Genetic variation in the HLA region is associated with susceptibility to herpes zoster.

Herpes zoster, commonly referred to as shingles, is caused by the varicella zoster virus (VZV). VZV initially manifests as chicken pox, most commonly in childhood, can remain asymptomatically latent in nerve tissues for many years and often re-emerges as shingles. Although reactivation may be related to immune suppression, aging and female sex, most inter-individual variability in re-emergence risk has not been explained to date. We performed a genome-wide association analyses in 22,981 participants (2280 shingles cases) from the electronic Medical Records and Genomics Network. Using Cox survival and logistic regression, we identified a genomic region in the combined and European ancestry groups that has an age of onset effect reaching genome-wide significance (P>1.0 × 10(-8)). This region tags the non-coding gene HCP5 (HLA Complex P5) in the major histocompatibility complex. This gene is an endogenous retrovirus and likely influences viral activity through regulatory functions. Variants in this genetic region are known to be associated with delay in development of AIDS in people infected by HIV. Our study provides further suggestion that this region may have a critical role in viral suppression and could potentially harbor a clinically actionable variant for the shingles vaccine.

Intrapericardial neuroendocrine tumour in a dog.

An 11-year-old neutered male Border Terrier presented for pericardiectomy after a nine-month history of tricavitary effusion, dyspnoea and lethargy. Transthoracic echocardiography revealed a fluid-filled structure at the heart base, starting at the mid-right ventricle and extending to the middle of the right atrium. Almost complete compression of the right atrium and the cranial vena cava was noted. Thoracic computed tomography revealed a heterogeneously enhancing and poorly marginated mass within the cranial aspect of the pericardium. A median sternotomy and subtotal pericardiectomy were performed. A non-distinct fluid-filled structure within the pericardium adhered to the epicardium was visualised. The structure was removed via marsupialisation along with extirpation of enlarged sternal lymph nodes. Histopathological examination of the sternal lymph nodes revealed expansile, well-demarcated, unencapsulated nodules of neoplastic cells consistent with a neuroendocrine tumour suspected to be thyroid in origin. After surgery, intractable pleural effusion resulted in euthanasia. Intrapericardial ectopic thyroid tumours are rarely reported in animals. The location of the mass and unusual presentation may have made it challenging for echocardiography to identify this neoplasia. Thoracic computed tomography at an earlier stage may have identified the neoplasia and potentially allowed for surgical intervention.

Emergency Laparotomy Follow-Up Study (ELFUS): prospective feasibility investigation into postoperative complications and quality of life using patient-reported outcome measures up to a year after emergency laparotomy.

BACKGROUND: Emergency laparotomy carries a significant risk profile around the time of surgery. This research aimed to establish the feasibility of recruitment to a study using validated scoring tools to assess complications after surgery; and patient-reported outcome measures (PROMs) to assess quality of life and quality of recovery up to a year following emergency laparotomy (EL). METHODS: We used our local National Emergency Laparotomy Audit (NELA) register to identify potential participants at a single NHS centre in England. Complications were assessed at 5, 10 and 30 days after EL. Patient-reported outcome measures were collected at 1, 3, 6 and 12 months after surgery using EQ5D and WHODAS 2.0 questionnaires. RESULTS: Seventy of 129 consecutive patients (54%) agreed to take part in the study. Post-operative morbidity survey data was recorded from 63 and 37 patients at postoperative day 5 and day 10. Accordion Complication Severity Grading data was obtained from 70 patients. Patient-reported outcome measures were obtained from patients at baseline and 1, 3, 6 and 12 months after surgery from 70, 59, 51, 48, to 42 patients (100%, 87%, 77%, 75% and 69% of survivors), respectively. CONCLUSIONS: This study affirms the feasibility of collecting PROMs and morbidity data successfully at various time points following emergency laparotomy, and is the first longitudinal study to describe quality of life up to a year after surgery. This finding is important in the design of a larger observational study into quality of life and recovery after EL.

