

SETTING

Acute stroke and medical units in teaching and district general hospitals, in the UK.

PATIENTS

The CHHIPS Pilot Study aims to recruit 2050 patients, with clinically suspected stroke, confirmed by brain imaging, who have no compelling indication or contraindication for BP manipulation.

STUDY OUTCOMES

The primary outcome measure will be the effects of acute pressor therapy (initiated < or = 12 h from stroke onset) or depressor therapy (started < or = 24 h post-ictus) on death and dependency at 14 days post-stroke. Secondary outcome measures will include the influence of therapy on early neurological deterioration, the effectiveness of treatment in manipulating BP levels, the influence of time to treatment and stroke type on response and a cost-effectiveness analysis.

"Asian yuppies...are always looking for something new and different": creating a tobacco culture among young Asians

OBJECTIVE

To identify and analyse the themes employed by the Asian based transnational tobacco companies to construct a tobacco culture among Asian young men and women.

METHODS

Systematic review of relevant tobacco industry documents made public through the Master Settlement Agreement.

RESULTS

The industry utilised six vehicles and themes to construct a tobacco culture in Asia: music, entertainment (including nightclubs, discos, and movies), adventure, sport (including motorsports, soccer, and tennis), glamour (beauty and fashion), and independence.

CONCLUSIONS

The tobacco industry set about constructing a tobacco culture that sought to make smoking desirable, even normal, for young men and women. Understanding the way industry constructed this culture provides insights into ways that culture might now be challenged. Countering the transnational nature of many activities will require coordinated effort at the international, regional, and national levels. Implementation of the Framework Convention on Tobacco Control (FCTC) will be a powerful tool in this process. All nations throughout Asia are encouraged to support the FCTC and its broad protocols addressing advertising and sponsorship. Measures are also required to disassociate smoking from progress in sex equality.

"A phony way to show sincerity, as we all well know": tobacco industry lobbying against tobacco control in Hong Kong

OBJECTIVE

To examine the tobacco industry's efforts to influence public policy and block the legislative process on tobacco control in Hong Kong, 1973 to 1997.

METHOD

Systematic review of relevant tobacco industry documents made public via the Master Settlement Agreement.

RESULTS

The tobacco industry in Hong Kong has sought to manipulate the policymaking process and delay the introduction of tobacco control legislation in Hong Kong from at least 1973. The industry ensured that each of the government's initial meagre steps toward tobacco control were delayed and thwarted by drawn out "cooperation" followed by voluntary concessions on issues the industry regarded as minor. By the 1980s the government had became increasingly active in tobacco control and introduced a number of initiatives, resulting in some of the tightest legislative restrictions on smoking in Asia. The tobacco industry was successful in thwarting only one of these initiatives.

CONCLUSIONS

Throughout the 1980s and 1990s two factors played a significant role in hindering the tobacco industry from successfully blocking policy initiatives: a growing political imperative, and an active and sophisticated tobacco control movement. Political will to promote public health and a strong tobacco control advocacy presence can enable governments to resist the enormous pressure exerted upon them by multinational tobacco companies.

"Asia is now the priority target for the world anti-tobacco movement": attempts by the tobacco industry to undermine the Asian anti-smoking movement

STUDY OBJECTIVE

To identify and examine the strategies utilised by multinational tobacco companies to undermine and discredit key anti-tobacco activists and organisations in the Asian region.

METHOD

A series of case studies drawing upon material gathered through systematic reviews of internal tobacco industry documents.

DATE SOURCES

Tobacco industry documents made public as part of the settlement of the Minnesota Tobacco Trial and the Master Settlement Agreement.

RESULTS

The industry sought to identify, monitor, and isolate key individuals and organisations. The way industry went about fulfilling this mandate in the Asian region is discussed. Industry targetted individuals and agencies along with the region's primary anti-smoking coalition.

CONCLUSIONS

Attack by multinational tobacco companies is a virtual quid pro quo for any individual or agency seriously challenging industry practices and policies. Understanding their tactics allows anticipatory strategies to be developed to minimise the effectiveness of these attacks.

A programme for reducing smoking in pre-operative surgical patients: randomised controlled trial

We assessed the efficacy of a comprehensive programme for stopping smoking in 210 smokers scheduled for surgery, before admission and 3 months after attending a pre-operative clinic. Participants were randomly allocated to receive an intervention incorporating nicotine replacement therapy for patients smoking more than 10 cigarettes per day ("dependent smokers"), or to a control group to receive usual care. Dependent smokers allocated to the intervention group were more likely to report abstinence before surgery than those allocated to receive usual-care (63 (73%) vs. 29 (56%), respectively; OR 2.2 (95% CI 1.0-4.8)), and 3 months after attendance (16 (18%) vs. 3 (5%), respectively; OR = 3.9 (95% CI 1.0-21.7).

Visualizing the photonic band gap in hollow core photonic crystal fibers

The light radiated from the guided mode of a hollow core photonic crystal fiber into free space is measured as a function of angle and wavelength. This enables the direct experimental visualization of the photonic band gap and the identification of localized modes of the core region.