Polyomaviruses of the skin: integrating molecular and clinical advances in an emerging class of viruses

BACKGROUND

Human polyomaviruses (HPyVs) are small, nonenveloped, double-stranded DNA viruses that express tumour antigen proteins. Fourteen species of polyomaviruses have been discovered in humans, and since the 2008 discovery of the first cutaneous polyomavirus - Merkel cell polyomavirus (MCPyV) - six more species have been detected in the skin: trichodysplasia spinulosa-associated polyomavirus (TSPyV), HPyV6, HPyV7, HPyV9, HPyV10 and HPyV13. Of these cutaneous species, only MCPyV, TSPyV, HPyV6 and HPyV7 have been definitively associated with diseases of the skin, most commonly in immunocompromised individuals. MCPyV is a predominant aetiology in Merkel cell carcinomas. TSPyV is one of the aetiological factors of trichodysplasia spinulosa. HPyV6 and HPyV7 have been recently linked to pruritic skin eruptions. The roles of HPyV9, HPyV10 and HPyV13 in pathogenesis, if any, are still unknown, but their molecular features have provided some insight into their functional biology.

RESULTS

In this review, we summarize the known molecular mechanisms, clinical presentation and targeted therapies of each of the eight cutaneous HPyVs.

CONCLUSIONS

We hope that heightened awareness and clinical recognition of HPyVs will lead to increased reports of HPyV-associated diseases and, consequently, a more robust understanding of how to diagnose and treat these conditions.

Chronic Pruritus: A Review of Neurophysiology and Associated Immune Neuromodulatory Treatments

Chronic pruritus remains a difficult condition to treat with many non-specific therapeutic options. Recent scientific discoveries have elucidated the physiology associated with pruritus. Combined with clinical and experimental trials with immune-modulatory agents, chronic pruritus now has novel treatment options with known mechanisms of action. This review goes over recent scientific progress in understanding the molecular mechanisms governing pruritus, the cross-talk between the immune and nervous systems that regulate itch, and central nervous pathways and projections affected by itch. In light of these recent discoveries, we briefly discuss a growing body of data from relevant clinical trials investigating immunomodulatory drugs targeting specific interleukin receptors (IL-4/13/31) and intracellular signaling (e.g., Janus kinase) pathways. We focus on the physiological processes that control this complex physical and emotional experience, as well as the role of newer drugs used to treat chronic itch.

Limits on interactions between weakly interacting massive particles and nucleons obtained with CsI(Tl) crystal detectors

The Korea Invisible Mass Search (KIMS) experiment presents new limits on the weakly interacting massive particle (WIMP)-nucleon cross section using data from an exposure of 3409 kg.d taken with low-background CsI(Tl) crystals at the Yangyang Underground Laboratory. The most stringent limit on the spin-dependent interaction for a pure proton case is obtained. The DAMA signal region for both spin-independent and spin-dependent interactions for the WIMP masses greater than 20 GeV/c2 is excluded by the single experiment with crystal scintillators.

Alternative 5'-untranslated regions of mouse GH receptor/binding protein messenger RNA are derived from sequences adjacent to the major L2 promoter

Heterogeneity of 5' untranslated region (5'UTR) sequences is a common feature of growth hormone receptor/binding protein (GHR/BP) mRNA from a number of species. Two major 5'UTR sequences (designated L1 and L2 in the mouse) have been cloned from rodents, ruminants and primates, and are known to correspond to transcripts generated from independently regulated promoters. A variable number of other 5'UTRs with diverse sequences have been cloned from rat, human and bovine tissues. To characterize alternative 5'UTR usage in mouse GHR/BP mRNA, we carried out 5' rapid amplification of cDNA ends using RNA from non-pregnant mouse liver and adipose tissue. Three novel 5'UTR sequences were obtained. Sequencing of genomic DNA revealed that exons corresponding to these three sequences are clustered within 1 kb downstream of the exon encoding 5'UTR L2, and the associated L2 promoter. The novel 5'UTRs are present at very low levels relative to the total pool of GHR/BP mRNA in liver, fat, kidney, and mammary gland as determined by ribonuclease protection assays. On the basis of these data, we propose that these 5'UTR sequences may result from the use of cryptic transcription start sites and splice donor sites under the influence of the adjacent L2 promoter/enhancer region.