Superconductivity on the border of itinerant-electron ferromagnetism in UGe2

The absence of simple examples of superconductivity adjoining itinerant-electron ferromagnetism in the phase diagram has for many years cast doubt on the validity of conventional models of magnetically mediated superconductivity. On closer examination, however, very few systems have been studied in the extreme conditions of purity, proximity to the ferromagnetic state and very low temperatures required to test the theory definitively. Here we report the observation of superconductivity on the border of ferromagnetism in a pure system, UGe2, which is known to be qualitatively similar to the classic d-electron ferromagnets. The superconductivity that we observe below 1 K, in a limited pressure range on the border of ferromagnetism, seems to arise from the same electrons that produce band magnetism. In this case, superconductivity is most naturally understood in terms of magnetic as opposed to lattice interactions, and by a spin-triplet rather than the spin-singlet pairing normally associated with nearly antiferromagnetic metals.

Red/Green color opponency at detection threshold.

By means of visual stimnulus without temporal or spatial edges, we have achieved better isolation of chromatic signals at detection threshold than has been reported previously. Under various states of adaptation, the spectral sensitivity of the chromatic mechanism detecting middle- and long-wavelength lights corresponds with that deduced from suprathreshold red/green hue equilibriums.

A profile of the belief system and attitudes to end-of-life decisions of senior clinicians working in a National Health Service Hospital in the United Kingdom.

There is evidence from outside the United Kingdom to show that physicians' religious beliefs influence their decision making at the end of life. This UK study explores the belief system of consultants, nurse key workers and specialist registrars and their attitudes to decisions which commonly must be taken when caring for individuals who are dying. All consultants (N = 119), nurse key workers (N = 36) and specialist registrars (N = 44) working in an acute hospital in the north-east of England were asked to complete a postal questionnaire. In all, 65% of consultants, 67% of nurse key workers and 41% of specialist registrars responded. Results showed that consultants' religion and belief systems differed from those of nurses and the population they served. Consultants and nurses had statistically significant differences in their attitudes to common end of life decisions with consultants more likely to continue hydration and not withdraw treatment. Nurses were more sympathetic to the idea of physician-assisted suicide for unbearable suffering. This study shows the variability in belief system and attitudes to end of life decision making both within and between clinical groups. This may have practical implications for the clinical care given and the place of care. The personal belief system of consultants was not shown to affect their overall attitudes to withdrawing life-sustaining treatment or physician-assisted suicide.

Rods are rods and cones cones, and (never) the twain shall meet.

More than 100 photopigment G protein-coupled receptors (opsins) have been sequenced and organized into six classes. Rod photoreceptors in various species have been found to express an opsin from one of the two rhodopsin classes, while cones express an opsin from one of the four remaining classes. It has now been discovered that salamander short-wavelength sensitive cones and green rods express the same opsin, while manifesting other features that classically distinguish rods from cones.

A photoreceptor-specific cadherin is essential for the structural integrity of the outer segment and for photoreceptor survival.

A cadherin family member, prCAD, was identified in retina cDNA by subtractive hybridization and high throughput sequencing. prCAD is expressed only in retinal photoreceptors, and the prCAD protein is localized to the base of the outer segment of both rods and cones. In prCAD(-/-) mice, outer segments are disorganized and fragmented, and there is progressive death of photoreceptor cells. prCAD is unlikely to be involved in protein trafficking between inner and outer segments, since phototransduction proteins appear to be correctly localized and the light responses of both rods and cones are only modestly compromised in prCAD(-/-) mice. These experiments imply a highly specialized cell biological function for prCAD and suggest that localized adhesion activity is essential for outer segment integrity.

The gain of rod phototransduction: reconciliation of biochemical and electrophysiological measurements.

We have resolved a central and long-standing paradox in understanding the amplification of rod phototransduction by making direct measurements of the gains of the underlying enzymatic amplifiers. We find that under optimized conditions a single photoisomerized rhodopsin activates transducin molecules and phosphodiesterase (PDE) catalytic subunits at rates of 120-150/s, much lower than indirect estimates from light-scattering experiments. Further, we measure the Michaelis constant, Km, of the rod PDE activated by transducin to be 10 microM, at least 10-fold lower than published estimates. Thus, the gain of cGMP hydrolysis (determined by kcat/Km) is at least 10-fold higher than reported in the literature. Accordingly, our results now provide a quantitative account of the overall gain of the rod cascade in terms of directly measured factors.

Cryogenic loading of argon pressure medium in diamond anvil high pressure cells with in situ pressure determination.

A versatile system for cryogenic loading of argon pressure medium into the sample space of a diamond anvil cell has been developed. The system has been designed such that, with suitable adaptors, a wide range of diamond anvil cell designs can be pressurized. The pressure in the cell can be monitored during pressurization using the ruby fluorescence method via optical fiber access into the loading chamber. This enables the precise and accurate setting of the loading pressure in the cell.

G-protein cascades: gain and kinetics.

G-protein cascades provide amplification in a wide variety of biological signal transducers--from hormonal and synaptic systems to the receptor cells of vision and olfaction. Through recent understanding of the molecular mechanisms involved, it is possible to construct a quantitative description of the amplification and speed of response of the cascade. The gain and kinetics can now be described in terms of physical parameters, such as enzyme activities and the densities and lateral diffusion coefficients of the proteins involved.

Molecular mechanisms of vertebrate photoreceptor light adaptation.

An important recent advance in the understanding of vertebrate photoreceptor light adaptation has come from the discovery that as many as eight distinct molecular mechanisms may be involved, and the realization that one of the principal mechanisms is not dependent on calcium. Quantitative analysis of these mechanisms is providing new insights into the nature of rod photoreceptor light adaptation.

Note: Moissanite backing plates for use in diamond anvil high pressure cells.

The use of moissanite (single crystal SiC) for backing plates within diamond anvil cells (DACs) has been developed. These have significant technical advantages in certain experiments. For example, moissanite is non-magnetic so is suitable for use in high magnetic fields and for magnetization experiments. Being translucent to light, including x-rays, means that openings are not required in the backing plate and as such has significant mechanical advantages and can provide enhanced scattering angles for x-ray diffraction experiments. The new backing plates have been successfully tested to over 25 GPa using diamond anvils with 0.5 mm culets.

Mice lacking G-protein receptor kinase 1 have profoundly slowed recovery of cone-driven retinal responses.

G-Protein receptor kinase 1 (GRK1) ("rhodopsin kinase") is necessary for the inactivation of photoactivated rhodopsin, the light receptor of the G-protein transduction cascade of rod photoreceptors. GRK1 has also been reported to be present in retinal cones in which its function is unknown. To examine the role of GRK1 in retinal cone signaling pathways, we measured in mice having null mutations of GRK1 (GRK1 -/-) cone-driven electroretinographic (ERG) responses, including an a-wave component identified as the field potential generated by suppression of the circulating current of the cone photoreceptors. Dark-adapted GRK1 -/- animals generated cone-driven ERGs having saturating amplitudes and sensitivities in both visible and UV spectral regions similar to those of wild-type (WT) mice. However, after exposure to a bright conditioning flash, the cone-driven ERGs of GRK1 -/- animals recovered 30-50 times more slowly than those of WT mice and similarly slower than the cone-driven ERGs of mice homozygously null for arrestin (Arrestin -/-), whose cone (but not rod) response recoveries were found to be as rapid as those of WT. Our observations argue that GRK1 is essential for normal deactivation of murine cone phototransduction and provide the first functional evidence for a major role of a specific GRK in the inactivation of vertebrate cone phototransduction.

The light response of ON bipolar neurons requires G[alpha]o.