The effect of 10 : 1 compression and soft copy interpretation on the chest radiographs of premature neonates with reference to their possible application in teleradiology

The aim of the study was to assess the potential application of teleradiology in the neonatal intensive care unit (NICU) by ascertaining whether any decrease in conspicuity of anatomic detail or interventional devices in the chest radiographs of premature infants is caused by picture archiving and communication system (PACS)-based soft copy interpretation of 10 : 1 compressed images. One hundred digital chest radiographs of low-birthweight infants were obtained in the NICU using a storage phosphor system. Laser-printed images were interpreted and the data set for each radiograph was then irreversibly compressed by a 10 : 1 ratio. Four radiologists with extensive PACS experience used a five-point grading system to score laser-printed hard copy images for the visibility of six parameters of anatomic landmarks and interventional devices in the chest. Compressed soft copy images displayed on 2K PACS workstation were subsequently scored using the same approach. Statistical manipulation demonstrated no loss of anatomic detail in five of the six parameters scored, with minimal difference in one landmark, the retrocardiac lung assessment. While further study is required to assess the clinical impact of the variance noted when evaluating lung parameters, the preservation or improvement of information in the remaining parameters following irreversible compression and soft copy interpretation is promising for the potential use of teleradiology in this population.

Controlled trial of nimodipine in amyotrophic lateral sclerosis

Calcium channel blocking drugs antagonize excitatory amino acid receptor activation, decrease calcium entry into damaged neurons, and might help to slow or reverse amyotrophic lateral sclerosis (ALS). We enrolled 87 patients with ALS in a randomized, placebo-controlled, prospective, double-blind crossover study of nimodipine therapy. Monthly measures of isometric muscle strength and respiratory function compared the effects of drug and placebo. No difference in adverse events occurred in placebo vs drug-treated patients, but diarrhoea, nausea, and lightheadedness were more common with nimodipine. There was no significant difference in the rate of decline of pulmonary function or limb strength during treatment with drug or placebo. Nimodipine was ineffective in slowing the progress of ALS.

Anthropometric status, serum prealbumin level and immune response to measles vaccination in Mali children

Protein energy malnutrition (PEM) is known to depress cell-mediated immunity. Its effect on humoral immunity is less clear-cut. The purpose of the study was to assess seroconversion following measles vaccination according to child nutritional status as assessed by anthropometry and serum thyroxine-binding prealbumin (TBPA). Prior to vaccination, 200 Malian children aged 8-22 months (mode: 9 months) and free of infection were weighed and measured. A venous blood sample was drawn for determination of serum TBPA by radial immunodiffusion and of measles specific immunoglobulins (Ig) by Enzyme-linked Immuno-Sorbent Assay (ELISA). IgG and IgM were again assayed 6 weeks post-vaccination after excluding pre-immune subjects. Seroconversion took place in 91 per cent of the children (95 per cent confidence interval: 86-96 per cent). Based on the NCHS standards, 30 per cent of the children were wasted (weight-for-height less than -2.0 SD) and 18 per cent were stunted (height-for-age less than -2.0 SD). Low serum TBPA (less than 10 mg/dl) was found in 38 per cent of them. TBPA was significantly correlated with weight-for-height and weight-for-age (P less than 0.001), but not with height-for-age. Seroconversion was not significantly related to age, anthropometric indices or TBPA. This study using sensitive methods for the assessment of protein status and of the immune response confirms that children should be vaccinated against measles irrespective of their nutritional status, and PEM was not shown to impair their antibody response.

The effect of spine fusion on respiratory function in Duchenne muscular dystrophy

Serial measures of respiratory function were made in 17 patients with Duchenne muscular dystrophy who underwent segmental spine fusion and in 22 patients who did not. No significant differences were observed between the 2 groups (operated vs. nonoperated) in terms of declining respiratory function. Nonetheless, all operated patients reported either improved sitting comfort, appearance, or both. Thus, our results suggest that there are distinct benefits from segmental spine fusion; however, there was no salutary effect upon respiratory function either in the short term or after up to 5 years follow-up.

Synthesis and biodistribution of labelled p-iodo phentermine (IP), N,N,-dimethyl-p-iodo phentermine (IDMP) and N-isopropyl-p-iodo phentermine (IIP) in rats

p-Iodo-phentermine (IP) and two of its derivatives, N,N,-dimethyl-p-iodo-phentermine (IDMP) and N-isopropyl-p-iodo-phentermine (IIP) were synthesized and radiolabelled with iodine by isotopic exchange. They were evaluated as potential brain imaging agents and compared to IAMP biodistribution in rats did not show any superiority to IAMP.