ON bipolar neurons in retina detect the glutamate released by rods and cones via metabotropic glutamate receptor 6 (mGluR6), whose cascade is unknown. The trimeric G-protein G(o) might mediate this cascade because it colocalizes with mGluR6. To test this, we studied the retina in mice negative for the alpha subunit of G(o) (Galpha(o)-/-). Retinal layering, key cell types, synaptic structure, and mGluR6 expression were all normal, as was the a-wave of the electroretinogram, which represents the rod and cone photocurrents. However, the b-wave of the electroretinogram, both rod- and cone-driven components, was entirely missing. Because the b-wave represents the massed response of ON bipolar cells, its loss in the Galpha(o) null mouse establishes that the light response of the ON bipolar cell requires G(o). This represents the first function to be defined in vivo for the alpha subunit of the most abundant G-protein of the brain.

Characterization of a membrane-bound phospholipid desaturase system of candida lipolytica.

Several characteristics of the microsomal phospholipid desaturase of Candida lipolytica are described. The phospholipid desaturase reaction required molecular oxygen and reduced pyridine nucleotides as essential cofactors and was inhibited by cyanide but not by carbonmonoxide, indicating that it required cytochrome b5. Desaturation of both 1-acyl-2-[14-C]oleoyl-sn-glycero-3-phosphorylcholine and 1,2-di-[14C] oleoyl-sn-glycero-3-phosphorylcholine appeared to follow Michaelis-Menten kinetics, with apparent Km values of 2.5 10-minus 4 M and 9.5 10-minus 4 M, respectively. Desaturation of the di-[14C] oleoylphosphatidylcholine took place at both position-1 and position-2; the distearoyl or dielaidoyl phosphatidylcholines were not desaturated. Rate of desaturation of the 1=acyl-2-[14-C] oleoyl-glycerophosphorylcholine by microsomes from cold-grown cells was equal to or slightly less than that by microsomes from cells grown at the normal growth temperature of 25 degreesC, measured in the temperature range 10-30 degrees C. However, the rate of desaturation of [14-C]-oleoyl-CoA desaturase was greater with the microsomal preparation from cold-grown cells than with that from 25 degreesC grown cells. These data suggest that the observed increase of diunsaturated fatty acids in cold-grown cells may perhaps be explained by the increased activity of the oleoyl-CoA desaturase acting at the low temperature.

Acylation of proteins of the archaebacteria Halobacterium cutirubrum and Methanobacterium thermoautotrophicum.

Although the membrane lipids of extremely halophilic archaebacteria are exclusively derived from diphytanylglycerol diether, which is non-acylated, small amounts of fatty acids have been detected in these organisms. These fatty acids are formed by the action of a fatty acid synthase (FAS), shown to be present in the extreme halophile Halobacterium cutirubrum, despite the fact that only a fraction of the activity of FAS remains at the high salt concentration (> 4 M) present in the cytoplasm. It has now been demonstrated that fatty acids do not occur in lipid-bound form but largely in the form of acylated proteins in the red membrane of H. cutirubrum. In contrast, the bacteriorhodopsin of the purple membrane of this extreme halophile does not appear to be acylated. The thermophilic methanogen, Methanobacterium thermoautotrophicum had a much higher fatty acid synthase activity than the extreme halophile, and the synthase activity of the methanogen was optimal under its normal (anaerobic) growth conditions. The methanogen also utilized the resulting fatty acids to acylate its membrane proteins. The major fatty acids in both organisms were palmitic and stearic acids with small amounts of myristic and 18:1 acids, and these were bound to protein through both ester and amide linkages.

Amplification and kinetics of the activation steps in phototransduction.

We can summarize our investigation of amplification in the activation steps of vertebrate phototransduction as follows. (1) A theoretical analysis of the activation steps of the cGMP cascade shows that after a brief flash of phi photoisomerizations the number of activated PDE molecules should rise as a delayed ramp with slope proportional to phi, and that, as a consequence, the cGMP-activated current should decay as a delayed Gaussian function of time (Eqn. 20). (i) Early in the response to a flash, the normalized response R(t) can be approximated as rising as 1/2 phi At2 (after a short delay), where A is the amplification constant characteristic of the individual photoreceptor. (ii) The delayed ramp behavior of PDE activation and the consequent decline of current in the form of the delayed Gaussian are confirmed by experiments in a variety of photoreceptors; the analysis thus yields estimates of the amplification constant from these diverse photoreceptors. (iii) Eqn. 20 further predicts that the response-intensity relation at any fixed time should saturate exponentially, as has been found experimentally. (2) The amplification constant A can be expressed as the product of amplification factors contributed by the individual activation steps of phototransduction, i.e., A = nu RG cGP beta sub n (Eqns. 9 and 21), where (i) nu RG is the rate of G* production per Rh*; (ii) cGP is the efficiency of the coupling between G* production and PDE* production; (iii) beta sub is the increment in hydrolytic rate constant produced by one PDE*, i.e., a single activated catalytic subunit of PDE; and (iv) n is the Hill coefficient of opening of the cGMP-activated channels. (3) The amplification factor beta sub includes the ratio kcat/Km, which characterizes the hydrolytic activity of the PDE in vivo where cG << Km. Two different analyses based upon photocurrents were developed which provide lower bounds for kcat/Km in vivo; these analyses establish that kcat/Km probably exceeds 10(7) M-1 s-1 (and is likely to be higher) in both amphibian and mammalian rods. Few biochemical studies (other than those using trypsin activation) have yielded such high values. A likely explanation of many of the relatively low biochemical estimates of kcat/Km is that Km may have been overestimated by a factor of about 4 in preparations in which stacks of disks are left intact, due to diffusion with hydrolysis in the stacks.(ABSTRACT TRUNCATED AT 400 WORDS)

Correlation of enzyme activities with fluorescence anisotropy of dansyl-labeled cytochrome b5/NADH-cytochrome-b5 reductase systems in phosphatidylcholine vesicles.

The changes in steady-state fluorescence lifetimes and anisotropy decay parameters, as well as enzyme activities, of dansyl-labeled cytochrome b5 (DNS-cytochrome b5), on interaction with NADH-cytochrome-b5 reductase in DMPC vesicles, have been measured as a function of temperature. Steady-state fluorescence of DNS-cytochrome b5 in DMPC vesicles with and without cholesterol was increased on interaction with reductase at temperatures both above and below the DMPC phase transition. In all systems three fluorescence decay components of the dansyl label in DNS-cytochrome b5 were observed. In the reductase-containing system, the long (major) decay time component of DNS-cytochrome b5 and the fraction of the total fluorescence associated with this component increased over the temperature range 15-30 degrees C. In time-resolved anisotropy measurements, the order parameters of DNS-cytochrome b5 in DMPC vesicles increased on interaction with reductase at temperatures above the DMPC phase transition, and this increase was even more pronounced in cholesterol-containing vesicles, at temperatures from 15-30 degrees C. The enzyme activity of the DNS-cytochrome-b5 reductase system in DMPC vesicles was also greatly increased in the presence of cholesterol. These results show that interaction of vesicle-bound DNS-cytochrome b5 and NADH-cytochrome-b5 reductase leads to an increased degree of order of the dansyl-labeled cytochrome with little change in its rotational flexibility, and suggests that the increased order can be correlated with increased enzyme activity.

Deficiency of Bax and Bak protects photoreceptors from light damage in vivo.

Photoreceptors of bax(-/-)bak(-/-) but neither bax(-/-) mice nor bak(-/-) mice are protected from developmental apoptosis, suggesting that bax(-/-)bak(-/-) photoreceptors may also be protected from pathologic apoptosis. To test this possibility, we exposed bax(-/-)bak(-/-) and bax(-/-) mice to bright light, which normally induces photoreceptor death. Photoreceptors in bax(-/-)bak(-/-) mice were protected from death compared to bax(-/-) mice as indicated by a reduction in the number of TUNEL-positive photoreceptor nuclei 24 h following light damage and almost complete preservation of photoreceptors 7 days following light damage. These results provide the first in vivo evidence that combined deficiency of Bax and Bak can rescue cells from a pathologic stimulus more effectively than Bax deficiency and suggest that combined deficiency of Bax and Bak may also protect cells from other insults.